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Nerve & Tendon MCQs

Practice Set 18 of 53

This practice set contains high-yield board review questions covering key concepts in Nerve & Tendon. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 341

Topic: Nerve & Tendon

A 40-year-old mechanic complains of lateral forearm pain that worsens with resisted forearm pronation and supination. There is no demonstrable motor weakness. He has local tenderness approximately 4 cm distal to the lateral epicondyle. Injection of local anesthetic provides temporary relief. The nerve involved is most likely compressed by which of the following structures?

. Ligament of Struthers
. Lacertus fibrosus
. Arcade of Frohse
. Osborne's fascia
. Arcade of Struthers

Correct Answer & Explanation

. Arcade of Frohse

Explanation

This clinical presentation is characteristic of Radial Tunnel Syndrome (pain predominantly, without motor weakness, as opposed to PIN syndrome). The most common site of compression of the deep branch of the radial nerve / posterior interosseous nerve (PIN) in this region is the Arcade of Frohse, the proximal fibrous edge of the superficial head of the supinator muscle.

Question 342

Topic: Nerve & Tendon

A 7-year-old boy sustains a displaced lateral condyle fracture of the humerus.

The family refuses surgery, and the fracture goes on to a nonunion. Years later, which of the following is the most likely late complication to develop?

. Median nerve palsy
. Anterior interosseous nerve syndrome
. Radial nerve palsy
. Tardy ulnar nerve palsy
. Posterior interosseous nerve entrapment

Correct Answer & Explanation

. Tardy ulnar nerve palsy

Explanation

A nonunion of a lateral condyle fracture typically leads to a progressive cubitus valgus deformity due to the failure of the lateral column of the distal humerus to support the elbow joint properly. Over time, this valgus deformity stretches the ulnar nerve behind the medial epicondyle, resulting in a tardy ulnar nerve palsy years or even decades after the initial injury.

Question 343

Topic: Nerve & Tendon

A 24-year-old male sustains a severe traction injury to his brachial plexus, resulting in a C5-C6 root avulsion. An Oberlin transfer is planned to restore active elbow flexion. Which donor nerve fascicle is classically utilized in this procedure to transfer to the biceps motor branch of the musculocutaneous nerve?

. A redundant fascicle from the ulnar nerve
. The thoracodorsal nerve
. The medial pectoral nerve
. A fascicle from the median nerve (FCR branch)
. The intercostobrachial nerve

Correct Answer & Explanation

. A redundant fascicle from the ulnar nerve

Explanation

The classic Oberlin transfer utilizes a redundant fascicle from the ulnar nerve (usually one supplying the flexor carpi ulnaris) and transfers it directly to the motor branch of the biceps (part of the musculocutaneous nerve) to restore elbow flexion in patients with upper trunk (C5-C6) brachial plexus injuries.

Question 344

Topic: Nerve & Tendon
A 28-year-old rugby player presents unable to actively flex the distal interphalangeal (DIP) joint of his ring finger after grabbing an opponent's jersey. Radiographs reveal a small bony avulsion fragment located at the level of the proximal interphalangeal (PIP) joint. According to the Leddy and Packer classification, what type of injury is this?
. Type I
. Type II
. Type III
. Type IV
. Type V

Correct Answer & Explanation

. Type II

Explanation

Jersey finger represents an avulsion of the flexor digitorum profundus (FDP) tendon. Leddy and Packer classification: Type I involves retraction to the palm, both vincula ruptured (high risk of ischemia, requires urgent repair). Type II involves retraction to the PIP joint level, where it is held by the intact vinculum longus; a small bony fragment may be seen at this level. Type III involves a large bony avulsion that is caught at the A4 pulley (DIP joint level). This patient has a Type II injury.

Question 345

Topic: Nerve & Tendon

A 30-year-old carpenter sustains a sharp laceration over the dorsal aspect of his proximal interphalangeal (PIP) joint, completely severing the central slip of the extensor mechanism. If this injury is misdiagnosed and left untreated, what classic finger deformity will predictably develop over the ensuing weeks?

. Swan neck deformity
. Boutonniere deformity
. Mallet finger
. Pseudo-boutonniere deformity
. Intrinsic plus hand

Correct Answer & Explanation

. Boutonniere deformity

Explanation

Disruption of the central slip at the PIP joint initially results in a subtle extension lag. Over time, the lateral bands subluxate volarly. Once the lateral bands fall volar to the axis of rotation of the PIP joint, they act as flexors of the PIP joint and hyperextensors of the DIP joint, creating the classic Boutonniere deformity.

Question 346

Topic: Nerve & Tendon

A 6-year-old girl falls off the monkey bars and sustains a displaced extension-type supracondylar humerus fracture. On examination, she is unable to make an 'A-OK' sign, instead demonstrating a pinch with the pulps of her index finger and thumb. Which nerve is most likely injured?

. Radial nerve
. Ulnar nerve
. Anterior interosseous nerve
. Posterior interosseous nerve
. Musculocutaneous nerve

Correct Answer & Explanation

. Anterior interosseous nerve

Explanation

The anterior interosseous nerve (AIN), a branch of the median nerve, is the most commonly injured nerve in extension-type supracondylar humerus fractures. It innervates the flexor pollicis longus and flexor digitorum profundus to the index finger; an injury results in an inability to flex the IP joint of the thumb and DIP joint of the index finger (positive 'A-OK' or 'pinch' test).

Question 347

Topic: Nerve & Tendon

A 28-year-old carpenter sustains a laceration to the volar aspect of his index finger, resulting in an inability to flex the distal interphalangeal (DIP) joint.

During zone II flexor tendon repair, the surgeon must be mindful of the tendon's blood supply. The segmental vascular supply to the flexor tendons within the digital sheath is provided primarily by:

. Small branches from the palmar digital arteries entering through the vincula
. Direct branches from the superficial palmar arch
. Diffusion from the surrounding synovial fluid exclusively
. Longitudinal vessels arising directly from the muscle belly
. Branches from the common digital arteries piercing the A2 pulley

Correct Answer & Explanation

. Small branches from the palmar digital arteries entering through the vincula

Explanation

Flexor tendons in Zone II receive nutrition via a dual mechanism: vascular perfusion and synovial diffusion. The vascular supply is provided segmentally by small branches of the digital arteries that enter the dorsal aspect of the tendons through the vincula (vincula brevia and longa).

Question 348

Topic: Nerve & Tendon

A 5-year-old boy presents to the emergency department after falling from monkey bars. He sustained a displaced extension-type supracondylar humerus fracture. Examination reveals an inability to flex the interphalangeal joint of the thumb and the distal interphalangeal joint of the index finger. Which of the following nerves is most likely injured?

. Anterior interosseous nerve
. Posterior interosseous nerve
. Ulnar nerve
. Radial nerve
. Musculocutaneous nerve

Correct Answer & Explanation

. Anterior interosseous nerve

Explanation

The anterior interosseous nerve (AIN) is a branch of the median nerve and is the most commonly injured nerve in extension-type supracondylar humerus fractures. Injury to the AIN results in the inability to form an 'OK' sign due to weakness of the flexor pollicis longus and the flexor digitorum profundus to the index finger.

Question 349

Topic: Nerve & Tendon

A patient with a chronic high median nerve palsy requires tendon transfers to restore function. Which of the following combinations of tendon transfers is most appropriate to restore thumb flexion, thumb opposition, and index/long finger flexion?

. Brachioradialis (BR) to FPL, ECRL to FDP, EIP to APB
. ECRL to FPL, FCU to FDP, ADM to APB
. ECU to FPL, ECRB to FDP, PL to APB
. BR to FPL, ECU to FDP, EIP to APB
. ECRL to FPL, BR to FDP, EDM to APB

Correct Answer & Explanation

. Brachioradialis (BR) to FPL, ECRL to FDP, EIP to APB

Explanation

In a high median nerve palsy, there is loss of thumb flexion (FPL), index/long finger flexion (FDP), and thumb opposition (APB). A common set of transfers includes the Brachioradialis (BR) to the Flexor Pollicis Longus (FPL) to restore thumb flexion, the Extensor Carpi Radialis Longus (ECRL) to the FDP of the index and long fingers to restore finger flexion, and the Extensor Indicis Proprius (EIP) to the Abductor Pollicis Brevis (APB) (Burkhalter transfer) to restore opposition.

Question 350

Topic: Nerve & Tendon
A 28-year-old carpenter sustains a deep laceration to his volar palm, exactly at the proximal edge of the A1 pulley, resulting in an inability to flex his digits. In which flexor tendon zone did this injury occur?
. Zone I
. Zone II
. Zone III
. Zone IV
. Zone V

Correct Answer & Explanation

. Zone II

Explanation

Zone II (historically termed 'no man's land' by Bunnell due to historically poor surgical outcomes) extends from the proximal aspect of the A1 pulley to the insertion of the flexor digitorum superficialis (FDS) on the middle phalanx. Both FDS and FDP tendons run tightly together in the fibro-osseous sheath in this zone, making repair technically demanding.

Question 351

Topic: Nerve & Tendon

The recurrent motor branch of the median nerve provides critical motor innervation to the thenar eminence. Which of the following muscles is typically NOT innervated by the recurrent motor branch of the median nerve?

. Abductor pollicis brevis
. Opponens pollicis
. Superficial head of the flexor pollicis brevis
. Deep head of the flexor pollicis brevis
. None of the above; all are innervated by the recurrent median nerve.

Correct Answer & Explanation

. Deep head of the flexor pollicis brevis

Explanation

The thenar muscles include the abductor pollicis brevis (APB), opponens pollicis (OP), and flexor pollicis brevis (FPB). The recurrent motor branch of the median nerve innervates the APB, OP, and the superficial head of the FPB. The deep head of the FPB is typically innervated by the deep branch of the ulnar nerve (though dual innervation can occur). The adductor pollicis is also innervated by the ulnar nerve.

Question 352

Topic: Nerve & Tendon



A 55-year-old female with long-standing type 2 diabetes presents with a painful, catching ring finger that locks in flexion. She is diagnosed with stenosing tenosynovitis (trigger finger). Which annular pulley is primarily implicated in the pathogenesis of this condition, and what is its anatomic relationship to the corresponding joint?

. A1 pulley; located at the level of the proximal interphalangeal (PIP) joint
. A2 pulley; located over the mid-portion of the proximal phalanx
. A1 pulley; located at the level of the metacarpophalangeal (MCP) joint
. C1 pulley; located immediately distal to the A1 pulley
. A3 pulley; located at the level of the PIP joint

Correct Answer & Explanation

. A1 pulley; located at the level of the metacarpophalangeal (MCP) joint

Explanation

Trigger finger is caused by a size mismatch between the flexor tendon (often with a reactive nodule) and the retinacular sheath, primarily at the A1 pulley. The A1 pulley is located palmar to the metacarpophalangeal (MCP) joint. The A2 pulley is over the proximal phalanx, and the A3 pulley is over the PIP joint.

Question 353

Topic: Nerve & Tendon

A 45-year-old man presents with numbness in his small and ring fingers and intrinsic muscle weakness. Physical examination reveals a 'claw' posture of the ring and small fingers. Which of the following clinical findings would best differentiate a high ulnar nerve compression (cubital tunnel syndrome) from a low ulnar nerve compression (Guyon's canal syndrome)?

. A positive Froment's sign
. Weakness of the dorsal interossei
. A positive Wartenberg's sign
. Less pronounced clawing of the ring and small fingers (ulnar paradox)
. Preservation of two-point discrimination on the volar tip of the small finger

Correct Answer & Explanation

. Less pronounced clawing of the ring and small fingers (ulnar paradox)

Explanation

The 'ulnar paradox' refers to the phenomenon where a higher ulnar nerve lesion (at the elbow) results in a less pronounced claw deformity compared to a lower lesion (at the wrist). This occurs because a high lesion paralyzes the ulnar-innervated half of the flexor digitorum profundus (FDP) to the ring and small fingers, reducing the flexion force at the DIP joints. In a low lesion, the FDP is intact and forcefully flexes the DIP joints against the paralyzed intrinsics, creating a severe claw. Additionally, loss of sensation over the dorsal ulnar aspect of the hand indicates a lesion proximal to the wrist, as the dorsal sensory branch of the ulnar nerve branches off proximal to Guyon's canal.

Question 354

Topic: Nerve & Tendon

A 6-year-old girl falls from monkey bars and sustains a widely displaced extension-type supracondylar fracture of the distal humerus.

On physical examination prior to reduction, she is unable to flex the interphalangeal joint of the thumb and the distal interphalangeal joint of the index finger, resulting in an inability to make an 'A-OK' sign. Which nerve is most likely injured?

. Radial nerve
. Ulnar nerve
. Anterior interosseous nerve (AIN)
. Posterior interosseous nerve (PIN)
. Musculocutaneous nerve

Correct Answer & Explanation

. Anterior interosseous nerve (AIN)

Explanation

The anterior interosseous nerve (AIN), a motor branch of the median nerve, is the most commonly injured nerve in extension-type supracondylar humerus fractures. It innervates the flexor pollicis longus (FPL) and the flexor digitorum profundus (FDP) to the index and middle fingers. Injury results in the inability to flex the IP joint of the thumb and DIP joint of the index finger, preventing the patient from making an 'OK' sign.

Question 355

Topic: Nerve & Tendon

During surgical decompression of the ulnar nerve at the elbow, an anatomical release is planned.

What is the most proximal potential site of ulnar nerve compression that must be evaluated?

. Arcade of Struthers
. Medial intermuscular septum
. Osborne's ligament
. Aponeurosis of the flexor carpi ulnaris
. Deep flexor pronator aponeurosis

Correct Answer & Explanation

. Arcade of Struthers

Explanation

The potential sites of ulnar nerve compression around the elbow from proximal to distal include: the Arcade of Struthers (about 8 cm proximal to the medial epicondyle), the medial intermuscular septum, the medial epicondyle itself, Osborne's ligament (cubital tunnel), and the deep aponeurosis of the FCU.

Question 356

Topic: Nerve & Tendon

A 28-year-old professional cyclist presents with intrinsic muscle weakness in his right hand but normal sensation over the volar and dorsal aspects of the small finger. He is diagnosed with ulnar nerve compression at Guyon's canal. This clinical presentation most likely correlates with compression at which specific zone of Guyon's canal?

. Zone 1
. Zone 2
. Zone 3
. Zone 4
. Zone 5

Correct Answer & Explanation

. Zone 2

Explanation

Guyon's canal is divided into three zones. Zone 1 is proximal to the bifurcation; compression here causes mixed motor and sensory deficits. Zone 2 contains only the deep motor branch; compression here (often from a ganglion or hook of hamate fracture) causes isolated motor weakness of ulnar-innervated intrinsic muscles, with normal sensation. Zone 3 contains the superficial sensory branch; compression causes isolated sensory deficits.

Question 357

Topic: Nerve & Tendon
A 25-year-old male rugby player attempts to tackle an opponent by grabbing his jersey. He feels a sudden pop in his right ring finger and presents unable to actively flex the distal interphalangeal (DIP) joint. Radiographs demonstrate a large bony avulsion fragment located volar to the proximal interphalangeal (PIP) joint, failing to retract completely into the palm. According to the Leddy-Packer classification, what type of flexor digitorum profundus (FDP) avulsion injury is this?
. Type I
. Type II
. Type III
. Type IV
. Type V

Correct Answer & Explanation

. Type II

Explanation

The Leddy-Packer classification categorizes FDP avulsion injuries (Jersey finger). Type I: The tendon retracts all the way into the palm; blood supply is severely compromised, requiring repair within 7-10 days. Type II: The tendon retracts to the level of the PIP joint, caught by the intact vincula; there may be a small fleck of bone. Type III: A large bony avulsion fragment that catches at the A4 pulley, preventing further retraction. The scenario describes a fragment at the PIP joint, which is characteristic of Type II, where it is held by the vincula longum.

Question 358

Topic: Nerve & Tendon

De Quervain's tenosynovitis involves inflammation of the first dorsal compartment of the wrist. Which tendons are located within this compartment?

. Extensor pollicis longus and extensor pollicis brevis
. Abductor pollicis longus and extensor pollicis brevis
. Abductor pollicis longus and abductor pollicis brevis
. Extensor carpi radialis longus and brevis
. Extensor digitorum communis and extensor indicis proprius

Correct Answer & Explanation

. Abductor pollicis longus and extensor pollicis brevis

Explanation

The first dorsal compartment contains the Abductor Pollicis Longus (APL) and Extensor Pollicis Brevis (EPB). The Extensor Pollicis Longus (EPL) is in the third compartment and routes around Lister's tubercle. De Quervain's is classically diagnosed with a positive Finkelstein's or Eichhoff's test.

Question 359

Topic: Nerve & Tendon

A 45-year-old typist complains of numbness and tingling in the small and ring fingers of her right hand. Examination reveals a positive Tinel's sign at the elbow and weakness of the dorsal interossei. The flexor carpi ulnaris (FCU) strength is normal. Where is the most likely site of compression?

. Between the two heads of the FCU (Cubital tunnel)
. Guyon's canal
. Ligament of Struthers
. Arcade of Frohse
. Pronator teres syndrome

Correct Answer & Explanation

. Between the two heads of the FCU (Cubital tunnel)

Explanation

The symptoms indicate ulnar nerve compression. While FCU strength is often preserved due to its proximal innervation (branches sometimes arise proximal to the compression), compression typically occurs at the cubital tunnel (Osborne's ligament/between the heads of FCU). Guyon's canal compression would not cause Tinel's at the elbow.

Question 360

Topic: Nerve & Tendon

A 35-year-old female undergoes surgical release of the first dorsal extensor compartment for recalcitrant De Quervain's tenosynovitis.

To prevent incomplete relief of symptoms, the surgeon must specifically look for and release a separate subsheath that frequently houses which of the following tendons?

. Extensor pollicis longus
. Abductor pollicis longus
. Extensor pollicis brevis
. Extensor carpi radialis longus
. Extensor indicis proprius

Correct Answer & Explanation

. Extensor pollicis brevis

Explanation

De Quervain's tenosynovitis involves the first dorsal compartment, which contains the abductor pollicis longus (APL) and extensor pollicis brevis (EPB) tendons. Anatomical variations are common, and in a significant percentage of patients (up to 40%), the EPB is located within its own distinct subsheath. Failure to identify and release this EPB subsheath is the most common cause of persistent symptoms following surgery.

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