What nerve is associated with the innervation of the 4th and 5th fingers?

The ulnar nerve is primarily responsible for the innervation of the 4th and 5th fingers (the ring and little fingers). This nerve facilitates both sensory and motor functions in these digits, enabling activities such as gripping and sensation. The ulnar nerve controls several intrinsic muscles of the hand, including the hypothenar muscles, which are crucial for the fine motor skills necessary for the movements of the ring and little fingers.

In contrast, the radial nerve primarily extends the wrist and fingers and is more involved with the thumb and back of the hand. The median nerve mainly innervates the thumb, index finger, middle finger, and part of the ring finger. The axillary nerve is associated with the deltoid and teres minor muscles, affecting the shoulder area rather than the fingers. Thus, the ulnar nerve is the correct choice for innervating the 4th and 5th fingers.