Upper limb

Extensor Hood of the Ring Finger

Aponeurosis dorsalis digiti IV manus

Origin

Dorsal aspect of the base of the proximal phalanx of the ring finger, where the tendon of extensor digitorum joins the lumbrical and the interossei

Insertion

Base of the middle and distal phalanx of the ring finger

Function

Distributes the pulling force of extensor digitorum and the intrinsic hand muscles across the proximal and distal interphalangeal joints

Innervation

Mixed: radial nerve (extensor digitorum) and median/ulnar nerve (lumbrical and interossei)

Movement & chain

Allows the metacarpophalangeal joint of the ring finger to flex while the interphalangeal joints remain extended, such as during a precision grip.

Palpation

Palpable along the dorsum of the 4th digit over the MCP and proximal phalanx.

Clinical

Coordinates IP extension with MCP flexion; terminal tendon avulsion at the DIP joint produces a mallet finger deformity.

Segmental innervation

C7–C8 (radial nerve) & C8–T1 (ulnar nerve)

In clinical practice

Focus on hand function and edema prevention; ensure IV cannulas and splints maintain functional hand position to prevent joint contractures.

Region in the model

Upper limb