Bones of the leg and foot, their connections
The tibia on the proximal epiphysis has: medial and lateral condyles with articular surfaces; intercondylar eminence with medial and lateral tubercles: anterior and posterior field; fibular articular surface on the lateral side below the condyle. On the diaphysis of the tibia there are: anterior edge (sharp) - upward passes into the tuberosity, the lateral edge facing the fibula and the medial edge; surfaces: medial, lateral and posterior with the line of the soleus muscle. The distal epiphysis has: the fibular notch along the lateral edge; the medial malleolus with the malleolar groove at the back; articular surfaces: malleolar and bottom.
The fibula has: on the proximal epiphysis a head, a neck, on the head - an apex and an articular surface; on the diaphysis: anterior, posterior and interosseous edges; lateral, posterior and medial surfaces; on the distal epiphysis: lateral malleolus with articular surface and fossa (posterior).
The bones of the foot are divided into tarsal bones: 7 short spongy bones and metatarsal bones consisting of 5 short tubular bones; as well as phalanges of fingers - three in each finger, except for the first, which has two phalanges. The tarsal bones lie in two rows: in the proximal (posterior) - talus and calcaneus, in the distal (anterior) - scaphoid, sphenoid: medial, intermediate, lateral and cuboid bones.
The talus bone consists of a body, head, and neck. On top of the body there is a block with the upper, medial and lateral malleolar articular surfaces. Below the body there are calcaneal articular surfaces: anterior, middle and posterior. Between the middle and posterior calcaneal surfaces there is a groove of the talus. On the head lies the scaphoid articular surface. The talus has processes: lateral and posterior, on the latter there are medial and lateral tubercles, separated by a groove for the flexor pollicis longus tendon.
The calcaneus has a body ending posteriorly with the calcaneal tubercle. There are talar articular surfaces on the body: anterior, middle and posterior. Between the middle and posterior there is a groove of the calcaneus, which, together with the groove of the talus, forms the sinus of the tarsus. At the distal end of the body there is a cuboidal articular surface. Processes and other grooves of the calcaneus - supporting process of the talus on the medial surface, groove of the peroneus longus tendon on the lateral surface.
The scaphoid bone at the distal end has three articular surfaces for the sphenoid bones, and a tuberosity along the medial edge for the attachment of the tibialis posterior muscle.
The sphenoid bones have a characteristic triangular shape, and on the anterior and posterior sides and sides there are articular surfaces - in the front for articulation with the first three metatarsals, in the back for articulation with the scaphoid bone, on the sides for articulation between themselves and the cuboid bone.
The cuboid bone also has articular surfaces at the back for articulation with the calcaneus, in front with the metacarpal bones, and along the medial surface for connection with the lateral sphenoid and scaphoid bones. On the lower surface there is a tuberosity and a groove for the tendon of the peroneus longus muscle.
The metatarsal and phalangeal bones are short tubular bones, each of which consists of a base, body and head. Articular surfaces are located on the head and base
The bones of the lower leg have connections: the tibiofibular joint, formed by the flat articular surfaces of the fibular head and the upper epiphysis (lateral part), the tibia; the articular capsule is tightly stretched and strengthened by the anterior and posterior ligaments of the head of the fibula; limited range of motion; sometimes the tibiofibular joint can communicate with the cavity of the knee joint; tibiofibular syndesmosis is a continuous connection with short and thick fibrous fibers between the fibular notch on the distal epiphysis of the tibia and the articular surface of the lateral malleolus, reinforced by the anterior and posterior tibiofibular ligaments; the synovial membrane of the ankle joint is invaginated into the tibiofibular syndesmosis; interosseous membrane of the leg - a fibrous membrane stretched between the interosseous edges of the tibia and fibula in the area of their diaphysis; it has openings at the top and bottom for the passage of blood vessels and nerves.
There is almost no movement in the joints of the lower leg bones, which is associated with the supporting function of the lower limb and the formation of a mobile ankle joint. The formation of the ankle joint involves: the tibia with its lower and medial ankle articular surfaces; the fibula with the articular surface of the lateral malleolus; the talus with its upper and medial ankle joints; ankle (medial and lateral articular surfaces), located on the block. The ankles fork-shaped cover the block, forming a typical trochlear joint, complex due to the articulation of three bones. The articular capsule is attached at the back along the edge of the articular surfaces of the articulating bones. On the sides the capsule is thick and strong, in the front and at the back - thin, loose, folded, reinforced by powerful lateral ligaments: medial (deltoid) - thick, strong, fanning out from the medial malleolus to the talus, navicular and calcaneal bones; in the ligament there are parts: tibial-navicular, tibial-calcaneal, anterior and posterior tibiotalar; lateral as part of the anterior talofibular, posterior talofibular, calcaneofibular ligaments. The ligaments are so strong, especially the medial one, that with maximum stretching they are capable of tear off the ankle. The movements performed in the ankle joint are: flexion (plantar) and extension (dorsiflexion) around the frontal axis; adduction and abduction around the sagittal axis c; pronation and supination around the vertical axis.
The subtalar joint is formed by the posterior articular surfaces of the talus and calcaneus, which correspond well to each other. The capsule at the joint is thin, stretched, and strengthened by ankle ligaments.
The talocaleonavicular joint is formed by the articular surface on the head of the talus, which articulates anteriorly with the navicular bone and inferiorly with the calcaneus. The articular surface of the calcaneus is supplemented by the plantar calcaneonavicular ligament, which at the head of the talus becomes fibrocartilage. The articular capsule is attached along the edge of the articular surfaces, closing a single cavity. The capsule is strengthened by strong ligaments: the interosseous talocalcaneal ligament, up to 0.5 cm thick, and the talonavicular ligament on top. The joint is spherical in shape, but with one sagittal axis of movement. Together with the subtalar joint, it forms a combined joint with a limited range of movements in the form of adduction and abduction, rotation of the foot outward and inward.
The calcaneocuboid joint is saddle-shaped; The articular capsule on the medial side is thick and tight, on the lateral side it is thin and loose, strengthened by ligaments: the plantar calcaneocuboid and long plantar. Movements in a limited volume are carried out around the longitudinal axis in the form of a slight rotation, complementing the movements in the talocaleonavicular joint.
The transverse (Schopar) joint of the tarsus includes the calcaneocuboid and talonavicular joints so that the joint space takes on the appearance of a Latin S, passing across the foot. The common ligament of joints - bifurcated (lig. bifurcatum) - serves as a kind of key, when cut, the joint cavity opens wide. It is Y-shaped and consists of the calcaneonavicular and calcaneocuboid ligaments.
The sphenavicular joint is flat, complex, as it is formed by three sphenoid and one scaphoid bones, reinforced by the dorsal and plantar sphenavicular and intra-articular intersphenoid ligaments. The joint cavity can communicate with the tarsometatarsal joints.
Tarsometatarsal (Lisfranc) joints - flat with a limited range of motion, include the following three joints: the joint between the medial cuneiform and first metatarsal bones; the joint between the intermediate, lateral cuneiform bones and the II, III metatarsals; the joint between the cuboid bone and the IY, Y metatarsals bones; tarsometatarsal joints are strengthened by tarso-metatarsal ligaments (dorsal and plantar) and interosseous cuneiformatatarsal ligaments, of which the medial cuneotarsal ligament is considered in practice to be the key to these joints.
The intermetatarsal joints are flat, formed by the lateral surfaces of the bases of the metatarsal bones, reinforced by the dorsal and plantar metatarsal interosseous ligaments. Movement in them is severely limited.
The metatarsophalangeal joints are formed by the spherical heads of the metatarsal bones and the concave bases of the proximal phalanges. The capsules are thin, loose, reinforced by collateral and plantar ligaments. The deep transverse metatarsal ligament connects the heads of the metatarsal bones and strengthens the joint capsules. Flexion and extension, adduction and abduction are limited.
Interphalangeal joints - proximal and distal, except for the thumb joint, where there is one interphalangeal joint. They belong to the trochlear joints, strengthened by collateral and plantar ligaments.