Anatomy, Bony Pelvis and Lower Limb, Foot Joints

The foot is a complex mechanical structure of the human body composed of 33 joints, 26 bones, and more than a hundred muscles, tendons, and ligaments that all work together to bear weight, allow for locomotion, and transmit force. The joints of the foot are made wherever two or more of the foot bones meet. The joints between the tarsal bones of the foot are known as the intertarsal joints. The specific intertarsal joints of the foot include the subtalar joint, talocalcaneonavicular joint, calcaneocuboid joint, cuneonavicular joint, cuboideonavicular joint, and the intercuneiform joint.  All the toes of the foot except the big toe have three joints, which include the metatarsophalangeal joint (MPJ) found at the base of the toe, the proximal interphalangeal joint (PIP) found in the middle of the toe, and the distal phalangeal joint (DP) found near the tip of the toe. The big toe has the metatarsophalangeal joint and one interphalangeal joint (IPJ). A layer of cartilage covers the surfaces of the joints where the bones meet which allows them to glide smoothly with each other as they move. A thin membrane called the synovium encloses the joint and secretes a fluid to lubricate them.