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Nerve & Tendon MCQs

Practice Set 31 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 601

Topic: Nerve & Tendon

A 20-year-old collegiate baseball pitcher presents with medial elbow pain, decreased pitching velocity, and ulnar nerve paresthesias. MRI confirms a full-thickness tear of the anterior bundle of the ulnar collateral ligament (UCL). During UCL reconstruction, the ulnar bone tunnel is typically created at the sublime tubercle. Which nerve is at greatest risk of iatrogenic injury during the exposure and drilling of this ulnar tunnel?

. Anterior interosseous nerve
. Posterior interosseous nerve
. Median nerve
. Medial antebrachial cutaneous nerve
. Ulnar nerve

Correct Answer & Explanation

. Ulnar nerve

Explanation

The anterior bundle of the UCL inserts distally on the sublime tubercle of the ulna. The ulnar nerve runs immediately posterior to the medial epicondyle and the sublime tubercle in the cubital tunnel. During the dissection and drilling of the ulnar bone tunnels for UCL reconstruction, the ulnar nerve is at high risk of iatrogenic injury. While the medial antebrachial cutaneous nerve (MACN) is at risk during the superficial skin incision, the ulnar nerve is most at risk during the deep tunnel preparation.

Question 602

Topic: Nerve & Tendon

A 20-year-old collegiate baseball pitcher presents with medial elbow pain during the late cocking and early acceleration phases of throwing. An MRI arthrogram reveals a high-grade partial tear of the ulnar collateral ligament (UCL). After failing 3 months of conservative management, surgical reconstruction is planned. Which of the following surgical approaches and techniques best minimizes the risk of postoperative ulnar neuropathy by allowing the ulnar nerve to remain in its native anatomic position?

. Classical Jobe figure-of-eight technique
. Muscle-splitting approach with the docking technique
. Medial epicondyle osteotomy
. Submuscular ulnar nerve transposition
. Flexor-pronator mass detachment approach

Correct Answer & Explanation

. Muscle-splitting approach with the docking technique

Explanation

The muscle-splitting approach, often used in conjunction with the docking technique for UCL reconstruction, involves longitudinally splitting the flexor carpi ulnaris (FCU) muscle belly to access the sublime tubercle without detaching the flexor-pronator mass. This approach avoids obligatory handling or transposition of the ulnar nerve, allowing it to safely remain in its native cubital tunnel. In contrast, the classic Jobe technique involved detachment of the flexor-pronator mass and routine ulnar nerve transposition, which was historically associated with a higher rate of postoperative ulnar neuropathy.

Question 603

Topic: Nerve & Tendon

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

During the preoperative evaluation, the hand is pink with palpable pulses, but she is unable to flex the interphalangeal joint of the thumb and the distal interphalangeal joint of the index finger. Which nerve is most likely injured, and what is the typical prognosis?

. Median nerve; requires immediate microsurgical exploration
. Anterior interosseous nerve; resolves spontaneously in 2 to 3 months
. Ulnar nerve; requires immediate nerve transposition
. Radial nerve; resolves spontaneously in 2 to 3 months
. Posterior interosseous nerve; requires exploration if no recovery by 3 weeks

Correct Answer & Explanation

. Anterior interosseous nerve; resolves spontaneously in 2 to 3 months

Explanation

The anterior interosseous nerve (AIN) is the most commonly injured nerve in extension-type supracondylar humerus fractures (often with posterolateral displacement). It is a purely motor branch of the median nerve, innervating the flexor pollicis longus and the flexor digitorum profundus to the index and long fingers. The injury is typically a neuropraxia, and spontaneous recovery usually occurs within 2 to 3 months. Acute exploration is not indicated.

Question 604

Topic: Nerve & Tendon

A 6-year-old girl sustains an extension-type completely displaced supracondylar humerus fracture. Examination reveals she is unable to flex the interphalangeal joint of her thumb and the distal interphalangeal joint of her index finger. Which nerve is most likely injured?

. Ulnar nerve
. Radial nerve
. Anterior interosseous nerve
. Poster 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. Injury to the AIN results in the inability to flex the interphalangeal joint of the thumb (flexor pollicis longus) and the distal interphalangeal joint of the index finger (flexor digitorum profundus).

Question 605

Topic: Nerve & Tendon

A 6-year-old boy falls from the monkey bars and sustains a painful, swollen elbow. Radiographs demonstrate an extension-type supracondylar humerus fracture with posteromedial displacement of the distal fragment.

Based on the direction of displacement, which of the following nerve injuries is most likely to be present?

. Anterior interosseous nerve
. Radial nerve
. Ulnar nerve
. Median nerve (main trunk)
. Musculocutaneous nerve

Correct Answer & Explanation

. Radial nerve

Explanation

In extension-type supracondylar humerus fractures, the direction of displacement dictates the structures at risk. With posteromedial displacement of the distal fragment, the proximal fracture spike is driven anterolaterally. This places the radial nerve at the highest risk of injury. Conversely, if the distal fragment is displaced posterolaterally, the proximal spike is driven anteromedially, jeopardizing the median nerve and its anterior interosseous nerve (AIN) branch. The AIN is the most commonly injured nerve overall, but the radial nerve is specifically associated with posteromedial displacement.

Question 606

Topic: Nerve & Tendon

A 6-year-old boy sustains a completely displaced extension-type supracondylar fracture of the humerus. On physical examination in the emergency department, the patient is unable 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?

. Median nerve (main trunk)
. Anterior interosseous nerve
. Radial nerve
. Posterior interosseous nerve
. Ulnar 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. It provides motor innervation to the flexor pollicis longus, the radial half of the flexor digitorum profundus, and the pronator quadratus. Injury results in the inability to form an 'A-OK' sign (loss of IP flexion of the thumb and DIP flexion of the index finger).

Question 607

Topic: Nerve & Tendon

A 58-year-old male presents with deteriorating handwriting, difficulty buttoning his shirts, and frequent tripping over the last six months. On physical examination, flicking the nail of his middle finger results in reflexive flexion of the thumb and index finger. This specific clinical sign indicates pathology in which of the following anatomic locations?

. Lumbar nerve root
. Cervical spinal cord
. Brachial plexus
. Ulnar nerve at the cubital tunnel
. Median nerve at the carpal tunnel

Correct Answer & Explanation

. Cervical spinal cord

Explanation

The scenario describes the Hoffmann sign. A positive Hoffmann sign indicates an upper motor neuron lesion, characteristic of cervical myelopathy (compression of the cervical spinal cord). It does not indicate lower motor neuron pathology such as radiculopathy, brachial plexopathy, or peripheral nerve entrapment (cubital or carpal tunnel syndromes).

Question 608

Topic: Nerve & Tendon

A 42-year-old male construction worker presents with chronic numbness in his small and ring fingers and weakness in grip strength. Exam reveals a positive Froment's sign and intrinsic muscle atrophy. Intraoperatively, during decompression, the ulnar nerve is found to subluxate anteriorly over the medial epicondyle upon elbow flexion. What is the most appropriate surgical management?

. In situ decompression of the ulnar nerve alone.
. Ulnar nerve anterior transposition or medial epicondylectomy.
. Guyon's canal decompression.
. Endoscopic in situ decompression.
. Medial ulnar collateral ligament reconstruction.

Correct Answer & Explanation

. Ulnar nerve anterior transposition or medial epicondylectomy.

Explanation

In patients with ulnar nerve subluxation or instability at the elbow during flexion, an in situ decompression alone is contraindicated. Decompressing without stabilizing the nerve can lead to continued or worsened subluxation, causing a severe friction neuritis over the medial epicondyle. An anterior transposition (subcutaneous, intramuscular, or submuscular) or a medial epicondylectomy is recommended to address both the compression and the dynamic instability.

Question 609

Topic: Nerve & Tendon

A 48-year-old weightlifter feels a 'pop' in his anterior elbow during a heavy deadlift, followed by ecchymosis and weakness in supination. MRI confirms a complete distal biceps tendon avulsion. He opts for surgical repair using a single-incision anterior approach. Which nerve is at greatest risk of iatrogenic injury during the superficial dissection of this specific surgical approach?

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

Correct Answer & Explanation

. Lateral antebrachial cutaneous nerve (LABCN)

Explanation

The single-incision anterior approach for distal biceps tendon repair primarily places the lateral antebrachial cutaneous nerve (LABCN) at risk during the superficial exposure. The LABCN exits the deep fascia lateral to the biceps tendon and must be identified and protected. While the posterior interosseous nerve (PIN) is at risk during deep retractor placement or drilling of the posterior radius cortex, the LABCN is statistically the most commonly injured nerve overall in the single-incision anterior approach.

Question 610

Topic: Nerve & Tendon
A 55-year-old carpenter presents with a 6-month history of paresthesias in the right small and ulnar half of the ring finger, along with subjective weakness in hand grip. Electromyography confirms a compressive ulnar neuropathy at the elbow. During surgical decompression, the surgeon must systematically release several potential sites of compression. Which of the following anatomic structures is NOT a recognized site of ulnar nerve compression in this region?
. Ligament of Struthers
. Arcade of Struthers
. Medial intermuscular septum
. Osborne's ligament
. Aponeurosis of the flexor carpi ulnaris

Correct Answer & Explanation

. Ligament of Struthers

Explanation

The Ligament of Struthers is a potential site of MEDIAN nerve compression in the distal arm (associated with an anomalous supracondylar process of the humerus), not the ulnar nerve. Recognized sites of ulnar nerve compression around the elbow include the Arcade of Struthers (a fascial band extending from the medial head of the triceps to the medial intermuscular septum), the medial intermuscular septum (especially susceptible after anterior transposition of the nerve), the medial epicondyle, Osborne's ligament (the retinaculum bridging the two heads of the FCU), and the deep flexor-pronator aponeurosis.

Question 611

Topic: Nerve & Tendon

During an in situ ulnar nerve decompression for cubital tunnel syndrome, a surgeon sequentially releases the structures of the cubital tunnel. Which of the following structures constitutes the primary roof of the cubital tunnel?

. Medial intermuscular septum
. Arcade of Struthers
. Osborne's ligament
. Ligament of Struthers
. Lacertus fibrosus

Correct Answer & Explanation

. Osborne's ligament

Explanation

The roof of the cubital tunnel is primarily formed by Osborne's ligament (the cubital tunnel retinaculum spanning from the medial epicondyle to the olecranon) and the aponeurosis of the two heads of the flexor carpi ulnaris (FCU). The Arcade of Struthers is a fascial band located proximal to the medial epicondyle.

Question 612

Topic: Nerve & Tendon

A 50-year-old mechanic complains of numbness in his small and ring fingers, accompanied by intrinsic muscle weakness. Electromyography (EMG) confirms compressive neuropathy of the ulnar nerve at the elbow. Which of the following anatomic structures represents the most common site of ulnar nerve compression in this syndrome?

. Arcade of Struthers
. Medial intermuscular septum
. Osborne's ligament
. Deep flexor pronator aponeurosis
. Guyon's canal

Correct Answer & Explanation

. Osborne's ligament

Explanation

Cubital tunnel syndrome is the second most common compressive neuropathy of the upper extremity. The most frequent site of ulnar nerve compression at the elbow is between the humeral and ulnar heads of the flexor carpi ulnaris (FCU), deep to Osborne's ligament (the fascial band connecting the two heads). The Arcade of Struthers and the medial intermuscular septum are less common sites.

Question 613

Topic: Nerve & Tendon

During an anterior submuscular transposition of the ulnar nerve for refractory cubital tunnel syndrome, the surgeon must mobilize the nerve proximally to prevent tethering. Which of the following structures is located approximately 8 cm proximal to the medial epicondyle and must be carefully released to prevent a new site of nerve compression?

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

Correct Answer & Explanation

. Arcade of Struthers

Explanation

The arcade of Struthers is a fascial band extending from the medial head of the triceps to the medial intermuscular septum, located approximately 8 cm proximal to the medial epicondyle. During anterior transposition of the ulnar nerve, failure to release the arcade of Struthers can lead to proximal tethering and iatrogenic compression of the nerve. The ligament of Struthers is an anomalous structure in the distal humerus associated with median nerve and brachial artery compression. Osborne's ligament forms the roof of the cubital tunnel. The arcade of Frohse is associated with PIN compression.

Question 614

Topic: Nerve & Tendon

A 45-year-old man presents with numbness and tingling in his small and ring fingers, along with subjective weakness in his grip. Electromyography confirms isolated ulnar neuropathy at the elbow. During surgical decompression, which of the following structures is identified as the most common primary site of ulnar nerve compression?

. Arcade of Struthers
. Medial intermuscular septum
. Osborne's ligament (cubital tunnel retinaculum)
. Flexor carpi ulnaris (FCU) aponeurosis
. Deep flexor pronator aponeurosis

Correct Answer & Explanation

. Osborne's ligament (cubital tunnel retinaculum)

Explanation

Cubital tunnel syndrome is the second most common compression neuropathy in the upper extremity. While compression can occur at multiple sites (Arcade of Struthers, medial intermuscular septum, Osborne's ligament, FCU aponeurosis, and deep flexor pronator aponeurosis), the most frequent primary site of compression is at the cubital tunnel retinaculum, also known as Osborne's ligament, which spans between the olecranon and the medial epicondyle.

Question 615

Topic: Nerve & Tendon

A 20-year-old collegiate baseball pitcher is undergoing ulnar collateral ligament (UCL) reconstruction utilizing an autograft. To minimize the risk of postoperative ulnar neuropathy, a common and devastating complication, which of the following intraoperative principles is most critical regarding the handling of the ulnar nerve?

. Routine anterior submuscular transposition of the ulnar nerve in all cases regardless of preoperative symptoms
. Placing the ulnar bone tunnel as far posteriorly as possible to avoid proximity to the nerve
. Avoiding excessive traction and retractors on the ulnar nerve if it is left in situ, and resecting the medial intermuscular septum to prevent tethering
. Creating an enlarged ulnar bone tunnel to intentionally allow for concomitant decompression of the nerve within the cubital tunnel
. Performing a routine medial epicondylectomy to offload tension on the ulnar nerve pathway

Correct Answer & Explanation

. Avoiding excessive traction and retractors on the ulnar nerve if it is left in situ, and resecting the medial intermuscular septum to prevent tethering

Explanation

Ulnar neuropathy is the most common complication following UCL reconstruction. Historically, routine anterior transposition was performed (as in the classic Jobe technique), which carried a high rate of nerve-related complications. Modern techniques (such as the docking technique or muscle-splitting approach) often leave the nerve in situ to preserve its vascularity. When leaving the nerve in situ, it is critical to avoid placing retractors directly on the nerve, to minimize traction, and to release the medial intermuscular septum if there is any tension, thereby preventing tethering or iatrogenic compression.

Question 616

Topic: Nerve & Tendon

A 42-year-old mechanic complains of clumsiness, weakness in his grip, and numbness in his small and ring fingers. During physical examination, the examiner asks the patient to hold a piece of paper laterally between his thumb and index finger. As the examiner pulls the paper away, the patient strongly flexes the interphalangeal (IP) joint of his thumb. Which muscle is compensating to produce this clinical sign?

. Adductor pollicis
. Flexor pollicis brevis
. Flexor pollicis longus
. Abductor pollicis brevis
. First dorsal interosseous

Correct Answer & Explanation

. Adductor pollicis

Explanation

This describes a positive Froment's sign, which tests for ulnar nerve palsy. The primary muscle for key pinch is the adductor pollicis (innervated by the ulnar nerve). When the adductor pollicis is weak, the patient compensates by hyperflexing the thumb interphalangeal (IP) joint using the flexor pollicis longus (FPL), which is innervated by the anterior interosseous nerve (AIN), a branch of the median nerve.

Question 617

Topic: Nerve & Tendon

A 45-year-old male bodybuilder undergoes a single-incision anterior approach for the repair of a complete distal biceps tendon rupture. Postoperatively, he complains of numbness over the radial aspect of his forearm. Which nerve was most likely injured or stretched during the surgical exposure?

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

Correct Answer & Explanation

. Lateral antebrachial cutaneous nerve (LABCN)

Explanation

The lateral antebrachial cutaneous nerve (LABCN) is the most commonly injured nerve during a single-incision anterior approach for distal biceps repair. It runs superficially in the subcutaneous tissues on the lateral aspect of the anterior elbow and provides sensation to the radial forearm. The posterior interosseous nerve (PIN) is at higher risk during a two-incision approach or with deep retractor placement on the radial neck.

Question 618

Topic: Nerve & Tendon

A 45-year-old diabetic man presents with persistent ulnar neuropathy 6 months after an in situ ulnar nerve decompression at the cubital tunnel. EMG shows active denervation in the abductor digiti minimi. During revision surgery, the nerve is embedded in dense scar tissue and subluxates anteriorly with elbow flexion. Which of the following is the most appropriate next step?

. Repeat in situ decompression and medial epicondylectomy
. Subcutaneous ulnar nerve transposition
. Guyon's canal release
. Submuscular ulnar nerve transposition
. Intermuscular ulnar nerve transposition

Correct Answer & Explanation

. Submuscular ulnar nerve transposition

Explanation

In the setting of revision cubital tunnel surgery, especially when the ulnar nerve is embedded in scar tissue and demonstrating subluxation, a submuscular transposition is widely considered the procedure of choice. It moves the nerve out of the scarred, poorly vascularized primary surgical bed and places it in a healthy, well-vascularized environment deep to the flexor-pronator mass, simultaneously correcting the dynamic subluxation.

Question 619

Topic: Nerve & Tendon

A 55-year-old male complains of numbness and tingling in his small and ring fingers that awakens him at night. Examination shows a positive Tinel's sign at the elbow and a positive Froment's sign. He has clinically palpable snapping over the medial epicondyle during elbow flexion. Electrodiagnostic studies confirm severe ulnar neuropathy at the elbow. He fails a 6-month trial of conservative management.

What is the primary indication for choosing an anterior transposition of the ulnar nerve over an in situ decompression in this patient?

. Decreased risk of postoperative neuroma formation
. Improved long-term electrodiagnostic outcomes in severe neuropathy
. Prevention of nerve subluxation
. Faster return to heavy manual labor
. Reduced risk of injury to the medial antebrachial cutaneous nerve

Correct Answer & Explanation

. Prevention of nerve subluxation

Explanation

Randomized controlled trials have generally shown no significant difference in clinical outcomes between simple in situ decompression and anterior transposition for the treatment of primary cubital tunnel syndrome. However, anterior transposition is specifically indicated in patients with a subluxating ulnar nerve, a valgus deformity of the elbow, or post-traumatic stiffness requiring a tension-free route. In this patient, the palpable snapping over the medial epicondyle indicates nerve subluxation, dictating an anterior transposition to prevent ongoing mechanical irritation.

Question 620

Topic: Nerve & Tendon

A 22-year-old collegiate baseball pitcher undergoes ulnar collateral ligament (UCL) reconstruction using a palmaris longus autograft. To minimize the risk of postoperative ulnar neuropathy, which of the following techniques or principles is recommended during the surgical approach?

. Routine subcutaneous transposition of the ulnar nerve
. Routine submuscular transposition of the ulnar nerve
. Splitting the flexor carpi ulnaris (FCU) muscle longitudinally
. Avoiding the use of a tourniquet
. Detaching the common flexor origin from the medial epicondyle

Correct Answer & Explanation

. Splitting the flexor carpi ulnaris (FCU) muscle longitudinally

Explanation

A muscle-splitting approach through the flexor carpi ulnaris (FCU) provides excellent exposure to the sublime tubercle and the native UCL while minimizing trauma to the ulnar nerve. Routine transposition of the ulnar nerve is not recommended unless there are preoperative ulnar nerve symptoms or the nerve subluxates during surgery, as transposition can paradoxically increase the risk of postoperative ulnar neuropathy.

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