Espiral AtlasInterphalangeal joints of the hand
articulationes interphalangeae manus
Study entry
Classification
Hinge synovial joints: proximal and distal in fingers 2 to 5, a single one in the thumb.
Surfaces
Head of each phalanx with the base of the next; the heads of the proximal and middle phalanges are flattened and have two small condyles.
Capsule
Capsule with collateral ligaments and a palmar ligament, as in the metacarpophalangeal joints; the palmar ligaments fuse with the digital fibrous sheaths, forming a smooth tunnel for the flexor tendons.
Movements
Only flexion and extension.
Blood supply
Deep digital arteries, branches of the superficial palmar arch.
Innervation
Digital nerves from the ulnar and median nerves.
Source: cap. 3, «Articulaciones del miembro superior: articulaciones metacarpofalángicas e interfalángicas»
Clinical correlation
Mallet finger
A sudden tension on the long extensor tendon may tear off part of its attachment at the base of the distal phalanx, for example when a baseball hits the fingertip and forces the distal interphalangeal joint into flexion while the finger tries to extend. Afterward, the person cannot extend the distal interphalangeal joint, and the finger resembles a hammer.
Related clinical cases
- Mallet finger