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 241
Topic: Nerve & Tendon
Percutaneous release of the A1 pulley is an accepted treatment for trigger finger. For which of the following digits is percutaneous release considered relatively contraindicated due to the anatomical vulnerability of the adjacent digital nerve?
Correct Answer & Explanation
. Index finger
Explanation
Percutaneous release of the index finger is generally contraindicated because its radial digital nerve crosses obliquely over the proximal aspect of the A1 pulley. This positioning makes the nerve highly susceptible to iatrogenic transection during a blind percutaneous approach.
Question 242
Topic: Nerve & Tendon
During a surgical reconstruction for a Blauth Type IIIA hypoplastic thumb, the surgeon performs a radical release of the adductor pollicis muscle to deepen the first web space. Which of the following neurovascular structures is at greatest risk of iatrogenic injury during this specific step?
Correct Answer & Explanation
. Deep palmar arch and ulnar nerve motor branch
Explanation
The adductor pollicis muscle lies deep in the palm, and its release requires careful dissection in proximity to the deep palmar arch and the ulnar nerve motor branch. These structures are at risk during this specific step of the procedure.
Question 243
Topic: Nerve & Tendon
A 55-year-old heavy laborer presents with elbow stiffness, loss of terminal extension, and painful clicking. Radiographs reveal osteophytes at the olecranon tip, coronoid, and several loose bodies in the olecranon fossa. Which physical exam finding is most typical for this primary osteoarthritis condition?
Correct Answer & Explanation
. Pain at the extreme end-ranges of elbow flexion and extension
Explanation
Primary osteoarthritis of the elbow classically presents with impingement pain at the extreme end-ranges of motion due to osteophyte formation and loose bodies in the fossae, while mid-arc motion typically remains relatively painless.
Question 244
Topic: Nerve & Tendon
A 50-year-old man complains of lateral elbow pain radiating down the posterior forearm. He has pain with resisted supination and middle finger extension, but Cozen's test is negative. There is no sensory deficit. This clinical presentation most closely mimics lateral epicondylitis but is actually due to entrapment of which nerve?
Correct Answer & Explanation
. Posterior interosseous nerve (PIN) at the Arcade of Frohse
Explanation
Radial tunnel syndrome (entrapment of the posterior interosseous nerve) presents with lateral forearm pain and can mimic lateral epicondylitis. Pain with resisted middle finger extension or resisted supination is characteristic, and unlike PIN palsy, there is typically no motor weakness, only pain.
Question 245
Topic: Nerve & Tendon
During the utility posterior approach for a terrible triad repair, the ulnar nerve is a critical structure to manage. What is the specific management strategy for the ulnar nerve described in the operative sequence?
Correct Answer & Explanation
. C) Identification, decompression, and protection in situ
Explanation
Correct Answer: CThe case details the ulnar nerve management: "The ulnar nerve would be identified, decompressed, and protected in situ." This approach aims to prevent iatrogenic injury to the nerve during the procedure while avoiding unnecessary transposition unless indicated by preoperative symptoms or significant intraoperative tension.
Question 246
Topic: Nerve & Tendon
A 32-year-old carpenter presents with progressive difficulty making a full fist with his right ring finger, particularly when attempting to grasp small objects. He reports a history of a 'Jersey finger' injury to the same digit 6 months prior, which was surgically repaired. On examination, when he attempts to actively flex his ring finger, his metacarpophalangeal (MCP) joint flexes, but his proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints paradoxically extend. Passive range of motion of the PIP and DIP joints is full. Based on the epidemiology and pathophysiology described in the case, which of the following is the most likely underlying mechanism for this patient's current deformity?
Correct Answer & Explanation
. Proximal retraction of the avulsed FDP tendon, causing the lumbrical to become functionally unopposed distally.
Explanation
The patient's presentation of a 'Jersey finger' injury (avulsion of the FDP insertion) followed by paradoxical IP extension during attempted active flexion is a classic description of a lumbrical plus deformity. Avulsion of the FDP insertion is a common scenario where the lumbrical muscle, which originates from the FDP, becomes functionally unopposed distally. Attempted FDP activation then primarily pulls on the lumbrical, leading to its paradoxical action.
Question 247
Topic: Nerve & Tendon
A 60-year-old patient is scheduled for surgical correction of a lumbrical plus deformity in the small finger. During pre-operative planning, the surgeon emphasizes the importance of a detailed history and physical examination. Which of the following findings on physical examination is considered the hallmark of lumbrical plus deformity?
Correct Answer & Explanation
. Paradoxical extension of the PIP and DIP joints during attempted active flexion of the digit.
Explanation
The hallmark lumbrical plus deformity manifests as MCP flexion with paradoxical PIP and DIP extension during attempted active flexion of the involved digit.
Question 248
Topic: Nerve & Tendon
A 5-year-old boy falls from monkey bars and sustains an extension-type supracondylar humerus fracture. Radiographs demonstrate that the distal fragment is displaced posteromedially. Based on this displacement pattern, which nerve is at the highest risk of injury?
Correct Answer & Explanation
. Anterior interosseous nerve
Explanation
In extension-type supracondylar fractures with posteromedial displacement of the distal fragment, the proximal fragment spikes anterolaterally, putting the radial nerve at greatest risk. Posterolateral displacement puts the anterior interosseous nerve (AIN) at highest risk.
Question 249
Topic: Nerve & Tendon
A 30-year-old recreational basketball player jams his right middle finger. He presents with an inability to actively extend the distal interphalangeal (DIP) joint. Radiographs show no fracture. What is the most appropriate treatment for this closed tendinous mallet finger?
Correct Answer & Explanation
. Splinting of the DIP joint in full extension for 6 to 8 weeks
Explanation
The standard of care for a closed, tendinous mallet finger is continuous, rigid splinting of the DIP joint in full extension or slight hyperextension for 6 to 8 weeks. The PIP joint must be left free to allow full range of motion.
Question 250
Topic: Nerve & Tendon
A 25-year-old rock climber presents with a sudden 'pop' and inability to flex the DIP joint of his middle finger. MRI confirms a Leddy-Packer Type I flexor digitorum profundus (FDP) avulsion. The tendon has retracted into the palm. Within what timeframe must surgical repair ideally be performed to prevent irreversible tendon necrosis and myostatic contracture?
Correct Answer & Explanation
. Within 7 to 10 days
Explanation
In a Leddy-Packer Type I Jersey finger, both the vincula brevia and longa are ruptured, and the FDP tendon retracts into the palm. The tendon loses its entire blood supply and relies on synovial diffusion; therefore, primary repair must be performed within 7 to 10 days before the tendon becomes necrotic and irreparably contracted.
Question 251
Topic: Nerve & Tendon
A 25-year-old rugby player sustains a jersey finger (avulsion of the flexor digitorum profundus). Imaging reveals a Leddy-Packer Type 1 injury, where the tendon has retracted into the palm. What is the recommended timing for surgical repair?
Correct Answer & Explanation
. Within 7 to 10 days
Explanation
A Type 1 FDP avulsion retracts into the palm, disrupting both the vincula brevia and longa, severely compromising the tendon's blood supply. Surgery must be performed within 7-10 days to prevent permanent tendon retraction and necrosis.
Question 252
Topic: Nerve & Tendon
When utilizing a crossed-pinning technique (one medial and one lateral K-wire) for the fixation of a pediatric supracondylar humerus fracture, what is the most significant iatrogenic risk associated with the medial pin placement?
Correct Answer & Explanation
. Ulnar nerve injury
Explanation
Placement of a medial pin in supracondylar humerus fractures carries a recognized risk of iatrogenic ulnar nerve injury due to the nerve's posterior course in the cubital tunnel. To mitigate this, the elbow is often extended slightly from hyperflexion during medial pin insertion.
Question 253
Topic: Nerve & Tendon
A 35-year-old carpenter underwent a primary flexor digitorum profundus (FDP) repair in his right ring finger one month ago. He now complains that he is entirely unable to make a full fist with his uninjured middle and small fingers. Which of the following biomechanical phenomena explains this presentation?
Correct Answer & Explanation
. Quadrigia effect
Explanation
The quadrigia effect occurs when the FDP tendon is over-advanced during repair. Because the FDP tendons to the middle, ring, and small fingers share a common muscle belly, over-tensioning one tendon restricts the excursion of the others.
Question 254
Topic: Nerve & Tendon
A 22-year-old collegiate rugby player sustained an injury to his right ring finger when he violently grabbed an opponent's jersey. He is unable to actively flex the distal interphalangeal (DIP) joint. Ultrasound confirms a Type I Leddy-Packer avulsion, with the flexor digitorum profundus (FDP) tendon retracted into the palm. Within what timeframe must surgical repair ideally be performed to prevent permanent contracture and tendon necrosis?
Correct Answer & Explanation
. Within 7 to 10 days
Explanation
A Type I "Jersey finger" involves retraction of the FDP tendon into the palm, which disrupts the vincula and severely compromises the tendon's blood supply. Surgical repair must be performed within 7 to 10 days to prevent permanent tendon necrosis and fixed contracture.
Question 255
Topic: Nerve & Tendon
A 30-year-old recreational basketball player sustained an untreated mallet injury to his middle finger eight months ago. He now presents complaining of a secondary finger deformity. Based on the pathophysiology of chronic mallet finger, which of the following deformities is he at greatest risk of developing?
Correct Answer & Explanation
. Swan neck deformity
Explanation
An untreated mallet finger leads to loss of terminal extensor tendon continuity. The extensor mechanism retracts proximally, concentrating extensor forces at the PIP joint. Over time, this stretches the volar plate, resulting in PIP hyperextension and DIP flexion (Swan neck deformity).
Question 256
Topic: Nerve & Tendon
A 25-year-old chef sustains a knife laceration to the volar aspect of his palm at the level of the A1 pulley. During surgical exploration, both the flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP) tendons are found cleanly transected. In which flexor tendon zone did this injury occur, and what is the current standard of care?
Correct Answer & Explanation
. Zone II; repair both FDP and FDS
Explanation
Zone II extends from the A1 pulley to the FDS insertion and contains both tendons within a tight fibro-osseous sheath. The current standard of care is the primary repair of both the FDS and FDP to optimize tendon gliding, preserve independent PIP joint flexion, and improve vascularity.
Question 257
Topic: Nerve & Tendon
What neurovascular structure is in closest proximity to the probe in the arthroscopic view of the elbow shown in Figure 50? Review Topic
Correct Answer & Explanation
. Radial nerve
Explanation
The image shows a view of the radiocapitellar joint from an anterior medial portal. The radial nerve lies on the elbow capsule at the midportion of the capitellum. It is at risk for injury when capsular excision is performed in this region.
Question 258
Topic: Nerve & Tendon
A 35-year-old man falls off of a roof and sustains an extra-articular supracondylar elbow fracture. He had normal sensation in all fingers after the injury and before undergoing surgery to repair the fracture. The ulnar nerve was not transposed but was inspected prior to wound closure. Ten days after surgery, the patient has numbness in his small finger and is unable to cross his fingers. His elbow range of motion is 40ยฐ to 100ยฐ. What is the next appropriate step in management?
Correct Answer & Explanation
. Continued observation
Explanation
This patient has an early postsurgical ulnar nerve palsy. The causes of this injury are laceration of the nerve during surgery, entrapment of the nerve in the fracture or hardware, or traction injury during surgery. If the orthopaedic surgeon is sure that the nerve was not lacerated at the end of the case or entrapped in the hardware, then the nerve is probably intact and will recover. Observation is the best treatment in this case because the nerve was checked before wound closure. Elbow splinting has not been shown to help with postsurgical nerve recovery. EMG findings may not be accurate this early following the injury.
Question 259
Topic: Nerve & Tendon
Figures 55a through 55c are the clinical photograph and radiographs of a 5-year-old boy who fell and injured his right elbow. His radial pulse is thready. Which neurologic deficit most commonly is associated with this injury?
Correct Answer & Explanation
. Inability to flex the thumb interphalangeal (IP) joint
Explanation
DISCUSSION: This injury is a type III supracondylar humerus fracture with posterolateral displacement. The area of ecchymosis is anteromedial, corresponding to the proximal spike of the humeral metaphysis. The brachial artery is likely tented over this spike, leading to diminished perfusion. The median nerve also resides in this area, and any neurological deficit is likely in its most vulnerable fibers, those of the anterior interosseous nerve (AIN). The AIN contains no sensory fibers, and its motor function involves flexion of both the thumb IP joint and the index distal IP joint. First dorsal web space anesthesia and an inability to extend the fingers would indicate radial nerve neuropraxia, which would be more likely with posteromedially displaced fractures and lead to anterolateral ecchymosis. Finger abduction is controlled by the ulnar nerve, which most often is injured in flexion injuries and iatrogenically by medially placed pins.
Question 260
Topic: Nerve & Tendon
Which method of flexor tendon repair that necessitates excursion through the A2 pulley allows for the most thorough assessment of tendon gliding?
Correct Answer & Explanation
. Strand repair with 6-0 epitendinous suture with Bier block anesthesia
Explanation
EXPLANATION: Wide-awake repair under only local anesthesia, regardless of the technique, allows direct inspection of the tendon repair and active excursion. Regional anesthesia and Bier block anesthesia do not allow active motion (Bier block necessitates continued use of a tourniquet, which limits muscle function). The A2 pulley should be preserved, especially the distal 50%, to maintain tendon function. All of the listed techniques for suture repair are acceptable options.
Test Yourself
Switch to an interactive, timed exam simulation to truly master this topic.
