The foot and ankle are composed of 28 bones, 33 joints, and an intricate network of muscles, tendons, and ligaments that work together to control movement and stability.

The region boasts a complex blood supply that ensures delivery of oxygen and nutrients, along with a sophisticated network of nerves. These nerves not only provide sensation and drive muscle function but also play a crucial role in proprioception, allowing us to instinctively sense the position and movement of our feet.

Bones of the Ankle

The ankle joint, or talocrural joint, connects the foot to the leg. It consists of the tibia and fibula, which form the sides of the joint, and the talus, a central bone that facilitates up-and-down movement (dorsiflexion and plantarflexion). The tibia and fibula are the bones of the leg, while the talus is at the core of the ankle’s movement. The prominent bony landmarks on either side of the ankle are the medial malleolus and the lateral malleolus.

Bones of the Foot

The foot is divided into three sections: the hindfoot, midfoot, and forefoot.

• The hindfoot includes the ankle and heel, composed of the talus and the calcaneus (heel bone).
• The midfoot, which bridges the hindfoot and forefoot, consists of smaller bones, including the navicular.
• The forefoot comprises the five metatarsal bones and the phalanges, which form the toes. The sesamoids beneath the first metatarsal act as pulleys, enhancing the efficiency of the great toe during movement.

Ankle and Foot Joints

The 33 joints in the ankle and foot allow for a wide range of movements:

• The ankle joint permits flexion and extension.
• The hindfoot joints enable side-to-side movements.
• The midfoot joints allow for subtle positioning of the forefoot.
• The condyloid joints of the toes (MTP and IP joints) facilitate toe positioning.

Together, these joints provide both the stability needed for weight-bearing and the agility required for navigating uneven surfaces. Each joint is covered by articular cartilage, a smooth, durable tissue that reduces friction and absorbs shock. Synovial fluid, produced by the joint lining, lubricates the cartilage to further minimize friction.

Soft Tissues of the Ankle and Foot

The bones of the foot and ankle are supported and held in place by soft tissues such as cartilage, ligaments, tendons, muscles, nerves, blood vessels, and bursae, all of which play essential roles in function and protection:

• Cartilage is the smooth, shiny tissue at the ends of bones, ensuring smooth joint movement.
• Ligaments are tough, rope-like structures that connect bones, stabilizing the joints.
• Tendons, which connect muscles to bones, enable movement. The largest and strongest tendon in this region is the Achilles tendon, followed by the tibialis posterior tendon.
• Around 20 muscles, including those in the leg and foot, control movement. Larger muscles in the leg connect to the foot via tendons around the ankle, controlling the ankle and hindfoot, while smaller muscles in the foot manage toe movement.
• Nerves from the leg control muscles, provide sensation to the skin, and contribute to proprioception, helping the body sense the foot’s position and movements.
• The skin is the final, yet critical, layer of protection. It encases the foot, shielding it from infection, and is both flexible enough to allow movement and tough enough to withstand daily wear and tear. The skin’s sensory and blood supply functions are crucial for temperature regulation and protection against injury.