The ankle joint is composed of the articular surface at the lower end of tibia and fibula and talus pulley, also called talocrural joint. The joint capsule is attached to the periphery of each articular surface, and its front and rear walls are thin and loose, and the ligaments on both sides are strengthened, and the medial ligament or triangular ligament is on the inside. It is very tough, starting from the medial ankle tip and spreading downward in a fan shape, ending at the inner side of talus, talus of calcaneus and scaphoid. There is a lateral ligament on the lateral side, which consists of three parts:

1. Anterior talofibular ligament, extending between lateral malleolus and talus neck;

2. Middle calcaneal ligament, from lateral malleolus down to the side of calcaneus;

3. Posterior talofibular ligament, from medial lateral malleolus to posterior talus process.

intertarsal joint

The tarsal joint is the joint between tarsal bones, which has a large number and small mobility. Talocalcaneal joint (subtalar joint), talocalcaneal joint and calcaneocuboid joint are more important.

1. talocalcaneal joint: It consists of the posterior articular surfaces of talus and calcaneus, and its medial and lateral talocalcaneal ligaments and talocalcaneal ligaments located in the tarsal sinus are strengthened respectively.

2. calcaneal joint: The anterior and middle articular surfaces of calcaneus and the posterior articular surface of scaphoid form a joint socket to receive talus and anterior and middle articular surfaces of talus. The gap between calcaneus and scaphoid is filled by calcaneus plantar ligament and calcaneus dorsal ligament. Calcaneal plantar ligament is a fibrocartilage ligament connecting calcaneus and scaphoid, which participates in the formation of medial longitudinal arch of foot. Because of its great elasticity, it is also called elasticity.

3. calcaneocuboid joint: It is composed of the articular surface of calcaneocuboid bone, and the ligament on the back of the joint is weak; The plantar ligament is strong, mainly the long plantar ligament, which is the longest plantar ligament. From the bottom of calcaneus to the front, it is divided into two bundles: superficial fiber and deep fiber. The superficial bundle ends at the base of the 2 nd to 4 th metatarsal bone, and the deep bundle ends at the base of the cuboid bone; The plantar ligament of the calcaneocuboid bone is a wide and short fibrous band connected to the bottom of the calcaneocuboid bone.

tarsometatarsal joint

Tarsometatarsal joint, also known as Lisfrance joint, consists of three cuneiform bones, the front end of cuboid bone and the bottom of five metatarsals. It belongs to a plane joint and can do slight sliding, flexion and extension movements.

Intermetatarsal joint

It is composed of the adjacent surfaces of the second to fifth metatarsal bases and belongs to a plane joint with little movement.

Metatarsophalangeal joint

It consists of metatarsal bone and proximal phalanx base, and can do slight flexion, extension, contraction and extension.

Interphalangeal joint

It consists of two phalangeal bases adjacent to each toe and a pulley, which belongs to pulley joint and can be used for flexion and extension.