UMich Practice Questions- Upper Limbs - Sheet1

Question 1

The two large cutaneous veins running up the forearm.

Answer 1

On the medial side is the basilic vein. On the lateral side, the cephalic vein.

Question 2

The vein of choice for withdrawing blood from the arm

Answer 2

Median cubital vein, which connects the basilic and cephalic

Question 3

What nerve provides cutaneous innervation of the dorsum of the hand for the first 2 1/2 digits. An injury to this nerve would correlate to the loss of sensation between the thumb and index finger on the dorsum of the hand.

Answer 3

Superficial radial n.

Question 4

What are the only muscles in the anterior forearm not supplied by the median nerve?

Answer 4

(innervation of) the brachioradialis (R), flexor carpi ulnaris, and the medial half of the flexor digitorum profundus (both U)

Question 5

What are the 10 things that pass through the carpal tunnel?

Answer 5

4 tendons of flexor digitorum superficials, 4 tendons of flexor digitorum profundis, flexor pollicus longus, median nerve

Question 6

Interruption of the median nerve in the cubital fossa affects what movement(s) of the thumb?

Answer 6

Flexion and opposition. The recurrent branch of the median nerve innervates the thenar compartment of the hand. This nerve innervates opponens pollicis, which opposes the thumb, and flexor pollicis brevis, which helps to flex the thumb. So, disrupting the median nerve would impair both flexion and opposition of the thumb.

Question 7

The best chance of saving collateral circulation to the stump of an amputated forearm would be when the ligature is placed just below which landmark?

Answer 7

Bifurcation of the brachial artery near the elbow. It forms two branches that become the radial and ulnar arteries.

Question 8

You suspect a localized tearing of the origin of a muscle producing the equivalent of “tennis elbow.” The muscle most likely involved is the:

Answer 8

Brachioradialis. Tennis elbow is usually caused by inflammation of the common extensor tendon on the lateral side of the forearm, but we know that that’s not what happened here. Instead, the patient tore a muscle at its origin, near the lateral epicondyle of the humerus. Brachioradialis originates from the upper two-thirds of the lateral supracondylar ridge of the humerus, so this is the muscle that she probably tore.

Question 9

Development of “tennis elbow” (lateral epicondylitis) involves the origin of which muscles?

Answer 9

Extensor carpi radialis brevis. “Tennis elbow” is due to repetitive use of the superficial extensor muscles of the forearm. The pain is felt on the lateral epicondyle and radiates down the posterior surface of the forearm. With tennis elbow, the repeated flexion and extension of the wrist strains the attachment of the common extensor tendon, producing inflammation of the periosteum of the lateral epicondyle and the common extensor attachment of the muscles.

Question 10

Which artery passes lateral to the pisiform bone?

Answer 10

Ulnar artery.

Question 11

What is the function of the posterior interosseous nerve?

Answer 11

Sensory from the wrist joint. The posterior interosseous is the sensory continuation of the deep radial nerve, distal to its motor branches for the extensor muscles.

Question 12

When falling on an outstretched hand, the most commonly dislocated carpal bone is the…

Answer 12

…Lunate bone, commonly disclocated anteriorly. Also remember, the scaphoid is frequently fractured when someone falls on an outstretched wrist.

Question 13

If the musculocutaneous nerve is severed at its origin from the brachial plexus, flexion at the elbow is greatly weakened but not abolished. What muscle remains operative and can contribute to flexion?

Answer 13

Brachioradialis. This muscle is innervated by the radial nerve–it flexes the elbow and assists in pronating and supinating the arm.

Question 14

After falling on the 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?

Answer 14

Brachioradialis: The Colles’ fracture is a fracture to the distal end of the radius. It usually occurs when someone tries to catch themselves from falling on an outstretched arm. So, you need to look in the answer choices for a muscle that inserts on the distal end of the radius. Brachioradialis inserts on the lateral side of the base of the styloid process of the radius, so this muscle could pull the broken piece of the radius out of place.

Question 15

The pulse of the radial artery at the wrist is felt immediately lateral to which tendon?

Answer 15

Flexor carpi radialis

Question 16

In withdrawing a blood sample from the median cubital vein the needle passes slightly deep and medial; which nerve might possibly be injured?

Answer 16

Medial antebrachial cutaneous nerve: it is a directbranch from the medial cord of the brachial plexus and provides cutaneous sensation to the medial side of the anterior forearm.

Question 17

Tell me about the lateral antebrachial cutaneous nerve.

Answer 17

The lateral and medial antebrachial cutaneous nerves supply the skin of the lateral and medial side of the anterior forearm, respectively. The lateral antebrachial cutaneous nerve is a branch of the musculocutaneous nerve, which runs on the lateral forearm near the cephalic vein.

Question 18

What innervates Fl. dig. profundis?

Answer 18

lateral two by median nerve, median two by ulnar n. (matches lumbricals)

Question 19

What innervates lumbricals?

Answer 19

Lateral two by median nerve, median two by ulnar n. (matches fl. dig. prof.)

Question 20

What innervates the interossi?

Answer 20

Ulnar n.

Question 21

What action do dorsal interossei perform? Palmar interossei?

Answer 21

Dorsal interossei abduct fingers away from midline, palmar adduct.

Question 22

A man suffers a penetrating wound through the anterior axillary fold, with resulting damage to one of the main terminal branches of the brachial plexus. Among the effects is a significant weakening of flexion of the elbow. One or more other effects to be expected is (are): Loss of cutaneous sensation on the tips of several fingers; Only weakening of flexion at the shoulder; Weakening of flexion at the shoulder and loss of cutaneous sensation on the anterolateral surace of the arm; Weakening of flexion at the shoulder and loss of cutaneous sensation on the anterolateral surface of teh forearm.

Answer 22

Weakening of flexion at the shoulder and loss of cutaneous sensation on the anterolateral surface of the forearm
Flexion at the elbow is produced by biceps brachii and brachialis, and both of these muscles are innervated by the musculocutaneous nerve. So, you know that the musculocutaneous nerve was damaged. Beyond innervating the muscles that flex the forearm, the musculocutaneous nerve gives off the lateral antebrachial cutaneous nerve which provides sensory innervation to the anterolateral surface of the forearm. This means that the other symptom that would be present is a loss of cutaneous sensation on the anterolateral surface of the forearm.

Question 23

A person sustains a left brachial plexus injury in an auto accident. After initial recovery the following is observed: 1) the diaphragm functions normally, 2) there is no winging of the scapula, 3) abduction cannot be initiated, but if the arm is helped through the first 45 degrees of abduction, the patient can fully abduct the arm. From this amount of information and your knowledge of the formation of the brachial plexus where would you expect the injury to be:

Answer 23

Suprascapular n.

Question 24

The nerve which passes through the quadrangular space of the posterior shoulder innervates which muscles?

Answer 24

This refers to the axillary nerve, which only innervates two muscles: deltoid and teres minor.

Question 25

What is the quadrangular space?

Answer 25

The quadrangular space is an area bounded medially by the long head of the triceps tendon, laterally by the humerus, superiorly by teres minor, and inferiorly by teres major–the axillary nerve and posterior humeral circumflex artery are transmitted through this space.

Question 26

What is the triangular space?

Answer 26

The triangular space is bounded laterally by the long head of the triceps, superiorly by teres minor, and inferiorly by teres major–it transmits the circumflex scapular artery.

Question 27

A surgeon begins by making an incision through the skin and subcutaneous tissue just below the clavicle, then cuts the clavicular head of the pectoralis major muscle and retracts it downward to obtain sufficient exposure of the area. He next encounters a partially severed muscle running downward and medially from the coracoid process. He divides the remaining fibers of the muscle and has you retract it downward. This exposes a bloody fat-filled space full of vessels and nerves. What space or cavity was opened when the surgeon reflected these muscles?

Answer 27

Axillary space

Question 28

Erb’s palsy

Answer 28

(C5,C6)

Waiter’s tip: Shoulder ADducted IR, elbow extended and pron b/c no Axillary, suprascap, or musculocutaneous

Question 29

Klumpke’s palsy

Answer 29

9C8,T1) via hanging traction or cervical rib:
Total claw hand!
Unopposed wrist ext, no lumbricals.

Question 30

Sat. night palsy

Answer 30

Radial nerve compression: wrist drop (no extension)

Question 31

Hand of Benediction

Answer 31

Median nerve lesion.

When trying to make a fist! No pronation or flexion at the wrist.

Question 32

Ulnar claw

Answer 32

ulnar nerve lesion

Question 33

Ape hand

Answer 33

Recurrent branch of median nerve dysfunction. No OAF

Question 34

What injury would cause atrophy of thenar eminence muscles, w/o damaging wrist and finger flexion?

Answer 34

Anteriorly dislocated lunate

Question 35

What nerve is damaged in a supracondylar fracture of the humerus?

Answer 35

Median n.

Question 36

What nerve is damaged with a midshaft fracture of the humerus?

Answer 36

Radial n.

Question 37

What nerve is damaged by a subluxation of the head of the radius?

Answer 37

This is nursemaid’s elbow: you get radial nerve damage and pronated hand (supinator damaged)

Question 38

Which of the following arteries is NOT involved in collateral circulation with the axillary artery around the shoulder? Circumflex scapular a, subscapular a, dorsal scapular a, suprascapulat a, thoracoacromial a?

Answer 38

Thoracoacromial a.