Netter's Questions - Shoulder
An elderly woman falls out on her outstretched hand and fractures the surgical neck of her humerus. Several weeks later she presents with significant weakness in abduction of her arm and some weakened extension and flexion at the shoulder. Which nerve is most likely injured?
Axillary nerve fractures in this portion of the humerus can place the axillary nerve in danger of injury. Her muscle weakness confirms that her deltoid muscle especially is weakened, and the deltoid and teres minor muscles are innervated by the axillary nerve.
Dislocation of the shoulder placed this nerve in jeopardy of injury.
Axillary nerve the axillary nerve (innervates the deltoid and teres minor muscles) can be injured by shoulder dislocations. This nerve passes through the quadrangular space before innervating its two muscles.
This muscle generally may not be the strongest flexor of the forearm at the elbow, but is the strongest supinator of the hand.
Biceps brachii the biceps brachii muscle flexes the forearm at the elbow. It also is the "power supinator" when the elbow is flexed, but is does not supinate when the elbow is extended.
A fracture of the first rib appears to have damaged the inferior trunk of the brachial plexus where it crosses the rib. which spinal nerve levels would most likely be affected by this injury?
C8-T1 The inferior trunk plexus crosses over the first rib, where it is vulnerable to injury. It arises from the C8 and T1 anterior rami of the spinal nerves.
A wrestler comes off the mat holding his right forearm flexed at the elbow and pronated, with his shoulder medially rotated and displaced inferiorly. Which of his bones is most likely broken?
Clavicle fractures of the clavicle are relatively common and occur most often in the middle third of the bone. The distal fragment is displaced downward by the weight of the shoulder and drawn medially by the action of the pectoralis major, teres major, and latissimus dorsi muscles.
What muscle is most likely responsible for an injury to the back that results in a weakened ability to extend and medially rotate the upper limb?
Latissimus Dorsi
What muscle is most likely responsible for a trauma to the lateral neck that results in a lesion to the dorsal scapular nerve and a weakened ability to shrug the shoulder?
Levator scapulae
Which tendon is most vulnerable to inflammation and sepsis in the shoulder joint?
Long head of biceps tendon The long head of the biceps tendon passes through the shoulder joint and attaches to the supraglenoid tubercle of the scapula. An infection in the joint could involve this tendon.
What muscle is most likely responsible for the loss of innervation to this pair of hypaxial (hypomere) muscles results in a bilateral weakened ability to retract the scapulae, but does not affect the ability to elevate the scapula?
Rhomboid major
A fracture of the clavicle results in some internal bleeding. Which of the following vessels is most likely the cause of the bleeding?
Subclavian vien the subclavian vein passes superficially between the clavicle and first first. The subclavian artery also parallels the vein, but deeper.
An 81-year old man presents with pain in his shoulder; it is especially acute upon abduction. Further examination reveals intramuscular inflammation that has spread over the head of the humerus. Which structure is most likely inflamed?
Subdeltoid bursa the subdeltoid bursa lies between the underlying supraspinatus tendon and the deltoid muscle, both of which are involved in abduction at the shoulder. Inflammation of these muscle tendons is common,.
A baseball pitcher delivers a 97mph fastball to a batter and suddenly feels a sharp pain in his shoulder on release of the ball. The trainer examines the shoulder and concludes that the pitcher has a rotator cuff injury. Which muscle is most vulnerable and most likely torn by this type of injury?
Supraspinatus the supraspinatus is most often torn in rotator cuff injuries. Repeated abduction and flexion can cause the tendon to rub on the acromion and coracoacromial ligament, leading to tears or rupture.
A football player has a dislocated shoulder. the trainer is able to reduce the dislocation, but the player still has significant pain over his dorsal shoulder and cannot abduct his arm in a normal manner. Which muscle has most likely been injured by the dislocation?
Supraspinatus muscle The supraspinatus muscle is often injured by shoulder dislocations, which usually occurs in an anteroinferior direction. The supraspinatus muscle is critical for initiating the first 15 degrees of abduction at the shoulder before the deltoid muscle takes over.
A 54 year old woman presents with a case of shingles (herpes zoster infection) that affects the sensory spinal nerve roots innervating the skin on her back overlying the inferior angle of her scapula. Which dermatome is most likely involved?
T6-T7 Herpes zoster infection affects the sensory distribution of spinal and cranial nerves in a pattern generally following a dermatome. In this instance, the dermatome affected is the area of skin overlying the inferior scapula which is in the T6-T7 dermatome.
A 51 year old man is admitted to the emergency department following a bicycle accident. His physical examination reveals weakened medial rotation, extension, and adduction of an upper limb. Which nerve is most likely injured?
Thoracodorsal nerve the thoracodorsal nerve innervated the latissimus dorsi which is the muscle that medially rotates, extends, and adducts the upper limb.
What muscle is most likely responsible for a work related injury that results in a weakness against resistance in elevation of the scapula and atrophy of one of the lateral neck muscles. The physician suspects damage to a cranial nerve?
Trapezius
A knife cute results in a horizontal laceration to the thoracic wall extending across the midaxillary and anterior axillary lines just above the level of the T4 dermatome. What patient presentation will the emergency department physician most likely observe on examination of the patient?
Winged scapula This laceration probably served the long thoracic nerve, which innervated the serratus anterior muscle. During muscle testing, the scapula will wing outwardly if this muscle is denervated.
An elderly woman falls and fractures her femoral neck ("breaks her hip"). Which of the following types of synovial joints was involved in the fracture? a. ball and socket (spheroid) b. condyloid (ellipsoid) c. hinge (ginglumus) d. plane (gliding) e. sadle (biaxial)
a. ball and socket
Burns are typically classified according to how deep into the tissue the burn injury extends. When a burn has been classified as a second degree burn, how deep has the burn penetrated the tissue? a. through the dermis b. through the epidermis c. through the investing fascia d. through the subcutaneous tissue e. into the underlying muscle
a. through the dermis a second degree burn penetrates both the epidermis and the dermis, but does not go further. A third degree burn includes the subcutaneous tissue below the dermis.
when examining you musculoskeletal system, the orthopedist may check the strength of a contracting muscle at a joint. As this is done, another muscle relaxes and would be designated by which of the following terms? a. agonist b. antagonist c. extensor d. fixator e. synergist
b. antagonist
A radiologist is examining a computer generated series of MR scans in the frontal plane. Which of the following terms is synonymous with the frontal plane. a. axial b. cornonal c. cross section d. sagittal e. transverse
b. cornonal
The brain and spinal cord are surrounded by membranous connective tissue layers. The pain associated with most CNS inflammatory processes is mediated by sensory nerves in which of these tissue layers? a. arachnoid mater b. dura mater c. endoneurium d. ependyma e. pia mater
b. dura mater the dura mater is heavily innervated by sensory nerve fibers, whereas the arachnoid and pia mater are not innervated.
A patient has difficulty digesting fats (i.e. french fries) and experiences pain after a heavy meal, which then subsides. Of the following organs of the GI tract, which would most likely be the culprit? a. colon b. gallbladder c. pancreas d. salivary glands e. stomach
b. gallbladder the gallbladder stores and concentrates bile, which is necessary for the emulsification of fats in our diet. When fats enter the GI tract, the gall bladder is stimulated, contracts, and releases concentrated bile into the second portion of the duodenum.
In designing a novel pharmaceutical agonist for use in controlling blood pressure, the scientists must be cognizant of which of the following distinguishing features of the autonomic nervous system? a. it is a one-neuron efferent system b. it is a two-neuron efferent system c. it is associated with 10 cranial nerves d. it releases only neuropeptides as transmitters e. it releases only norepinephrine as a transmitter
b. it is a two-neuron efferent system this is the only answer that accurately reflects the ANS. It is a two-neuron efferent system, and different transmitters are co-localized and released. Because of this, ACh, NE, and neuropeptides can be targeted at different synaptic sites pharmacologically to alter the response of the system. The only exception is the neuroendocrine cells of the adrenal sympathetic neurons innervated by preganglionic sympathetic fibers.
A physician will know what the term dorsiflexion of the foot means, but a patient being tested may not be familiar with the term. Therefore, the physician might instruct a patient to do what when she wants the patient to dorsiflex the foot? a. point your foot downward b. point your foot upward c. stand on your toes d. turn your foot to the inside e. turn your foot to the outside
b. point your foot upward dorsiflexion of the foot at the ankle occurs when one points the foot upward. This movement is the same as extension and is the opposite of flexion (plantar-flexion). Most patients will not be familiar with the term dorsiflexion (or extension), so the physician must phrase the instruction in words that are easily understood.
Long bones are responsible for most of our height. Which of the following portions of the long bone is most important in lengthening the bone? a. diaphysis b. epiphysis c. epiphysial plate d. metaphysis e. shaft
c. epiphysial plate. bone growth in length occurs at the epiphysial plate, where hyaline cartilage undergoes proliferation and ossification. Growth in width occurs at the diaphysis.
A physician diagnoses a congenital malformation in a tissue that is a derivative of the embryonic endoderm. Which of the following tissues or structures is the most likely the malformed one? a. biceps muscle b. epidermis of the arm c. epithelium of the trachea d. dermis of the hand e. femur
c. epithelium of the trachea the only tissue listed that is derived from the embryonic endoderm is the epithelial lining of the trachea. the epidermis is derived from the ectoderm, and all other options are derived from the mesoderm.
A congenital defect of the spinal cord occurs during the third week of embryonic development. which of the following events characterizes this crucial period of embryonic development? a. blastocyst formation b. embryoblast formation c. gastrulation d. morula formation e. zygote formation
c. gastrulation Gastrulation is the defining event of the this week of embryonic development. this is when the trilaminar disc (ectoderm, mesoderm, endoderm) develops and when the ectoderm begins to migrate medially and fold along the midline axis to form the future neural tube and the spinal cord.
In a patient with a reabsorption problem, the physician diagnoses the problem as being associated with the large intestine. Which of the following portions of the GI system can be excluded from further examination of the patient? a. ascending colon b. cecum c. ileum d. rectum e. sigmoid colon
c. ileum the ileum is part of the small intestine, and therefore it can be excluded by the physician. All the other listed options are part of the large intestine and must be considered in his examination.
When fluids are lost to the extracellular space, which of the following systems or organs is critical in returning the fluids to the vascular system? a. arachnoid granulations b. gallbladder c. lymphatic system d. respiratory system e. thyroid gland
c. lymphatic system a considerable amount of fluid is lost to the extracellular compartment at the level of the capillaries. the fluid can be recaptures by the lymphatic vessels and returned to the venous system. Important proteins are not easily reabsorbed by the venous system. The arachnoids granulations allow cerebrospinal fluid in the nervous system to return to the venous system.
Bleeding into the pericardial sac would also suggest that blood would be present in which of the following cavities? a. abdominal b. left pleural c. mediastinum d. right pleural e. vertebral
c. mediastinum the pericardium and the heart reside in the mediastinum (middle sac). the region between the two pleural cavities, all of which are in the thoracic cavity.
A patient experiencing a central nervous system (CNS) inflammatory process will be activating which of the following phagocytic glial cells? a. astrocytes b. ependymal cells c. microglia d. oliogdendrocytes e. schwann cells
c. microglia Microglias are the endogeneous glial cells in the CNS that are phagocytic and respond to any breach in the blood-brain barrier or to infection.
Which of the following approaches is the best one for imaging bony structures because it subjects the patient to the lowest dosage of x-rays but is still highly accurate? a. computed tomography (CT) b. magnetic resonance imaging (MRI) c. plain radiography d. positron emission tomography (PET) e. ultrasound
c. plain radiography plain radiography used the lowest dosage of x-rays. CT is often a good way to image bony structures but uses a higher dosage of x-rays. none of the other imaging modalities use x-rays, and none are as accurate as CT or plain radiography at delineating the fine features of bony structures.
A patient is having difficulty becoming pregnant. Her physician suspects a problem associated with the portion of her reproductive system that receives the ovulated oocyte. Which of the following structures is the focus of the physician's concern? a. ductus deferens b. urethra c. uterine tube d. uterus e. vagina
c. uterine tube the ovulated oocyte is usually captured and passes into the uterine (fallopian) tube, where fertilization could normally occur if sperm were present. The resulting zygote would undergo cell divisions and travel into the uterine cavity, where it would normally become implanted.
Following fertilization, how long does it usually take for the blastocyst to become implants in the uterine wall? a. 24 hours b. 48 hours c. 3 days d. 6 days e. 9 days
d. 6 days implantation of the blastocyst usually occurs around the fifth to sixth day after fertilization in the uterine tube.
During cardiac catheterization, the physician watches the blood flow from the right ventricle into which of the following vessels? a. aorta b. coronary arteries c. inferior vena cava d. pulmonary trunk e. superior vena cava
d. pulmonary trunk. venous blood from the body passes through the right side of the heart (right atrium and right ventricle) and then passes into the pulmonary trunk, which divides into a right pulmonary artery and a left pulmonary artery carrying blood away from the heart and to the lungs for gas exchange.
Clinically, the bones can be classified by their shape. Which of the following shapes is used to define the patella (kneecap)? a. flat b. irregular c. long d. sesamoid e. short
d. sesamoid
A neurologist is concerned about a patient's inability to walk without a distinct limp (movement disorder). Which of the following portions of the peripheral nervous system (PNS) will the neurologist examine first? a. autonomic b. enteric c. myenteric d. somatic. e. submuscosal
d. somatic the neurologist will examine the somatic division of the PNS first to determine if the problem is associated with a peripheral nerve and/or skeletal muscle. Skeletal muscle is innervated by the somatic nervous system.
A kidney stone becomes lodged in the portion of the urinary system between the kidney and the bladder. In which of the following structures will the stone be found? a. bile duct b. oviduct c. thoracic duct d. ureter e. urethra
d. ureter the ureter is the duct connecting the kidney to the urinary bladder.
A fall on outstretched hand results in swelling and pain on the lateral aspect of the wrist. Radiographic examination confirms a Colles' fracture. Which bones is most likely fractured?
distal radius the colles' fracture is a fracture to the distal radius, it presents with a classic dinner fork deformity with the dorsal and proximal displacement of the distal fragment. This is an extension-compression fracture.
As an x-ray beam passes through the human body, which of the following is the correct order of attenuation of the photons, from greatest to least attenuation? a. bone-fat-lung-soft tissues-water-air b. bone-fat-soft tissue-lung-water-air c. bone-lung-soft tissue-fat-water-air d. bone-soft tissue-lung-fat-water-air e. bone-soft tissue-water-fat-lung-air
e. bone-soft tissue-water-fate-lung-air the densest structures in the body are bone with the greatest attenuation of photons, followed by soft tissues, water (the reference medium), fat, lung (mostly air), and then air itself. On a plain radiograph, a very dense tissue like bone appears white, while air appears black.
Malformation of the primitive heart would most likely point to a problem with the development of which embryonic tissue? a. amnion b. chorion c. ectoderm d. endoderm e. mesoderm
e. mesoderm the heart (cardiac muscle) is a derivative largely of the mesoderm. later in its development, the neural crest (neutral folds of ectoderm) also plays an important role.
When a nurse takes a patient's pulse during a routine examination, the nurse will typically feel the pulse in which of the following arteries? a. brachial artery b. carotid artery c. dorsalis pedis artery d. femoral artery e. radial artery
e. radial artery typically the radial artery pulse is taken at the wrist and is easily felt. the dorsalis pedis artery is also important because it is the pulse farthest from the heart; it is detected on the dorsal surface of the foot.
Notes on a patient's chart indicate that the patient has had multiple fractures of the axial skeleton. Which of the following bones is part of the axial skeleton? a. clavicle b. coxal bone c. humerus d. scapula e. sternum
e. sternum the sternum is part of the central axis of the body and the axial skeleton. All the other bones listed are part of the appendicular skeleton (bones associated with the limbs)
In response to a perceived threat of danger, which of the following PNS components will be globally activated? a. enteric b. parasympathetic c. postganglionic d. preganglionic e. sympathetic
e. the sympathetic the sympathetic division of the ANS is functionally the "fight or flight" responder to any threat, perceived or real, and mobilizes the body globally.
The lymphatic and immune system are vitally important in defense of the body. Most of the lymph ultimately drains back into the venous system by which of the following structures? a. arachnoid granulations b. choroid plexus c. cisterna chyli d. right lymphatic duct e. thoracic duct
e. thoracic duct the thoracic duct drains lymph from about three quarters of the body and returns it to the venous system at the junction of the left internal jugular and left subclavian veins. The cisterna chyli is the beginning of the thoracic duct in the upper abdomen.
A patient who presents with an autoimmune disease characterized by loss of weight, rapid pulse, sweating, shortness of breath, bulging eyes (exophthalmos), a muscle wasting likely has over secretion of a hormone produced and stored in which endocrine organ? a. ovary b. pancreas c. pinal gland d. posterior pituitary gland e. thyroid gland
e. thyroid gland these signs and symptoms are characteristic of Graves' disease (hyperthyroidism), an excess synthesis and release of thyroid hormone, which up regulates metabolism.
Of the following types of medical imaging approaches, which is the least invasive and least expensive? a. computed tomography b. magnetic resonance imaging c. plain radiograph d. positron emission tomography e. ultrasound
e. ultrasound ultrasound uses very high-frequency longitudinal sound waves, is relatively safe, and is coast effective compared with other imaging modalities. Unfortunately, it is not suitable for all imaging; its resolution is limited and is cannot penetrate bone.
Despite injury to the radial nerve in the arm, a patient is still capable of supination of the forarm. This is due to what nerve?
musculocutaneous nerve while the supinator muscle id denervated (loss of radial nerve), the bieceps brachii muscle is innervated by the musculocutaneous nerve and is a powerful supinator when the elbow is flexed.
