Anatomy Exam 2: Practice Questions

CC: Trigger finger

Irritation of tendon causes swelling - forms nodule Nodule only slides back and forth under pulley with increased force, causing trigger effect Final stage - finger gets locked in either flexion or extension

Located in both major ball and socket joints, which accessory structure of a synovial joint forms a fibrocartilaginous lip on the "socket" portion of the joint?

Labrum

While having an IV needle inserted into the cephalic vein of the forearm, the patient suddenly screamed in pain and felt tingling in part of the skin of the forearm supplied by the nerve accompanying the vein. What nerve was injured?

Lateral antebrachial cutaneous n.

Most intrinsic hand muscles are innervated by the ulnar nerve. 2 lumbrical m. are innervated by branched of the median nerve as well as which m. compartment in the hand?

Thenar compartment

A patient playing softball cuts the palm of their hand as they scoop up a piece of glass along with the ball. If the only nerve damaged is the recurrent branch of the median nerve, they lose what movement of the thumb?

Thumb opposition

After trying to throw a curve ball, a pitcher lost sensation from the tip of the little finger. This indicates injury to which nerve?

Ulnar n.

CC: Shoulder dystocia

Upper BP injury; occurs when a newborn comes out of the vaginal canal during delivery if neck if positioned in such a way

Radial deviation of wrist

abduction

Ulnar deviation of wrist

adduction

A 27-year-old female presents to the clinic complaining of wrist pain after cycling 25 miles the day before. Physical exam reveals swelling at the wrist, compressing the contents of Guyon's canal. What action would you expect to be weakened in this patient?

adduction of the digits

A 6-year old female is brought to ED with an obvious deformity at the elbow. The father states he was swinging the girl around when he felt a "pop". What is the most likely structure to have been affected?

anular ligament

A 21-year-old patient has a lesion of the upper trunk of the brachial plexus. Which of the following is the most likely diagnosis?

arm tending to lie in medial rotation

Quadrangular space @ surgical neck & between triceps, teres minor and major (most lateral & superior)

axillary n. posterior circumflex humeral a.

Supination of the hand and forearm would be diminished by loss of radial n. function. But one very powerful supinator would remain intact and unaffected, namely:

biceps brachii

Muscles that flex the elbow

biceps brachii, brachialis, brachioradialis, pronator teres

Muscles that supinate

biceps brachii, supinator

After falling on ice, it was determined that a patient had a colles' fracture. Care must be taken to relieve tension on the broken distal end of the radius created by the pull of which muscle?

brachioradialis

CC: Carpal Tunnel Syndrome

caused by tenosynovitis; most common upper limb nervous system issue

A sixteen-year-old boy receives a superficial cut on the thumb side of his forearm. The superficial vein most likely affected is the:

cephalic v.

Triangular space @ surgical neck (most medial + next to quad)

circumflex scapular a.

A 44-year-old female presents to the emergency department with shoulder pain and disfigurement after a fall. Which structure has most likely been damaged?

coracoclavicular ligament

CC: Winged scapula

damage to long thoracic n. = paralysis of serratus anterior mm. *weakened protraction and difficulty abducting arm *accentuated when patient asked to push hands against a wall with arms flexed (outstretched)

CC: Wrist drop

damage to radial n.

What is most likely to occur from a fracture at the surgical neck of the humerus?

damage to the axillary n. and posterior circumflex humeral artery (PCHA)

A 35-year-old male body builder has enlarged his shoulder muscles to such a degree that the size of the quadrangular space is greatly reduced. Which of the following muscles would have weakness due to nerve entrapment?

deltoid

muscles that laterally rotate the shoulder

deltoid (posterior), infraspinatus, teres minor

Muscles innervated by axillary nerve

deltoid and teres minor

Muscles that abduct the shoulder

deltoid, supraspinatus

The point of insertion of the flexor digitorum profundus tendon to the index finger is on the:

distal phalanx

A 35-year-old man is admitted to the hospital after a severe car crash. Radiologic examination reveals an injury to the dorsal surface of the neck and a fracture of the medial border of the right scapula. During physical examination, the patient presents with the scapula retracted laterally on the affected side. Which of the following nerves has most likely been injured on that side?

dorsal scapular

What mm. are involved in performing a chin up? What movements are involved in a chin up?

elbow flexion and shoulder extension in the sagittal plane biceps brachii, brachialis, brachioradialis, latissimus dorsi, teres major, posterior deltoid

Muscles that extend the wrist

extensor carpi radialis longus and brevis, extensor carpi ulnaris, extensor digitorum

Muscles that flex the wrist

flexor carpi radialis, flexor carpi ulnaris, palmaris longus

Which muscle in the anterior compartment of the forearm is innervated by the ulnar n.?

flexor carpi ulnaris

Muscles innervated by ulnar nerve

flexor carpi ulnaris, flexor digitorum profundus

What mm is innervated by branches of both the median and ulnar n.?

flexor digitorum profundus

A patient comes in complaining that she cannot flex her PIP joints. Which of the following muscles appear to be paralyzed on further examination of her finger?

flexor digitorum superficialis (flexes PIP)

Compression of the median n. in the carpal tunnel affects which mm?

flexor pollicis brevis

CC: Tenosynovitis

inflammation caused from overuse of the synovial membranes/ tendon sheaths in the carpal tunnel = can lead to carpal tunnel syndrome

Patient presents with an inability to extend their wrist. What additional symptom might they also be experiencing? What nerve is responsible?

lack of sensation on the lateral dorsum of hand Radial n.

During insertion of an IV cannula in the median cubital vein, the patient suddenly lost feeling on the radial side of the forearm. What nerve was injured?

lateral antebrachial cutaneous n.

Anatomical snuff box

lateral border: abductor pollicis longus and extensor pollicis brevis medial border: extensor pollicis brevis floor: scaphoid and trapezium contains: radial artery, radial nerve, cephalic vein

CC: Upper brachial plexus injury (Erb's palsy)

lateral cord, cannot elevate shoulder not flexion of elbow; often associated with hand pronation

A 16 year old patient has weakness flexing the MCP joint of the ring finger and is unable to adduct the same finger. Which of the following muscles is most likely paralyzed?

palmar interosseous

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?

pectoralis major

A patient presents to the clinic with complaints of not being able to lift his arm out from his body. During muscle testing you find his strength to only be a ⅗. What cord does the nerve that innervates the weak muscle arise from?

posterior cord

Axillary n. arises directly from which part of the brachial plexus?

posterior cord

muscles that medially rotate the shoulder

subscapularis, teres major, pectoralis major, latissimus dorsi, anterior deltoid

CC: SLAP tear

superior labral from anterior to posterior) - very common sports injury; where you tear cartilage in the labrum of the GH joint

A 20 y/o presents to the ER with bruising and swelling over the long head of the biceps brachii m. after attempting to do heavy curls at the gym. What is the origin of the tendon? What attaches here?

supraglenoid tubercle *coracobrachialis, biceps brachii short head, pectoralis minor

A 56-year-old woman is admitted to the hospital after a severe car crash. A large portion of her chest wall needed to be surgically removed and replaced with a musculoosseous scapular graft involving the medial border of the scapula. Which of the following arteries will most likely recompensate the blood supply to the entire scapula?

suprascapular a.

What are the contents from superficial to deep of the scapular notch/foramen? (Army over Navy)

suprascapular a. | transverse scap. lig | suprascapular n.

A 34 year old male presents with weakness initiating abduction of the arm at the glenohumeral joint. Where is the most likely site of the lesion?

suprascapular notch

A 19-year-old man is brought to the emergency department after dislocating his shoulder while playing soccer. Following reduction of the dislocation, he has pain over the dorsal region of the shoulder and cannot abduct the arm normally. An MRI of the shoulder shows a torn muscle. Which of the following muscles is most likely to have been damaged by this injury?

supraspinatus mm.

Muscles that adduct the humerus

teres major, pectoralis major, latissimus dorsi, coracobrachialis

Muscles that extend the elbow

triceps brachii, anconeus

Muscles innervated by radial nerve

"Try A Big Chocolate Chip Sundae, Double Dip Cherries And Peanuts Preferably Included" -Triceps -Anconeus -Brachioradialis -(Ext.) Carpi radialis longus -(Ext.) Carpi radialis brevis -Supinator -(Ext.) Digitorum -(Ext.) Digiti minimi -(Ext.) Carpi ulnaris -Abductor poll. longus -(Ext.) Poll. brevis -(Ext.) Poll. longus -(Ext.) Indicis *For the neighboring words that start with the same letter (eg: chocolate and chip), notice that the longer word in the mnemonic, corresponds to the longer of the two muscle names (ex: ext. carpi radialis longus and ext. carpi radialis brevis)

Contents of the axilla

1) brachial plexus 2) axillary artery 3) axillary vein 4) lymph nodes 5) axillary fat

Anterior Brachial Compartment

1. Coracobrachialis mm: 2. Biceps brachii mm (L &S): flexes, supinates 3. Brachialis mm:

Posterior Shoulder MM Compartment

1. Deltoid: flexes, laterally & medially rotates, and abducts humerus (15-90 degrees) 2. Supraspinatus mm: abducts humerus first 15 degrees 3. Infraspinatus mm: laterally rotates humerus 4. Subscapularis mm: medially rotates humerus 5. Teres minor mm: laterally rotates humerus *minor over major 6. Teres major mm: adducts, medially rotates humerus

What are the 3 joints of the elbow?

1. Humeroulnar 2. Humeroradial 3. Proximal radioulnar

Pectoral MM Compartment

1. Pectoralis major mm: flexes, extends, adducts, and medially rotates brachium 2. Pectoralis minor mm: stabilizes scapula 3. Subclavius mm: anchor and depress scapula 4. Serratus anterior mm: protracts scapula, upward rotation of glenoid

Intrinsic Hand MM (3 Groups)

1. Thenar (lumpy soft tissue) + Abductor pollicis brevis + Flexor pollicis brevis + Opponens pollicis + Adductor pollicis 2. Hypothenar + Abductor digiti minimi + Opponens digiti minimi + Flexor digiti minimi 3. Lumbricals & interossei + dorsal interossei (DAB) + Palmar interossei (PAD)

Posterior Brachial Compartment

1. Triceps brachii mm (L+L+M): extends

The thenar compartment of the hand is associated with which digit?

1st

While salsa dancing in an alley, a 26 y/o female hit her elbow against a wall. Radiographic imaging shows a complete avulsion fracture of the medial condyle. Which of the following actions are most likely affected?

1st: what mm are attached to the medial epicondyle? 2nd: what mm actions do they do? *flexion of the wrist

What happens to the radius and ulna when the antebrachium is supinated?

2 bones are parallel Head of radius rotates (spins) on an axis thru its head; distal radius rotates around head of ulna; carried out by supinator + biceps brachii mm.

Several deficits in muscle function of the right upper limb were noted, including inability to abduct the arm. This was caused by denervation of which muscle? A. deltoid B. infraspinatus C. latissimus dorsi D. teres minor E. trapezius

A. deltoid

Anterior Antebrachial Compartment (AF = 8 mm. = 3Ps + 5Fs) Flex & pronates (n: median, 2 exceptions for ulnar) *Place L thumb in R elbow and lay 4 fingers overtop to show this

AF (flexors) *from anatomical position = anterior = toward front = forward 1. Pronator teres 2. Flexor carpi radialis: flexes, abducts wrist 3. Palmaris longus: flexes wrist 4. Flexor carpi ulnaris: flexes, adducts wrist 5. flexor digitorum superficialis: flexes wrist & digits 2-5 6. flexor digitorum profundus: flexes wrist & digits 2-5 7. Flexor pollicis longus: flexes wrist & 1st digit 8. Pronator Quadratus: pronates forearm

Damage to which nerve would be most detrimental to allowing abduction of the should joint and may be injured in fractures to the surgical neck of the humerus?

Axillary n.

A 22-year-old man is admitted to the hospital after a car collision. Physical examination reveals a glenohumeral joint shoulder dislocation. The patient has difficulty abducting his arm after 15 degrees and loss of sensation over the lateral aspect of his shoulder. Which nerve was most likely damaged with this injury? What are the nerve roots? What other injury can cause similar symptoms?

Axillary n. C5-6 surgical neck fractures of the humerus

Patient presents with an inability to abduct the arm beyond 15 degrees. Which nerve is damaged? What mm is normally responsible for this action?

Axillary n. (C5-6) deltoid mm

A sixteen-year-old boy received a superficial cut on the ulnar side of his forearm. The superficial vein most likely affected is the:

Basilic v.

Supination of the hand and forearm would be diminished by loss of radial nerve function. But one very powerful supinator would remain intact and unaffected, namely:

Biceps brachii

Which intermediate structure of the cubital fossa acts to protect deeper structures, such as the brachial artery?

Bicipital aponeurosis

Which artery is the main supplier of the arm region and will divide into radial and ulnar arteries in the cubital fossa region?

Brachial a.

Within the deeper portions of the cubital fossa, the median nerve is located just deep to or medical to which artery?

Brachial a.

Where can you test for a pulse in the hand?

Brachial artery in the thenar eminence

Which m. typically associated with the superficial posterior forearm does not act as an extensor m.?

Brachioradialis m.

CC: Anterior interosseous syndrome

Cannot make the "OK" = inability to flex at DIP of index finger and IP joint of thumb)

Which superficial vein of the upper limb drains most lateral regions?

Cephalic v.

CC: Impingement syndrome

Chronic bursitis overtime can cause this; most commonly of the subacromial bursae betting impinged between the acromion and tendons of the supraspinatus attaching to the greater tubercle

A scaffold falls on the right shoulder of a construction worker lacerating the side of his neck and suprascapular area, severing C5 spinal nerve just lateral to the vertebral column. Subsequent to the injury, the patient could not elevate the tip of his shoulder or retract it and have difficulty fully abducting his arm. Given the scenario answer the following question: Due to bleeding, the surgeon ligated (tied of) the suprascapular a. as it crossed the top of the scapula. There was no concern however, as she knew that direct collateral branches of which artery would supply to normal distribution of the suprascapular artery?

Circumflex scapular a.

What type of synovial joint exists between the metacarpals and proximal phalanges?

Condyloid

After ramming the point of his shoulder into a practice dummy, a football player suffered a severe shoulder separation. Although this is a dislocation of the acromioclavicular joint, several structures could be torn, including the one that gives the joint its greatest strength and stability, namely the:

Coracoclavicular Lig

There is a transection of the posterior cord. Which of the following will NOT be affected? A. Medial rotation of the arm B. Abduction of the arm C. Extension of the arm D. Scapular protraction

D.

All synovial joints have the following structures (or spaces) in common, except: A. synovial capsule B. synovial cartilage C. synovial cavity D. meniscus E. synovial fluid

D. meniscus

A woman riding a mountain bike on a rough trail hits a rut and is thrown from the bike. Her upper arm hits a tree, fracturing the humerus just above the insertion of the teres major muscle. Later, during examination, it is noted that she cannot extend her forearm at the elbow or hand at the wrist. Which nerve must have been injured? A. Axillary B. Median C. Musculocutaneous D. Radial E. Ulnar

D. radial nerve

Dorsal MM Compartment

DE + DAB at dorsal interossei

Dermatomes of hand

Digit 1 (thumb/pollicis): C6 Digits 2 & 3: C7 Digits 4 & 5: C8

What is the difference between a shoulder dislocation and separation?

Dislocation = GH joint + humeral head gets dislocated from the glenoid fossa; dislocations most commonly occur in an anterior direction Separation = AC joint

Which m. to the superficial layer of the anterior forearm is not innervated by the median nerve?

Flexor carpi ulnaris m.

What m. is innervated by branches of both the median and ulnar n.?

Flexor digitorum profundus

9 Structures that pass thru the Carpal Tunnel

Flexor pollicis longus Flexor digitorum superficialis (4) Flexor digitorum profundus (4) Median n.

What are the 4 joints of the shoulder?

Glenohumeral Acromioclavicular Sternoclavicular Scapulothoracic

The fibrocartilaginous structure which deepens the shoulder socket is the:

Glenoid labrum

CC: Most common complaint in bike riders

Hand pain from the ulnar nerve

What happens to the radius and ulna when the antebrachium is pronated?

Head of radius rotates (spins) on axis thru its head > distal radius rotates around head of ulna > carried out by pronator teres + pronator quadratus mm.

What is DeQuervain's tenosynovitis?

Inflammation of tendons and synovial sheaths in first tunnel - abductor pollicis longus and extensor pollicis brevis

A worker doing repetitive lifting develops an inflammation in the tendon of the origin of the extensor carpi radialis brevis m., commonly called "tennis elbow". The focal point of pain would most likely be near which palpable bony landmark?

Lateral epicondyle of the humerus

Which intrinsic muscles of the hand is(are) responsible for flexion or the metacarpophalangeal joints (2-5) and extension of the interphalangeal joints (2-5)?

Lumbricals

CC: Fine motor activity of the fingers

Lumbricals & Interossei mm.: both flex at MCP and extend IP joints = important for fine motor skills and grasping functions like writing with a pen!

CC: Lymphatics in regard to breast cancer

Lymphatic fluid flows into axilla during lumpectomy (~20 lymph nodes in axillary) *surgical importance

CC: Rotator cuff tear

Majority of injuries = supraspinatus mm. tendon (which does the first 15 degrees of abduction at the GH joint); impacting overhead movements incomplete tear = cannot initiate abduction

Retraction of the scapula move it in what direction?

Medially

Patient lacks sensation to the thenar palmar aspect of the hand. WHat nerve is affected?

Median n.

The signs and symptoms of carpal tunnel syndrome may vary among patients, but they always result from compression of what structures in the carpal tunnel?

Median n.

Which nerve traverses the carpal tunnel?

Median n.

The point of insertion of the flexor digitorum superficialis tendon to the index finger is on the:

Middle phalanx

While putting metal panels on the roof of a barn, one of the panels slips out of the hands of the man on the roof. During an attempt to catch the panel, a worker below is struck by its sharp edge. The panel hits across the anterior surface of his right arm at midlength and the impact severs all of the tissue to the bone. When examined in the emergency room it is noted that the patient can only weakly flex his elbow and the lateral side of his forearm is numb. In addition to the muscles, which nerve is injured?

Musculocutaneous (biceps brachii impacted - antebrachial cut.

CC: Epicondylitis (Tennis elbow)

Overuse strain of the common extensor and flexor origins causing inflammation and pain around the LATERAL epicondyle

CC: Epicondylitis (Golfer's elbow)

Overuse strain of the common extensor and flexor origins causing inflammation and pain around the MEDIAL epicondyle

Posterior Antebrachial Compartment (PE = 12 mm. = 2As + 1B + 1S + 8Es) Extends & supinates (n: radial)

PE (*from anatomical position): extension 1. brachioradialis: flexes forearm, mid-prone/supine position 2. Extensor carpi radialis longus: extends, abducts wrist 3. extensor carpi radialis brevis: extends, abducts wrist 4. Extensor digitorum: extends wrist & digits 2-5 5. extensor digiti minimi: extends digit 5 (pinky) 6. extensor carpi ulnaris: extends, adducts wrist 7. supinator 8. abductor pollicis longus: abducts thumb 9 and 10. extensor pollicis brevis & extensor pollicis longus: extends thumb 11. extensor indicis: extends digit 2 (pointer)

Palmer MM Compartment

PF + PAD at palmer interossei

A 34-year-old female skier presents to the ER after falling directly on her left shoulder. An x-ray is obtained and reveals that she has a shoulder separation. Which of the following typically occurs in this type of injury?

Partial or complete tearing of the coracoclavicular ligament

In a fracture of the surgical neck of the humerus, which artery may be injured?

Posterior circumflex humeral a.

The axillary nerve arises directly from which part of the brachial plexus?

Posterior cord

A two year old child will not go to take her nap. Her mother tightly holds her left hand as she leads her to the bedroom. Refusing to go further, the child suddenly attempts to jerk away and then sits down screaming and holding her left elbow. In an attempt to calm her down her mother offers her a cookie, but she cannot supinate her left hand to receive it. Which joint is dislocated?

Proximal radio-ulnar joint *Nursemaid elbow = Elbow pull, subluxation of radial head, where the head of her radius has been pulled out of the anular ligament and no longer attached to the radio-ulnar joint

CC: Testing integrity of the spinal cord by skin on the hand

Quickly test integrity of spinal cord by testing skin on hand, locations mean something if not sensed (thumb, pointer and middle fingers, or ring and pinky fingers)

What is the main joint of the wrist?

Radiocarpal joint

In the forearm, which bone is located laterally?

Radius

Several weeks after surgical dissection of her left axilla for the removal of lymph nodes for staging and treatment of her breast cancer, a 32-year-old woman was told by her general physician that she had "winging" of her left scapula when she pushed against resistance during her physical examination. She told the physician that she had also experienced difficulty lately in raising her right arm above her head when she was combing her hair. In a subsequent consult visit with her surgeon, she was told that a nerve was accidentally injured during the diagnostic surgical procedure and that this produced her scapular abnormality and inability to raise her arm normally. What was the origin of this nerve?

Roots of the brachial plexus

A student rollerblading on the diag and while trying to avoid a bicyclist falls heavily on their R wrist. After the fall they note sever pain in the anatomical snuff box. Radiological studies reveal a fracture of the bone in the floor of the snuff box called the:

Scaphoid

What is the proximal attachment of the long head of the triceps brachii m.?

Scapula

CC: Breast implant placement

Submuscular: extends below the lower margin of pectoralis muscle, beneath the breast gland.

During a strenuous game of tennis a 55 y.o. woman complained of severe shoulder pain that forced her to quit the game. During PE it was found that she could not initiate abduction of her arm, but if her arm was elevated at 45 degrees from the vertical (at her side) position, she had no trouble fully abducting it. Injury to which muscle was responsible?

Supraspinatus m.

Which tendon of the rotator cuff is most commonly damaged, typically due to close proximity to the coraco-acromial arch?

Supraspinatus m.

A worker doing repetitive lifting develops an inflammation in the tendon of the extensor carpi radialis brevis muscle, commonly called "tennis elbow." THe focal point of pain would most likely be near which palpable bony landmark?

lateral epicondyle of humerus

A worker doing repetitive lifting develops and inflammation in the tendon of the origin of the extensor carpi radialis brevis m. commonly called "tennis elbow." the focal point of pain would most likely be near which palpable bony landmark?

lateral epicondyle of humerus

A 39-year-old woman complains of an inability to reach the top of her head to brush her hair with her right hand. History reveals that she had undergone a mastectomy procedure of her right breast 2 months earlier. Physical examination demonstrates winging of her right scapula. Which nerves were most likely damaged during surgery?

long thoracic n.

A 27-year-old man was admitted to the emergency department after an automobile collision in which he suffered a fracture of the lateral border of the scapula. Six weeks after the accident, physical examination reveals weakness in medial rotation and adduction of the humerus. Which nerve was most likely injured?

lower subscapular n.

Because of scarring of a patient's median cubital vein, the technician chooses to insert an infusion needle into her basilic vein at the level of the medial epicondyle. Despite the certainty that the needle does not pass through the deep (investing) fascia, there is still a chance that it might nick or impale which of the following?

medial antebrachial cutaneous n.

A patient is found to have weakness of pronation of the forearm and flexion of the wrist joints, and a fracture in the elbow joint. Where is the most likely location of the fracture?

medial epicondyle = common origin site of forearm flexors (AF = anterior compartment)

A patient presents with inability to extend her finger and thumb, an can only weakly abduct her thumb. What nerve is still functioning that she is she still able to abduct her thumb?

median n.

Anterior interosseous n. is a branch of which nerve?

median n.

The signs and symptoms of carpal tunnel syndrome may vary among patients, but they always result from compression of what structure in the carpal canal?

median n.

The point of insertion of the flexor digitorum superficialis tendon to the index finger is on the:

middle phalanx

A 38-year-old homebuilder was involved in an accident and is unable to supinate his forearm. Which of the following nerves are most likely damaged? What other action would be affected? Would this cause any sensory loss, if so what area?

musculocutaneous forearm flexion Yes, lateral cutaneous branch

CC: Bursitis

overuse or trauma resulting in inflammation of the subacromial bursae of the shoulder

A 27-year-old female presents with a penetrating knife wound to the posterior shoulder. During exploratory surgery, a portion of the knife blade is found lodged between the long head of the triceps and the surgical neck of the humerus. Which artery is most likely to be affected?

posterior humeral circumflex a.

Muscles that pronate

pronator teres, pronator quadratus, brachioradialis

3-year-old girl brought into the emergency department with severe pain in her right arm. She is accompanied by her distraught parents. The father states that they were in the park, swinging her by her arms when she suddenly began crying and clutching her arm to her chest. On exam the girl is tearful and cradling her arm with the elbow fixed. She will not allow you to move her arm and will not cooperate with neurological exam. Which of the following is the most likely diagnosis?

radial head subluxation

After a motorcycle accident a 55 year old male presents with difficulty pointing the index finger to indicate the location of his arm pain. Which nerve was likely injured?

radial n.

Triangular interval *easiest to locate = between triceps (below quad space)

radial n. profundi brachii a.

While walking into the grocery store, a 42-year-old slipped on wet pavement and fell against the curb, injuring his right arm. The Radiographic images showed a midshaft fracture of the humerus. Which pair of structures was most likely injured at the fracture site?

radial n. and deep brachial a.

What joint is responsible for holding 90% of the weight of the hand?

radiocarpal joint

CC: Skier's thumb

rupture of ulnar collateral ligament of 1st (thumb/pollicis) MCP joint

A student is rollerblading on the diag and while trying to avoid a bicyclist falls heavily on their right wrist. After the fall they note severe pain in the anatomical snuff box. Radiological studies reveal a fracture of the bone deep to the snuff box called the:

scaphoid

What is the most commonly fractured bone in the hand?

scaphoid

A 15-year-old male presents with loss of cutaneous sensation over the fifth finger and lateral portion of the fourth finger. What nerve is injured, causing this loss of sensation?

ulnar