Anatomy of the Foot & Ankle

Bones of the Foot:

• Tarsal Bones: The seven tarsal bones form the back part of the foot and include the calcaneus (heel bone), talus, navicular, cuboid, and the three cuneiform bones.
• Metatarsal Bones: These are five long bones that make up the midfoot and connect to the toes.
• Phalanges: The toes are composed of 14 phalanges—proximal, middle, and distal—forming the toe’s structure.

Joints of the Foot:

• Ankle Joint: The junction between the tibia, fibula, and talus bone. It allows for dorsiflexion (lifting the foot) and plantarflexion (pointing the foot).
• Subtalar Joint: Located beneath the ankle joint, this joint permits inversion (rolling the foot inward) and eversion (rolling the foot outward).
• Midfoot Joints: These include the naviculocuneiform, cuneiform-metatarsal, and intercuneiform joints, which contribute to the foot’s arch and flexibility.
• Metatarsophalangeal (MTP) Joints: The joints connecting the metatarsal bones to the phalanges.
• Interphalangeal (IP) Joints: These are the joints connecting the phalanges of the toes.

Ligaments and Tendons:

• Medial Collateral Ligament (MCL) and Lateral Collateral Ligament (LCL): These ligaments provide stability to the ankle joint, preventing excessive inward (varus) or outward (valgus) movement.
• Plantar Fascia: A thick band of tissue running along the sole of the foot, supporting the arch and absorbing shock.
• Achilles Tendon: The largest and strongest tendon, connecting the calf muscles to the heel bone. It enables plantarflexion.
• Peroneal Tendons: These tendons run along the outer side of the ankle, enabling ankle stability and eversion.
• Anterior and Posterior Tibial Tendons: These tendons support the arch of the foot and control foot movement.

Muscles:

• Intrinsic Muscles: Located within the foot, they control fine movements and support the arches.
• Extrinsic Muscles: Originate outside the foot and extend into the foot to control more significant movements like ankle flexion and toe curling.

Arches of the Foot:

• Medial Longitudinal Arch: The inner arch that runs from the heel to the big toe, providing shock absorption and weight distribution.
• Lateral Longitudinal Arch: The outer arch that runs from the heel to the fifth toe, contributing to stability during walking and running.
• Transverse Arch: The arch that runs across the foot, maintaining balance and flexibility.

Nerves:

• Sural Nerve: Provides sensation to the outer part of the foot.
• Saphenous Nerve: Supplies sensation to the inner part of the foot and ankle.
• Deep Peroneal Nerve: Innervates the muscles of the front of the leg and foot.

Blood Supply:

The foot and ankle receive blood supply from various arteries, including the dorsalis pedis artery on the top of the foot and the posterior tibial artery on the inner ankle.

Understanding the complex interplay of these anatomical structures is essential for diagnosing and treating various foot and ankle conditions and ensuring optimal function, stability, and mobility. If you experience any discomfort or issues with your foot and ankle, it’s recommended to seek professional medical evaluation for accurate diagnosis and appropriate care.