Hello everyone! Assalamoalaikum (peace be upon you) In this video, we are going to discuss the TEMPOROMANDIBULAR JOINT. So focus on the name TEMPOROMANDIBULAR, here temporo means temporal bone and mandibular means the so this joint is present between the temporal and mandible bones. Okay, if you see this diagram here, you can clearly spot this temporal bone and here is the mandible, so here can see how Mandible is kind of fits in the temporal bone and makes a joint that is known as Temporomandibular joint or simply the TMJ. If we talk about it's type, it is the Condylar variety of synovial joint,to understand this condylar variety see this diagram of the Mandible, if we see this bone here is Condylar process,this process is fitted in the temporal bone making the Temporomandibular joint, so as Condylar process is fitted in the temporal bone,this joint is of Condylar variety because here Condyle articulates.hope you understand why it is called Condylar variety. Now let's see its articulating surface,here we can see articulating surface clearly, In upper surface we have the temporal bone ,also we can see this fossa in temporal bone. fossa is mandibular fossa and so here in this fossa Mandible articulates ,,so Upper articulating surface is formed by the mandibular fossa of the temporal bone and the lower articulating surface is formed by Condylar process of mandible. Now let's talk about its Ligaments, so total 4 Ligaments are present here, one is fibrous capsule, which covers the joint. second is Lateral Temporomandibular Ligament that is present Laterally between temporal bone and the mandible bone. these two are the main Ligaments, other than these two we have 2 more accessory ligaments present here , so if we see the joint from the posterior part we can see this Ligament here that is Stylomandibular ligament which is present between the Styloid process and the Mandible and just above stylomandibular ligament we have one more Ligament here that is the Sphenomandibular ligament, that is attached from the sphenoid bone to the Mandible bone. Now let's discuss the Articular disc, to understand this let's focus on this diagram, so here we can see a disc-like structure which is present between the articulating surfaces. this disc-like structure is known as the articulating disc. The articular disc divides the joint into upper and lower compartments. The upper compartment permits gliding movement, and the lower compartment permits rotary as well as gliding movements. It has a concavo-convex superior surface and concave inferior surface and at the periphery, this disc is attached to the fibrous capsule. We can divide the disc into various regions, anterior, anterior thick band, intermediate region, posterior thick band and bilaminar region. The bilaminar region contains venous plexuses. what is the function of this disc? It helps in reducing friction between the Articulating surface and also act as a shock absorber, it helps in lubricating the joint. Now let's jump to the Relations of the Temporomandibular Joint, Anteriorly it is related to the Lateral pterygoid muscle, masseteric nerve and vessels. Posteriorly we have the Parotid gland, external auditory meatus, superficial temporal vessels, and auriculo- temporal nerve.Its medial side is present with Spine of sphenoid, sphenomandibular ligament, auriculotemporal nerve, chorda tympani nerve, and middle meningeal artery. Laterally it is related to Skin, fascia, parotid gland, facial nerve. Superiorly Middle cranial fossa is present and Inferiorly Maxillary artery and vein is present. Talking about its Nerve Supply, blood supply and Lymphatic Supply it is supplied by the Auriculotemporal nerve and Masseteric nerve. It receives branches from the superficial temporal artery and Maxillary artery. and it drains into the upper cervical lymph nodes. Now let's discuss the Movements of Temporomandibular Joint.so its movement includes Depression which is opening of the mouth , Elevation that is closing of your mouth, Protrusion that's the protraction of chin, Retrusion that is retraction of chin and Lateral or side-to-side movements during chewing or grinding.if you have seen our video on muscle of mastication you can easily understand these movements. Also in the Complete Denture Course on our app, we have covered the mandibular movements. Now if you want to feel the movements of your TMJ, what you can do you can palpate it using your finger, keep your finger at pre-auricular joint or into the external auditory meatus. The movements of the joint can be divided into the upper compartment movements and the lower compartment movement. The upper compartment movement means the movement between the upper articular surface and the articular disc, and the lower compartment movement means those occurring between the disc and the head of the mandibular condyle. Remember, forward movement occurs in the menisco-temporal compartment, that is the upper compartment. When you open your mouth slightly the movement happens in the lower compartment, but when you open your mouth wide the movement happens in the upper compartment. What happens in side-to-side movement? For example, if we have the head of right side gliding forward, the condylar head of one side will glide forward, and the condylar head of other side will merely rotate on a vertical axis. Now which muscles produce which kind of movement? Now depression is brought about by the lateral pterygoid muscle. Elevation is brought about by the masseter, anterior vertical middle oblique fibers of the temporalis muscle, and medial pterygoid muscle of both sides. These are also known as anti-gravity muscles. It can be a viva question. Protrusion happens by lateral and medial pterygoid and superficial oblique fibers of masseter. Retraction is done by posterior horizontal fibers of temporalis and deep vertical fibers of masseter. Now in lateral or side-to-side movement, imagine that you are chewing from your left side. Now if you chew from the left side, the movement will be taking place with the help of right lateral pterygoid, right medial pterygoid which push the chin to the left side. Then the left muscles will activate, the left temporalis (the anterior fibers of it), the left masseter (the deep fibers) will chew the food. Let's discuss the clinical anatomy: • Dislocation of the mandible is seen during the excessive opening of the mouth. • Any injury, like overclosure or malocclusion, can cause Derangement of the articular disc • During any operations on the temporomandibular joint, the VII nerve and auriculotemporal nerve should be preserved with care. Name the 7th Nerve? That's a question for you! Let's summarise: TMJ is a synovial joint of the condylar variety present between the temporal and mandible bones. Upper articulating surface is formed by the mandibular fossa of the temporal bone and the lower articulating surface is formed by the Condylar process of the mandible. we have total 4 Ligaments that are fibrous capsule, lateral temporomandibular ligament , sphenomandibular ligament and stylomandibular ligament. It is supplied by Auriculotemporal nerve and Masseteric nerve and it drains into the upper cervical lymph nodes. it's clinical anatomy includes the Dislocation of the Mandible and the derangement of the articular disc. Important questions include: 1: Describe the temporomandibular joint under following a. Type, b. Articular surfaces c. Ligaments d. Movements e. Nerve and blood supply 2• Write short note on movements of the Temporomandibular joint So I hope you find this video helpful. I think you should revise this video again because its very important. I will see you in the next video. Take care. Allah hafiz!