What are the metacarpal bones and where are they located?

The metacarpal bones are the five small long bones that form the bony framework of the palm. They are numbered from the thumb side (lateral) to the little finger side (medial) and connect the carpal bones in the wrist to the phalanges in the fingers.

What are the main parts of a metacarpal bone?

Each metacarpal consists of three parts: the base (proximal, expanded end for articulation), the shaft (central part, concave on the palmar side and convex dorsally), and the head (distal, rounded end for articulation with a phalanx).

How is the first metacarpal (thumb) different from the others?

The first metacarpal is unique because it is the shortest and most robust, rotated 90° medially, and has a saddle-shaped base that articulates only with the trapezium. It also ossifies differently, with a secondary center at the base instead of the head, and often has two sesamoid bones on its palmar surface.

How do metacarpal bones develop (ossify)?

Metacarpals ossify from two centers: a primary center for the shaft appears around the 9th week of fetal life, and secondary centers appear later. For the 2nd to 5th metacarpals, the secondary center is in the head (appears around age 2, fuses around 16), while the first metacarpal has its secondary center in the base (appears around age 2, fuses around 18).

What bones do the metacarpals connect to in the hand?

The metacarpals connect the carpal bones of the wrist at their bases to the phalanges of the fingers at their heads, forming the structural link between the wrist and digits.

Metacarpal Bones Anatomy – Structure of the Hand

❓ Frequently Asked Questions

What are the metacarpal bones and where are they located?

What are the main parts of a metacarpal bone?

How is the first metacarpal (thumb) different from the others?

How do metacarpal bones develop (ossify)?

What bones do the metacarpals connect to in the hand?