A patient has a tiny (0.2 cm), but exquisitely painful tumor under the nail of her index finger. Prior to surgery to remove it, local anesthetic block to a branch of which of the following nerves would be most likely to achieve adequate anesthesia?
The tumor in question is probably a glomus tumor, which is a benign tumor notorious for producing pain far out of propoion to its small size. The question is a little tricky (but impoant clinically for obvious reasons) because it turns out that the most distal aspect of the dorsal skin of the fingers, including the nail beds, is innervated by the palmar digital nerves rather than the dorsal digital nerves. Specifically, the median nerve through its palmar digital nerves supplies the nail beds of the thumb, index finger, middle finger, and half of the ring finger.The axillary nerve musculocutaneous nerve , and radial nerves do not supply the nail beds. Ref: Moon D.A., Foreman K.B., Albeine K.H. (2011). Chapter 32. Forearm. In D.A. Moon, K.B. Foreman, K.H. Albeine (Eds), The Big Picture: Gross Anatomy.
Axillary nerve
Median nerve
Musculocutaneous nerve
Radial nerve