anatomy and physiology mcqs

Question #124

During clinical finals you examine a patient who has been complaining of tingling in her fingers. You notice she has some wasting over the thenar eminence but when you test sensation it appears to be intact. What is the most likely diagnosis?

Carpal tunnel syndrome classically presents with tingling in the fingers which is worse at night. The patient will wake up and find the symptoms improve with shaking.

Although the median nerve supplies the lateral 3 ½ digits often the patient is unable to distinguish this and will just complain of tingling in all the fingers.

The median nerve supplies the three thenar muscles (remember OAF: opponens pollicis, abductor pollicis brevis, flexor pollicis brevis) so compression of the nerve will cause weakness in these muscles and ultimately wasting.

The median nerve gives off a small branch before the carpal tunnel – the palmar cutaneous branch which supplies the skin over the thenar eminence. If sensation is altered here then the lesion must be proximal to the carpal tunnel.

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