The lower leg is the part of the leg between the knee and the foot. The bony structures are formed by the shin bone (tibia) and fibula, which in turn are connected by a tight ligament connection, the Membrana interossea cruris. Below the knee, between the tibia and fibula, there is a taut joint, an amphiarthrosis, whereas the two lower leg bones above the ankle joint are connected by a ligament, the so-called syndesmosis tibiofibularis.
The joint between upper and lower leg (knee joint) is a hinge joint. It allows movements in the degrees of freedom, extension and flexion as well as rotational movements to a small extent. As plane joints, the tibia-cubicle joints (art. talofibularis proximal and distal) only allow displacement movements, but the tibia-cubicle joint far from the body forms the ankle fork and thus stabilizes the upper ankle joint.
Classification of the lower leg muscles
The lower leg muscles are divided into two groups, each with two further subgroups, according to the function and position of the muscles. The anterior lower leg muscles are divided into extensors (extensor muscles) on the lateral front side and the fibula muscles, which are located in the area of the fibula on the outer side. The posterior lower leg muscles are divided into superficial flexors (flexors), which are collectively referred to in anatomy as the musculus triceps surae, and the deep flexor muscles.
Front lower leg muscles
The extensor muscles of the front lower leg are: The main function of the anterior tibialis muscle is to lift the foot. Its tendon is redirected by ligaments of the ankle joint and ends at the inner side of the foot approximately in the middle of the foot arch rather at the back of the foot. The tibialis anterior muscle is able to lift the foot and especially the edge of the foot via this attachment (supination).
The extensor digitorum longus muscle, also known as the “long toe extensor”, causes dorsal extension (lifting) of the second to fifth toe in the metatarsophalangeal joint of the toe and of the foot in the upper ankle joint. The musculus extensor hallucis longus, which is responsible for pulling up the big toe, is called the “long big toe extensor”. Depending on the position of the foot, it can also support the inward or outward rotation of the lower ankle joint.
- Musculus tibialis anterior
- Musculus extensor digitorum longus and
- Musculus extensor hallucis longus.
The fibula muscles include: The musculus peroneus longus is called the “long fibula muscle”. Similar to the anterior tibialis muscle, it is located in the middle of the foot flexure, but on the side of the sole of the foot. Its primary task is to stretch the foot towards the ground and turn it inwards.
The tendon of the musculus peroneus longus also gives the foot stability in the transverse arch due to its transverse course. Like the musculus peroneus longus, the “short fibula muscle” or Musculus fibularis brevis, provides plantar flexion, i.e. the extension of the foot downwards. In humans, its tendon runs in a common tendon sheath with that of the musculus peroneus longus.
- Musculus peroneus longus
- Musculus fibularis brevis
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