Final answer:
The ulnar nerve innervates all the hypothenar muscles, including the abductor digiti minimi, flexor digiti minimi brevis, and opponens digiti minimi. These muscles act on the little finger and form the rounded contour of the little finger.
Step-by-step explanation:
The ulnar nerve innervates all the hypothenar muscles. The hypothenar muscles include the abductor digiti minimi, flexor digiti minimi brevis, and opponens digiti minimi, which are located on the medial aspect of the palm. These muscles act on the little finger and form the hypothenar eminence, the rounded contour of the little finger.