TMJ Anatomy – Anatomy and Biomechanics of the Temporomandibular Joint

TMJ Anatomy

Your TMJ, also known as your temporomandibular joint, is one of the most important joints in your body. 

The temporomandibular joint (TMJ) is a critical component of the human anatomy, connecting the mandible (lower jaw) to the skull. This synovial joint allows for a wide range of movements needed for everyday life, including opening and closing the mouth, eating, speaking, breathing, and communicating. The TMJ is a unique joint in that it both slides and rotates, which is a crucial aspect of its anatomy and function. Understanding the anatomy of the TMJ is important for those looking to understand how this joint works and the role it plays in oral health and overall well-being. In essence, the TMJ is a very valuable joint, playing a critical role in allowing us to perform many of the daily activities we take for granted.

The TMJ anatomy is very complex and goes above and beyond simply opening and closing your mouth. Without it, everyday life would be decidedly harder. Formed by the articulation of your mandible, coupled with the temporal bone, the TMJ is situated on the lateral aspect of the face, just to the front of the tragus of the ear. 


TMJ anatomy

Your temporomandibular joint (TMJ) is a fairly complex joint with a unique anatomy consisting of articulations located between three distinct surfaces. These surfaces are an important aspect of the joint anatomy, as they work together to allow the jaw to move and perform a wide range of functions. Understanding the anatomy of the TMJ is important for those looking to understand how this joint works and the role it plays in oral health and overall well-being. By exploring the different surfaces and articulations that make up the TMJ, we can gain a deeper appreciation for this intricate joint and the impact it has on our daily lives.

  • Mandibular fossa 
  • Articular tubercle 
  • The mandible head 

There are also temporomandibular joint ligaments that make up your TMJ. In total, there are three extracapsular ligaments in the TMJ that work to stabilize the joint. These include: 


Lateral ligament 

The lateral ligament is an important component of the temporomandibular joint (TMJ). It is a strong fibrous band that provides support and stability to the jaw as it moves. The lateral ligament helps to maintain proper jaw alignment and prevents dislocations of the jaw during movement. The articular aspect of the lateral ligament refers to its role in forming part of the articulating surface within the TMJ. Injuries or damage to the lateral ligament can lead to pain and discomfort in the TMJ and may require medical evaluation and treatment. In order to diagnose and properly treat the issue, healthcare providers may utilize a combination of physical exams, imaging tests, and other diagnostic tools to understand the extent of the damage and determine the best course of action.


Sphenomandibular ligament 

The sphenomandibular ligament is a strong band of tissue that connects the sphenoid bone in the skull to the mandible (lower jaw). It is one of the key components of the temporomandibular joint (TMJ), which allows for movement and function of the jaw. The sphenomandibular ligament helps to maintain the stability and proper alignment of the TMJ, and is essential for normal jaw function. Disruptions or damage to the ligament can lead to temporomandibular joint disorders (TMD), which can result in pain, discomfort, and decreased ability to chew and speak.


Stylomandibular ligament 

Finally, we have the stylomandibular ligament. 

The stylomandibular ligament is a fibrous band that connects the styloid process of the temporal bone to the mandible (jaw bone). It helps to provide stability and support to the temporomandibular joint (TMJ) by limiting excessive movement of the jaw. The stylomandibular ligament is one of the three ligaments that support the TMJ and play a crucial role in maintaining the proper function of the jaw joint.


Muscles of mastication

In order for you to chew your food, your jaw needs to be able to deal with tougher, harder foods that require a lot of chewing. This is where muscles of mastication come into the mix. 

There are three primary muscles of mastication, which are: 

    • Masseter : 

The masseter muscle is a muscles in the jaw region that plays a crucial role in chewing and grinding food. It originates from the zygomatic bone and inserts on the mandible. The masseter muscle is responsible for closing the jaw and helps to elevate the mandible. It is one of the four muscles of mastication, which are the muscles responsible for the movement of the jaw and control of the chewing process. The masseter muscle is also involved in clenching and grinding of the teeth, which can contribute to the development of temporomandibular joint (TMJ) disorders and related symptoms such as jaw pain, headaches, and muscles tension.

    • Temporalis :

The temporalis muscle is one of the muscles of mastication (chewing) in the human body. It is a large, fan-shaped muscle located in the temporal region of the skull, above and to the side of the ear. The temporalis muscle functions to elevate the mandible (lower jaw) during biting and chewing movements, and is an important muscles for controlling the position of the jaw. In addition to its role in mastication, the temporalis muscle also has a role in facial expression and can contribute to headaches and temporomandibular joint (TMJ) disorders in some individuals.

    • Lateral Pterygoid : 

The lateral pterygoid muscle is one of two muscles that make up the pterygoid muscle group. It is located in the head and neck region, and is involved in the movement of the jaw. This muscles is responsible for protraction of the mandible, which is the movement of the jaw forward, and elevation of the mandible, which is the movement of the jaw upward. The lateral pterygoid muscle works in concert with the other muscles of mastication, including the masseter and temporalis muscles, to control the movements of the jaw. Dysfunction or pain in the lateral pterygoid muscle can contribute to temporomandibular joint (TMJ) disorders and other orofacial pain conditions.

Along with these muscles, there are also a series of secondary muscles which support the primary ones, enabling the jaw to function as it should when we chew our food. 

As well as the above, bursa and discs located in the joint also play key roles into the overall functioning of the joint itself. 


TMJ biomechanics

Now that we understand more about the anatomy of the TMJ, we’re going to delve deeper into the biomechanics of the joint. 

Joint mobility and range of motion for the TMJ for example, is typically 45mm for depression, 3mm for retrusion, a lateral excursion which is ¼ of depression, and protrusion of 6 – 9mm on average. 

Discs in the joint also play essential roles into the functioning of the joint. A soft cartilage disc located in the joint functions as a layer of cushioning between the bones of the TMJ. This enables the TMJ to open smoothly. If this cartilage disc wears down, the TMJ will not operate as smoothly. 


Muscle activity on TMJ function

The temporomandibular joint (TMJ) is a complex and dynamic structure that requires coordination between the muscles and bone of the jaw to perform its functions. The muscles of mastication, including the masseter, temporalis, and lateral pterygoid muscles, play a crucial role in the movement and stability of the jaw during activities such as chewing, speaking, and swallowing. These muscles work in concert with the ligaments, bone, and articular disc within the TMJ to allow for smooth, pain-free jaw movement. An imbalance in muscles activity, such as overuse or tension, can result in temporomandibular disorders (TMD), leading to pain, discomfort, and limited jaw mobility.

Muscles responsible for the jaw opening are internal or medial pterygoid, geniohyoideus, mylohyoideus; digastric. 

Muscles responsible for the jaw closing are: masseter, temporal, external or later pterygoid. 


TMJ pathology and disorders

TMJ, also known as TMD (Temporomandibular joint Disorder/Dysfunction) is a very common dental issue that can lead to a wide range of health complications and ailments. 

When studying TMJ anatomy and temporomandibular joint movement, you must understand some of the risks associated with TMJ. 

Conditions such as arthritis, disc displacement, and bruxism are all closely linked with TMJ. Bruxism for example, is characterized by clenching of the teeth and jaw, and grinding of the teeth. This can place a lot of strain and pressure upon the TMJ, resulting in it becoming damaged. 

Arthritis or disc displacement can also cause very painfully issues, as the more the disc cartilage in the joint wears down, the more the bone will grind on one another and the more painful the condition will become. 


TMJ disorder symptoms and diagnosis

In order for an accurate diagnosis of a TMJ disorder to be carried out, you must seek professional dental treatment and be examined by your dentist. 

The good news is that, as painful as TMJ is, making a diagnosis is fairly simple as the symptoms are fairly easy to spot. Symptoms associated with a TMJ disorder include: 

  • Headache 
  • Jaw ache 
  • Damaged teeth 
  • Stiff/sore neck, back, and/or shoulders
  • Blurred vision 
  • Damaged mouth/tongue 
  • Locked jaw 
  • Tinnitus 
  • Vertigo 
  • Misalignment of the jaw 
  • Clicking or popping noises coming from the jaw 


TMJ treatment options

Read any temporomandibular joint PDF, or speak to any expert on TMJ anatomy, and you’ll quickly see that, as painful as TMJ can be, it can be treated in a number of different ways. 

For milder cases, conservative treatments such as physical therapy or oral splints worn in the mouth at night can be utilized. These are non-invasive, simple to prescribe and carry out, and are very effective with mild cases of TMJ. 

In more advanced TMJ cases however, muscle relaxants and injectables such as Botox may be prescribed. Botox acts as a muscle relaxant, helping muscles in the face connected to the TMJ to relax, thereby easing pressure and tension on the TMJ. 

In very extreme TMJ cases however, surgery may be required. Arthroplasty (total joint replacement) surgery may be carried out if splints, mouthguards, or other treatments fail to help ease the symptoms of TMJ. When this occurs, the TMJ is replaced with a custom-made titanium TMJ instead. It should be noted that TMJ surgery is very rare and is only recommended as a last resort. 



The TMJ anatomy ppt is a very complex joint responsible for a wide range of everyday processes relating to the mouth. 

With a unique structure and complex biomechanics behind it, if you suffer with TMJ or suspected TMJ, it’s essential to visit your dentist and seek professional dental treatment right away. 

In order to diagnose and treat TMJ disorders, an understanding of the basic TMJ anatomy and indeed, its biomechanics, is essential. 


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