From the Research
Lateral movements of the fingers are primarily controlled by the interosseous muscles and their tendons, specifically the dorsal interossei which abduct the fingers away from the middle finger and the palmar interossei which adduct the fingers toward the middle finger 1. The interosseous muscles originate between the metacarpal bones and insert via tendons onto the extensor expansions and proximal phalanges.
- The palmar (volar) interossei adduct the fingers toward the middle finger
- The dorsal interossei abduct the fingers away from the middle finger Additionally, the abductor digiti minimi specifically helps with lateral movement of the little finger. The extensor digitorum tendons also contribute indirectly to lateral finger movements when working in coordination with these intrinsic hand muscles. This arrangement allows for fine motor control and precision movements of the fingers. The interossei muscles are innervated by the ulnar nerve, except for the first two dorsal interossei which may receive partial innervation from the median nerve 2. Understanding these anatomical relationships is important for diagnosing and treating conditions affecting lateral finger movements, such as ulnar nerve injuries which can significantly impair these motions. The most recent and highest quality study on the topic of finger anatomy and movement is from 2020, which highlights the importance of the interosseous muscles and their tendons in lateral finger movements 3.