Anatomy practice questions exam 1

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teres minor and deltoid. The lateral rotators of the arm include the teres minor, deltoid, and infraspinatus muscles, but the infraspinatus muscle is innervated by the suprascapular nerve.

A 10-year-old boy falls off his bike, has difficulty in moving his shoulder, and is brought to an emergency department. His radiogram and angiogram reveal fracture of the surgical neck of his humerus and bleeding from the point of the fracture. Following this accident, the boy has weakness in rotating his arm laterally. Which of the following muscles are paralyzed? Teres minor and deltoid Teres major and teres minor Infraspinatus and deltoid Supraspinatus and subscapularis Teres minor and infraspinatus

L5. The quadratus femoris muscles-the flexors of the thigh-are innervated by the femoral nerve, which originates from the spinal cord at L2 to L4. In contrast, the hamstring muscles-the extensors of the thigh-are innervated by the sciatic nerve, which originates from L4 to S3. Therefore, the lesion occurs at the level of L5 (between L4 and S3).

A 12-year-old girl suffers from a type of neural tube defect called tethered cord syndrome, a congenital anomaly that results from defective closure of the neural tube. This syndrome is characterized by an abnormally low conus medullaris, which is tethered by a short, thickened filum terminale, leading to progressive neurologic defects in the legs and feet. This girl has strong muscle function of the flexors of the thigh, but she has weakness of the extensors (hamstrings). A lesion has occurred at which of the following spinal cord levels?

spina bifida occulta

A 15-year-old active boy was sent to an orthopedist for a physical examination by his hockey coach. The physician observed a dimple covered by a hairy patch on the inferior part of his back and suspected the boy had a pathologic condition (see figure). What condition did the physician likely suspect?

biceps brachii. A lesion of the radial nerve causes paralysis of the supinator and brachioradialis. The biceps brachii muscle is a flexor of the elbow and also a strong supinator; thus, supination is still possible through action of the biceps brachii muscle. Other muscles cannot supinate the forearm.

A 17-year-old boy is injured in an automobile accident. He has a fracture of the shaft of the humerus. After this accident, supination is still possible through contraction of which of the following muscles?

profunda brachii artery. The radial nerve accompanies the profunda brachii artery in the radial groove on the posterior aspect of the shaft of the humerus. The posterior humeral circumflex artery accompanies the axillary nerve around the surgical neck of the humerus. Other arteries are not associated with the radial groove of the humerus.

A 17-year-old boy is injured in an automobile accident. He has a fracture of the shaft of the humerus. Which of the following arteries may be damaged?

anterior horn and lateral horn of spinal cord. The ventral root of a thoracic spinal nerve contains sympathetic preganglionic fibers, which have cell bodies located in the lateral horn of the gray matter of the spinal cord, and general somatic efferent fibers, which have cell bodies located in the anterior horn of the gray matter of the spinal cord. The dorsal root ganglion contains cell bodies of GSA and general visceral afferent (GVA) fibers, and the sympathetic chain ganglion contains cell bodies of postganglionic sympathetic nerve fibers.

A 17-year-old boy is involved in a group fight, and a stab wound lacerates a ventral root of his thoracic spinal nerve. Cell bodies of the injured nerve fibers are located in which of the following nervous structures? Anterior horn and lateral horn of spinal cord Dorsal root ganglia and sympathetic trunk Lateral horn of spinal cord and dorsal root ganglia Sympathetic trunk and lateral horn of spinal cord Anterior horn of spinal cord and sympathetic trunk

A 17-year-old boy presents in the Emergency Room with an anterior entry gunshot wound through the manubriosternal joint (sternal angle). If the bullet passed directly posterior, it most likely would lodge in which of the following vertebral bodies?

posterior humeral circumflex. The posterior humeral circumflex artery anastomoses with an ascending branch of the profunda brachii artery, whereas the lateral thoracic and subscapular arteries do not. The superior ulnar collateral and radial recurrent arteries arise inferior to the origin of the profunda brachii artery.

A 17-year-old boy with a stab wound received multiple injuries on the upper part of the arm and required surgery. If the brachial artery were ligated at its origin, which of the following arteries would supply blood to the profunda brachii artery?

axillary nerve. The axillary nerve may be damaged in approximately one of seven shoulder dislocations. This nerve innervates the deltoid and teres minor muscles as well as supplying innervation to the skin overlying the deltoid in the superolateral aspect of the arm. Loss of innervation to the deltoid muscle would explain the weakness in abduction of the upper limb. The teres minor assists the infraspinatus muscle in external rotation of the shoulder.

A 17-year-old male football player suffers a shoulder injury and arrives at the ER 2 hours after the injury. The physician diagnoses a shoulder dislocation, and after administration of a local anesthetic solution, the doctor repositions the head of the humerus into the glenoid cavity of the scapula (reduction). No fractures are seen on X-rays. However, the patient displays weakness in abduction and external rotation at the shoulder. A loss of sensation is also noted at the superior and lateral aspects of the arm. What nerve was most likely damaged in this injury?

pectoralis major. The pectoralis major is innervated by the lateral and medial pectoral nerves originating from the lateral and medial cords of the brachial plexus, respectively. The subscapularis, teres major, latissimus dorsi, and teres minor muscles are innervated by nerves originating from the posterior cord of the brachial plexus.

A 20-year-old man fell from the parallel bar during the Olympic trial. A neurologic examination reveals that he has a lesion of the lateral cord of the brachial plexus. Which of the following muscles is most likely weakened by this injury?

infraspinatus. In Erb-Duchenne paralysis (or upper trunk injury), the nerve fibers in the roots of C5 and C6 of the brachial plexus are damaged. The infraspinatus, a lateral rotator muscle, is innervated by the suprascapular nerve (C5 and C6). All the other muscles, including the flexor carpi ulnaris, palmar interossei, adductor pollicis, and palmaris brevis muscles, are innervated by the ulnar nerve (C8 and T1).

A 21-year-old man celebrating his birthday gets a little carried away with his friends and starts a bar fight. He is stabbed with a knife that severs the roots of C5 and C6 of the brachial plexus. Which of the following muscles is likely to be paralyzed?

latissimus dorsi. The latissimus dorsi adducts the arm, and the supraspinatus muscle abducts the arm. The infraspinatus and the teres minor rotate the arm laterally. The serratus anterior rotates the glenoid cavity of the scapula upward, abducts the arm, and elevates it above a horizontal position.

A 21-year-old woman walks in with a shoulder and arm injury after falling during horseback riding. Examination indicates that she cannot adduct her arm because of paralysis of which of the following muscles? Latissimus dorsi Teres minor Supraspinatus Infraspinatus Serratus anterior

loss of sensory fibers from the second intercostal nerve. The intercostobrachial nerve arises from the lateral cutaneous branch of the second intercostal nerve and pierces the intercostal and serratus anterior muscles. It may communicate with the medial brachial cutaneous nerve, and it supplies skin on the medial side of the arm. It contains no skeletal motor fibers but does contain sympathetic postganglionic fibers, which supply sweat glands.

A 22-year-old patient received a stab wound in the chest that injured the intercostobrachial nerve. Which of the following conditions results from the described lesion of the nerve?

pidural space. The space between the vertebral canal and the dura mater is the epidural space, which contains the internal vertebral venous plexus. The spinal cord and blood vessels lie deep to the pia mater. The space between the arachnoid and dura maters is the subdural space, which contains a film of fluid. The subarachnoid space contains cerebrospinal fluid (CSF).

A 23-year-old jockey falls from her horse and complains of headache, backache, and weakness. Radiologic examination would reveal blood in which of the following spaces if the internal vertebral venous plexus was ruptured?

rhomboid major. The rhomboid major is a superficial muscle of the back; is innervated by the dorsal scapular nerve, which arises from the ventral primary ramus of the fifth cervical nerve; and adducts the scapula. The semispinalis capitis, multifidus, rotator longus, and iliocostalis muscles are deep muscles of the back; are innervated by dorsal primary rami of the spinal nerves; and have no attachment to the scapula.

A 25-year-old man with congenital abnormalities at birth has a lesion of the dorsal scapular nerve, making him unable to adduct his scapula. Which of the following muscles is most likely paralyzed?

ventral roots of the sacral spinal nerves. The cauda equina is the collection of dorsal and ventral roots of the lower lumbar and sacral spinal nerves below the spinal cord. Dorsal and ventral primary rami and dorsal roots of the thoracic spinal nerves and lumbar spinal nerves do not participate in the formation of the cauda equina.

A 25-year-old soldier suffers a gunshot wound on the lower part of his back and is unable to move his legs. A neurologic examination and magnetic resonance imaging (MRI) scan reveal injury of the cauda equina. Which of the following is most likely damaged?

splenius capitis. All the deep (intrinsic) muscles in the back, including splenius capitis, are supplied by the posterior primary rami of spinal nerves. The brachial plexus is formed from ventral primary rami of spinal nerves. Therefore, the deep muscles of the back retain intact motor supplies when the brachial plexus is damaged. The latissimus dorsi is one of the superficial extrinsic muscles of the back. All the members of this group, except the trapezius muscle, are innervated by ventral primary rami of spinal nerves via the brachial plexus. Thus, the latissimus dorsi could be paralyzed following a brachial plexus injury. The levator scapulae is another member of the superficial extrinsic group of back muscles, and receives its motor supply from the brachial plexus. The rhomboid major muscle is another component of the superficial extrinsic muscles of the back, with motor innervation from the brachial plexus. The rhomboid minor is a small subportion of the rhomboid muscle sheet. As with the larger rhomboid major, it is supplied by ventral primary rami via the brachial plexus.

A 25-year-old woman suffers several lesions of her right side brachial plexus as a result of multiple stab wounds in the neck and axilla. Which of the following muscles will retain its intact motor supply?

C6 spinal nerve roots. The MRI shows a herniation of the C5 disc, i.e., the disc between the fifth and sixth cervical vertebrae. Because there are eight cervical spinal cord segments, but only seven cervical vertebrae, each pair of cervical spinal nerve roots exits the vertebral canal above its matching numbered vertebra. Therefore, a posterolateral herniated disc mainly impinges upon the spinal nerve roots of the next higher spinal segment. Thus, it is the C6 spinal nerve roots that enter the C5 intervertebral foramen, where they may be impinged by the bulging C5 disc. The anterior (ventral) and posterior (dorsal) primary rami of spinal nerves are located outside the vertebral canal. Therefore, these structures are not impinged by a herniated disc, regardless of the vertebral level. The C5 spinal nerve roots enter the C4 intervertebral foramen, where they may be impinged by a bulging C4 disc. The primary rami of spinal nerves are located outside the vertebral canal and are well-removed from the intervertebral discs. In the cervical region, a posterolateral herniated disc likely impinges upon the spinal nerve roots of the next higher spinal segment. Thus, the C7 nerve roots are more closely related to the C6 disc. Reference:

A 26-year-old female gymnast presents with complaints of periodic pain and muscle spasms in her left upper limb. Thorough physical and radiographic examinations reveal a posterolateral cervical intervertebral disc herniation, as shown in the accompanying sagittal magnetic resonance imaging (MRI) scan. The bulging disc is most likely impinging mainly on which of the following structures?

posterior (dorsal) roots. A rhizotomy is a neurosurgical procedure that selectively severs problematic spinal nerve roots to relieve pain or spastic paralysis (e.g., as often seen in cerebral palsy patients). The posterior roots are the only site where afferent (sensory) fibers are segregated from efferent (motor) fibers. In selective dorsal rhizotomy (SDR), severing the left C6-8 posterior roots could relieve the pain symptoms in the left forearm of this patient because they carry only sensory information.

A 35-year-old woman suffers intractable pain in her left forearm. Neurosurgical consultation leads to a decision to conduct a rhizotomy to relieve the condition. At which of the following locations is the rhizotomy best performed to relieve the patient's pain?

The answer is deltoid muscle and gravity. The lateral fragment of the clavicle is displaced downward by the pull of the deltoid muscle and gravity. The medial fragment is displaced upward by the pull of the sternocleidomastoid muscle. None of the other muscles are involved.

A 37-year-old female patient has a fracture of the clavicle. The junction of the middle and lateral thirds of the bone exhibits overriding of the medial and lateral fragments. The arm is rotated medially, but it is not rotated laterally. The lateral portion of the fractured clavicle is displaced downward by which of the following?

Rectus capitis posterior minor

A 37-year-old man is brought to the emergency department with a crushed second cervical vertebra (axis) that he suffered after a stack of pallets fell on him at work. Which of the following structures would be intact after the accident?

internal vertebral venous plexus. The internal vertebral venous plexus is valveless and communicates with pelvic veins. This facilitates transmission of tumor cell between the pelvis and the spine

Metastatic prostate cancer is frequently found in vertebrae. A possible direct route of spread of this cancer to vertebrae is via which of the following?

levator scapulae. The levator scapulae are attached to the transverse processes of the upper cervical vertebrae. All of the other muscles are attached to the spinous processes.

Mrs. Jones was riding in the front seat of her son's van when the vehicle abruptly stopped. Unfortunately, she was not wearing her seatbelt and was thrown forward. As a result of the accident, the transverse processes of her cervical vertebrae were crushed against the dashboard of the van. Which of the following muscles might be paralyzed?

axillary nerve. The quadrangular space of the shoulder is an important passageway allowing the posterior humeral circumflex vessels and their companion axillary nerve to pass from the axilla to the posterior aspect of the shoulder. The neurovascular bundle runs across the surgical neck of the humerus to enter the quadrangular space. The space itself (sometimes termed the lateral axillary hiatus) is formed by four structures: teres major, teres minor, long head of the triceps, surgical neck of the humerus. The vessels contribute to the collateral network around the shoulder. The axillary nerve supplies the teres minor and deltoid muscles and a cutaneous area on the superolateral aspect of the arm (i.e., the skin overlying the lower aspect of the deltoid muscle).

Physical examination of a 45-year-old man who had been stabbed in the back of the shoulder shows a deep wound penetrating into the quadrangular space of the shoulder, causing bleeding from the severed blood vessels there. Which of the following neural structures is most likely damaged as well? Musculocutaneous nerve Lateral cord of the brachial plexus Radial nerve Axillary nerve Medial cutaneous nerve of the arm

failure of the vertebral arches to form correctly. The vertebral arches form the posterior aspect of the vertebral canal and serve to protect the spinal cord. Failure of them to form correctly results in spina bifida and leaves the spinal cord and associated tissues vulnerable to injury.

Spina bifida results from failure of the ___________________.

Bright fluid in the gap between the proximal and distal portions of a torn supraspinatus tendon

The MRI shown above is that of a patient who cannot initiate shoulder abduction. The finding that confirms your clinical diagnosis is which of the following?

Jefferson (burst) fracture. Jefferson fracture occurs at the anterior arch of the atlas. The lateral masses of the atlas are thus more widely displaced than normal.

The above CT image shows a vertebral fracture in a patient who dove into a shallow pool and struck his head. What is this type of fracture known as?

Peau d' orange and interference with lymph drainage. Peau d' orange is a sign of advanced breast cancer, usually inflammatory breast cancer. It occurs due to lymphedema caused by the tumor interfering with lymph drainage.

The above image is a close up photograph of an abnormal breast. What is the name of this condition and its cause?

second part of the axillary artery. The lateral thoracic wall receives significant arterial supply from the branches of the axillary artery. The axillary artery is divided into three parts by the overlying pectoralis minor muscle. The lateral thoracic artery, along with the thoracoacromial trunk, typically branches from the second part of the axillary artery, deep to the pectoralis minor. It descends along the lateral border of the pectoralis minor to supply the lateral aspect of the chest wall, including much of the breast and the serratus anterior muscle. However, this vessel is variable and may originate from other source points. Remember, arteries are often named for the regions they supply, not necessarily for their branching patterns.

The lateral thoracic artery provides the main blood supply to the lateral side of the chest wall, including much of the breast. To deter excessive blood loss during a surgical procedure involving the breast, a surgeon can clamp the lateral thoracic artery near its origin. Which of the following arteries gives rise to this artery?

second part of the axillary artery lies deep to the muscle. The pectoralis minor muscle overlies the axillary artery in such a way as to divide it into three parts: first (prepectoral; medial), second (subpectoral; deep), third (postpectoral; lateral). The first part is medial to the pectoralis minor, running from the lateral border of the first rib to the medial border of the pectoralis minor. The second part is deep to the muscle. The third part is lateral to the pectoralis minor, running from the lateral border of the muscle to the inferior border of the teres major muscle.

The pectoralis minor muscle is an important landmark in identifying and describing neighboring structures in the chest and axillary regions. Which of the following relationships of the pectoralis minor is correct?

deltoid. The deltoid is the primary abductor of the upper limb past the first 15 degrees of abduction.

The physical therapist is testing the action of one of your patient's muscles by bringing the patient's upper limb away from her side and then asking the patient to abduct against resistance. What is the muscle being tested? Deltoid Pectoralis major Pectoralis minor Latissimus dorsi Serratus anterior

the posterior divisions of all 3 cords. Each trunk gives rise to an anterior and a posterior division. All 3 posterior divisions unite to form the posterior cord.

The posterior cord of the brachial plexus is formed by the ________________.

lateral to the tendon of the flexor carpi radialis. The most common location for measuring pulse rate is on the radial artery at the wrist. Here, the vessel lies on the anterior side of the distal end of the radius, lateral to the tendon of the flexor carpi radialis. It is covered only by skin and a thin superficial fascia and can be palpated easily against the radius. Note the placement of the index and middle fingers of the physician in the given photo.

The pulse of the radial artery is readily palpable where the vessel passes which of the following structures?

adduction of the arm. In a traditional (Halsted) radical mastectomy, both the pectoralis major and minor muscles are removed with the breast and associated axillary tissue. The primary actions of the pectoralis major are adduction, flexion, and medial rotation of the arm. These actions are weakened but not lost postoperatively. Other neighboring muscles (e.g., subscapularis, latissimus dorsi, biceps brachii, anterior deltoid) also perform these actions and can compensate somewhat for loss of the pectoralis major.

The traditional radical mastectomy includes removal of the pectoralis major muscle. Which of the following movements is most affected postoperatively by this surgical procedure?

visceral afferent cells bodies are located in spinal ganglia. Spinal or dorsal root ganglia contain all afferent cell bodies for the body (somatic and visceral).

Visceral afferent cell bodies are located in _________________.

hyoid

Which of the following bones is part of the axial skeleton?

superior thoracic. The pectoralis minor divides the axillary into 3 parts: proximal, deep, and distal. Part 1 has one branch, the superior thoracic artery.

Which of the following branches of the axillary artery is given off proximal to the pectoralis minor?

The answer is lateral pectoral nerve. The deltopectoral triangle is a useful landmark for three structures, the: lateral pectoral nerve, cephalic vein, and the thoracoacromial arterial trunk.

Which of the following is found in the deltopectoral triangle?

The answer is rectus capitis posterior major. The subcostal nerve innervates all of the muscles of the suboccipital triangle, including the rectus capitis posterior major.

Which of the following muscles is innervated by the suboccipital nerve?

odontoid process)

Which of the labeled structures is derived from the body of the first cervical vertebra in this labeled X-ray showing a transoral view of the upper cervical vertebrae?

cervical. Because of thick disks and flat facets joints, rotation is most free in the cervical region.

You are examining a 61-year-old patient who has generalized back pain and stiffness. In trying to determine which part of the spine the physical therapist should concentrate on to relieve stiffness you are aware that, of the presacral part of the vertebral column, the region that permits the most rotation is:

has not begun to walk upright. The lumbar curvature is a secondary curvature and does not develop until a child begins to walk upright.

You are examining an abandoned infant that you estimate to be close to 1 year of age. In evaluating the infant, you notice that there is no lumbar lordosis. What may this tell you about the infant?

T12. The transition from the thoracic to the lumbar region takes places almost entirely within T12 and thus it is the most frequently fractured vertebra.

You are examining the lateral spine radiograph of your 65-year-old female patient for an insufficiency fracture of her spine. You know that transitional stresses cause which of the following vertebra to be the most commonly fractured?

inferiorly. The inferior part of the joint is the only part not reinforced by the rotator cuff muscles and is therefore the weakest part of the capsule.

You are treating a 35-year-old patient with recurrent glenohumeral dislocations. You can prescribe exercises that strengthen the group of muscles that cover all parts of the joint capsule except:

The answer is axillary. The axillary nerve is subject to damage during glenohumeral joint dislocations because it winds around the surgical neck of the humerus.

You are treating a 37-year-old male wrestler who dislocated his glenohumeral joint. He now also has some loss of sensation over the lateral side of his proximal arm. You are concerned that he may have sustained damage to which of the following nerves?

serratus anterior. The serratus anterior holds the medial border of the scapula against the thoracic wall. When paralyzed, the scapula projects posteriorly producing the "winged" appearance.

You are working in the ED treating a 34-year-old patient who was in a knife fight and has a wound under his right axilla. He seems unable to fully abduct his arm above horizontal. When you ask him to press against the wall you notice that he has a "winged scapula". Which muscle is likely paralyzed? Pectoralis major Rhomboid major Trapezius Serratus anterior Latissimus dorsi

The answer is the second part of the subclavian artery can be compressed against the first rib as it passes posterior to the scalenus anterior muscle.

You arrive at the scene of a motor vehicle accident and the driver is severely bleeding from a laceration in his right brachial artery near the head of the humerus. You know you can control bleeding to this vessel by doing which of the following?

axillary. The axillary passes through the quadrangular space with the posterior humeral circumflex artery.

You suspect your 49-year-old patient has quadrangular space syndrome. What nerve would be compressed in this syndrome?

serratus anterior. The serratus anterior is known as the boxer's muscle.

Your 12-year-old male patient is interested in a career in boxing and wants to learn exercises that specifically strengthen his "boxer's muscles" which is most important when reaching or punching anteriorly. What is this muscle? Latissimus dorsi Serratus anterior Sternocostal head of pectoralis major Subclavius Trapezius

coracobrachialis. The musculocutaneous nerve typically pierces the coracobrachialis muscle. This nerve becomes the lateral cutaneous nerve of the forearm

Your 27-year-old weightlifter patient with arm muscle hypertrophy is having sensory loss on the anterior surface of his lateral forearm during arm flexion. You suspect which of the following muscles is the most likely to be compressing the affected nerve?

lymphangitis. Lymphangitis (inflammation of lymphatic vessels) in the upper limb is characterized by the development of warm and tender streaks in the skin.

Your 33-year-old patient has warm, tender red streaks in the skin of her upper limb and is very tender in her axilla. What do you suspect?

teres major. The teres major is not part of the rotator cuff that helps hold the humeral head in the glenoid fossa.

Your 45-year-old patient has frequent humeral dislocations. You refer him to a physical therapist for exercises to strengthen his rotator cuff muscles. Which of the following is not part of this group of muscles? Supraspinatus Teres major Teres minor Infraspinatus Subscapularis

supraspinatus tendon and/or subacromial bursa. Pain upon shoulder abduction in older men is often associated with calcific supraspinatus tendinitis, and inflammation of the subacromial bursa.

Your 67-year-old patient has a very painful shoulder upon abduction. You order radiography that reveals the calcifications where? The subscapularis tendon The deltoid muscle The supraspinatus tendon and/or subacromial bursa The long biceps tendon AC joint

infraspinatus. The infraspinatus, supraspinatus, and teres minor attach into the greater tuberosity of the humerus. Thus, avulsion or other fracture of the greater tuberosity results in three of the four rotator cuff muscles becoming detached from the humerus. Often, it is the extreme contraction of the supraspinatus during initiation of abduction that is mainly responsible for avulsion of the greater tuberosity

violent contraction of the shoulder muscles causes avulsion of the greater tuberosity of the left humerus. Which of the following muscles is attached to the displaced bone fragment?

profunda brachii artery. It is important to recognize where neurovascular structures have close positional relations to each other and to underlying bony structures in order to predict the likely second order functional consequences of damage to the bones. In the given AP X-ray, the midshaft of the humerus is fractured slightly distal to the radial groove. At this point, the profunda brachii vessels (deep vessels of the arm) and the radial nerve emerge from the radial groove in a bundle tightly wrapped against the body of the humerus. A fracture here may readily damage any of these neurovascular structures. Lesion of the vessels may produce swelling in the posterior compartment of the arm and loss of supply to the muscles therein. Lesion of the nerve will result in major motor and sensory deficits in the posterior aspect of the forearm and hand.

The given anteroposterior (AP) X-ray depicts a humeral shaft fracture in a 22-year-old man. Given the location of the fracture, which of the following structures is most likely damaged?

pectoralis major. The breast lays upon the pectoralis major and the structure is the soft tissue density of muscle.

The image above shows a medial-lateral-oblique mammographic image of the right breast of a woman. Mammograms are a specialized form of radiography. The structure indicated by the letter "A" is which of the following?

axillary artery. The brachial plexus is divided into five geographic parts: Roots (or ventral rami of C5-T1), Trunks, Divisions, Cords, terminal Branches (or Nerves). These sections of the brachial plexus can be remembered with the mnemonics, "Real Truckers Drink Cold Beer" or "Remember Those Darn Cervical Nerves". The cords are named according to their important positional relationship to the second part of the axillary artery, deep to the pectoralis minor muscle. Here, the nerves form a cradle-like bed for this segment of the vessel as it passes through the axilla. Thus, the lateral cord is located lateral, the medial cord is medial, and the posterior cord is posterior to the axillary artery.

The lateral cord of the brachial plexus is named because it lies immediately lateral to which of the following structures?

supraspinatus part of the rotator cuff. This is the most common cause of a rotator cuff injury. Repetitive overhead motions of the upper limb can impinge the supraspinatus and/or its tendon between the greater tubercle of the humerus and the osseofibrous coraco-acromial arch. This causes degenerative changes (attrition) that ultimately result in a sudden tear of the supraspinatus tendon.

A 38-year-old baseball pitcher felt a sharp pain in his shoulder when he threw the ball very hard. After a visit by the pitching coach, he threw another pitch but he told the catcher that the pain was unbearable. He left the game and went to the dressing room where he was examined by the team's orthopedic surgeon, who detected tenderness near the greater tubercle of the humerus. An MRI taken the next day revealed a tear in the pitcher's rotator cuff. Which of the following statements is most likely based on this finding? Acute rupture of the supraspinatus part of the rotator cuff Acute rupture of the subscapular tendon Acute tear of latissimus dorsi tendon Acute tear of teres major tendon

Trapezius

A 38-year-old woman with a long history of shoulder pain is admitted to a hospital for surgery. Which of the following muscles becomes ischemic soon after ligation of the superficial or ascending branch of the transverse cervical artery?

fifth lumbar nerve. A posterolateral herniation of the intervertebral disk at disk level L4-L5 affects the fifth lumbar nerve root but rarely affects the fourth lumbar nerve root because of a progressive descending obliquity of the fourth and fifth lumbar nerve roots. The first seven cervical nerves exit above the corresponding vertebra, and the eighth cervical nerve exits below the seventh cervical vertebra because there are eight cervical nerves but only seven cervical vertebrae. The rest of the spinal nerves exit below their corresponding vertebrae.

A 39-year-old woman with headaches presents to her primary care physician with a possible herniated disk. Her magnetic resonance imaging (MRI) scan reveals that the posterolateral protrusion of the intervertebral disk between L4 and L5 vertebrae would most likely affect nerve roots of which of the following spinal nerves?

fifth cervical and fourth thoracic nerves. All cervical spinal nerves exit through the intervertebral foramina above the corresponding vertebrae, except the eighth cervical nerves, which run inferior to the seventh cervical vertebra.

A 42-year-old woman with metastatic breast cancer is known to have tumors in the intervertebral foramina between the fourth and fifth cervical vertebrae and between the fourth and fifth thoracic vertebrae. Which of the following spinal nerves may be damaged?

spina bifida occulta

A 45-year-old man goes to his family physician complaining of lower back pain after spending a weekend clearing trees off his property. During examination, the doctor notes a tuft of hair and a dimple on the skin of the patient's lower back. A plain film reveals a congenital defect in his L5 vertebra, indicated by the black arrow in the given X-ray. No other structural abnormalities are noted. Based on these findings, what is the most likely diagnosis for this patient?

pectoral group of axillary lymph nodes. Most cancer cells from the right upper outer quadrant of the breast initially pass to the three to five pectoral lymph nodes.

A 45-year-old woman consulted her physician about a painless lump in the right upper outer quadrant of her breast. During palpation of her axilla, the physician detected enlarged, firm lymph nodes. A mammogram showed a malignant breast tumor. In which of the following groups of axillary lymph nodes would most of the cancer cells initially lodge?

Jefferson (burst) fracture of C1. The C1 vertebra, or atlas, is normally a closed ring with no vertebral body. Excessive vertical, or downward, force on the top of the head can fracture the anterior and posterior arches of C1 in multiple places, leading to a Jefferson (burst) fracture of C1.

A 46-year-old supervisor was reading a work order on a construction site when a 60 lb bag of concrete mix was accidentally dropped on the apex of his head. He was immobilized and brought to the ER where he presented with upper neck pain but no neurological signs. Based upon the given axial CT scan and the patient's presentation, which of the following diagnoses is most likely?

long thoracic nerve. The long thoracic nerve innervates the serratus anterior muscle. Paralysis of this muscle causes a "winged scapula," in which the vertebral or medial border and inferior angle of the scapula protrude away from the thorax. Other nerves do not supply the serratus anterior muscle.

A 47-year-old woman has had a lumpectomy and axillary dissection to check for metastasis. She has come in for her follow-up appointment, and her physician notices on her physical examination that the medial part of her scapula protrudes from her back and that she is not able to raise her arm above the horizontal level. Which of the following nerves has been damaged during her surgery?

iliocostalis. The posterior primary rami of the spinal nerves innervate the erector spinae including the iliocostalis

A 48-year-old woman crashes into a tree during a skiing lesson and is brought to a hospital with multiple injuries that impinge the posterior primary rami of several thoracic spinal nerves. Such lesions could affect which of the following muscles?

iliocostalis. The posterior primary rami of the spinal nerves innervate the erector spinae including the iliocostalis.

Weakness extending the wrist and fingers

A 48-year-old woman falls on an icy sidewalk and lands on her right elbow. She suffers a midshaft humeral fracture, as seen on the given X-ray. The attending physician wants to assess whether the nerve residing in the spiral groove of the humerus is damaged. What sign or symptom would confirm damage to this nerve?

anterior axillary lymph nodes. The primary lymphatic drainage route for the lateral half of the breast (including the axillary tail) plus part of the medial half of the breast is first into the anterior (pectoral; Level 1) axillary lymph nodes. These lymph nodes are located along the lateral border of the pectoralis minor muscle. Further metastasis would spread progressively to the central axillary (Level 2) nodes, then the apical axillary (Level 3) nodes.

A 48-year-old woman is diagnosed with a malignant tumor in the superolateral quadrant of the right breast, including the axillary tail. If it metastasizes, this cancer will most likely spread first to which of the following locations?

anterior (pectoral) nodes. Lymph from the breast drains mainly (75%) to the axillary nodes, more specifically to the anterior (pectoral) nodes.

A 49-year-old woman is diagnosed as having a large lump in her right breast. Lymph from the cancerous breast drains primarily into which of the following nodes?

posterior [dorsal] primary ramus

A lesion of what would cause loss of sensation in the skin overlying the trapezius muscle?

lumbar cistern. The lumbar cistern is the distended prolongation of the subarachnoid space inferior to the conus medullaris of the spinal cord; cerebrospinal fluid can be extracted from the lumbar cistern without concern of damaging the spinal cord.

A lumbar puncture extracts cerebrospinal fluid from the ______________.

Denticulate ligament

A middle-aged coal miner injures his back after an accidental explosion. His magnetic resonance imaging (MRI) scan reveals that his spinal cord has shifted to the right because the lateral extensions of the pia mater were torn. Function of which of the following structures is most likely impaired?

upper trunk and posterior cord. Both the upper trunk and posterior cord of the brachial plexus are damaged. The abductors of the arm are the deltoid and supraspinatus muscles. The deltoid is innervated by the axillary nerve, which arises from the posterior cord of the brachial plexus. The supraspinatus is innervated by the suprascapular nerve, which arises from the upper trunk of the brachial plexus. The middle and lower trunk give rise to no branches. The lateral and medial cords supply no abductors of the arm.

A victim of an automobile accident is unable to abduct her left arm. This indicates damage to which of the following parts of the brachial plexus?

axillary nerve. The axillary nerve runs posteriorly to the humerus, accompanying the posterior humeral circumflex artery through the quadrangular space and innervating the teres minor and deltoid muscles. None of the other nerves pass through the quadrangular space.

A young man is brought to the emergency department after being mugged. He was stabbed in the shoulder after refusing to give his wallet to his assailant. If the stab wound lacerated the posterior humeral circumflex artery passing through the quadrangular space on the shoulder region, which of the following nerves might be injured?

Motor control of the brachioradialis.

A young woman working in a meat processing plant accidentally suffers deep lacerations in the posterior compartment of her right arm, approximately over the spiral groove of the humerus. Examination in the emergency room indicates the trunk of the radial nerve is not damaged. However, some branches of the radial nerve are lesioned. Which of the following is most likely intact?

latissimus dorsi. The latissimus dorsi forms boundaries of the auscultation and lumbar triangles and receives blood from the thoracodorsal artery. The levator scapulae, rhomboid minor, and splenius capitis muscles do not form boundaries of these two triangles. The trapezius muscle forms a boundary of the auscultation triangle but not the lumbar triangle. The levator scapulae, rhomboid minor, and trapezius muscles receive blood from the transverse cervical artery. The splenius capitis muscle receives blood from the occipital and transverse cervical arteries.

After an automobile accident, a back muscle that forms the boundaries of the triangle of auscultation and the lumbar triangle receives no blood. Which of the following muscles might be ischemic?

anterior gray horn of the spinal cord. Cell bodies of somatic motor neurons (α-motor neurons) innervating skeletal muscle are located within the anterior (ventral) gray horn of the spinal cord, at all segmental levels throughout the entire length of the spinal cord.

Amyotrophic lateral sclerosis (ALS; Lou Gehrig's disease) is a progressive, fatal neurodegenerative disease caused by degeneration of the motor neurons controlling skeletal (voluntary) muscle movement. Postmortem analysis of which of the following structures would show the cell bodies of neurons affected by this disease?

posterior humeral circumflex artery. Fracture of the surgical neck of the humerus occurs commonly and damages the axillary nerve and the posterior humeral circumflex artery.

An 11-year-old boy falls down the stairs. A physician examines a radiograph of the boy's shoulder region (see figure). If the structure indicated by the letter B is fractured, which of the following structures is most likely injured?

The answer is infraspinatus. The scapular notch transmits the suprascapular nerve below the superior transverse ligament, whereas the suprascapular artery and vein run over the ligament. The suprascapular nerve supplies the supraspinatus and infraspinatus muscles. The axillary nerve innervates the deltoid and teres minor muscles. The subscapular nerves innervate the teres major and subscapularis muscles.

An 11-year-old boy falls down the stairs. A physician examines a radiograph of the boy's shoulder region. If subscapular notch is calcified, which of the following muscles is most likely paralyzed?

suprascapular and axillary. The abductors of the arm are the deltoid and supraspinatus muscles, which are innervated by the axillary and suprascapular nerves, respectively. The thoracodorsal nerve supplies the latissimus dorsi, which can adduct, extend, and rotate the arm medially. The upper and lower subscapular nerves supply the subscapularis, and the lower subscapular nerve also supplies the teres major; both of these structures can adduct and rotate the arm medially. The musculocutaneous nerve supplies the flexors of the arm, and the radial nerve supplies the extensors of the arm. The dorsal scapular nerve supplies the levator scapulae and rhomboid muscles; these muscles elevate and adduct the scapula, respectively.

An 18-year-old boy involved in an automobile accident presents with arm that cannot abduct. His paralysis is caused by damage to which of the following nerves? Suprascapular and axillary Thoracodorsal and upper subscapular Axillary and musculocutaneous Radial and lower subscapular Suprascapular and dorsal scapular

trapezius, scapula, latissimus dorsi. The triangle of auscultation is a space in the back bounded by the lateral edge of the trapezius muscle, medial border of the scapula, and upper edge of the latissimus dorsi muscle. Placing a stethoscope within the triangle of auscultation enables the medical student to hear breathing sounds because (1) this site offers a gap between layers of bone and muscle, and (2) the location lies directly over the midposterior chest wall and the lung, which is ideal for auscultation.

An internal medicine attending physician asks a medical student to place the bell of her stethoscope on the triangle of auscultation to hear a patient's breathing sounds. Which of the following structures make up the boundaries of this triangle?

supraspinatus. The greater tubercle of the humerus is the insertion site of three (of the four) rotator cuff muscles: supraspinatus, infraspinatus, and teres minor. Avulsion of this structure could result in detachment of any of these rotator cuff muscles, depending upon the size and scope of the fracture. However, the wrestler is unable to initiate abduction of the upper limb, which implies damage to the supraspinatus muscle

As a result of chronic stress associated with an intense high school weight-lifting program, a 15-year-old boy suffers an avulsion fracture of the greater tubercle of the humerus. In the ER, he displays difficulty initiating abduction of the upper limb. Which of the following muscles was involved in this fracture? Supraspinatus Long head of biceps brachii Long head of triceps Subscapularis Infraspinatus

splenius capitis. The posterior (dorsal) primary rami of spinal nerves innervate the deep (intrinsic) muscles of the back including the splenius capitis and cervicis muscles, suboccipital muscles, transversospinales muscles (including the semispinalis, multifidus, and rotatores muscles), and several other small muscles. Thus, damage to the cervical posterior (dorsal) primary rami, specifically C2-6, would result in paralysis of the splenius capitis muscle.

As a result of multiple vertebral fractures incurred in an automobile crash, an 8-year-old girl suffers a series of torn posterior primary rami of spinal nerves C1-6. Which of the following muscles will be paralyzed as a result?

S2. The medullary cone (conus medullaris) is the tapered terminal end of the spinal cord, composed of the sacral and coccygeal segments. In adults, the conus medullaris typically lies within the T12-L3 vertebral levels, but it generally ends at approximately L2. Thus, displacement fractures of these vertebrae are likely to affect one or more of the sacral-coccygeal spinal cord segments. In this case, given the statistical range of variation for the medullary cone, the displaced fracture fragment of the L1 vertebral body is more likely to impinge the lower lumbar and upper sacral segments of the medullary cone.

Attempting to do a backflip with his bicycle off a high ramp at the finish line of a race, a 24-year-old professional BMX rider fell from a height of 20 ft and attempted to land on his feet. A sagittal CT reveals a burst fracture of the L1 vertebral body with a posterior displaced fracture fragment compressing the medullary cone (conus medullaris). Which of the following spinal cord segments would most likely be impinged by the bone fragment in this injury?

thoracic kyphosis. Osteoporosis tends to affect the horizontal trabecular bone in the vertebral bodies resulting in vertebral body collapse and kyphosis (Dowager hump).

In an 87-year-old woman with severe osteoporosis, which of the following would you most likely expect?

cephalic vein. The great saphenous vein is a large cutaneous vessel that ascends the medial aspect of the lower limb to ultimately drain into the femoral vein at the top of the limb. The cephalic vein is a distinctive cutaneous vessel that ascends the lateral aspect of the arm to ultimately drain into the axillary vein. At first glance, these two veins might seem to be traveling opposite venous routes. However, notice that each vein is aligned along the first digit side (great toe and thumb) of its respective limb. Remember that the upper and lower limbs rotate in opposite directions during their development, resulting in the great toe placed on the medial side of the foot and the thumb on the lateral side of the hand. The alignment of the great saphenous and cephalic veins with the first digits in the limbs denotes them as developmental equivalents.

In both the upper and lower limbs, the superficial veins begin in a dorsal cutaneous arch that drains into medial and lateral cutaneous veins aligned mainly along the first and fifth digit sides of the limb. Which of the following veins in the upper limb is the equivalent of the great saphenous vein in the lower limb?

lateral side of the clavipectoral triangle. The coracoid process can be palpated deeply within the clavipectoral (deltopectoral triangle).

In order to test the activity of the long head of the biceps brachii, you want to palpate the coracoid process in your 24-year-old patient. Where would you find this structure?

C6. The anterior tubercle of C6 is known as the carotid tubercle because deep pressure against it will stop or greatly slow flow in the common carotid artery.

In the ED you are treating a patient with a severe upper neck wound. You want to temporarily stop the bleeding from the common carotid artery. To do so you would press strongly against the anterior tubercle of which cervical vertebrae?

ligamentum flava. It runs between the lamina of the vertebrae and would have had to have penetrated to transect the patient's spinal cord.

In the ED, you treat a 26-year-old patient who shows a knife wound in his back in which the knife penetrated his spinal cord at T3,rendering him a paraplegic. In order for the knife to reach the cord, it had to pierce which of the following ligaments?

subscapular and dorsal scapular. The subscapular artery anastomoses with the suprascapular, dorsal scapular and intercostal arteries.

In viewing an upper limb angiogram of your 76-year-old patient, you are surprised to see that all but the most distal part of her right axillary artery is totally occluded yet her entire upper limb remains healthy. You suspect blood is reaching her upper limb via an anastomosis between which of the following?

teres minor. Throwing motions are complex mechanical events that involve multiple muscles interacting in moment-to-moment changing ways, with rotation of the humerus being one important outcome. The four rotator cuff muscles (supraspinatus, infrapsinatus, teres minor, subscapularis), plus several other muscles that cross the glenohumeral joint, contribute significant forces to rotation of the arm. The teres minor and infraspinatus (i.e., half the rotator cuff group) lie completely across the posterior aspect of the glenohumeral joint and are primary lateral (external) rotators. These muscles are aided by the posterior fibers of the deltoid muscle.

Lateral rotation of the arm is an important mechanical component of "bringing the arm back" when preparing to throw an object. What muscle acts to produce lateral rotation of the arm?

retraction of the scapula. The rhomboids, retractors of the scapula, are innervated by the dorsal scapular nerve.

Lesion of the dorsal scapular nerve will have the greatest affect on the ____________.

occipital triangle

Lesion of the trunks of the brachial plexus is most likely to occur from a penetrating wound into which of the following labeled areas in the given drawing of the neck regions?

The answer is initially to the ipsilateral anterior or pectoral group of axillary nodes. At least 75% of the lymph from the breast drains to the ipsilateral lymph nodes, first passing through the anterior or pectoral groups. The thoracic duct does not principally drain lymph from the right breast.

Lymphatic drainage of the breast is important because of its role in the metastasis of cancer cells. Which of the following is correct about the lymph drainage of the right breast?

medial to the radial artery. The FCR tendon is directly medial to the radial artery at the wrist.

A surgeon plans to use the tendon of the flexor carpi radialis to make a pseudo-joint for a very arthritic first carpal-metacarpal joint. He would find this tendon where at the wrist?

Trapezius, scapula, latissimus dorsi

dorsal scapular. The dorsal scapular nerve innervates the rhomboid muscles and severance of this nerve results in the scapula on the affected side being displaced from the midline.

A 27-year-old intoxicated male presents by ambulance after an altercation at a local tavern. Paramedics note an apparent stab wound to the right posterolateral neck (posterior to the sternocleidomastoid muscle). There was minimal blood noted at the scene and there is no active bleeding at this time. The patient is on no regular medications and has no known medication allergies. His stated weight is 195 lbs and he quit smoking 1 year ago. Although his speech is slurred and he has the odor of alcohol on his breath, he is somewhat cooperative and polite. The airway appears to be clear and breath sounds are equal. Initial vital signs include a blood pressure of 155/95, pulse of 105, and respiratory rate of 22. After removing his jacket and shirt, the nurse notices the right scapula is laterally displaced. Which of the following nerve injuries would most likely explain this finding?. Spinal accessory Thoracodorsal Dorsal scapular Long thoracic Axillary

fracture of the coracoid process. The pectoralis minor inserts on the coracoid process, originates from the second to the fifth ribs, and is innervated by the medial and lateral pectoral nerves that arise from the medial and lateral cords of the brachial plexus. It depresses the shoulder and forms the anterior wall of the axilla. The pectoralis minor has no attachment on the clavicle.

A 27-year-old patient presents with an inability to draw the scapula forward and downward because of paralysis of the pectoralis minor. Which of the following would most likely be a cause of his condition?

ulnar nerve. The ulnar nerve crosses the elbow by passing behind the medial epicondyle of the humerus in close apposition to the medial collateral ligament (ulnar collateral ligament; UCL). The nerve must be treated with care during any reconstructive procedure at the medial side of the elbow. It may be involved in postoperative scar tissue formation, especially if transposed during the procedure.

A 31-year-old professional baseball pitcher suffers a torn medial collateral ligament of the elbow in his throwing arm. Two weeks later, he undergoes "Tommy John surgery," in which the tendon of the palmaris longus muscle is transplanted into the elbow to reconstruct the damaged ligament. During the operative procedure, the surgeon must be keenly aware of the close relationship of which of the following structures to the medial collateral ligament?

paraplegia and incontinence. Transection of the spinal cord results in loss of all motor and sensory functions movements that emerge from the cord inferior to the site of the lesion. General sensory, somatic motor, and visceral motor fibers for the pelvis and lower limbs would be lost inferior to the level of T9 due to the transection of the spinal cord. Also, parasympathetic outflow to the pelvis and perineum would be eliminated due to the origin of these nerve fibers from S2-4. The CT image reveals a T9 spinal fracture dislocation, and the clinical findings indicate a spinal cord transection. Therefore, this patient would present with paraplegia (or paralysis of both lower limbs), fecal and urinary incontinence, impotence, and loss of motor functions and sensation below the level of the T9 lesion, which is right above the level of the umbilicus (supplied by T10).

A 34-year-old man fell 25 ft out of a barn loft, landing on his back. He was found unconscious and taken to the ER. The given sagittal CT reformat image reveals a T9 spinal fracture dislocation, as noted by the black arrow. The patient had unequivocal clinical findings indicating spinal cord transection. Given the results of this CT image and the clinical information, what deficits will the patient incur?

iliocostalis. The dorsal primary rami of the spinal nerves innervate the deep muscles of the back, including the iliocostalis. The other muscles are the superficial muscles of the back, which are innervated by the ventral primary rami of the spinal nerves.

A 34-year-old woman crashes into a tree during a skiing lesson and is brought to a hospital with multiple injuries that impinge the dorsal primary rami of several spinal nerves. Such lesions could affect which of the following muscles?

supraspinatus. The supraspinatus, one of the four rotator cuff muscles, has the primary action of initiating abduction of the arm. It is the only rotator cuff member that does not have a main action of rotating the arm. The supraspinatus tendon is subject to possible degenerative changes related to subacromial bursitis or other overuse syndromes, which may lead to its rupture. In case of tendon rupture, the patient typically presents with the abduction motion deficit condition described here.

A 35-year-old left-handed baseball pitcher experiences a severe spasm of pain while abducting his left arm in beginning to throw a pitch, and is unable to continue playing. Subsequently, he cannot initiate abduction of the left arm. However, if that arm is passively elevated through the first 15° of abduction, he can complete bringing the arm up to a right angle. The tendon of which of the following muscles is most likely torn? Infraspinatus Subscapularis Supraspinatus Teres major Teres minor

Flexing the hip by raising the straightened left leg with the patient lying in the supine position increases pain in the back with radiation down the left leg

A 35-year-old man presents with pain radiating from his lower back into his left lower limb, periodic sensory loss and paresthesia in that limb, and associated motor weakness. His physician suspects unilateral entrapment of lumbar nerve roots secondary to a herniated lumbar intervertebral disc. In examining the patient, the physician conducts a straight-leg raising test. Which of the following best describes a positive straight-leg raising sign (Lasèque's sign) for this condition in this patient?

median nerve. The contents of the cubital fossa from medial to lateral side are the median nerve, the brachial artery, the biceps brachii tendon, and the radial nerve. Thus, the median nerve is damaged. The radial recurrent artery ascends medial to the radial nerve.

A 35-year-old man walks in with a stab wound to the most medial side of the proximal portion of the cubital fossa. Which of the following structures would most likely be damaged?

upper trunk of the brachial plexus. The illustration shows an injury in which the cervicobrachial angle (the angle between the neck and shoulder) is stretched widely. This abnormal impact eventually results in the postural presentation of a "waiter's tip" deformity (Erb-Duchenne palsy). This combination of injury and postural deformity is related to damage to both the C5 and C6 roots or upper trunk of the brachial plexus. The C5 and C6 roots converge to form the upper trunk of the brachial plexus and contribute heavily to the suprascapular, axillary, and musculocutaneous nerves. The suprascapular nerve supplies the supraspinatus and infraspinatus muscles. The axillary nerve controls the deltoid and teres minor muscles. The musculocutaneous nerve supplies the anterior compartment of the arm (coracobrachialis, biceps brachii, brachialis muscles). Therefore, a significant weakness in abduction and lateral rotation of the shoulder, flexion of the shoulder and elbow, and supination of the forearm would result from this brachial plexus injury. The ultimate postural deformity is a contracture effect in which the intact muscles act unopposed to draw the limb into a position that is the opposite of the actions of the affected muscles. Lower roots of the brachial plexus is incorrect. The lower roots (C8, T1) have a strong projection into the ulnar nerve. Trauma here would result in an ultimate postural deformity of "claw hand" due to the loss of flexion of the medial digits. That injury does not match this patient's clinical presentation. Posterior divisions of the brachial plexus is incorrect. The posterior divisions supply the radial, axillary, upper and lower subscapular, and thoracodorsal nerves. The primary postural effect resulting from trauma here would be a case of "wrist drop" expressed due to loss of the extensor muscles innervated by the radial nerve. Medial cord of the brachial plexus is incorrect. The medial cord projects into the ulnar and median nerves. Damage to the ulnar nerve will result in "claw hand." The classic median nerve deformity of "ape hand" probably would not be realized because the median nerve also receives a strong input from the lateral cord. Lateral root of the median nerve is incorrect. The median nerve is formed by lateral and medial roots derived from the lateral and medial cords, respectively. Trauma to either root would weaken the territory of the median nerve but likely not result in the classic median nerve postural defect of "ape hand." The lateral root does not contribute to the suprascapular and axillary nerves, which have been affected in this patient.

A 50-year-old man falls off a ladder while cleaning his windows, landing on the ground as seen in the given drawing. He does not seek medical aid, believing his general soreness will go away with time. However, after several months, he develops a postural deformity of his left upper limb that includes an adducted, medially rotated, and extended shoulder, extended elbow, and pronated forearm. The injury and subsequent condition reflect damage to what structure?

herniation of the nucleus pulposus of an IV disc usually occur posterolaterally. The herniation usually occur posterolaterally because the anulus fibrosus is relatively thin at this site. In addition, the posterior longitudinal ligament does not support the anulus in this location.

A 52-year-old construction worker complained of pain in what he called the "small of his back." As he moved slowly down a ladder, he felt pain that spread down the back of his right leg. He consulted his family doctor who examined him and said that he had symptoms of a herniated IV disc. Which of the following statements about herniation of IV discs is most accurate?

Anterior longitudinal ligament

A 60-year-old man does a series of stretching exercises every morning as part of his fitness routine. In one exercise, he holds his hands behind his head and extends his back as far as possible. Which of the following ligaments resists this movement of the back?

latissimus dorsi. The axilla is a large, pyramidal space between the side of the chest and the upper part of the brachium. Its major importance is as a passageway from the root of the neck to the upper limb. The axilla is demarcated by four walls: anterior, posterior, medial, lateral. The posterior wall is composed of the latissimus dorsi, teres major, and subscapularis muscles. The posterior axillary fold forms the palpable lower margin of the wall and is composed of the latissimus dorsi and teres major. The subscapularis is not part of the posterior axillary fold. Damage to the latissimus dorsi would severely hinder adduction, extension, and medial rotation of the arm.

A 65-year-old man is brought to the emergency room after being attacked in his office by a disgruntled co-worker. The attacker reportedly used a long, narrow-bladed letter-opener to inflict multiple stab wounds to the man's back. Physical examination shows a puncture wound in the posterior axillary fold. The patient presents with weakness in extension, adduction, and medial rotation of his arm. Which of the following muscles is most likely cut in this injury?

inferior dislocation of the head of the humerus. Inferior dislocation of the head of the humerus may damage the axillary nerve, which arises from the posterior cord of the brachial plexus, runs through the quadrangular space accompanied by the posterior humeral circumflex vessels around the surgical neck of the humerus, and supplies the deltoid and teres minor, which are lateral rotators of the arm.

A 7-year-old boy falls from a tree house and is brought to the emergency department of a local hospital. On examination, he has weakness in rotating his arm laterally because of an injury of a nerve. Which of the following conditions is most likely to cause a loss of this nerve function?

spinal ganglion of T10. In this patient, herpes zoster, or shingles, is a painful skin rash affecting the dermatome distribution pattern of the left 10th thoracic (T10) nerve, as evidenced by the involvement of the umbilicus.

A 77-year-old man presents with shingles on his anterolateral abdomen and umbilicus, as shown in the figure. Shingles (or herpes zoster) is caused by the varicella zoster virus, which resides latent in sensory ganglia in the body for many years. When a patient is immunocompromised, this virus can cause a painful skin rash called shingles, which usually presents unilaterally along the infected nerve's dermatome distribution. Given the location of the rash, what ganglion is most likely affected in this patient?

extension of the arm. The thoracodorsal nerve innervates the latissimus dorsi, which adducts, extends, and medially rotates the arm. The arm is abducted by the supraspinatus and laterally rotated by the infraspinatus, teres minor, and deltoid (posterior part) muscles. The scapula is elevated by the trapezium and levator scapulae muscles and adducted by the rhomboid and trapezius muscles.

A ballet dancer falls to the floor and hurts herself during a practice session before opening night. She sustains an injury to the thoracodorsal nerve that would probably affect the strength of which of the following movements? Extension of the arm Adduction of the scapula Elevation of the scapula Abduction of the arm Lateral rotation of the arm

accessory nerve. The accessory nerve (CN XI) traverses the posterior triangle of the neck to reach the deep surface of the trapezius muscle after it innervates the sternocleidomastoid muscle. Its position within the triangle is superficial, and it is at this location that this nerve is vulnerable to injury. Damage to the distal accessory nerve would inhibit elevation of the scapula and lateral rotation of the scapula during abduction greater than 90 degrees. Both of these actions were affected in this patient.

A dermatologist performed a biopsy on a suspicious mole on the right side of the posterior neck of a 57-year-old male construction worker. Pathology confirmed a malignant melanoma, so the physician excised a substantial amount of tissue surrounding the mole. After the procedure, the patient experienced difficulty elevating his right shoulder and lifting his right arm over his head. No sensory deficits were seen. What nerve was most likely damaged in this patient? Accessory nerve Axillary nerve Dorsal scapular nerve Long thoracic nerve Thoracodorsal nerve

ternocleidomastoid. The sternocleidomastoid muscle (SCM) is abnormally shortened and/or excessively contracting in this baby girl with congenital torticollis (L: twisted neck). The etiology of congenital torticollis is unknown, but it is thought to be due to damage to the SCM during birth or intrauterine malposition. In this baby, the congenital torticollis presents with the head tilted (or laterally bent) toward the affected SCM (right side in this patient) and the chin is elevated and turned toward the contralateral (left) side. Bilateral contraction of the SCM causes flexion of the neck to move the chin toward the sternum. When the right SCM contracts alone, it functions to bring the mastoid process of the temporal bone closer to the sternum, which results in tilting the head toward the right side and elevation of the chin to the left. The excessive contraction (or tone) of the right SCM causes the inability of this baby to have her head turned to the right side. The accessory nerve (CN XI) provides motor innervation to the trapezius and SCMs, and the congenital torticollis, seen in this patient, is due to shortening or excessive contraction of the right SCM

A newborn baby girl is unable to move her head to the right, even when her pediatrician tries to assist the movement, as seen in the photo. Her range of motion in the neck is limited in rotation and lateral bending, and her head posture is abnormally tilted toward the right and her chin is elevated and turned toward the left side. What muscle is most likely responsible for the baby's abnormal range of movement and head posture?

sclerotome. The fibrocartilage anulus fibrosus composing the outer portion of each intervertebral disc (in all regions) is derived from sclerotomic mesenchyme that condenses between adjacent vertebral bodies. The sclerotome itself is derived from the paraxial mesoderm. Dermatome is incorrect. The dermatome (derived from the paraxial mesoderm) gives rise to dermis and hypodermis. Intermediate mesoderm is incorrect. The intermediate mesoderm gives rise to much of the urogenital system. Myotome is incorrect. The myotome (also derived from the paraxial mesoderm) gives rise to premuscle tissue that forms much of the skeletal musculature of the body. Notochord is incorrect. The notochord mostly degenerates during development. However, the portions located between the vertebral bodies form the nucleus pulposus in the core of each intervertebral disc.

A newborn infant is diagnosed with a congenital vertebral defect in which the anulus fibrosus of each lumbar intervertebral disc is poorly formed. This condition may be related to a developmental insufficiency of tissue derived from which of the following embryonic sources?

dorsal scapular artery. The dorsal scapular artery arises directly from the third part of the subclavian artery and replaces the deep (descending) branch of the transverse cervical artery. The suprascapular and transverse cervical arteries are branches of the thyrocervical trunk of the subclavian artery. The thoracoacromial artery is a short trunk from the first or second part of the axillary artery and has pectoral, clavicular, acromial, and deltoid branches.

A patient bleeding from the shoulder secondary to a knife wound is in fair condition because there is vascular anastomosis around the shoulder. Which of the following arteries is most likely a direct branch of the subclavian artery that is involved in the anastomosis?

superior thoracic. The superior thoracic artery is a direct branch of the axillary artery. The thoracoacromial trunk has four branches: the pectoral, clavicular, acromial, and deltoid.

A patient comes in with a gunshot wound and requires surgery in which his thoracoacromial trunk needs to be ligated. Which of the following arterial branches would maintain normal blood flow?

lack of sweating on the lateral side of the forearm. The musculocutaneous nerve contains sympathetic postganglionic fibers that supply sweat glands and blood vessels on the lateral side of the forearm as the lateral antebrachial cutaneous nerve. The musculocutaneous nerve does not supply the extensors of the forearm and the brachioradialis. This nerve also supplies tactile sensation on the lateral side of the forearm but not the arm and supplies blood vessels on the lateral side of the forearm but not the hand.

A patient with a stab wound receives a laceration of the musculocutaneous nerve. Which of the following conditions is most likely to have occurred?

breast overlies the 2nd to the 6th ribs. In normal, young adult females, the breast typically overlies the 2nd-6th ribs and their costal cartilages. The breast normally extends from lateral margin of sternum parasternal line to the midaxillary line. The upper lateral quadrant of the mammary gland typically sends an axillary tail around the lateral edge of the pectoralis major muscle and into the axilla. Mammary gland tissue is located in the superficial fascia of the anterior chest wall. However, the axillary tail pierces the deep fascia at the lower border of the pectoralis major muscle to enter the axilla.

A physician conducts a breast examination of a 24-year-old woman. Which of the following features constitutes a normal condition?

The medullary cone ends at or above the L3 level

A physician orders a lumbar puncture (spinal tap) for his 43-year-old female patient in order to obtain a sample of cerebrospinal fluid (CSF). He explains to her that this procedure will be done in the lower back, between the spinous processes of the L3 and L4 vertebrae. What is the best reason for performing the lumbar puncture at this location?

supraspinatus tendonitis. This patient is experiencing shoulder impingement syndrome, in which impingement of the supraspinatus tendon leads to supraspinatus tendonitis. Supraspinatus tendonitis is a result of stressful repetitive overhead motions, such as lifting heavy objects, which this patient noted in his summer job. This type of tendonitis presents with a painful arc of motion (between 80 and 150 degrees in this patient) during abduction of the upper limb.

A right-handed 21-year-old college student visits his physician because of pain in his right shoulder that developed after starting a summer job on a construction crew 2 weeks ago. He explains that on his job site he regularly lifts heavy construction materials over his head. During physical examination, the patient experiences sharp pain in the range of 80 to 150 degrees of abduction at the glenohumeral joint. What is the most likely diagnosis? Infraspinatus tendonitis Supraspinatus tendonitis Acromioclavicular (AC) joint arthritis Degenerative arthritis of the shoulder Broken clavicle

subscapularis muscle. The subscapularis muscle inserts on the lesser tubercle of the humerus. The supraspinatus, infraspinatus, and teres minor muscles insert on the greater tubercle of the humerus. The coracohumeral ligament attaches to the greater tubercle.

A rock climber falls on his shoulder, resulting in a chipping off of the lesser tubercle of the humerus. Which of the following structures would most likely have structural and functional damage? Subscapularis muscle Supraspinatus muscle Infraspinatus muscle Teres minor muscle Coracohumeral ligament

levator scapulae. The levator scapulae arise from the transverse processes of the upper cervical vertebrae and inserts on the medial border of the scapula. The other muscles are attached to the spinous processes of the vertebrae.

After a 26-year-old man's car was broadsided by a large truck, he is brought to the emergency department with multiple fractures of the transverse processes of the cervical and upper thoracic vertebrae. Which of the following muscles might be affected?

long thoracic nerve. The photo demonstrates a case of "winged scapula," indicative of lesion of the long thoracic nerve and subsequent paralysis of the serratus anterior muscle. The nerve is located on the lateral thoracic wall, on the superficial aspect of the serratus anterior, where it is not afforded the protection of the muscle it innervates (like most motor nerves), especially when the limb is elevated. In this patient, shrapnel wounds to the lateral thoracic wall caused damage to the long thoracic nerve and subsequent loss of innervation to the serratus anterior muscle. When the affected limb is protracted, the medial border and inferior angle of the scapula pull away from the posterior chest wall, giving the scapula a wing-like appearance. Additionally, the affected arm cannot be abducted above the horizontal plane because the serratus anterior is not available to superiorly rotate the glenoid cavity of the scapula to allow full abduction. Following damage to the long thoracic nerve, it takes several weeks for a winged scapula to the develop because the trapezius muscle, which attaches to the spine of the scapula, must stretch before winging is apparent.

An 18-year-old soldier presents with shrapnel wounds in the lateral wall of his right chest following an explosion of a landmine. After several months of recovery, his physical therapist observes that his scapula moves away from the thoracic wall when he leans on his right hand, as noted by the black arrow in the given photo. Which of the following nerves is likely damaged?

dislocation of the cervical region of the vertebral column may occur without damage to the spinal cord. Because of the large vertebral canal in the cervical region and the shape of the facet joins, a subluxation of the vertebrae may occur without damaging the spinal cord; however, a severely dislocated vertebra may injure the spinal cord

An 8-year-old girl fell during a gymnastics competition when she was performing on the uneven bars. She landed on the posterior part of her neck. On examination, there was marked muscle spasm and pain in her neck. Her neck was immobilized, and she was taken to a hospital and examined by an orthopedist. He ordered radiographs of her neck. The radiologist reported that there was anterior subluxation (incomplete dislocation) of C2 on C3 vertebrae. Which of the following statements best describes aspects of the cervical region of the vertebral column?

The answer is suspensory ligaments. Fibrous lobar septa are connective tissue partitions that separate the glandular lobes of the breast and compartmentalize breast tissue. These septa run through the depth of the breast from the dermis of the skin to the underlying pectoral fascia and are most pronounced in the superior aspect of the breast, where they are termed suspensory (Cooper's) ligaments of the breast. Edema and/or tumor growth within the breast can apply traction on the suspensory ligaments, and this tension causes dimpling of the skin that resembles an orange peel.

An 80-year-old woman comes to the physician because of a lump in her right breast. Physical examination shows a 2-cm mass in the right breast with dimpling of the overlying skin and peau d'orange (edema of the breast with the skin assuming the appearance of an orange peel). Examination of a biopsy specimen confirms a diagnosis of carcinoma. Involvement of what structure is the most likely cause of this patient's skin dimpling?

Intercostobrachial nerve

An anesthesiologist administers an anesthetic solution into the axillary sheath of a 19-year-old college baseball player in preparation for repair of the ulnar collateral ligament of the elbow. After 5 minutes, the patient experiences numbness and paresthesia distal to the middle aspect of the arm; however, the medial aspect of the arm and elbow remain sensitive to pain. What nerve provides sensory innervation to the sensitive area and was not blocked by the anesthetic solution?

ligamentum flavum. The cerebrospinal fluid (CSF) is located in the subarachnoid space, between the arachnoid layer and the pia mater. In a lumbar puncture, the needle penetrates the skin, fascia, ligamentum flavum, epidural space, dura mater, subdural space, and arachnoid mater. The pia mater forms the internal boundary of the subarachnoid space; thus, it cannot be penetrated by needle. The posterior longitudinal ligament lies anterior to the spinal cord; thus, it is not penetrated by the needle. The filum terminale externum is the downward prolongation of the spinal dura mater from the second sacral vertebra to the dorsum of the coccyx. The annulus fibrosus consists of concentric layers of fibrous tissue and fibrocartilage surrounding and retaining the nucleus pulposus of the intervertebral disk, which lies anterior to the spinal cord.

An elderly man at a nursing home is known to have degenerative brain disease. When cerebrospinal fluid (CSF) is withdrawn by lumbar puncture for further examination, which of the following structures is most likely penetrated by the needle?

notochord. The nucleus pulposus is the sole remnant of the embryonic notochord, the initial longitudinal skeletal axis of the body. The developing bodies and intervertebral discs of the vertebral column replace the notochord, except for the nucleus pulposus. Remember that each intervertebral disc is composed of two parts: the central nucleus pulposus and the peripheral anulus fibrosus.

An infant suffers a vertebral malformation in which the nucleus pulposus component of multiple intervertebral discs is hypertrophied. From what embryonic structure is the hypertrophied structure derived?

Brachialis or supinator (form floor of cubital fossa)

Because of repeated bad needle sticks, a heroin addict develops an infected abscess in the floor of the cubital fossa. Which of the following structures is the abscess most likely to invade first?

displaced and locking facets (dislocation) in the cervical region. Because of the relatively flat facets in the cervical region the vertebrae may dislocate without fracture and one superior facet may "jump" and become locked over the inferior facet.

Cervical spine CT scanning of a young adult ED patient brought in after automobile trauma is reported to show "jumped facets." What does this refers to?

E. The medial epicondyle is the site of origin for the common flexor tendon and pronator teres. The common flexors include the flexor carpi radialis and ulnaris and palmaris longus muscles, which can flex the elbow and wrist joints. Thus, destruction of this area causes weakness of pronation because the pronator teres is paralyzed but the pronator quadratus is normal. Similarly, destruction of this area causes paralysis of the flexors of the wrist. However, it can be weakly flexed by the flexor pollicis longus, flexor digitorum superficialis, and profundus muscles.

Choose the appropriate lettered site or structure in the radiograph of the elbow joint (see figure) and its associated structures to match the following description: Destruction of this area would most likely cause weakness of pronation of the forearm and flexion of the wrist joints.

B. The lunate bone articulates with the radius and triquetrum.

Choose the appropriate lettered structure in the radiograph of the bones of the hand (see figure). Which bone articulates with the radius and triquetrum?

E. The base of the proximal phalanx of the thumb is the site of attachment for the flexor pollicis brevis, which, along with the opponens pollicis, forms the thenar eminence. It is also the site of attachment for the adductor pollicis brevis.

Choose the appropriate lettered structure in the radiograph of the bones of the hand (see figure).Which is the site of attachment of the muscles that form the thenar eminence?

pia mater.

Denticulate ligaments are lateral extensions of the _____________.

spina bifida cystica

Disease: failure of one or more neural arches to fuse completely and herniation of meninges and sometimes the spinal cord as well.

dimpling of the overlying skin. Breast cancer may cause dimpling of the overlying skin because of shortening of the suspensory (Cooper's) ligaments and inverted or retracted nipple because of pulling on the lactiferous ducts. Polymastia is a condition in which more than two breasts are present.

During a breast examination of a 56-year-old woman, the physician found a palpable mass in her breast. Which of the following characteristics of breast cancer and its diagnosis is correct?

Rhomboid major and trapezius

During a domestic dispute, a 16-year-old boy receives a deep stab wound around the superior angle of the scapula near the medial border, which injures both the dorsal scapular and spinal accessory nerves. Such an injury could result in paralysis or weakness of which of the following muscles?

pierced the pectoralis minor muscle to reach the cords of the brachial plexus. The pectoralis minor is one component (along with pectoralis major and subclavius) of the anterior wall of the axilla. This muscle overlies and defines the second part of the axillary artery, which lies between the cords of the brachial plexus, in the center of the axilla. The knife would have to pierce the pectoralis minor to reach these neurovascular structures. The teres major is one component of the posterior wall of the axilla, along with the latissimus dorsi and subscapularis muscles. The trunks of the brachial plexus are located in the posterior triangle of the neck, above and outside of the axilla. This nerve branches from the upper trunk of the brachial plexus and runs across the root of the neck to the scapula. It does not enter the axilla.Winged scapula occurs as a result of damage to the long thoracic nerve and subsequent paralysis of the serratus anterior muscle. The long thoracic nerve arises from the upper roots of the brachial plexus and descends through the posterior triangle of the neck onto the medial wall of the axilla. This nerve is well removed from the described wound.

During an attempted robbery, a 20-year-old man of average body build is stabbed once with a long, narrow knife. Initial examination in the emergency room indicates the knife penetrated the anterior wall of the right axilla and reached approximately the center of the axillary space. Which of the following is most likely true of this injury?

palmaris longus or flexor carpi radialis

During an attempted suicide, a depressed young woman slashes the front of her wrist with a razor blade. However, she cuts only to the depth of the superficial aspect of the flexor retinaculum before passing out at the sight of her own blood. Which of the following muscle tendons may be severed?

Subarachnoid space

During an outbreak of meningitis at a local college, a 20-year-old student presents to a hospital emergency department complaining of headache, fever, chills, and stiff neck. On examination, it appears that he may have meningitis and needs a lumbar puncture or a spinal tap. Cerebrospinal fluid (CSF) is normally withdrawn from which of the following spaces?

thoracodorsal nerve. Successful transposition of muscle flaps in reconstructive surgery hinges largely on maintaining the neurovascular pedicles that supply the muscle. The latissimus dorsi muscle is innervated by the thoracodorsal (middle subscapular) nerve, a branch of the posterior cord of the brachial plexus. Lesion of this nerve during dissection of the chest wall will cause loss of the muscle flap

Following a radical mastectomy procedure, a surgeon plans to conduct a breast reconstruction utilizing a latissimus dorsi muscle flap. What nerve will the surgeon need to keep intact during the surgical dissection of the chest wall to prevent atrophy of the muscle flap? Long thoracic nerve Intercostobrachial nerve Medial pectoral nerve Thoracodorsal nerve Axillary nerve

lactiferous sinus. The lactiferous sinus, at the distal end of the lactiferous duct, fills during suckling to allow for release of milk.

The expansion of the lactiferous duct, near the nipple, is the _______________ .

clavicle. The clavicle is the most commonly fractured bone in the body, owing to it serving as the sole bony attachment of the upper limb to the body.

The first bone in the body to ossify and one of the most commonly fractured bones in the body is the______________.

posterior circumflex humeral artery. The radiograph shows a fracture of the surgical neck of the humerus. The posterior humeral circumflex artery, accompanied by the axillary nerve, lies against the posterior aspect of the surgical neck as it passes into the quadrangular space of the shoulder. This fracture places both of these structures in immediate danger

The given X-ray reveals a fracture of the proximal humerus, indicated by the black arrow. Given the location of the fracture, what artery is most likely damaged in this patient?

atlantoaxial joint. The dens of the axis is held in place by a complex of strong ligaments that includes the cruciform ligaments complex.

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