What areas does the ulnar nerve provide sensory innervation to?

The ulnar nerve primarily provides sensory innervation to the area of the hand that includes the anterior middle of the ring finger and extends to the pinkie finger. This is attributed to the ulnar nerve's distribution, which innervates the medial side of the hand. It plays a major role in sensation for the little finger, half of the ring finger, and the associated palm area. This sensory pathway allows the ulnar nerve to convey fine touch and temperature sensations from these specific digits.

In contrast, the other areas mentioned, such as the dorsal surface of the hand, the tip of the thumb and index finger, and the lateral aspect of the forearm, are innervated by different nerves. The dorsal surface of the hand receives sensory innervation mainly from the radial nerve, while the sensory areas for the thumb and index finger are largely served by the median nerve. The lateral aspect of the forearm is also primarily supplied by the musculocutaneous nerve. Understanding these distinctions is crucial for recognizing nerve pathologies and their effects on sensation in various regions of the upper limb.