Froment’s sign is seen in?
**Core Concept**
Froment's sign is a clinical test used to assess the integrity of the ulnar nerve, specifically the adductor pollicis muscle, which is innervated by the ulnar nerve. This test evaluates the strength of the adductor pollicis muscle and its ability to contract in opposition to the flexor pollicis longus muscle.
**Why the Correct Answer is Right**
When performing Froment's sign, the patient is asked to hold a piece of paper between their thumb and index finger, and then asked to adduct their thumb against resistance. In a normal individual, the adductor pollicis muscle contracts and the thumb is adducted. However, if the ulnar nerve is damaged, the adductor pollicis muscle is weakened, and the patient will compensate by using the flexor pollicis longus muscle, flexing the interphalangeal joint of the thumb to maintain the grip.
**Why Each Wrong Option is Incorrect**
* **Option A:** The pronator drift test is used to assess the integrity of the median nerve, not the ulnar nerve.
* **Option B:** The Tinel's sign is a clinical test used to assess nerve regeneration, not a specific muscle or nerve injury.
* **Option C:** The Mallet finger test is used to assess the integrity of the extensor tendon of the finger, not the ulnar nerve.
**Clinical Pearl / High-Yield Fact**
Froment's sign is a useful clinical test for diagnosing ulnar nerve injury, particularly at the elbow or wrist. It is essential to remember that a positive Froment's sign indicates ulnar nerve damage, and further investigation is necessary to determine the level and extent of the injury.
**Correct Answer: C. Mallet finger test is used to assess the integrity of the extensor tendon of the finger, not the ulnar nerve.**