Froment's test is primarily used to assess which condition?

Froment's test is primarily utilized to evaluate the integrity of the ulnar nerve, specifically focusing on the functioning of the adductor pollicis muscle, which is responsible for adducting the thumb. In the context of an ulnar nerve lesion, patients often exhibit a compensatory mechanism using the flexor pollicis longus muscle to grasp an object between the thumb and the index finger, leading to a characteristic pinch grip. This test assesses whether the patient can maintain this grip without compensating by flexing the thumb. A positive Froment's sign indicates that the patient experiences difficulty in maintaining the grip due to weakness in the adductor pollicis, thus highlighting the dysfunction associated with ulnar nerve damage.

Other options refer to different nerve lesions that have their specific tests and clinical implications. Median nerve lesions may impact thumb opposition and the ability to perform the ‘OK’ sign, while radial nerve lesions primarily affect wrist extension and finger extension. Musculocutaneous nerve lesions predominantly affect the flexion of the elbow and are less related to functions evaluated by Froment's test. Therefore, the test's design and purpose firmly link it to the assessment of ulnar nerve function.