BoneLong bone
Proximal phalanx of the thumb
Phalanx proximalis sinistra
- Location:
- Hand — digits
- Paired structure: one on the left and one on the right side of the body.
Function
The first segment of each finger — its base meets the metacarpal head (the knuckle) at the MCP joint and its head forms the PIP joint that lets the finger curl.
Landmarks
- Base
- Shaft
- Head
- Palmar ridge (flexor sheath)
Articulations (joints)
- Metacarpal 1
- Next phalanx distally
Clinical relevance
Proximal phalanx shaft fractures spiral and rotate — any overlapping fingernails on making a fist need fixation.
Educational anatomy reference, not medical advice. About this content.