BoneLong bone
Middle phalanx of the index
Phalanx media sinistra
- Location:
- Hand — digits
- Paired structure: one on the left and one on the right side of the body.
Function
The finger's middle segment, hinged between PIP and DIP joints; the flexor digitorum superficialis inserts on its palmar base.
Landmarks
- Base
- Shaft
- Head
- Palmar ridge (flexor sheath)
Articulations (joints)
- Proximal phalanx of the index
- Next phalanx distally
Clinical relevance
Central-slip injuries at the middle phalanx's base produce boutonniere deformity — the PIP juts through a torn extensor hood.
Educational anatomy reference, not medical advice. About this content.