Foot anatomy

The foot is a complex structure comprising bones, joints, muscles, ligaments, and tendons that work together to provide support, balance, and mobility. It is a crucial component of the lower limb and plays a key role in locomotion and weight-bearing.

Left Sole of a Male Foot

Foot Arche (PSF)

Gerrish's Text-book of Anatomy (1902) - Fig. 201

Gerrish's Text-book of Anatomy (1902) - Fig. 198

Bones of the Foot

Bones of the Foot

The foot consists of 26 bones, which can be grouped into three main sections:

Tarsal Bones

The tarsal bones form the hindfoot and midfoot. They include:

• Calcaneus (heel bone): The largest bone in the foot, supporting weight during standing and walking.
• Talus: Connects the foot to the ankle joint and articulates with the tibia and fibula.
• Navicular bone: Located medially, aiding in arch formation.
• Cuboid bone: Situated laterally, stabilizing the foot.
• Cuneiform bones (medial, intermediate, and lateral): Three wedge-shaped bones that support the metatarsals.

Metatarsal Bones

The metatarsals are five long bones in the midfoot, numbered from medial to lateral:

• Support the arches of the foot.
• Provide attachment points for muscles and ligaments.

Phalanges

The phalanges are the bones of the toes:

• Each toe has three phalanges (proximal, middle, distal), except for the hallux (big toe), which has two.

Joints of the Foot

The foot contains several important joints that allow for movement and flexibility:

• Ankle joint: Formed by the talus, tibia, and fibula, enabling dorsiflexion and plantarflexion.
• Subtalar joint: Between the talus and calcaneus, allowing inversion and eversion.
• Tarsometatarsal joints: Connect the tarsal bones to the metatarsals, providing stability.
• Metatarsophalangeal joints: Connect the metatarsals to the phalanges, enabling toe movement.
• Interphalangeal joints: Between the phalanges, facilitating flexion and extension of the toes.

Arches of the Foot

The foot has three main arches that distribute weight and provide shock absorption:

• Medial longitudinal arch: The highest arch, supported by the calcaneus, talus, navicular, cuneiforms, and first three metatarsals.
• Lateral longitudinal arch: A lower arch formed by the calcaneus, cuboid, and fourth and fifth metatarsals.
• Transverse arch: Spans the width of the foot and is supported by the cuboid, cuneiforms, and metatarsals.

Muscles of the Foot

The muscles of the foot are divided into two groups:

Intrinsic Muscles

Located within the foot itself, these muscles are responsible for finer movements:

• Plantar muscles: Located on the sole, grouped into four layers.
• Dorsal muscles: Include the extensor digitorum brevis and extensor hallucis brevis.

Extrinsic Muscles

Originate in the lower leg and insert into the foot, responsible for larger movements:

• Anterior compartment: Includes the tibialis anterior, extensor digitorum longus, and extensor hallucis longus.
• Posterior compartment: Includes the gastrocnemius, soleus, and tibialis posterior.
• Lateral compartment: Includes the fibularis longus and fibularis brevis.

Ligaments and Tendons

The foot is stabilized and supported by numerous ligaments and tendons:

• Plantar fascia: A thick connective tissue that supports the medial longitudinal arch.
• Achilles tendon: Connects the calf muscles to the calcaneus, enabling plantarflexion.
• Deltoid ligament: A strong ligament supporting the medial side of the ankle.
• Lateral ligaments: Stabilize the lateral side of the ankle.

Blood Supply

The foot receives blood from the:

• Anterior tibial artery: Becomes the dorsalis pedis artery on the dorsum of the foot.
• Posterior tibial artery: Supplies the plantar surface.

Nerve Supply

The foot's sensory and motor innervation is provided by:

• Tibial nerve: Innervates the sole.
• Deep fibular nerve: Innervates the dorsum.
• Superficial fibular nerve: Provides sensory innervation to the lateral foot.
• Sural nerve: Supplies the lateral side.
• Saphenous nerve: Supplies the medial side.

Common Conditions

• Plantar fasciitis: Inflammation of the plantar fascia, causing heel pain.
• Flat feet (pes planus): Loss of the medial longitudinal arch.
• Bunions (hallux valgus): Deformity of the first metatarsophalangeal joint.
• Achilles tendinitis: Inflammation of the Achilles tendon.
• Metatarsalgia: Pain in the metatarsal region.
• Gout: Arthritis caused by uric acid crystals, commonly affecting the big toe.

See Also

• Human skeleton
• Gait
• Ankle
• Orthopedics