Human Foot is incredibly complex in structure. It consists of The 26 bones consist of 14 phalanges, 5 metatarsals and 7 tarsal bones. You can broadly classify the foot into forefoot, midfoot and hindfoot.
Structure of the Foot:
Forefoot -The forefoot consists of five metatarsal bones with the phalanges or toes. Metatarsal bones are strongest of the foot bones. The first metatarsal is responsible for bearing weight although it is the shortest of the metatarsals. It is associated with several tendons. The second, third and fourth metatarsals provide stability to the foot. They are associated only with minor tendons. On the plantar surface, slightly above the first metatarsal are two sesamoid bones. One is small oval shaped bone that develops inside a tendon. These small bones are well supported by tendons and ligaments. The forefoot also consists of 14 phalangeal bones.
Midfoot ““ The midfoot consists of five tarsal bones of the total seven tarsal bones. These tarsal bones are usually navicular, cuboid and three cuneiform. This gives a scope for the presence of multiple joints within the midfoot. The midfoot is then connected to the forefoot by Tarsometatarsal joints. The cuneiforms, navicular and cuboid bones of the midfoot play a significant role in determining the total foot structure.
Hindfoot ““ The calcaneus and the talus bones constitute the hindfoot. The largest tarsal bone that forms the heel is known as Calcaneus and Talus forms the pivot of the ankle.
There are 20 muscles in the foot responsible for giving the foot shape. They hold the bones in their position and give flexibility to the foot during movements.
The primary muscles of the foot are ““
- The Anterior Tibial muscle ““ It allows the upward movement of the foot.
- The Posterior Tibial muscle ““ It supports the arch of the foot.
- The Peroneal tibial ““ It controls the outside movement of the ankle.
- The Extensors ““ These muscles initiate the step and help raise the toes and ankles.
- The Flexors ““ These muscles help in stabilizing the toes against the ground.
There are smaller muscles that help the toes to lift and curl.
Apart from muscles there are tendons. Tendons are elastic tissues that connect muscles to the bones and joints. The strongest and biggest tendon in the foot is the Achilles tendon.Â It extends from the calf muscle down to the heels. It facilitates running, jumping, walking, climbing stairs and standing on toes.
Ligaments are responsible for holding the tendons in their place and stabilizing the joints. The longest ligament is plantar fascia. It causes the formation of the arch on the foot sole, extending from the toes to the heel. Its expansion and contraction allows the curving and flattening of the arch while walking. Plantar fascia provides balance and strength to the foot so that it bears the entire body’s weight.Â There are medial ligaments, located on the inside of the foot and there are lateral ligaments located on the outside of the foot providing stability enabling the foot’s upward and downward movement.
Foot And Toe Movement
The movement of the toe takes place at the joints. The joints are able to move in two directions that is in plantar flexion or in dorsiflexion motion. Apart from this joints also allow adduction and abduction movements of the toes as well.
The foot on the whole performs two movement eversion and inversion. All the joints present both in the hind foot and in the mid foot play a major role in the complex movements which combine together for the movement of the ankle joint.
Arches of the Foot:
There three arches in a foot. They are:
- The Medial Longitudinal Arch:This arch is the highest arch in the foot and is the most important one too. It comprises of the first three metatarsals along with along with the navicular, talus, calcaneus, cuneiforms.
- The Lateral Longitudinal Arch:This arch is lower and flat as compared to the medial arch. It is comprises of fifth and fourth metatarsals along with the cuboid and calcaneus bones.
- The Transverse Arch: This arch comprises of the five metatarsal bases along with the cuneiform and cuboid bones.
The arches of the foot are balanced by the bones, tendons and the muscles of the foot which maintain the proper shape of the arches and also provide support to them.
Muscles of the Foot:
There are basically two types of muscles in the foot. They are:
- Intrinsic Muscles: These are located inside the foot and helps in the movement of the toes. The various types of intrinsic muscles comprises of extensors or dorsiflexors, flexors or plantar flexors and adductors of the toes. Most of these intrinsic muscles help in supporting the arches of the foot.
- Extrinsic Muscles:These muscles are located on the outer side of the foot in the lower part of the leg. Most of these muscles comprise of gastrocnemius muscles or the calf muscles. These muscles have long tendons which connect the ankle and the muscles on the foot bones and help them in their movement. But the bone of talus does not have any tendon attachments.