Which intrinsic hand muscle group is innervated by the ulnar nerve?

Which intrinsic hand muscle group is innervated by the ulnar nerve?

• A. Interossei and hypothenar muscles
• B. Abductor digiti minimi
• C. Adductor pollicis only
• D. Lateral two lumbricals

Answer: (A)

The ulnar nerve primarily supplies the intrinsic hand muscles, especially the interossei and the hypothenar group. This is the best answer because those muscles form the core set of intrinsic hand muscles innervated by the ulnar nerve, with the interossei (both dorsal and palmar) responsible for finger abduction and adduction, and the hypothenar muscles (including the abductor digiti minimi, flexor digiti minimi brevis, and opponens digiti minimi) helping move the little finger. The thenar muscles and the lateral two lumbricals are supplied by the median nerve, so they don’t belong to the ulnar-innervated group. While a single muscle like abductor digiti minimi is indeed part of the hypothenar group, the question asks for the broader intrinsic hand muscle group innervated by the ulnar nerve, which is the interossei plus hypothenar muscles. Adductor pollicis is also ulnar, but it is not the whole group, and the lateral two lumbricals are innervated by the median nerve.

The ulnar nerve primarily supplies the intrinsic hand muscles, especially the interossei and the hypothenar group. This is the best answer because those muscles form the core set of intrinsic hand muscles innervated by the ulnar nerve, with the interossei (both dorsal and palmar) responsible for finger abduction and adduction, and the hypothenar muscles (including the abductor digiti minimi, flexor digiti minimi brevis, and opponens digiti minimi) helping move the little finger. The thenar muscles and the lateral two lumbricals are supplied by the median nerve, so they don’t belong to the ulnar-innervated group. While a single muscle like abductor digiti minimi is indeed part of the hypothenar group, the question asks for the broader intrinsic hand muscle group innervated by the ulnar nerve, which is the interossei plus hypothenar muscles. Adductor pollicis is also ulnar, but it is not the whole group, and the lateral two lumbricals are innervated by the median nerve.