The ligament of Shopar’s joint is wave-shaped, located at the edge of the back surface of the heel. Almost immediately, it branches, forming the medial and lateral ligaments. In a section, the joint resembles the Latin letter S in a supine position; externally, its gap is defined by the ankles and the anterior articular edge of the tibia.
In the photographs of the atlas of the skeleton, it is clearly visible 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 tibia, 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.
Lower leg anatomy
The tibia is the 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 lower leg. The tibia is the thickest part of the tibia, its body is trihedral in shape with three distinct edges.
The fibula is almost the same length as the tibia, but much thinner than it. The body of the bone is trihedral prismatic in shape, curved behind and twisted along the longitudinal axis.
A foot is arranged and functions as an elastic movable arch, the task of which is to create a certain elevation so that a person rests on individual points, and not on the whole foot. Such anatomy of the foot avoids overstrain in the muscles and joints. Thanks to the vaulted structure, a person can walk straight.
Intertarsal joints
- Ankle joint due to the lateral processes (ankles) together with the talus forms a kind of block. Protection is provided by the joint bag and ligaments, so that the ankle joint can produce posterior and anterior flexion movements.
- The subtalar joint is a less mobile joint between the calcaneus and the talus.
- The ram-calcaneo-navicular joint (lines of the joints of Shopar and Lisfranc) is formed by the bones of the tarsus. A ligament connecting the calcaneus and talus passes through their cavities.
- The heel-cuboid joint forms the articular surfaces of the cuboid and calcaneus. The joint is strengthened by a common bifurcated ligament, starting on the calcaneus.
- The wedge- shaped joint is formed by the articular surfaces of the sphenoid and scaphoid bones.
Tarsal-metatarsal joints and ligaments of the foot connect the bones of the tarsus with the short tubular bones of the metatarsus. They are inactive, the joint capsule and ligaments that strengthen them are stretched 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 large (2 phalanges) consists of three phalanges. The bones have a certain bend directed upwards, 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 large skeleton of each finger, it consists of a proximal, intermediate and distal phalanx.
Serious static and dynamic loads of the foot can withstand 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 make foot movements. Shin muscle group:
- The front group is the tibial muscle and long extensor fingers. The lateral muscle group is the long fibular and short fibular muscle.
- The posterior group is the most powerful - the triceps muscle of the lower leg, the long flexor of all fingers, the plantar and posterior tibial muscle.
Nerves of the foot
Each joint communicates with the central nervous system, including the foot. Communication is supported by peripheral nerves:
- posterior tibial;
- surface;
- deep fibular;
- calf.
The system of nerve fibers is responsible for sensations: a feeling of cold, warmth, touch, pain, position in space. They transmit downward impulses from the central nervous system to the periphery. Such stimulation provokes arbitrary muscle contractions and a number of reflexes.
According to medical statistics, injuries of a joint of Shopar are quite rare. However, statistics do not always take into account the erroneous diagnosis factor. In this regard, the frequency of dislocations in Shopar's joint is higher than 0.5%.
The cause of the dislocation may be a sudden fall from the 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
It is caused by inflammatory processes in the periosteum, developing against the background of excessive loads and injuries. Inflammation occurs in the outer and inner layers of the bone, including Shopar's joint. People with flat feet and women who like to wear high heels suffer more often.
Hypoplasia of the metatarsal bones of the foot is characterized by the presence of a shortened forefoot. Deformation can be congenital or post-traumatic. In addition to an obvious cosmetic defect, pain and contracture of adjacent joints with subluxation in the metatarsophalangeal joint are felt.