NATA-BOC Clinical Evaluation and Diagnosis 2 — Questions and Answers
Question 1: A patient presents with a positive Thompson test. Which structure is most likely injured?
- Anterior cruciate ligament
- Achilles tendon (Correct answer)
- Posterior tibialis tendon
- Patellar tendon
Correct answer: Achilles tendon
The Thompson test (calf squeeze test) assesses the integrity of the Achilles tendon. A positive result, indicated by the absence of passive plantar flexion when the calf is squeezed, suggests a rupture of the Achilles tendon.
The Thompson test is performed with the patient lying prone and the foot hanging off the edge of the table. The athletic trainer squeezes the calf musculature; a normal response is passive plantar flexion of the foot. If the foot does not plantar flex, it indicates a disruption of the Achilles tendon, which is the only tendon connecting the gastrocnemius-soleus complex to the calcaneus. The ACL is assessed by the Lachman test, and the patellar tendon is evaluated through resisted knee extension.
Question 2: Which clinical sign is most indicative of a Grade III lateral ankle sprain?
- Point tenderness over the lateral malleolus
- Positive anterior drawer test with a firm endpoint
- Positive talar tilt test with no endpoint (Correct answer)
- Ecchymosis limited to the anterior talofibular ligament
Correct answer: Positive talar tilt test with no endpoint
A positive talar tilt test with no definitive endpoint indicates complete rupture of the calcaneofibular ligament, consistent with a Grade III sprain involving multiple ligament tears and gross instability.
Lateral ankle sprains are graded I through III based on severity. Grade I involves stretching with minimal tearing, Grade II involves partial tearing with moderate instability, and Grade III involves complete rupture with gross instability. The talar tilt test assesses the calcaneofibular ligament. When performed on a Grade III sprain, the lack of an endpoint indicates there is no ligamentous resistance to inversion stress. A firm endpoint would suggest the ligament is still partially intact (Grade I or II).
Question 3: During evaluation of a shoulder injury, the patient cannot maintain 90 degrees of abduction against gravity. Which nerve is most likely compromised?
- Long thoracic nerve
- Axillary nerve (Correct answer)
- Suprascapular nerve
- Musculocutaneous nerve
Correct answer: Axillary nerve
The axillary nerve innervates the deltoid muscle, which is the primary abductor of the shoulder beyond 15 degrees. Inability to maintain abduction against gravity suggests axillary nerve compromise.
The axillary nerve (C5-C6) innervates the deltoid and teres minor muscles. The deltoid is the primary mover for shoulder abduction from approximately 15 to 90 degrees and beyond. Axillary nerve injury commonly occurs with anterior shoulder dislocations or fractures of the surgical neck of the humerus. The suprascapular nerve innervates the supraspinatus (which initiates abduction 0-15 degrees) and infraspinatus. The long thoracic nerve innervates the serratus anterior, and its injury causes scapular winging.
Question 4: An athlete complains of numbness in the thumb, index, and middle fingers that worsens at night. Which test would be most appropriate to confirm the suspected diagnosis?
- Froment sign
- Phalen test (Correct answer)
- Finkelstein test
- Allen test
Correct answer: Phalen test
The Phalen test is used to diagnose carpal tunnel syndrome, which involves compression of the median nerve. Numbness in the thumb, index, and middle fingers that worsens at night is a classic presentation of this condition.
Carpal tunnel syndrome results from compression of the median nerve as it passes through the carpal tunnel at the wrist. The median nerve provides sensory innervation to the palmar side of the thumb, index finger, middle finger, and the lateral half of the ring finger. Night symptoms are characteristic because wrist flexion during sleep increases pressure in the tunnel. The Phalen test involves holding the wrists in maximal flexion for 60 seconds; reproduction of symptoms is a positive result. The Froment sign tests ulnar nerve function, the Finkelstein test assesses De Quervain tenosynovitis, and the Allen test evaluates vascular supply to the hand.
Question 5: Which clinical finding best differentiates a meniscal tear from a ligamentous injury of the knee?
- Presence of an effusion
- Joint line tenderness with a positive McMurray test (Correct answer)
- Positive valgus stress test
- Quadriceps atrophy
Correct answer: Joint line tenderness with a positive McMurray test
Joint line tenderness combined with a positive McMurray test (pain and/or clicking with tibial rotation during knee extension) is highly suggestive of a meniscal tear, helping differentiate it from ligamentous injuries.
The McMurray test is performed by flexing the knee fully, applying a valgus or varus force, and then extending the knee while internally or externally rotating the tibia. A positive test produces a palpable click or pain along the joint line, indicating a meniscal tear. Joint line tenderness alone has moderate sensitivity but when combined with a positive McMurray test, specificity increases significantly. Effusion can occur with both meniscal and ligamentous injuries. Valgus stress testing assesses the MCL. Quadriceps atrophy is a chronic finding that may accompany various knee pathologies.
Question 6: An athlete sustains a direct blow to the lateral aspect of the knee. Which structure is most at risk for injury?
- Lateral collateral ligament
- Medial collateral ligament (Correct answer)
- Posterior cruciate ligament
- Lateral meniscus
Correct answer: Medial collateral ligament
A direct blow to the lateral knee creates a valgus force, placing stress on the medial structures. The medial collateral ligament is the primary restraint against valgus stress and is most commonly injured with this mechanism.
When a valgus force is applied to the knee (blow to the lateral side), the medial side of the joint is forced open. The MCL is the primary static stabilizer against valgus stress at the knee. This mechanism is extremely common in contact sports, particularly football. The LCL would be injured by a varus force (blow to the medial knee). The PCL is typically injured by a posterior-directed force on the proximal tibia (dashboard injury). The lateral meniscus is somewhat protected by its loose peripheral attachment and greater mobility compared to the medial meniscus.
NATA-BOC Clinical Evaluation and Diagnosis 2
A patient presents with a positive Thompson test.
Which structure is most likely injured?