Proximal phalanx of the thumb

Phalanx proximalis digiti I manus

SkeletalSkeletonArmLeft and right

View left in 3D View right in 3D

What it is
Proximal phalanx of the thumb, a short long bone with a concave base and a pulley-shaped head.
Function
Forms a lever of the finger moved by the long flexor and extensor tendons.
Size
≈ 25 mm long
Clinical note
Each finger has three phalanges but the thumb only two (14 per hand).

Nearby skeletal structures Capitate, Distal phalanx of the thumb, First metacarpal, Fourth metacarpal, Proximal phalanx of the index finger, Proximal phalanx of the middle finger, Second metacarpal, Third metacarpal, Trapezium, Trapezoid