Hi, welcome back. In this third and last lecture of Section four, we are going to explore the muscles of the ankle antonyms. The ankle is divided into sections and upper joined and the lower joint. The upper joint is between talus and tibia fibula, and is called Taylor Kuril joint. In this joint two movements are made plantar and dorsal flexion. The other part is where Taylor's meets calcaneus called the subtalar joint.

This is where inversion and E version take place. You might want to take a look at section one, lecture two to update the anatomy of the bones in the foot. And be aware that in between tibia and fibula, there is this membrane called the interest your membrane where muscles arise from, as well as from the boom We will start at Taylor Crowell joined with plantar flexion. The main mover here is triceps Hooray. We talked about it in lecture two of this section. For plantar flexion all three heads of triceps are active.

Another plantar flexor is tibialis posterior. This muscle is closer to the bones than triceps. A deeper muscle we call this and its origin is found at the posterior side of tibia fibula, and the interstitial membrane. It inserts at several spots at the plantar side of the mid foot at navicular Kuni form one and the basis of metatarsal two, three, and four. We'll talk about the assisting perennial or fibula muscles later on. torso flexion in the Taylor Kuril joint is enabled by three muscles tibialis anterior and to extend tibialis anterior starts here at the anterior side of tibia at inserts at the medial and plantar side of CUNY for one and at the base of metatarsal and then we see two more muscles for dorsiflexion.

Let's start with extensor digitorum. As in the hand the extensor inserts at the distal phalanges of digits 234 and five. The muscles origin is that the fibular head and part of the tibia and interest to membrane. As you might have noticed, digit one or hallux is not included here. That is because digit one has an extension of its own extensor pollicis longus. arising from the middle third of fibula, and the interest of your membrane.

It inserts at the distal phalanx of digit one. As you will understand that these two long extensor muscles not only contribute In dorsiflexion, but also in extending all joints of the toes. Now we descend to the subtalar joint for in an E version. Before we take a look at the muscles I'd like to explain a little about biomechanics again. When a muscle passes at one side of the axis of a movement, it will cause a movement in the same direction as it passes the axis. And these pictures you will see this illustrated.

So when we discussed the inversion and E version muscles, please keep this in mind. First, we look at inversion. Three out of five muscles we just met because they are passing the axis of inversion at the medial side. They inverted the ankle. Even though tibialis posterior is active in plantar flexion and tibialis anterior in dorsal flexion. They work together when it comes to inversion.

Two new muscles need our attention. flexor digitorum longus and flexor hallucis longus. flexor digitorum longus arises from the posterior side of tibia right here and becomes a tendon before passing underneath the medial malleolus towards the insertions at the distal phalanges of digits 234 and five. Again, digit one is excluded here but has a flexor of its own flexor hallucis longus. It arises here at the posterior side of fibula, and inserts at the distal phalanx of digital one. And as with the extensors, these flexors do not only enable inversion, but are active in flexing all joints of the toes.

They are only weakly active in plantar flexion. That's why they are not discussed there. Let's move on to a version extensor digitorum isn't hurting muscle because it is passing the axis for energy version at the lateral side. So in extension that is the same as dorsal flexion extensor digitorum works together with extensive analysis longest, but here they split up extensor pollicis longus inverts the subtalar joint due to its origin and insertion, but extensor digitorum longus efforts it we can see two new muscles here. capillaries longest and fibula areas brave is the Latin word say peroneus longus engravers or para knee is longest and bravest. But all names are used.

Both fibula muscles arise from the fibula. The long one at the proximal part and the short one from the distal half. descenders tendons at the posterior lateral side of the lateral millio is the short one inserts at the basis of metatarsal five, where the long one wraps around the plantar side of the foot to insert at the basis of the proximal phalanx of digit one and CUNY for more. Now we have reached the toes, meaning hallux digit one and digits 234 and five. Part of how the toes are moved we already know because we missed extensor and flexor digitorum longus and extend a flexor hallucis longus. But there are short versions of these flexors and extensors as well.

Flexor digitorum braveness arises from calcaneus and inserts at the basis of the second phalanges. So they are able to flex The mtps and the pips of digits 234 and five, flexor alysus brave is is the same muscle but now four digit one. It arises from the solar foot from the planter upon the roses, and inserts at the proximal phalanx of digit one, enabling flexion of the MTP one. extensor digitorum braveness arises from the dorsal side of calcaneus and inserts at the basis of the second phalanges of digits two, three and four. Enabling extension in the mtps and pips. Media to this muscle you can see extensor alysus breakers that inserts at the proximal failings of digit one, enabling extension of the MTP one.

You have learned about most muscles now, but not each and every one. The other small intrinsic foot muscles are as they are in the hand, arising from tassel and tarsal bones and inserting at the phalanges of the toes to spread and close the toes. If you need or want to know these muscles in detail, I'd suggest taking a good look in an anatomical Atlas where you can find this information, but it is beyond the frame of this course. We've come to the end of lecture three of Section four. Thank you for watching this session. I hope to see you again in section five to discuss the muscles of the abdomen, the back of the neck