Muscles of the sole of the foot

Among the muscles in this area is the abductor of the big toe, the abductor hallucis muscle. This muscle originates from the front side of the heel at the lower surface and moves to the sesamoid bone of a metatarsal and to the base of the base joint of the big toe. This muscle spreads the toe outwards and also contributes to a slight flexion of the big toe.

The opposite movement is made possible by the tightening of the big toe. The short flexor of the big toe, the muscle flexor hallucis brevis, is also partially fused with this muscle. This has its origin in a metatarsal bone.

In its course, it divides into two muscle bellies, one of which lies further inwards, the other further outwards. The two muscle bellies are divided into two partial tendons, one of which is also attached to the sesamoid bone and the base joint. The flexor muscle is especially important for the flexion of the big toe.

This movement is called plantaflexion. It involves moving the toe away from the lower leg and down. In addition to the short flexor muscle, there is also a long flexor muscle of the big toe.

This is not counted directly among the muscles in the big toe because it originates at the back of the lower leg bone. There it pulls from the outside diagonally to the sole of the foot in order to finally start with its tendon at the end joint of the first toe. The muscle has a thicker muscle belly and contributes significantly to the support of the arch of the foot. It is one of the most important muscles for counteracting flat feet, where the foot lies on the ground incorrectly.

Middle foot musculature

Between the little and the big toe there are other muscles, some of which support the functions of other muscles and some of which perform other important tasks to stabilize the arch of the foot. These include the lumbicral muscles. These four small muscles are each located on the inward-facing side of the tendons of the long toe flexor.

They support the bending movement of the toes and at the same time pull the toes together. The latter movement is also called adduction. They also increase the stiffness of the arch of the foot and thus contribute to the stability of the entire foot.

Individual anatomical differences occur especially in these small muscles. This means that they can occur in both reduced and increased numbers. Another muscle that is located very centrally in the sole of the foot is the sole quadrilateral muscle (M. quadratus plantae).

This muscle is also connected to the lateral outer edge of the long toe flexor and supports its function. It also helps to strengthen the arch of the foot. Furthermore, there are small muscles between the individual toes, which are called interbone muscles (Musculi interossei).

They are distributed towards the sole of the foot and the back of the foot. The muscles directed towards the sole of the foot cause the third to fifth toe to be pulled towards the second toe. They also contribute to a slight flexion in the basic joints of the toes.

The small muscles that are directed towards the back of the foot are more likely to carry out a spreading movement of the toes. The short flexor of the toes, the M. flexor digitorum brevis, also runs under the sole of the foot. A small muscle that runs from the lower surface of the heel bone to the middle section of the bone of the second to fourth toe.

The muscle leads to a bending movement of the toes. In addition to the short flexor muscle of the toes, there is also a larger and longer one. This is not located on the foot itself, but belongs to the rear muscle group on the lower leg.

From the rear surface of the tibia, this muscle moves to the end limbs of the second to fifth toe. Besides a bending movement, it also contributes to a rotation of the foot around the longitudinal axis. This is done in such a way that the inner edge of the foot is raised while the outer edge of the foot is lowered. This movement is called supination and is the opposite of pronation.