Definition
Tendons are stable, partially stretchable connections between muscles and bones. The tibialis posterior tendon connects the posterior tibialis muscle in the lower leg with the bone attachments under the foot. Movement of the muscle is thus passed on to the foot via the tendon and leads to flexion of the sole of the foot, lifting of the inner side of the foot and lifting of the foot in general. Tendons can be irritated or tear under heavy strain. The tibialis posterior reflex can also be tested on the tendon.
Function of the posterior tibialis tendon
Tendons are connecting structures between muscles and bones. They transmit the force of the muscles to the bones and thus cause movement at the joints. The tendon of the posterior tibialis muscle transmits the force to the bones in the foot.
This causes the foot to tilt inwards (supination) and to bend the sole of the foot and the toes. These movements are called supination and plantar flexion. Tendons also stabilize the large joints, in this case the ankle joint, and can also give shape to other structures.
The tendon of the posterior tibialis muscle helps to stabilize the transverse arch of the foot and thus prevents a splayfoot. Tendons can also store strength and later release it again. During regular movement, such as running, the tibialis posterior tendon can store strength and relieve the calf muscles, resulting in a softer movement.
This can also protect the joints and bones. Tendons are subject to heavy strain throughout their lives and can therefore show functional losses in old age. This is manifested by pain and a greater risk of injury. Tears, inflammations or malformations can also lead to the tendon not being able to perform its function, or not sufficiently.
Course of the tibialis posterior tendon
The tibialis posterior tendon begins at the lower leg at the end of the posterior tibialis muscle and crosses under the tendon of the long toe flexor muscle. This is called chiasma crurale or lower leg crossing. Then the tendon runs through the tarsal tunnel, a connective tissue supporting apparatus of the ankle.
At the ankle, the tendon runs along the inner ankle and can be used just below or above the ankle to test the tibialis posterior reflex. The tendon splits into several end pieces and attaches to the sphenoid bone and scaphoid bone. These are tarsal bones. Further attachments are the individual toes, which can be flexed by the posterior tibialis muscle.
All articles in this series: