Long muscles of the back of the foot

The longer muscles of the foot are characterized by the fact that they have a very long course and their long tendons run over the back of the foot to the toes. Since they are located outside the foot and have their origin there as well, they are called extrinsic muscles and are the counterpart of the intrinsic muscles. The long toe extensor pulls from the outside of the knee joint bone diagonally to the region of the ankle joint.

Finally, a long tendon emerges from the relatively small muscle belly. Approximately at the height of the ankle, the tendon divides into 4 further partial tendons. These tendons now run along the end limbs of the second to fifth toe.

Like the short foot muscles, the muscle is excited by the fibular nerve. The innervation of the muscle leads to stretching and bending in the direction of the lower leg of the toes that it stimulates. This is also a case of dorsiflexion.

Since the muscle runs from the knee through the ankle joint to the toes, it not only influences the movement of the toes, but also executes a movement in the ankle joint. There it causes the rotation of the foot around the longitudinal axis in such a way that the outer edge of the foot is lifted while the inner edge is lowered towards the bottom. The heel does not rotate with the foot.

This type of movement also occurs in the wrist and elbow joint and is called pronation. On the foot, pronation is synonymous with eversion. Similar to the short muscles of the foot, the long muscles of the foot have a separate muscle that performs the same movement at the big toe.

This is the long big toe extensor (Musculus extensor hallucis longus). Its origin is located directly next to the plug for the remaining toes and in its neighborhood it also moves across the ankle joint to the end joint of the big toe. This muscle leads to the same movement as the other muscles on the back of the foot. It also supports pronation in the ankle joint.