Bones of the Foot

The human foot contains a total of 26 bones, forming a complex structure that supports body weight, enables locomotion, and provides balance. These bones are organized into three functional groups: the tarsal bones (forming the hindfoot and midfoot), the metatarsal bones (forming the forefoot), and the phalanges (toes). Each group plays a distinct role in foot mechanics and contributes to the structural arches that provide spring and stability during walking and running.

Tarsal Bones

There are seven tarsal bones located in the hindfoot and midfoot. These are the talus, calcaneus, navicular, cuboid, and the three cuneiform bones (medial, intermediate, and lateral).

1. Talus

The talus is the second largest tarsal bone and forms the lower part of the ankle joint by articulating with the tibia and fibula. It has no muscular attachments and transmits the entire weight of the body to the foot via the calcaneus and navicular bones.

• Superior surface: Articulates with the tibia (trochlea of talus).
• Inferior surface: Articulates with the calcaneus at the subtalar joint.
• Head: Articulates anteriorly with the navicular.

2. Calcaneus

The calcaneus is the largest tarsal bone and forms the heel. It serves as the primary weight-bearing bone of the foot during standing and walking.

• Posterior surface: Provides attachment for the Achilles tendon.
• Superior surface: Articulates with the talus at the subtalar joint.
• Anterior surface: Articulates with the cuboid.

3. Navicular

The navicular is a boat-shaped bone located medially in the midfoot. It articulates with the talus posteriorly and the three cuneiforms anteriorly.

• Tuberosity of navicular: Prominent medial projection for attachment of the tibialis posterior tendon.

4. Cuboid

The cuboid is located on the lateral side of the foot. It articulates with the calcaneus posteriorly, the fourth and fifth metatarsals anteriorly, and the lateral cuneiform and navicular medially.

5. Cuneiform Bones

There are three cuneiform bones: medial, intermediate, and lateral. These bones lie anterior to the navicular and articulate with the first three metatarsals.

Cuneiform	Location	Articulations
Medial cuneiform	Most medial of the three	Navicular, 1st and 2nd metatarsals
Intermediate cuneiform	Between medial and lateral	Navicular, 2nd metatarsal
Lateral cuneiform	Most lateral of the three	Navicular, 2nd and 3rd metatarsals

Metatarsal Bones

The foot has five metatarsal bones, labeled I through V from medial to lateral. They are long bones with a base (proximal), shaft (body), and head (distal). These bones form the framework of the forefoot and play a vital role in weight transfer during gait.

• 1st metatarsal: Shortest and thickest; bears the most weight and articulates with the medial cuneiform.
• 2nd metatarsal: The longest and deeply recessed between the medial and lateral cuneiforms.
• 3rd metatarsal: Articulates with the lateral cuneiform.
• 4th and 5th metatarsals: Articulate with the cuboid.

Each metatarsal has:

• Base: Proximal end articulating with tarsal bones.
• Head: Distal end forming joints with the proximal phalanges.
• Styloid process of 5th metatarsal: Lateral projection serving as attachment for the fibularis brevis tendon.

Phalanges

The toes contain a total of 14 phalanges: each of the lesser toes (2nd to 5th) has three (proximal, middle, distal), while the great toe (hallux) has only two (proximal and distal).

Types of Phalanges

Toe	Phalanges Present
Great toe (Hallux)	Proximal, Distal
Toes 2–5	Proximal, Middle, Distal

Structure

• Proximal phalanges: Articulate with metatarsals at the metatarsophalangeal joints.
• Middle phalanges: Absent in the hallux, present in toes 2–5.
• Distal phalanges: Flattened ends support the nail beds and tip of the toes.

Arches of the Foot

The bones of the foot are arranged in arches that distribute weight and absorb shock. These include the medial longitudinal arch, lateral longitudinal arch, and transverse arch.

• Medial longitudinal arch: Formed by calcaneus, talus, navicular, cuneiforms, and 1st to 3rd metatarsals; highest and most elastic.
• Lateral longitudinal arch: Composed of calcaneus, cuboid, and 4th to 5th metatarsals; flatter and more rigid.
• Transverse arch: Runs across the midfoot and forefoot, formed by the cuneiforms and bases of the metatarsals.

Ossification

Ossification of the foot bones occurs at different times. Most tarsal bones ossify from a single center except the calcaneus, which has a secondary ossification center for the apophysis. The calcaneus ossifies first (around 5 months intrauterine), followed by the talus, cuboid, and others postnatally.

Articulations

The bones of the foot form numerous joints, many of which are synovial:

• Ankle joint (talocrural): Between talus and tibia/fibula.
• Subtalar joint: Between talus and calcaneus.
• Transverse tarsal joint: Between talus/navicular and calcaneus/cuboid.
• Tarsometatarsal joints: Between tarsals and metatarsals.
• Metatarsophalangeal joints: Between metatarsals and phalanges.
• Interphalangeal joints: Between phalanges.

Clinical Correlations

• Flatfoot (pes planus): Collapse of the medial longitudinal arch, often associated with ligament laxity or posterior tibial tendon dysfunction.
• High arch (pes cavus): Abnormally elevated medial arch; may be congenital or due to neuromuscular disorders.
• Jones fracture: A fracture of the 5th metatarsal base near the styloid process.
• Bunion (hallux valgus): Lateral deviation of the great toe, often associated with abnormal angulation of the 1st metatarsal.
• Stress fractures: Common in metatarsals (especially 2nd), caused by repetitive microtrauma.

Palpation and Surface Anatomy

• Calcaneus: Easily palpable at the heel.
• Navicular tuberosity: Medially located; used as a reference for foot alignment.
• 5th metatarsal base: Easily palpable lateral bony prominence.
• Heads of metatarsals: Palpable on the plantar surface during extension of the toes.
• Phalanges: Easily identified on toe dorsum.