Second metacarpal

Os metacarpi II

SkeletalSkeletonArmLeft and right

View left in 3D View right in 3D

What it is
Long bone of the palm behind the index finger, with a base at the carpus, a slender shaft and a rounded head forming the knuckle.
Function
Forms the skeleton of the palm and the knuckle joint of its finger.
Size
≈ 56 mm long
Clinical note
The metacarpal heads are the knuckles seen when making a fist.

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