Bones of the Foot

Main Regions and Surfaces of the Foot

The anatomy of the foot involves a strict division into surfaces and regions. In clinical and topographic anatomy, two main surfaces are distinguished:

• Sole — Planta.
• Dorsum of the foot — Dorsum pedis.

The skeletal framework includes three consecutive regions:

1. Tarsus — Tarsus.
2. Metatarsus — Metatarsus.
3. Bones of the digits (phalanges) — Digiti pedis.

Each digit of the foot has its own Latin nomenclature designation:

• First digit (great toe) — Hallux or Digitus primus.
• Second digit — Digitus secundus.
• Third digit — Digitus tertius.
• Fourth digit — Digitus quartus.
• Fifth digit (little toe) — Digitus minimus or Digitus quintus.

Tarsal Bones (Ossa tarsi)

The tarsus comprises 7 spongy bones, which are conveniently divided for study into two rows: proximal (closer to the leg) and distal.

The proximal row consists of only two, but the largest, bones:

• Talus — Talus. Its superior aspect forms a specialized trochlea (Trochlea tali). This trochlea features three articular surfaces necessary for the articulation with the bones of the leg.
• Calcaneus — Calcaneus. This is a massive bone whose posterior part forms a robust calcaneal tuberosity (Tuber calcanei).

The distal row includes five bones:

• Cuboid bone (Os cuboideum) — lies anterior to the calcaneus.
• Navicular bone (Os naviculare) — located anterior to the talus.
• Three cuneiform bones (Ossa cuneiformia) — lie anterior to the navicular bone. These include:
• Medial cuneiform bone (Os cuneiforme mediale) — projects at the level of the first metatarsal bone.
• Intermediate cuneiform bone (Os cuneiforme intermedium) — located at the level of the second metatarsal bone.
• Lateral cuneiform bone (Os cuneiforme laterale) — located at the level of the third metatarsal bone.

Metatarsal Bones (Ossa metatarsi I–V)

The metatarsal bones are similar to one another in shape, size, and ray orientation. In their internal structure, they are entirely analogous to the metacarpal bones of the hand.

Each of the five metatarsal bones has a central part (shaft) and two ends:

• Base — Basis ossis metatarsi. This is the proximal end of the bone.
• Body — Corpus ossis metatarsi. In cross-section, it has a triangular shape. An important anatomical feature: the dorsal surface of the body is more convex, while the plantar surfaces (medial and lateral) are somewhat concave.
• Head — Caput ossis metatarsi. This is the distal end of the metatarsal bone.

Bones of the Digits (Ossa digitorum, Phalanges)

The bones of the digits of the foot are represented by phalanges. Their number is strictly determined:

• Digits II–V each have three phalanges: proximal (Phalanx proximalis), middle (Phalanx media), and distal (Phalanx distalis).
• First digit (hallux) is structured differently: it consists of only two phalanges (proximal and distal).

The anatomical structure of each individual phalanx includes:

• Base — Basis phalangis.
• Body — Corpus phalangis. It is bilateral: the dorsal surface is slightly convex, and the plantar surface is slightly concave.
• Head — Caput phalangis.

A specific feature distinguishes the distal phalanges: their heads bear rough tuberosities (Tuberositas phalangis distalis).