Grays Review II

Question 1

Wrist drop and weakness of grasp, but normal extension of elbow joint. No loss of sensation in the affected limb. Which nerve was most likely affected?

• Ulnar
• Anterior interosseus
• Posterior interosseus
• Median
• Superficial radial

Answer 1

PIN

The radial nerve travels between the heads of the triceps brachii in the arm, and then enters the cubital fossa, wher eit divides into the superficial and deep branch. The dep branch continues as the PIN, innervating extensors of the forearm. Wristdrop means radial, but sensation is intact so it can’t be superficial radial.

Question 2

Flexion and supination of the forearm are severely weakened. She also hass loss of sensation on the lateral forearm. What neve was injured?

• Radial
• Musculocutaneous
• Median
• Laterla cord of brachial plexus
• Lateral cutaneous nerve of forearm.

Answer 2

Musculocutaneous.

Musculocutaneous innervates the biceps brachii, the most powerful supinator. It also innervates the anterior arm muscles, which flex the elbow joint. It also continues as the lateral cutaneous nerve to innervate the lateral forearm.

Question 3

A woman was bitten on the thumb by a dog. The wound became infected and the infeciton spread into the radial bursa. The tendons of which muscle will most likely be affected?

• Flexor digitorum profundus
• Flexor digitorum superficialis
• Flexor pollicis longus
• Flexor carpi radialis
• Flexor pollicis brevis

Answer 3

Tenosynovitis of teh thumb may be spread through teh synovial sheath of the flexor pollicis longus tendon/radial bursa.

Whereas, tendons fo the flexor digitorum superficialis & profundus are envoloped in the ulnar bursa/synovial flexor sheath.

Question 4

Can’t extend the left wrist, fingers, and thumb- but he can extend teh elbow. Sensation is lost in teh lateral half of the dorsum of the hand. What nerve has most likely been injured and where in the arm?

Answer 4

Radial, mid humerus.

It’s obviously radial because it innevates the extensor (posterior )compartments of the arm & fore arm. Elbow extension is intact if it can still supply the triceps brachii, so it’s fractured mid-humerus.

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Question 5

Injury to the radial nerve in the spiral groove would demonstrate which?

• Weakness of thumb abduction and thumb extension
• Weakness of thumb opposition
• Inability to extend the elbow

Answer 5

Weakness of thumb abduction and thumb extension.

This injury paralyzes the snuffbox (abductor pollicis longus muscle and both extensors of the thumb) and will lead to wrist drop (inability to extend wrist).

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Question 6

What artery arises form the brachial artery, accompanies the median nerve into the forearm, and anastomoses with the anterior ulnar recurrent artery?

Answer 6

Inferior ulnar collateral artery (from brachial artery)

Question 7

He can’t abduct his arm more than 15 degrees and can’t rotate the arm laterally. He has a fracture of the humerus and sensory loss over the shoulder area. Where is the fracture?

• Fracture of the medial epicondyle
• Fracture of the glenoid fossa
• Fracture of the surgical neck of the humerus
• Fracture of the middle third of the humerus

Answer 7

Fracture of the surgical neck.

Abduction from 15- 90 degrees is the deltoid, innervated by the axillary nerve. Lateral rotation is the deltoid muscle, teres minor, and infraspinatus. The deltoid and the teres minor are both lost. The axillary nerve can be damaged at the surgical neck of the humerus.

Question 8

How can you test lateral epicondylitis/tennis elbow?

Answer 8

Observe the presence of pain when the wrist is extended against resistance.

Question 9

Someone has injury at the second part of the axillary artery. Luckily, there’ s arich collaterla pathway provided by teh anastomoses between which arteries?

Answer 9

Suprascapular & circumflex scapular

Suprascapular comes off the subclavian proximal to teh axillary artery; the subscapular artery is the major branch of the third par tof the axillary artery, giving off the thoracodorsal and circumflex scapular arteries. So, blood can flow fromthe circumflex in a retrograde direction into axillary artery

Question 10

Fracture at the spinal groove of the humerus. A cast is placed and then 3 days later she complains of severe pain over her entire arm. The arm is swollen, pale, and cool. Radial pulse absent. Any movement causes severe pain.

What is this?

Answer 10

Compartment syndrome: increased pressure withina confined space by a fascial compartment -> impairs blood supply –> pale and loss of pulses distlal to compartment

Question 11

A child fell while holding hands and walking with his two parents. Any movement of his right UE is painful and he holds it at hsi side with his elbow extended and forearm pronated. No hematomas or swelling. What structure was most likely injured?

Answer 11

Anular ligament!

This is nursemaid’s elbow: radial head slipped out because of the underdevelopment of the radial head and laxity of the anular ligament in children.

Question 12

A guy got stabbed in the left posterior triangle of his neck. His left shoulder seems to be drooping lower than the right shoulder and the superior angle of the scapula juts otu slightly. Turning his head is symmetric. What nerve is most likely injured?

• Suprascapular nerve in supraspinous fossa
• Terminal segment of the dorsal scapular nerve
• Upper trunk of brachial plexus
• Spinal accessory nerve in the posterior cervical triangle
• Thoracodorsal nerve in the axilla

Answer 12

Spinal accessory nerve in the posterior cervical triangle

Question 13

Woman has weak wrist extension and paraesthesia on the back of her arm & forearm. What spinal nerve was most likely injured?

Answer 13

Radial nerve –> C7

Question 14

Post-op, a woman’s left shoulder droops; has weakness in turning his head to the right; impairment of abduction of her left upper limb to the level of the shoulder. What structure was injured?

• Suprascapular nerve
• Long thoracic nerve
• The junction of spinal nerves C5 and C6 of the brachial plexus
• Radial nerve

Answer 14

Spinal accessory nerve (CN XI) arises from C1-C4 rootlets that ascend through the foramen magnum to then exit the cranial cavity to innervate teh traps and sternocleidomastoid muscles –> head rotation and raising shoulders.

Question 15

Fine motor function in the right hand is reduced, including opposition of the thumb; abduction & adduction of the digits; and interphalangeal joint extension. Also has anesthesia of the skin on the medial forearm.

Long flexor muscles of the hand and long extensors of the wrist are both normal.

What neural structure is most likely impaired?

• Median nerve
• Middle trunk of brachial pelxus
• Radial nerve
• Lower trunk of brachial plexus
• T1 ventral ramus

Answer 15

T1 ventral ramus

• provides sensation to medial forearm via medial antebrachial cutaneous nerve from medial cord
• Gives motor supply to all of the intrinsic muscles
  
  • Because long flexors and intact, the median nerve and ulnar nerve are not injured.
  • Extensors are intact, so radial nerve is fine.

Question 16

A woman has winging of her left scapula and has difficulty raising her left arm above her head. A nerve was damaged. What was the origin of this damaged nerve?

• Upper trunk of brachial plexus
• Posterior division of middle trunk
• Ventral rami
• Posterior cord
• Lateral cord

Answer 16

It’s long thoracic, which paralyzed the serratus anterior –> protrusion of the medial border of the scapular. It originates form the ventrla rami of C5, C6, and C7

Question 17

A man can abduct his arm and extend the forearm, and sensation in the forearm and hand is normal. However, hand grasp is very weak and he can’t extend his wrist against gravity. What was injured?

• Posterior cord of brachial plexus
• Radial nerve at the distal third of humerus
• Radial and ulnar
• Radial, ulnar, and median
• Radial and musculocutaneous

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Answer 17

Radial nerve at the distal third of the humerus.

If he can extend his forearm, then his triceps brachii is fine. However, weakened hand grasp and wrist drop means the extensors in the forearm are malfunctioning. Yet, sensation is fine, so the superficial branch of the radial nerve are intact. The radial nerve separates into the superficial and deep branches at the distal third of the humerus.

Question 18

A man falls directly on his shoulder. He has a vertical fracture through the entire length of the floor of the intertubercular sulcus of the right humerus. The muscle most likely affected is innervated by a nerve composed of which of the following nerve roots?

• C3 & C4
• C6-8
• C4 & C5
• C2-4
• C5-7

Answer 18

The lat dorsi attaches to the intertubercular sulcus of the humerus and is supplied by the thoracodorsal nerve (C6-8)

Question 19

A man has a wound on his plam. He can’t touch teh pad of his index finger with his thumb, but can grib a sheet of paper between all fingers and has no loss of sensation on the skin of his hand. What nerve and branch was probably injured?

Answer 19

Recurrent branch of median n (thenar muscles)

Question 20

A man has excruciating pain in his posterior forearm. When palpated 2cm distal and posteromedial to the lateral epicondyle, the pain is so bad he grimaces. What injury is most likely?

• Compression of ulnar nerve by flexor carpi ulnaris
• Compression of median nerve by pronator teres
• Compression of upserficial radial nerve by brachioradialis
• Compression of deep radial nerve by supinator

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Answer 20

Compression of deep radial nerve by supinator

The deep branch of radial nerve travels between the two heads of the supinator and is located just medial & distal to the lateral epicondyle.

Whereas, the superficial radial nerve goes down the lateral aspect of the posterior forearm and would not cause pain due to pressure applied to the posterior forearm.

Question 21

A maid was straightening a sheet when she caught the end of her index finger in a fold. She experienced sudden pain over the base of the terminal phalanx. Hours later, the end of her right index finger was swollen and she couldn’t completely extend the terminal IP joint. Which was most likely injured?

• Proper palmar digital branch of the median nerve
• The vinculum longa
• The insertion of the tendon of the extensor digitorum onto the base of the distal phalynx
• Insertion of hte flexor digitorum profundus tendon
• Insertion of the flexor digitorum superficialis tendon

Answer 21

Insertion of the tendon of the extensor digitorum onto the base of the distal phalanx

Question 22

Accidentally injured the ulnar nerve at the wrist. Which would be lost?

• Flexion of the PIP at the pinky
• Adduction of the pinky

Answer 22

Adduction of the pinky because PADs are innervated by the deep ulnar nerve.

Flexion of the PIP at the pinky is from the flexor digitorum superficialis, innervated by median nerve.

Question 23

A man can extend the metacarpophalangeal joints of all his fingers, but cannot extend the IP joints of the 4th and 5th digits and extension of the IP joints at the 2nd and 3rd digits is very weak. Sensation in hand is fine. What nerve was most likely injured?

• Radial nerve at elbow
• Median nerve at wrist
• Ulnar nerve mid forearm
• Deep branch of ulnar nerve
• Recurrent branch of median nerve.

Answer 23

Injuring the deep branch of ulnar nerve paralyzes all the interosseus muscles and the lumbrical muscles of digits 4 & 5.

Because extension of the MCP joints is normal (extensor digitorum), the radial nerve is fine. There’s some extension in digits 2 and 3 (lumbricals of 2 and 3), so median nerve is intact. If the ulnar nerve was injured midforearm, then sensation in the hand would be lost.

Question 24

A man is cut across teh entire length of the distal transverse crease on teh anterior surface of the wrist. The cut is down to the surface of the flexor retinaculum, but not into it. Which of these deficits will be found?

• Weakend pronation of fore arm
• Inability to abduct thumb
• Weakened flexion of thumb
• Weakened opposition of the thumb
  
  • Inability to adduct the thumb

Answer 24

Inability to adduct the thumb, because that’s deep ulnar nerve, which passes superficially to the flexor retinaculum.

Question 25

Most commonly dislocated carpal bone?

Most commonly fractured carpal bone?

Answer 25

Dislocated: Lunate; may compress the median nerve

Fractured: Scaphoid

Question 26

Woman ‘s first 3 digits are extended and can’t be flexed. Digits 4 & 5 are partially flexed at the MCP joint, but much more flexed at the DIPs. Sensation is absent in the lateral palm and palmar surfaces of digits 1-3 & half of 4. Which nerve has/have most likely been injured?

• Median nerve
• Ulnar and median nerves
• Ulnar nerve
• Radial nerve
• Radial and ulnar nerves

Answer 26

Median nerve only.

• This is hand of benediction.
• Digits 4 & 5 are partially flexed by the intact flexor digitorum profundus.
• Lesion to median
  
  • Weakened flexion of all digits’ PIPs (flexor digitorum superficialis)
  • Loss of flexion in DIPs of 2&3 (flexor digitorum profundus)
  • Weakened flexion of MCP joints of digits 2&3 (lumbricals).
• Lesion of both median and ulnar would cause weakness or paralysis or flexion of all digits.

Question 27

A man can’t flex his DIPs of digits 4 and 5.

• Trauma to ulnar nerve at wrist
• Trauma to ulnar nerve at the trochlea

Answer 27

Trauma to ulnar nerve at trochlea (flexor digitorum profundus)

Trauma to the ulnar at the wrist would not affect the IPs, although it would paralyze the pads/dabs, hypothenar muscles, etc

Question 28

He can’t oppose the tip of the thumb to the tip of the index (making the OK sign). He can touch the tips of the ring and little fingers to the pad of his thumb though. What nerve was most likely injured?

• Median
• PIN
• Radial
• Recurrent median
• AIN

Answer 28

AIN

If he can oppose his thumb to his pinky and ring finger, then his median nerve (thenars) must be intact. The issue must be with the index finger’s DIP’s flexion (flexor digitorum profundus), which is done by the median nerve’s AIN branch.

Question 29

Complete claw hand, but can extend the wrist. What happened?

• Ulnar nerve severed at wrist
• Median nerve injured at carpal tunnel
• Median and ulnar nerve damaged at wrist
• Median and ulnar nerve injured at elbow.
• Median, ulnar, and radial nerves injured mid humerus.

Answer 29

Median and ulnar nerve damaged at wrist

If you can extend the wrist (extensor carpi radialis & ulnaris), then your radial nerve is fine. Complete claw hand means the lumbricals (median & ulnar n) is malfunctioning. Lumbricals are intrinsic to the hand, so wrist - not elbow.

Question 30

Ulnar nerve was completely at the distal crease of the wrist. What is most likely to occur?

• Can’t touch tip of thumb to tips of other digits
• Loss of sensation on the dorsum of the emdial side of the hand
• Unable to flex IP joints
• Decrased ability to extend IP joints

Answer 30

Decreased ability to extend IP joints

The pads & dabs are most importnat in extending the IP joints because they insert on the extensor hoods of the fingers; the lumbricals also help in addition to flexing the MCP joints. Ulnar nerve injury ar the wrist will paralyze the interossei and medial two lumbricals, but the dorsal cutaneosu branch to the dorsum of the hand is unaffected.

Question 31

Does injury to the ulnar nerve in Guyon’s canal cause loss of sensation to the medial palm and palmar surface of the medial 1.5 digits?

Answer 31

Yes.

Also motor loss of the hypothenars, pads/dabs, and medial 2 lumbricals.

Question 32

A boy was bit by a dog in the common flexor synovial sheath of his forearm. Into which of the digits could the infeciton spread most easily?

Answer 32

Fifth

The common flexor sheath encloses the long flexor tendons fo the finger sin teh carpal tunnel and proximal palm. This sheaht is usually continuous with the flexor sheath of the pinky, which continues within the palm.

Question 33

A man accidentally puncutred the ventral side of the pinky a the base of the distal phalanx. Infection spread into the palm, within the sheath of the flexor digitorum profundus tendons. If left untreated, where will infeciton spread?

Central compartment

hypothenar comparmtent

midpalmar compartment

thenar compartment

Answer 33

Midpalmar compartment

The sheath of the long tendons of the pinky runs through the midpalmar space

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Question 35

Patient cut their wrist. Deepest part of the wound is between the tendons of the flexor carpi radialis and the flexor digitorum superficialis. This patient is most likely to have a deficit in..

• Adduction/Abduction of fingers
• Extension of index finger
• Flexion of the ring and pinky
• Sensation over the base of the pinky
• Opposition of the thumb and slightly weakened flexion of the second and third digits.

Answer 35

Opposition of the thumb and slightly weakened flexion of the second and third digits.

The median nerve passes through teh carpal tunnel w/ the tendons of the flexor digitorum profundus, flexor digitorum superficialis, and flexor pollicis longus to supply the thenar muscles of the hand.

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Question 36

A man has weakness in his fingers. He can hold a piece of paper between his thumb and index finger, but his OK sign has an extended DIP. Pronation and wrist flexion are weakened. What branch of what nerve is affected?

Answer 36

AIN of median supplies the deep layer of anterior forearm (flexor digitorum profundus, pronator quadratus, flexor pollicis longus).

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Question 37

Dislocation of the humerus at the glenohumeral joint. The head of the humerus is displaced ___ly.

Answer 37

Inferiorly, because it comes out of the rotator cuff.

Question 38

Shoulder separation. What usually occurs?

• Displacement of the head ofthe huemrus from the glenoid cavity
• Partial/complete tearing of coracoclavicular ligament
• Partial/complete tearing of the coracoacromial ligament

Answer 38

Shoulder separation: either both the AC and coracoclavicular ligaments are partially or completely torn through.

• Distal end of clavical may deviat eupwards
• Upper limb may droop away inferiorly

Question 39

Tendinopathy of the long head of biceps brachii results in

• Pain in anterior shoulder during forced contraction
• Pain in lateral shoulder during forced contraction
• Pain during abduction and flexion of shoulder jiont
• Pain during extension and adduction of shoulder jiont
• Pain in lateral shoulder during flexion of shoulder joint

Answer 39

Pain in anterior shoulder during forced contractio

Long head of biceps brachii assists in shoulder flexion and would cause pain in the anterior comparmtent o fhte hsoulder, wher eit originates at the supraglenoid tubercle.

Question 40

Loss of normal contour of the shoulder and an abnormal depression below the acormion. What injury was most likely?

• Avulsion of coronoid process
• Dislocated shoulder jiont
• Fracture of humerus midshaft
• Fracture of surgical neck of humerus
• Laceration of the axillary branch of the posterior cord

Answer 40

Anterior dislocation of humerus results in flattened deltoids and protruding acromion.