 Good day everybody. Dr. Sanjo Sanyal, Professor, Department Chair. This is going to be a demonstration of the muscles and the neurovascular structures in the anterior and the lateral compartment of the leg. So this is a supine cadaver. This is the right side. The radiation and the camera both are from the right side. This facial that we see here in front of us, this is the cruel facial. And we have split most of it. Little bit of it is remaining here and the little bit is on this side. The anterior compartment is between the anterior border of the tibia and this anterior intermuscular symptoms. So this much is the anterior compartment. The muscle that we see in front of us, this is the tibialis anterior. This is the most powerful dorsiflexor of the foot. And it goes through a tunnel here under the extrinsic adeniculum of the ankle. And it gets inserted onto the medial side of the medial cuneiform and the base of the first metatarsal bone. And when it contracts, it produces dorsiflexion of the foot. It also produces inversion of the foot. And it also helps to maintain the arch of the foot. Just lateral to the tibialis anterior, we have this muscle here, which I have lifted up next, this muscle. This is the extrinsic halosus longus. The extrinsic halosus longus also goes under the tunnel created by the extrinsic adeniculum. And here also, just like the previous, it also got a sign of its sheath. And the tendon then goes lateral to the tibialis anterior and gets inserted onto the base of the distal phalanx of the great toe. And as the term implies, it is an extrinsic of the great toe. Then we have the next muscle, which I have lifted up, this one. This is the extrinsic digitorum. And we can see the extrinsic digitorum has got multiple tendons. This was also going under the tunnel created by the extrinsic adeniculum. But we have removed part of the extrinsic adeniculum to show you one unique thing. When we remove the extrinsic adeniculum, the tendon undergoes this appearance. And this is referred to as bow stringing. On the other hand, here the tendon is still going under the extrinsic adeniculum, therefore it is not bow stringing. So that explains a very important function of the extrinsic adeniculum wherever it crosses a joint. The purpose of them is not only to hold the tendons in place, but also to prevent bow stringing. To continue, the extrinsic digitorum, as we can see, it gives these slips. This slip is going to the second toe. And it's also giving a slip to the third toe. This one is coming to the third toe. This is to the fourth toe. And we can see this is to the fifth toe. So we have these tendons going to the second, third, fourth and fifth toes. And of course, there is a little bit of sharing of the tendons. The next muscle that we see here is fused and almost inseparable from the extrinsic digitorum. But it is the lateral most part of the anterior compartment. And that is this one here. And we can see this muscle here. This is the fibularis tertius. The fibularis tertius is in the anterior compartment. And it goes and the tendon gets splayed out. And we can see the tendon getting splayed out and it gets inserted onto the dorsal aspect, the base of the fifth pedendarsal. This is an everter of the foot. It's a weak everter of the foot. So these are the muscles that we can see in the anterior compartment. Now let's take a look at the nerves and the vessels of the anterior compartment. This is the neurovascular structure in the anterior compartment of the leg. We have separated the tbls anterior and the extrinsic helices longus. And we can see these structures running. This is the anterior tbl artery with its venaecombitantes. And under that is the deep fibular nerve. This is the deep fibular nerve. Initially they run between the tbls anterior and extrinsic helices longus. And we can see it's running here. And as we trace it down, we notice that it goes under the extrinsic helices longus. And it comes lateral to the extrinsic helices longus. And we can see it clearly here. Anti-Tbl artery is the smaller terminal division of the popliteal artery. In the lower part of the foot, the anti-tbl artery gives medial and lateral malular branches. And then it continues under the extrinsic neculum and it becomes known as the dorsal aspedus artery. The dorsal aspedus artery can be palpated on the dorsum of the foot just lateral to the extrinsic helices longus tendon. The dfibular nerve supplies all the muscles of the anterior compartment. And I have lifted up the dfibular nerve here. This is the dfibular nerve. It is one of the terminal branches of the common fibular nerve. And it supplies all the muscles of the anterior compartment. And then it extends under the extrinsic neculum and it supplies the muscles of the dorsum of the foot and the first inter-digital cleft. Under the extrinsic neculum, the dfibular nerve can get compressed in the condition known as ski boot syndrome. In which case there will be paralysis of the muscles of the dorsum of the foot and numbness and tingling and paracetia in the first inter-digital cleft. The dfibular nerve because it is located so deep inside, it rarely gets injured in an isolated fashion. However, it can be injured as a common fibular nerve and it is winding behind the head and lateral to the neck of the fibular. In fibular fractures, the common fibular nerve can be injured. In which case the dfibular nerve will be paralyzed and that will lead to paralysis of the tibialis anterior tendon and all the muscles of the extrinsic compartment of the foot. Tibialis anterior paralysis will lead to foot drop which is a very serious disability. This is a proprietary functional electrical stimulator which is used in leg balsies especially foot drop. So these are some important clinical correlations pertaining to the anterior compartment. Now let's take a look at the lateral compartment. This is the lateral compartment. The lateral compartment is bounded again by this scroll fascia outside. Then there is an inter-muscular septum which I mentioned earlier, the anterior inter-muscular septum in front which gets attached to the anterior border of the fibula. And behind we have this again another inter-muscular septum here which gets attached to the posterior border of the fibula. So the lateral compartment is located from here to here. It is between the anterior inter-muscular septum, posterior inter-muscular septum, anterior border of the fibula and the posterior border of the fibula. Let's take a look at the muscles of the lateral compartment. This muscle that we can see here in front of us, this is the fibularis longus. It takes origin from above on the upper part of the fibula lateral surface. And it is inside this that the common fibula nerve divides into a superficial and deep fibula. And the tendon then runs down. Just under the fibularis longus we have this next muscle here and we can see the tendon here. This is the fibularis brevis tendon, this one. Fibularis longus and the fibularis brevis tendon, both of them go behind the natural maliolus. The fibularis longus tendon then goes deep to the sole of the foot. It travels in layer 4 of the sole of the foot. It goes from lateral to medial, like this the way my finger is pointing. It travels deep and it gets inserted to the same place as the tibialis anterior but from the opposite side. Namely, place of the fibularis longus and the medial cuneiform. Therefore, when the fibularis longus contracts, it produces aversion of the foot. It also helps to maintain the transverse arch of the foot by virtue of its unique insertion and its location and its course. The fibularis brevis tendon on the other hand, it also goes behind the lateral maliolus and here it is, both of them are bridged over by the fibular retiniculum. And then it goes and gets attached itself to the tuberosity of the fifth metatarsal bone which is located here. This also is an inverter of the foot. And here we have an important clinical correlation known as Dancer's fracture. When the fibularis brevis is actively contracting and the foot is in an averted position and at that position, if the person forcibly, passively inverts the foot, there is extreme tension exerted onto the tuberosity of the fifth metatarsal and it can lead to aversion fracture of this tuberosity and that is referred to as Dancer's fracture. It typically occurs in ladies who are dancing with high heats. These are some x-rays of Dancer's fracture, aversion fracture of the tuberosity of the fifth metatarsal bone. The nerve of the lateral compartment is this nerve here. This is the superficial fibular nerve. This is the other terminal division of the common fibular nerve and this supplies the fibularis longus and the fibularis brevis. And after it is supplied these, we can see that the nerve is continuing and we can see clearly here it pierces the deep fascia. This is the deep fascia or the cruel fascia and it becomes subcutaneous and we can see when exert traction here, the nerve moves here. This is the superficial fibular nerve and once it becomes subcutaneous, it supplies the skin of the antrolateral aspect of the leg as shown by my fingers and then it travels superficial to the extensor retiniculum. So therefore it cannot get entrapped there and then it comes to the dorsum of the foot and it supplies the majority of the dorsum of the foot and all the toes except the first interdigital cleft which we had mentioned was supplied by the deep fibular nerve. A person who suffers from repeated inversion injury of the foot, they can get what is known as attraction neuropathy of the superficial fibular nerve and in a very thin person who does not have much subcutaneous fat, if you were to plant or flex the foot and make the tendon start, we may sometimes be able to see the fibres of the superficial fibular nerve crossing like this and we can give local anesthesia to anesthetize the dorsum of the foot. That is the superficial fibular nerve. So these are the structures which I wanted to show you in the anterior and the lateral compartment with the respective clinical correlations. Thank you very much for watching Dr. Sanjay Sanyal signing out. David over the camera person, if you have any questions or comments, please put them in the comment section below. Have a nice day.