In addition, peroneus tertius, acting along with its anterior neighbors, can help to dorsiflex the ankle. The action of all three of the peroneal muscles is to evert the foot. The tendon of peroneus tertius passes under the extensor retinaculum, and in front of the lateral malleolus to insert here, on the base of the fifth metatarsal, next to peroneus brevis. Peroneus tertius arises from here on the fibula. Lastly, in front of peroneus brevis and longus, here’s peroneus tertius. Peroneus longus runs around the cuboid bone, and along a deeply placed fibrous tunnel, to insert right over here, on the base of the first metatarsal. To see the remarkable course of the peroneus longus tendon, we have to remove the entire sole of the foot. Peroneus brevis runs forward to insert here, on the base of the fifth metatarsal. Īt the ankle, the tendons of peroneus longus and brevis pass behind the lateral malleolus and beneath the peroneal retinaculum, longus behind, brevis in front. The other muscle in the picture here is tibialis anterior.Īt the ankle, the tendons of peroneus longus and brevis pass behind the lateral malleolus and beneath the peroneal retinaculum, longus behind, brevis in front. The deep peroneal nerve passes under the upper end of peroneus longus here, as we’ll see. Its origin extends up onto the head of the fibula, with a gap here. Peroneus longus arises from here on the proximal fibula. Lying on top of peroneus brevis, is peroneus longus.
Peroneus brevis arises from here on the distal fibula. Now we’ll move on, to look at the three muscles that evert the ankle: peroneus longus, brevis, and tertius. We looked at tibialis anterior, in its role as an ankle dorsiflexor, earlier in this section. The other muscle that can act as a foot invertor is tibialis anterior, which inserts so close to tibialis posterior that it has almost the same line of action. Here’s the action of tibialis posterior: it inverts the foot It has a wide insertion, here, on the navicular and first cuneiform bones and also under here, on the bases of the second, third and fourth metatarsals. Beyond the malleolus the tendon of tibialis posterior fans out. Its tendon passes immediately behind the medial malleolus, through a fibrous tunnel that’s covered by the flexor retinaculum. Tibialis posterior arises from the back of the tibia, the back of the fibula, and from the interosseous membrane in between. There are two muscles that produce inversion, tibialis anterior, which we’ve seen already, and tibialis posterior. extrinsic foot muscles and is suitable for studying the interplay between multiple muscles during tasks such as walking and standing 19. Keeping your leg straight, slowly push your affected foot outward against the band and away from your other foot without letting your leg rotate. Hold both ends of an exercise band and loop the band around the outside of your affected foot. Sit on the floor with your legs straight. Now that we’ve seen these fascial structures, let’s get back to the muscles, the ones that produce inversion and eversion. How do you fix a foot eversion Resisted ankle eversion.