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Nerve & Tendon MCQs

Practice Set 36 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 701

Topic: Nerve & Tendon

A 50-year-old carpenter presents with numbness in his small and ring fingers and intrinsic muscle weakness. He is diagnosed with cubital tunnel syndrome. During surgical decompression, the ulnar nerve is found to be compressed as it passes between the humeral and ulnar heads of the flexor carpi ulnaris (FCU). What is the eponymous name of the fascial band connecting these two heads?

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

Correct Answer & Explanation

. Osborne's ligament

Explanation

Correct Answer: COsborne's ligament (or the cubital tunnel retinaculum) is the fascial band that bridges the humeral and ulnar heads of the flexor carpi ulnaris (FCU) muscle. It forms the roof of the cubital tunnel and is a primary site of ulnar nerve compression at the elbow. The Arcade of Struthers (Option A) 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, and is another potential site of ulnar nerve compression. The Ligament of Struthers (Option B) is an anomalous structure associated with a supracondylar process that can compress the median nerve. The Lacertus fibrosus (Option D) is the bicipital aponeurosis, which can compress the median nerve. The Arcade of Frohse (Option E) is the proximal edge of the superficial head of the supinator, a common site of posterior interosseous nerve (PIN) compression.

Question 702

Topic: Nerve & Tendon

A 42-year-old female assembly line worker presents with chronic, deep aching pain in her proximal lateral right forearm. She has failed 6 months of conservative management for presumed lateral epicondylitis. Examination reveals maximal tenderness 4 cm distal to the lateral epicondyle and pain exacerbated by resisted forearm supination with the elbow extended. There are no sensory deficits in the hand. If surgical decompression is performed, which of the following structures is the MOST common site of compression for the affected nerve?

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

Correct Answer & Explanation

. Arcade of Frohse

Explanation

Correct Answer: C (Arcade of Frohse)This patient's presentation is classic for radial tunnel syndrome, which involves compression of the posterior interosseous nerve (PIN), a motor branch of the radial nerve. Symptoms include deep aching pain in the proximal lateral forearm, tenderness distal to the lateral epicondyle (unlike lateral epicondylitis, where tenderness is directly over the epicondyle), and pain with resisted supination. Because the PIN is a motor nerve, there are no sensory deficits. The most common site of PIN compression within the radial tunnel is the Arcade of Frohse, which is the proximal fibrous edge of the superficial head of the supinator muscle. The Arcade of Struthers and Osborne's fascia are associated with ulnar nerve compression (cubital tunnel). The Ligament of Struthers and Lacertus fibrosus (bicipital aponeurosis) are associated with median nerve compression (pronator syndrome).

Question 703

Topic: Nerve & Tendon

During surgical decompression for recalcitrant cubital tunnel syndrome, the ulnar nerve is found to be compressed approximately 8 cm proximal to the medial epicondyle. Which of the following anatomic structures is responsible for this compression?

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

Correct Answer & Explanation

. Arcade of Struthers

Explanation

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

Question 704

Topic: Nerve & Tendon

A 30-year-old male presents with progressive right elbow pain, numbness and tingling in the ring and small fingers, and weakness of intrinsic hand muscles. Clinical examination reveals a positive Tinel's sign at the cubital tunnel, severe ulnar nerve subluxation with elbow flexion, and significant intrinsic muscle wasting. What is the most appropriate surgical management?

. In situ ulnar nerve decompression.
. Medial epicondylectomy.
. Anterior subcutaneous ulnar nerve transposition.
. Anterior submuscular ulnar nerve transposition.
. Posterior ulnar nerve transposition.

Correct Answer & Explanation

. Anterior submuscular ulnar nerve transposition.

Explanation

For severe cubital tunnel syndrome with chronic symptoms, intrinsic muscle wasting, and particularly, gross ulnar nerve subluxation, in situ decompression alone is often insufficient and may lead to recurrent symptoms. Anterior submuscular ulnar nerve transposition is generally preferred in cases of severe compression, prior failed surgery, or significant instability/subluxation of the nerve, as it provides a more robust and stable environment for the nerve and is thought to offer better protection. Medial epicondylectomy can also decompress but does not address subluxation. Anterior subcutaneous transposition may be simpler but offers less protection and stability than submuscular for severe cases. Posterior transposition is not a standard approach.

Question 705

Topic: Nerve & Tendon

A patient with a distal humerus fracture and persistent ulnar nerve palsy post-operatively shows no signs of improvement after 6 weeks. What is the most appropriate next step in management?

. Continue observation for up to 6 months
. Start high-dose oral corticosteroids
. Perform a diagnostic ultrasound of the nerve
. Consider surgical exploration and anterior transposition of the ulnar nerve
. Refer for psychological counseling for chronic pain

Correct Answer & Explanation

. Consider surgical exploration and anterior transposition of the ulnar nerve

Explanation

Persistent ulnar nerve palsy after 6 weeks post-operatively, especially if it was noted acutely and has not shown signs of recovery, warrants consideration of surgical exploration and anterior transposition of the ulnar nerve. This is to address potential nerve entrapment by scar tissue, hematoma, or hardware, or to rule out nerve laceration. While some neuropraxias can recover over months, 6 weeks without any improvement is a strong indication for intervention, as further delay can lead to irreversible nerve damage. Observation for 6 months is too long. Corticosteroids are not indicated. Ultrasound can be helpful but surgical exploration is definitive. Psychological counseling is premature.

Question 706

Topic: Nerve & Tendon

When performing a posterior approach with an olecranon osteotomy, the ulnar nerve is typically identified and protected. What is the usual fate of the ulnar nerve after fracture fixation?

. It is resected to prevent future entrapment.
. It is always left in situ in the cubital tunnel.
. It is commonly transposed anteriorly, either subcutaneously or submuscularly.
. It is repaired to the triceps muscle.
. It is rarely identified, as it is deep to the bone.

Correct Answer & Explanation

. It is commonly transposed anteriorly, either subcutaneously or submuscularly.

Explanation

After identification and protection during distal humerus fracture surgery, the ulnar nerve is commonly transposed anteriorly. This is done to prevent potential entrapment in scar tissue, hardware, or malunion post-operatively, as well as to accommodate for any changes in the cubital tunnel anatomy during fixation. It can be transposed subcutaneously or submuscularly (under the flexor-pronator mass). Resecting the nerve is highly detrimental. Leaving it in situ risks entrapment. It is definitely identified as it's superficial in the cubital tunnel. It is not repaired to the triceps.

Question 707

Topic: Nerve & Tendon

What is the primary goal of restoring the carrying angle of the elbow during distal humerus fracture repair?

. To improve cosmetic appearance
. To prevent ulnar nerve compression
. To ensure proper biomechanics and function of the elbow joint
. To facilitate early wound healing
. To reduce the risk of heterotopic ossification

Correct Answer & Explanation

. To ensure proper biomechanics and function of the elbow joint

Explanation

The carrying angle is the slight valgus angle formed by the long axis of the humerus and the ulna when the arm is extended and supinated. Restoring the physiological carrying angle during distal humerus fracture repair is crucial for ensuring proper biomechanics and function of the elbow joint. Failure to do so can lead to cubitus varus or cubitus valgus deformities, causing instability, pain, altered gait mechanics, and potentially delayed ulnar nerve palsy (cubitus valgus). While cosmetics are a factor, biomechanics and function are paramount. Ulnar nerve compression is a risk of cubitus valgus, not the sole reason for restoration. It doesn't directly affect wound healing or HO risk.

Question 708

Topic: Nerve & Tendon

In the setting of a distal humerus fracture, which aspect of ulnar nerve management is typically not part of standard practice for a posterior approach?

. Identification and isolation of the nerve
. Intraoperative nerve monitoring (e.g., EMG)
. Routine primary repair of the nerve
. Anterior transposition if it's at risk of impingement or re-entrapment
. Gentle handling and protection throughout the procedure

Correct Answer & Explanation

. Routine primary repair of the nerve

Explanation

Routine primary repair of the ulnar nerve is typicallynotpart of standard practice unless there is a clear transection or severe laceration. For most cases, the nerve is identified, isolated, gently handled, protected, and often transposed anteriorly if at risk. Intraoperative nerve monitoring is increasingly used in complex cases. The goal is to prevent injury, and if a neuropraxia occurs, to manage it with observation or neurolysis/transposition, not primary repair unless completely severed.

Question 709

Topic: Nerve & Tendon

Which of the following is considered a potential consequence of an untreated cubitus valgus deformity following a malunited distal humerus fracture?

. Radial nerve palsy
. Median nerve entrapment
. Ulnar nerve neuropathy (tardy ulnar palsy)
. Compartment syndrome of the forearm
. Increased risk of shoulder dislocation

Correct Answer & Explanation

. Ulnar nerve neuropathy (tardy ulnar palsy)

Explanation

Cubitus valgus (increased valgus angle) deformity following a malunited distal humerus fracture can stretch and compress the ulnar nerve as it passes through the cubital tunnel posterior to the medial epicondyle. This chronic irritation can lead to a delayed or 'tardy' ulnar nerve palsy, characterized by paresthesia, weakness, and atrophy in the ulnar nerve distribution. Radial nerve palsy is associated with cubitus varus. Median nerve entrapment is not directly related to cubitus valgus. Compartment syndrome is acute. Shoulder dislocation is unrelated.

Question 710

Topic: Nerve & Tendon

Which of the following is the MOST common nerve injury associated with elbow dislocations?

. Radial nerve.
. Median nerve.
. Ulnar nerve.
. Musculocutaneous nerve.
. Anterior interosseous nerve.

Correct Answer & Explanation

. Ulnar nerve.

Explanation

The ulnar nerve is the most commonly injured nerve in association with elbow dislocations, occurring in approximately 5-15% of cases. It is vulnerable as it crosses the elbow in the cubital tunnel posterior to the medial epicondyle. While radial and median nerves can also be injured, they are less common. The musculocutaneous and anterior interosseous nerves are even rarer in this context.

Question 711

Topic: Nerve & Tendon

Which nerve is at highest risk during a medial approach to the elbow, which might be considered if other structures need repair alongside a radial head fracture (e.g., MCL)?

. Radial nerve
. Median nerve
. Ulnar nerve
. Musculocutaneous nerve
. Anterior interosseous nerve

Correct Answer & Explanation

. Ulnar nerve

Explanation

The ulnar nerve is the nerve at highest risk during a medial approach to the elbow. It runs in the cubital tunnel posterior to the medial epicondyle and is superficial in this region. Care must be taken to identify and protect it. Radial and median nerves are located more anterior and lateral to the medial epicondyle respectively, and are not the primary concern with a medial approach.

Question 712

Topic: Nerve & Tendon

A patient undergoing ORIF for a radial head fracture complains of numbness and tingling in the small and ring fingers post-operatively. Which nerve is most likely affected?

. Radial nerve
. Median nerve
. Ulnar nerve
. Musculocutaneous nerve
. Lateral cutaneous nerve of the forearm

Correct Answer & Explanation

. Ulnar nerve

Explanation

Numbness and tingling in the small and ring fingers are characteristic symptoms of ulnar nerve compression or injury. The ulnar nerve runs posteriorly to the medial epicondyle (cubital tunnel) and can be affected by direct trauma, swelling, or surgical manipulation during elbow procedures, including those for radial head fractures, particularly if a medial approach is used or the elbow is acutely swollen/positioned. Radial and median nerves would present with different sensory deficits.

Question 713

Topic: Nerve & Tendon

What is the primary role of the A4 pulley in the context of an FDP avulsion injury?

. It is the main pulley restricting FDP tendon retraction in Type I injuries.
. It provides the primary blood supply to the FDP tendon at the DIP level.
. It helps maintain the mechanical advantage of the FDP tendon, particularly during DIP flexion.
. Its integrity is crucial for preventing a boutonniere deformity.
. It prevents subluxation of the FDP tendon at the MCP joint.

Correct Answer & Explanation

. It helps maintain the mechanical advantage of the FDP tendon, particularly during DIP flexion.

Explanation

The A4 pulley, located over the middle of the distal phalanx, is crucial for maintaining the mechanical advantage of the FDP tendon for DIP joint flexion. Its integrity is important for effective FDP function. The A2 pulley is also very important for FDP mechanics. The A4 pulley does not primarily restrict retraction in Type I injuries (where the tendon often retracts to the palm). The vincula provide blood supply. It is not directly related to preventing a boutonniere deformity (which involves the central slip). It does not prevent FDP subluxation at the MCP joint (which involves the A1 pulley and sagitall bands).

Question 714

Topic: Nerve & Tendon

A 50-year-old carpenter sustained a Type I Jersey finger 3 days ago. During surgical exploration, the FDP tendon is found to be significantly retracted into the palm. What method is typically employed to retrieve the retracted tendon for repair?

. Use of a nerve hook through the flexor sheath.
. Extension of the incision proximally into the palm.
. Milking the forearm muscles to advance the tendon distally.
. Insertion of a specialized tendon retriever through the flexor sheath.
. Both B and D are common and effective techniques.

Correct Answer & Explanation

. Both B and D are common and effective techniques.

Explanation

Retrieving a significantly retracted FDP tendon (common in Type I injuries) often requires extending the Brunner's incision proximally into the palm to directly visualize and grasp the tendon. Additionally, specialized tendon retrievers can be used to pass through the flexor sheath from the distal incision to ensnare and pull the retracted tendon distally. Using a nerve hook alone may be insufficient for substantial retraction, and 'milking' muscles is not a precise surgical technique for tendon retrieval. Therefore, both extending the incision and using a tendon retriever are common and effective.

Question 715

Topic: Nerve & Tendon

Which factor is most likely to lead to a poor outcome following primary FDP repair for a Jersey finger?

. Repair within 7 days of injury.
. Adherence to an early active motion rehabilitation protocol.
. Smoking history of the patient.
. Use of a two-strand core suture technique.
. Associated A2 pulley rupture.

Correct Answer & Explanation

. Smoking history of the patient.

Explanation

Smoking significantly impairs wound healing and tendon repair due to its vasoconstrictive effects and negative impact on collagen synthesis, making it a strong predictor of poor outcomes and complications like re-rupture and stiffness. Repair within 7 days is associated with better outcomes, especially for Type I. Early active motion protocols are generally favored for improving outcomes. A two-strand core suture is typically considered a less strong repair compared to 4-strand or 6-strand, but its use alone is not the strongest predictor of poor outcome compared to smoking. An associated A2 pulley rupture would be addressed during surgery and may complicate rehab but not necessarily lead to a 'poor outcome' more than smoking.

Question 716

Topic: Nerve & Tendon

Following FDP repair, which of the following is a potential complication specifically associated with avulsion fractures where a large bone fragment is reattached?

. Lumbrical plus phenomenon.
. Quadriga effect.
. Non-union of the bony fragment.
. Swan neck deformity.
. Boutonniere deformity.

Correct Answer & Explanation

. Non-union of the bony fragment.

Explanation

When a bony avulsion fragment is reattached, particularly if it's large, a potential complication is non-union or malunion of the bony fragment. This can lead to persistent pain, tenderness, or mechanical issues. Lumbrical plus and quadriga effect are related to tendon shortening/tensioning. Swan neck and boutonniere deformities are typically associated with extensor mechanism imbalances or other conditions, not directly with bony fragment reattachment from a Jersey finger, although stiffness can contribute to such deformities over time. Therefore, non-union of the bony fragment is the most direct and specific complication related to reattaching a bone fragment.

Question 717

Topic: Nerve & Tendon

A patient presents with a chronic FDP rupture of the ring finger (6 months post-injury). On examination, he has a noticeable hyperextension of the PIP joint and flexion of the MCP joint of the affected digit when attempting to make a fist. This clinical presentation is consistent with:

. A quadriga effect.
. A boutonniere deformity.
. A swan neck deformity.
. A lumbrical plus phenomenon.
. Central slip rupture.

Correct Answer & Explanation

. A lumbrical plus phenomenon.

Explanation

This describes the lumbrical plus phenomenon. In a chronic FDP rupture, the FDP tendon is slack or absent. When the patient attempts to flex the finger, the lumbrical muscle is put under tension, and its pull on the lateral bands results in paradoxical DIP extension and PIP hyperextension. The MCP joint may flex as the lumbrical also flexes the MCP. Quadriga effect limits flexion of adjacent fingers. Boutonniere is PIP flexion and DIP hyperextension. Swan neck is PIP hyperextension and DIP flexion. Central slip rupture causes boutonniere. The specific pattern of attempted flexion leading to PIP hyperextension and DIP extension is key for lumbrical plus.

Question 718

Topic: Nerve & Tendon

A 32-year-old patient underwent FDP repair for a Type I Jersey finger 4 weeks ago. He is now in the early active motion phase of rehabilitation. He complains of pain and tenderness at the DIP joint with active flexion, but passive range of motion is full. What is the most common concern at this stage?

. Re-rupture of the FDP tendon.
. Persistent swelling and inflammation.
. Improper splint application causing pressure points.
. Developing adhesions limiting tendon glide.
. Early signs of infection.

Correct Answer & Explanation

. Developing adhesions limiting tendon glide.

Explanation

In the early active motion phase (typically starting around 3-4 weeks), pain with active motion combined with full passive range of motion is a common sign of developing adhesions within the flexor sheath. Adhesions restrict the smooth gliding of the tendon, causing pain when the patient attempts to actively move the digit against the resistance of the adhesions. Re-rupture would present with loss of active motion. Persistent swelling and infection would have more generalized symptoms. Improper splint application could cause pressure, but the specific presentation points to adhesions.

Question 719

Topic: Nerve & Tendon

What is the typical timeframe within which a Leddy and Packer Type I Jersey finger repair should ideally be performed to achieve the best outcomes and prevent tendon necrosis?

. Within 24 hours.
. Within 7-10 days.
. Within 3 weeks.
. Within 6 weeks.
. Anytime within 3 months, as long as appropriate rehabilitation is followed.

Correct Answer & Explanation

. Within 7-10 days.

Explanation

A Type I Jersey finger involves the FDP tendon avulsing without a bony fragment and retracting into the palm, often losing its blood supply from the vincula. This puts the tendon at high risk of necrosis. Therefore, surgical repair is considered urgent and should ideally be performed within 7-10 days of injury to maximize the chances of tendon survival and good functional outcome. Delays beyond this window significantly increase the risk of poor healing, tendon shortening, and the need for more complex reconstructive procedures.

Question 720

Topic: Nerve & Tendon

A patient is recovering from a FDP repair. He develops a 'swan neck deformity,' characterized by PIP hyperextension and DIP flexion. Which of the following is the most likely contributing factor in the context of a healed FDP repair?

. Flexor sheath adhesions limiting FDP excursion.
. Re-rupture of the FDP tendon.
. Laxity of the radial collateral ligament of the PIP joint.
. Chronic inflammation of the extensor mechanism.
. Over-tightening of the FDS tendon during surgery.

Correct Answer & Explanation

. Flexor sheath adhesions limiting FDP excursion.

Explanation

While swan neck deformity is classically associated with rheumatoid arthritis or other pathologies, it can occur after flexor tendon repair. If there are adhesions limiting the excursion of the FDP tendon, it can lead to a relative laxity of the FDP at the DIP joint. This laxity, combined with the normal pull of the extensor mechanism and potentially the intrinsic muscles, can result in PIP hyperextension and DIP flexion. Re-rupture would present with loss of active DIP flexion. The other options are less directly linked to FDP repair. Over-tightening of the FDS could lead to PIP flexion contracture, not hyperextension.

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