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Third Metacarpal Bone
Skeletal System

Third Metacarpal Bone

Os tertium metacarpi

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Quick Facts

Location: Hand.

Bone Type: Long bone.

Key Features: Head, body, base, medial and lateral surfaces, styloid process, and proximal and distal articular facets.

Articulates With: Proximal phalanx of middle finger, capitate, second and fourth metacarpal bones.

Arterial Supply: Palmar metacarpal arteries.

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Key Features & Anatomical Relations

The third metacarpal bone is one of the five metacarpal bones of the hand. It’s classified as a long bone and includes the following bony features:

- parts: head, body, and base;

- surfaces: medial and lateral surfaces;

- landmarks: styloid process, proximal and distal articular facets.

More information regarding these bony features can be found in the Parts, Surfaces and Landmarks tabs for this bone.

The third metacarpal bone is located:

- proximal to the proximal phalanx of middle finger;

- distal to the capitate bone;

- medial to the second metacarpal bone;

- lateral to the fourth metacarpal bone.

It articulates with the:

- proximal phalanx of middle finger at the third metacarpophalangeal joint;

- capitate bone, contributing to the formation of the carpometacarpal joints;

- second and fourth metacarpal bones, contributing to the formation of the intermetacarpal joints.


Ossification of the third metacarpal bone occurs at two ossification centers, these are found in the:

- body, which appears in utero at the ninth week;

- head, which appears within the second to third years.

These ossification centers fuse with each other during the fifteenth to nineteenth years (Standring, 2016).


In some individuals, the styloid process of the third metacarpal bone does not fuse with the rest of the bone. Instead it exists as an accessory bone, known the os styloideum, which is present between the second and third metacarpal bones (Tubbs, Shoja and Loukas, 2016).

Surface Anatomy

The following bony features of the third metacarpal bone are relevant to surface anatomy:

- the head can be palpated at the “knuckle” that is proximal to the proximal phalanx of the middle finger, particularly during flexion of the third metacarpophalangeal joint;

- the body and base can be palpated along the dorsal aspect of the hand.

List of Clinical Correlates

- Fracture of third metacarpal bone (base or body)

- Boxer’s fracture of third metacarpal bone

- Mauclaire’s disease


Standring, S. (2016) Gray's Anatomy: The Anatomical Basis of Clinical Practice. Gray's Anatomy Series 41st edn.: Elsevier Limited.

Tubbs, R. S., Shoja, M. M. and Loukas, M. (2016) Bergman's Comprehensive Encyclopedia of Human Anatomic Variation. Wiley.

Learn more about this topic from other Elsevier products

Metacarpal Bone

ScienceDirect image

The dorsally convex metacarpal bones act as skeletal arches to provide a gliding surface for the long extensor tendons and a concavity in which the long flexors and lumbrical muscles tuck away into the palm.

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