First Metatarsal Bone

Key Features & Anatomical Relations

The first metatarsal bone is the shortest of the five metatarsal bones of the foot. It is classified as a long bone and includes the following bony features:

- parts: head, body and base;

- surfaces: medial and lateral surfaces;

- landmarks: tuberosity, sesamoid grooves, and 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 first metatarsal bone is located:

- proximal to the proximal phalanx of great toe;

- distal to the medial cuneiform bone;

- medial to the second metatarsal bone.

It articulates with the:

- proximal phalanx of great toe at the first metatarsophalangeal joint;

- medial cuneiform bone, contributing to the formation of the tarsometatarsal joints.

Ossification

Ossification of the first metatarsal bone occurs at two ossification centers, these are found in the:

- body, which appears in utero at third month;

- base, which appears during the third year.

These ossification centers fuse with each other during the 17th and 20th years (Standring, 2016).

Variations

In some individuals:

- the first metatarsal bone presents an articular facet for the second metatarsal bone;

- an accessory bone, known as the os intermetatarseum, may be associated with the first metatarsal bone (Standring, 2016).

Surface Anatomy

The following bony features of the first metatarsal bone are relevant to surface anatomy:

- its medial surface is subcutaneous and therefore easily palpated along its entire length;

- the head is palpable, especially during plantarflexion of the great toe.

List of Clinical Correlates

- Fracture

- Lisfranc injury

- Brachymetatarsia

- Neuropathic (diabetic) foot ulcer of the metatarsal head

- Morton’s syndrome

References

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