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Nerve & Tendon MCQs

Practice Set 46 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 901

Topic: Nerve & Tendon

A patient undergoing a carpal tunnel release subsequently experiences an isolated loss of thumb opposition but retains normal sensation over the thenar eminence and volar aspect of the thumb. Which structure was most likely iatrogenically injured?

. Recurrent motor branch of the median nerve
. Palmar cutaneous branch of the median nerve
. Deep motor branch of the ulnar nerve
. Superficial radial nerve
. Anterior interosseous nerve

Correct Answer & Explanation

. Recurrent motor branch of the median nerve

Explanation

The recurrent motor branch of the median nerve innervates the thenar musculature (abductor pollicis brevis, opponens pollicis, superficial head of flexor pollicis brevis). Injury results in loss of opposition. Sensation remains intact because the proper digital nerves and palmar cutaneous branch are spared.

Question 902

Topic: Nerve & Tendon

What is the most common long-term complication associated with an un-united pediatric lateral condyle humerus fracture?

. Cubitus varus
. Tardy ulnar nerve palsy
. Volkmann ischemic contracture
. Radial head subluxation
. Median nerve palsy

Correct Answer & Explanation

. Cubitus varus

Explanation

Nonunion of a lateral condyle fracture typically leads to a progressive cubitus valgus deformity due to proximal migration of the lateral condyle. Over years or decades, this significant valgus alignment stretches the ulnar nerve behind the medial epicondyle, resulting in tardy ulnar nerve palsy.

Question 903

Topic: Nerve & Tendon

A 10-year-old child presents with a progressive elbow deformity and numbness in the small finger. History reveals a conservatively managed lateral condyle fracture at age 4. What is the most likely structural deformity and the associated nerve palsy?

. Cubitus varus leading to radial nerve palsy
. Cubitus valgus leading to tardy ulnar nerve palsy
. Cubitus varus leading to tardy ulnar nerve palsy
. Cubitus valgus leading to anterior interosseous nerve palsy
. Cubitus valgus leading to median nerve palsy

Correct Answer & Explanation

. Cubitus varus leading to radial nerve palsy

Explanation

Nonunion or premature lateral growth arrest following a lateral condyle fracture classically leads to a progressive cubitus valgus deformity. Over time, this valgus angulation stretches the ulnar nerve within the cubital tunnel, resulting in a tardy ulnar nerve palsy.

Question 904

Topic: Nerve & Tendon

A 6-year-old boy presents with a supracondylar humerus fracture that is posterolaterally displaced. On clinical examination, he is unable to flex the interphalangeal joint of his thumb and the distal interphalangeal joint of his index finger. Which nerve is most likely injured?

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

Correct Answer & Explanation

. Ulnar nerve

Explanation

The anterior interosseous nerve (AIN) is a branch of the median nerve and is the most commonly injured nerve in extension-type, posterolaterally displaced supracondylar fractures. It provides motor innervation to the flexor pollicis longus and flexor digitorum profundus to the index and middle fingers.

Question 905

Topic: Nerve & Tendon

A 4-year-old boy sustains a lateral condyle fracture of the humerus. Radiographs show 3 mm of displacement. The fracture is treated with closed reduction and percutaneous pinning. What is the most common long-term complication if this fracture fails to unite (non-union)?

. Cubitus varus and median nerve palsy
. Cubitus valgus and tardy ulnar nerve palsy
. Volkmann ischemic contracture
. Radial head subluxation
. Myositis ossificans

Correct Answer & Explanation

. Cubitus varus and median nerve palsy

Explanation

Lateral condyle non-unions characteristically lead to progressive cubitus valgus deformity. Over time, the valgus angulation stretches the ulnar nerve, resulting in a tardy ulnar nerve palsy.

Question 906

Topic: Nerve & Tendon

A 6-year-old child sustains a minimally displaced lateral condyle fracture of the humerus. Which of the following is the most common long-term complication if this injury goes unrecognized and untreated?

. Cubitus varus
. Tardy ulnar nerve palsy
. Radial head subluxation
. Avascular necrosis of the trochlea
. Median nerve palsy

Correct Answer & Explanation

. Cubitus varus

Explanation

Untreated lateral condyle fractures often lead to nonunion and progressive cubitus valgus. This valgus deformity progressively stretches the ulnar nerve, leading to tardy ulnar nerve palsy years later.

Question 907

Topic: Nerve & Tendon

Following a closed crush injury to the forearm, a patient exhibits a complete motor and sensory deficit in the distribution of the median nerve. Nerve conduction studies later indicate a Sunderland third-degree nerve injury. This classification signifies the disruption of the axon, the myelin sheath, and which other distinct neural structure?

. No other structures (axon and myelin only)
. Epineurium
. Perineurium
. Endoneurium
. Complete transection of all neural elements

Correct Answer & Explanation

. Perineurium

Explanation

In the Sunderland classification of peripheral nerve injuries: First-degree = focal demyelination (Neuropraxia); Second-degree = axonal damage with intact endoneurium (Axonotmesis); Third-degree = loss of axonal and endoneurial continuity, but intact perineurium and epineurium; Fourth-degree = disruption of axon, endoneurium, and perineurium with intact epineurium; Fifth-degree = complete nerve transection (Neurotmesis).

Question 908

Topic: Nerve & Tendon

A 6-year-old boy falls from monkey bars and sustains a widely displaced posterolateral extension-type supracondylar humerus fracture. Which nerve is most commonly injured in this specific fracture displacement pattern?

. Median nerve
. Anterior interosseous nerve (AIN)
. Radial nerve
. Ulnar nerve
. Musculocutaneous nerve

Correct Answer & Explanation

. Anterior interosseous nerve (AIN)

Explanation

In extension-type supracondylar humerus fractures, the direction of distal fragment displacement determines the structures at risk. Posterolateral displacement stretches the median nerve and specifically the anterior interosseous nerve (AIN) over the proximal metaphyseal spike. Posteromedial displacement places the radial nerve at risk.

Question 909

Topic: Nerve & Tendon

During an in situ ulnar nerve decompression for cubital tunnel syndrome, a tight fascial band is encountered just distal to the medial epicondyle, bridging the humeral and ulnar heads of the flexor carpi ulnaris (FCU). What is the specific anatomical name of this structure?

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

Correct Answer & Explanation

. Osborne's ligament

Explanation

Osborne's ligament (or the cubital tunnel retinaculum) forms the roof of the cubital tunnel, bridging the humeral and ulnar heads of the flexor carpi ulnaris (FCU) just distal to the medial epicondyle. The Arcade of Struthers is a fascial band located approximately 8 cm proximal to the medial epicondyle.

Question 910

Topic: Nerve & Tendon

A 30-year-old mechanic undergoes a Zone II flexor digitorum profundus (FDP) and superficialis (FDS) repair of the index finger. To optimize tendon gliding and minimize rupture risk, which of the following intraoperative pulley management strategies is most appropriate if the bulky repair catches during active flexion?

. Venting the A2 pulley up to 50% if needed
. Complete excision of the A4 pulley
. Resection of the A1 and A3 pulleys without touching A2 or A4
. Excision of all pulleys and immediate two-stage reconstruction
. Converting to a static immobilization protocol for 6 weeks

Correct Answer & Explanation

. Venting the A2 pulley up to 50% if needed

Explanation

Modern flexor tendon repair protocols demonstrate that venting up to 50% of the A2 pulley or completely venting the A4 pulley is safe if a bulky repair catches during excursion. This allows for smooth gliding and early active motion without causing clinically significant bowstringing.

Question 911

Topic: Nerve & Tendon

During surgical decompression for cubital tunnel syndrome, the ulnar nerve is traced distally into the forearm. Compression at this level is most commonly caused by the aponeurotic band between the two heads of the flexor carpi ulnaris (FCU). What is the name of this structure?

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

Correct Answer & Explanation

. Osborne's ligament

Explanation

Osborne's ligament (or Osborne's fascia) forms the roof of the cubital tunnel, bridging the olecranon and the medial epicondyle, and continues distally between the two heads of the FCU. The Arcade of Struthers is a distinct structure located proximal to the medial epicondyle.

Question 912

Topic: Nerve & Tendon

During an ulnar collateral ligament (UCL) reconstruction in a professional throwing athlete, the surgeon elects to use the docking technique rather than the traditional figure-of-eight (Jobe) technique. What is the primary anatomic and biomechanical advantage of the docking technique?

. It allows for an earlier return to competitive throwing
. It completely avoids the need for ulnar nerve handling or transposition
. It requires a significantly shorter graft harvest, allowing use of the palmaris longus
. It minimizes the size and number of drill holes in the medial epicondyle
. It provides a stiffer initial construct than native UCL anatomy

Correct Answer & Explanation

. It minimizes the size and number of drill holes in the medial epicondyle

Explanation

The docking technique utilizes a single larger socket in the medial epicondyle with smaller exit holes for sutures, rather than large intersecting tunnels. This minimizes bone loss in the medial epicondyle, thereby reducing the risk of iatrogenic epicondylar fracture.

Question 913

Topic: Nerve & Tendon

A 45-year-old male undergoes a single-incision anterior approach for a distal biceps tendon rupture repair. Postoperatively, he complains of numbness and paresthesia along the radial aspect of his forearm. Which of the following nerves is most commonly at risk and likely injured due to superficial retraction during this specific surgical approach?

. Median nerve
. Ulnar nerve
. Posterior interosseous nerve (PIN)
. Lateral antebrachial cutaneous nerve (LABCN)
. Superficial radial nerve

Correct Answer & Explanation

. Lateral antebrachial cutaneous nerve (LABCN)

Explanation

In a single-incision anterior approach for distal biceps repair, the lateral antebrachial cutaneous nerve (LABCN) is the most frequently injured nerve (typically via neurapraxia from retraction). It runs superficially in the subcutaneous tissue on the lateral aspect of the antecubital fossa. While the posterior interosseous nerve (PIN) is at risk during drilling of the radial tuberosity, LABCN injury is the most common sensory complication of the anterior approach.

Question 914

Topic: Nerve & Tendon

A 35-year-old weightlifter undergoes an acute distal biceps tendon repair using a single-incision anterior approach. Which nerve is at the highest risk of iatrogenic injury due to lateral retraction during this exposure?

. Median nerve
. Ulnar nerve
. Lateral antebrachial cutaneous nerve (LABCN)
. Posterior interosseous nerve (PIN)
. Superficial radial nerve

Correct Answer & Explanation

. Lateral antebrachial cutaneous nerve (LABCN)

Explanation

The lateral antebrachial cutaneous nerve (LABCN) is the most commonly injured nerve in a single-incision anterior approach to the distal biceps. The PIN is at higher risk during a two-incision approach or if dissection strays lateral to the bicipital tuberosity.

Question 915

Topic: Nerve & Tendon

During an ulnar collateral ligament (UCL) reconstruction utilizing a docking technique, what is the primary biomechanical rationale for precise graft placement on the medial ulna?

. To reconstruct the transverse band of the UCL
. To anatomically recreate the broad ulnar footprint on the sublime tubercle
. To avoid transposition of the ulnar nerve
. To provide rigid fixation without requiring bone tunnels
. To intentionally over-tension the graft to compensate for stretching

Correct Answer & Explanation

. To anatomically recreate the broad ulnar footprint on the sublime tubercle

Explanation

The anterior bundle of the UCL is the primary restraint to valgus stress and attaches to the sublime tubercle of the ulna. Modern reconstruction techniques emphasize anatomic recreation of this broad footprint to optimize graft tension throughout the elbow's arc of motion.

Question 916

Topic: Nerve & Tendon

A patient requires a first dorsal compartment release for De Quervain's tenosynovitis. The surgeon must be aware of anatomical variants. Which of the following is true regarding the first dorsal compartment?

. It contains the Extensor Pollicis Longus and Extensor Pollicis Brevis tendons.
. Multiple slips of the Abductor Pollicis Longus tendon are exceptionally rare.
. A subcompartmental septum separating the APL and EPB is found in 30-60% of patients.
. The superficial branch of the ulnar nerve is at high risk during the incision.
. It is located deep to the extensor retinaculum and palmar to the scaphoid.

Correct Answer & Explanation

. A subcompartmental septum separating the APL and EPB is found in 30-60% of patients.

Explanation

The first dorsal compartment contains the Abductor Pollicis Longus (APL) and Extensor Pollicis Brevis (EPB) tendons. Multiple slips of the APL are very common. A subcompartmental septum separating the APL and EPB is found in up to 30-60% of cases, and failure to release both subcompartments is a common cause of recurrent/persistent symptoms. The superficial branch of the radial nerve (not ulnar) is at risk.

Question 917

Topic: Nerve & Tendon

The ulnar nerve passes through several potential compression sites in the arm and elbow. The Arcade of Struthers is a potential site of entrapment located:

. Between the medial epicondyle and olecranon
. At the two heads of the flexor carpi ulnaris
. Approximately 8 cm proximal to the medial epicondyle
. Deep to the pronator teres
. At the level of Guyon's canal

Correct Answer & Explanation

. Approximately 8 cm proximal to the medial epicondyle

Explanation

The Arcade of Struthers is a fascial band or thickening of the medial intermuscular septum located approximately 8 cm proximal to the medial epicondyle. It extends from the medial intermuscular septum to the medial head of the triceps and is a known site of ulnar nerve compression, especially after anterior transposition.

Question 918

Topic: Nerve & Tendon

The Martin-Gruber anastomosis is an important anatomical variant to consider during nerve conduction studies and hand surgery. What is the most common direction of nerve fiber crossover in this anomaly?

. Median nerve (or AIN) to the ulnar nerve in the forearm
. Ulnar nerve to the median nerve in the forearm
. Radial nerve to the median nerve in the forearm
. Ulnar nerve to the median nerve in the palm (Riche-Cannieu)
. Anterior interosseous nerve to the posterior interosseous nerve

Correct Answer & Explanation

. Median nerve (or AIN) to the ulnar nerve in the forearm

Explanation

A Martin-Gruber anastomosis is an anomalous connection in the forearm where motor fibers cross from the median nerve (or its anterior interosseous branch) to the ulnar nerve. It occurs in about 15% of individuals. A Riche-Cannieu anastomosis is a connection between the deep branch of the ulnar nerve and the recurrent branch of the median nerve in the hand.

Question 919

Topic: Nerve & Tendon

During a submuscular ulnar nerve transposition, the surgeon must completely decompress the nerve by releasing potential sites of entrapment. The Arcade of Struthers is a recognized site of proximal entrapment. Where is this structure anatomically located?

. Approximately 8 cm proximal to the medial epicondyle
. Directly at the level of the medial epicondyle
. Between the humeral and ulnar heads of the flexor carpi ulnaris
. Approximately 4 cm distal to the medial epicondyle
. In the distal forearm at the proximal border of Guyon's canal

Correct Answer & Explanation

. Approximately 8 cm proximal to the medial epicondyle

Explanation

The Arcade of Struthers is a thin fascial band extending from the medial head of the triceps to the medial intermuscular septum. It is located approximately 8 cm proximal to the medial epicondyle. It is an important release site, especially when the ulnar nerve is anteriorly transposed.

Question 920

Topic: Nerve & Tendon

During the proximal portion of the volar (Henry) approach to the forearm, the arm is supinated during deep dissection. What is the primary anatomical rationale for this maneuver?

. To protect the posterior interosseous nerve
. To protect the median nerve
. To relax the brachioradialis muscle
. To bring the radial artery into the surgical field
. To protect the anterior interosseous nerve

Correct Answer & Explanation

. To protect the posterior interosseous nerve

Explanation

During the proximal volar (Henry) approach to the radius, the forearm must be fully supinated when detaching and reflecting the supinator muscle from its radial insertion. This maneuver physically moves the posterior interosseous nerve (PIN), which lies within the substance of the supinator, laterally and posteriorly, away from the surgical plane.

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