 Good day everybody. This is Dr. Sajya Sanyal, Professor, Department Chair. This is going to be a demonstration of the osteology of the leg. So what you're seeing in front of you is the tibia and the fibula, left leg oriented in the lateral axis. So just to bring up the speed up here, you can see there's a knee joint. So this is the upper end of the tibia, this is the upper end of the fibula. It is the tibia fibular articulation and this is the shaft of the tibia fibula and this is the ankle joint, the tibia fibular mortise and these are the bones of the foot. So let's focus on first the orientation of the tibia and the fibula because it is described as typically triangular in cross section. So the surface that you see here, this is the lateral surface of the tibia. Therefore the tibia typically has got an anterior border, an introsius border and a medial border. Between the anterior border and the introsius border is the lateral surface of the tibia. Between the anterior border and the medial border is the medial surface of the tibia. Therefore the tibia has got a lateral surface, a medial surface and a posterior surface. It is got an anterior border, a medial border, both of which are palpable and an introsius border. Medial surface of the tibia is absolutely featureless because it is subcutaneous and it is the one which is felt under the skin. So this is the anterior border which you can feel in front of your leg, the so called shin bone. This is the medial surface. So this is the portion which is covered by periosteum, fascia and skin. Therefore there are no muscle attachments there. This brings us to an important clinical correlation at this juncture. If there's a tibial fracture, it is very likely to become compound fracture. Compound fracture means when the bone fragments protrude out through the skin. It can be compound either from within or from without. Within means a fragment pierces through the skin and comes out. Compound from without means, a penetrating injury breaks the bone and causes it to communicate with the outside surface. So that's about the surfaces in the borders of the tibia. Just to recap, the tibia has got a medial surface, a lateral surface and a posterior surface. Only the medial surface, anterior border are felt and subcutaneous. Fibula on the other hand is even more complicated. It also is described as triangular and cross section. It has got an anterior border. You cannot feel it because it's covered by muscle. It's got a posterior border which also cannot be felt because it's covered by muscle. Attached to the anterior border and the posterior border are the anterior and the posterior intermuscular septum which gives lateral compartment of the leg which houses the fibularis longus and the fibularis breves. It has got an introsius border which gives attachment to the introsius membrane which connects it with the tibia and forms the tibiofibular syndesmosis. Just to recap, fibula has got anterior border, a posterior border and an introsius border. It has also got a medial surface, lateral surface and a posterior surface which cannot be felt because they're all covered by muscle. Only the upper end of the fibula can be felt. That's the head of the fibula and the lower end of the fibula can be felt which is the lateral malleolus. In contrast, the tibia, we can feel the upper portion completely and we can feel the lower portion as the medial malleolus. We can feel the entire medial surface. Let's come to the upper end of the tibia. This projection that you see here, you can feel it. This is the tibial tuberosity. This is the one which gives attachment to the ligamentum patellae or the patella ligament which is the extension of the quadriceps tendon across the patella and this is the one which is responsible for extension of the knee. It's a very strong and very powerful ligament. This is the location where my finger is located where we do a knee reflex hammer test for the knee jerk. Between the ligamentum patellae and the bone, there is a bursa and there is a deep intrapatilla bursa which is situated deep to the intrapatilla fat band. If you look a little laterally and anteriorly, you can see a bulge here. This is the antrolateral tubercle of GERD. This gives attachment to the iliotibial tract. The iliotibial tract is the thick, strong aponeotic expansion which comes down all the way from the thigh which is the continuation of the insertion of the gluteus maximus and the tensor facial tendon. This is the attachment of the iliotibial tract. Medially, we can see this attachment here. This is the attachment of the pezanserinas. Pezanserinas is the combined triple insertion like this, like the foot of a goose and it is the insertion of the sartorius muscle from the anterior compartment, the gracilis muscle from the medial compartment and semitian diagnosis muscle from the posterior compartment. All these three muscles form a combined insertion like the foot of a goose which is called the pezanserinas which is on the upper medial aspect of the tibial. These are the tibial connex and if they are flat that's why they refer to as the tibial plateau and this is the one which forms the knee joint and these are the intercondyler eminences. In between the two tibial flat connex and this is the intercondyler area which is outside the sanival membrane of the knee joint. As to the margins, we have the coronary ligament which extends from the menisci to the margins of the tibial connex and of course the tibial connex give attachment to many other structures. Medial and the lateral plateau retina column capsule of the knee joint. The head of the fibula is very easily palpable. The common fibula nerve initially runs behind the head of the fibula after it comes from the pocketial fossa and then it winds around the lateral to the neck of the fibula and it comes into the lateral compartment of the leg and deep inside the fibularis longus it divides into a deep division which runs like this and a superficial division. The deep division, the deep fibular nerve is the nerve of the anterior compartment of the leg and the superficial division is the nerve of the lateral compartment of the leg which supplies the fibularis longus in the fibularis previous. So therefore in fractures of the neck of the fibula. As our nerve is winding around the lateral aspect of the neck of the fibula it can get injured and can lead to pudra. This is a very stress x-ray of the right knee to show fracture of the head of the fibula. Common fibula nerve injury is quite likely. The most common site of fracture of the tibia is the junction between the upper two thirds and the lower one third because this is the weakest part of the tibia. There's a fracture of the tibia here in this region which is referred as a boot top fracture which roughly corresponds to the location of the weakest part of the tibia. People who wear calf length boots they can get a fracture just about that. That's why it is called the boot top fracture. This is an x-ray of the right leg to show boot top fracture. Please read the inscriptions very carefully. Quite often tibial fractures are associated with fibular fractures because they are intimately attached to each other and as I said already tibial fractures are quite likely to become compound. There's another fracture of the tibia which is possible in soldiers. It's called the stress fracture. It's also called the march fracture. It is typically described more commonly in the lower part of the tibia but it has also been described in the upper part of the tibia. These march fractures, stress fractures develop over weeks, months and years. These are micro fractures which gradually build up and they are quite often missed on x-ray. They produce persistent pain and in order to diagnose them very accurately we may require high resolution MRI images to diagnose a march or a stress fracture. This stress fracture may have been missed in the plain x-ray as shown on the left sign. However it is clearly demonstrated in the MRI image. So for the time being this is all that we will mention about the tibia and the fibula. There will be more videos which you'll follow which will mention the muscle attachments. Thank you very much for watching. The procedure is signing out. If you have any questions or comments please put them in the comment section below. Please like and subscribe. Have a nice day.