The ligament of Chopard's joint is undulating, located at the edge of the dorsal surface of the heel. Almost immediately, it branches, forming the medial and lateral ligaments. In cross-section, the joint resembles the Latin letter S in the supine position, externally its gap is determined by the ankles and the anterior articular edge of the tibia.
The pictures of the skeletal atlas clearly show how Chopard's joint is formed.
Features of joints, ligaments and cartilage
Anatomy of the foot has an extremely complex anatomical structure with a large number of joints that form two or more bones. The main one is the ankle, consisting of the tibia and fibula, lateral outgrowths and the talus. This joint is responsible for the main function of the foot - its mobility, the rest provide the necessary firmness and elasticity.
Anatomy of the lower leg
Shin - part of the leg from the knee to the heel, consisting of two bones: the tibia (located medially), the fibula (located laterally) and the patella. These tubular bones have inner and outer processes below. Between them is the interosseous space of the leg. The tibia is the thickest part of the lower leg, its body is triangular in shape with three distinct edges.
The fibula is almost the same length as the tibia, but much thinner. The body of the bone is trihedral, prismatic, curved at the back and twisted along the longitudinal axis.
The foot is arranged and functions as an elastic movable arch, the task of which is to create a certain elevation so that a person leans on individual points, and not on the entire foot. This anatomy of the foot avoids overstrain in the muscles and joints. Thanks to the vaulted structure, a person can walk upright.
Intertarsal joints
- The ankle joint, due to the lateral processes (ankles), together with the talus, forms a kind of block. The bursa and ligaments provide protection, allowing the ankle joint to perform posterior and anterior flexion movements.
- The subtalar joint is a less mobile articulation between the calcaneus and the talus.
- The talocalcaneal-navicular joint (Chopart and Lisfranc lines) is formed by the bones of the tarsus. A ligament connecting the calcaneus and talus passes through their cavities.
- The calcaneocuboid joint is formed by the articular surfaces of the cuboid and calcaneus bones. The joint is strengthened by a common bifurcated ligament starting at the calcaneus.
- The sphenoid joint is formed by the articular surfaces of the sphenoid and navicular bones.
The tarsal-metatarsal joints and ligaments of the foot connect the bones of the tarsus to the short tubular bones of the metatarsus. They are sedentary, the joint capsule and ligaments, strengtheningthem are pulled very tight, which allows them to take part in the formation of the elastic arch of the foot. Thanks to this, we are mobile in our movements and accurate.
Metatarsal or metatarsal bones
The metatarsus consists of 5 metatarsal tubular bones, each toe except the big one (2 phalanges) consists of three phalanges. The bones have some upward curvature, which allows them to participate in the formation of the arch of the foot.
The metatarsophalangeal and interphalangeal joints attach the phalanges of the fingers to the metatarsus. In addition to the thumb, the skeleton of each finger consists of proximal, intermediate and distal phalanges.
The foot withstands serious static and dynamic loads due to the anatomical features of the structure and the presence of a large number of elastic elements.
Muscles and nerves of the foot
As a result of contraction of the muscles of the lower leg and foot, a person can move the foot. Calf muscle group:
- Anterior group - tibialis muscle and long extensor fingers. Lateral muscle group - long peroneal and short peroneal muscle.
- The back group is the most powerful - the triceps muscle of the lower leg, the long flexor of all fingers, plantar and posterior tibial muscle.
Nerves of the foot
Each joint communicates with the central nervous system, including the foot. Communication is maintained by peripheral nerves:
- posterior tibial;
- superficial;
- deep fibular;
- calf.
The system of nerve fibers is responsible for sensations: the feeling of cold, heat, touch, pain, position in space. They transmit descending impulses from the CNS to the periphery. This stimulation provokes voluntary muscle contractions and a series of reflexes.
According to medical statistics, Chopard's joint injuries are quite rare. However, statistics do not always take into account the misdiagnosis factor. In this regard, the frequency of dislocations in the Chopard joint is above 0.5%.
The cause of dislocation may be a sudden fall from support to the foot, a sharp and strong blow to the protruding middle part. As a rule, injuries are provoked by an indirect mechanism of injury under the influence of a large force.
Metatarsal Periostitis
Caused by inflammatory processes in the periosteum, developing against the background of excessive stress and trauma. Inflammation occurs in the outer and inner layers of the bone, including Chopard's joint. People with flat feet and women who like to wear high heels suffer more from the disease.
Hypoplasia of the metatarsal bones of the foot is characterized by the presence of a shortened forefoot. The deformity may be congenital or post-traumatic. In addition to an obvious cosmetic defect, there is pain and contracture of adjacent joints with subluxation in the metatarsophalangeal joint.
