The articulation of the Mandible forms the Temporomandibular Joint (TMJ) is located anteriorly to the tragus of the ear, on the
lateral aspect of the face.
The muscles of mastication facilitate the movements of the TMJ.
Let us look at the anatomy Temporomandibular Joint; i.e., its articular surfaces and ligaments, including their clinical correlation.
The Articular Surfaces
The Temporomandibular Joint involves articulating three surfaces; the Mandibular Fossa, the Articular Tubercle (from the Squamous part of the Temporal Bone), and the Head of the Mandible. This joint has a unique mechanism; the articular surfaces of these bones never come into contact with each other, as they are separated by an articular Disc. When a person opens or closes their mouth, the Condyles glide along the joint socket of the temporal bone. The Articular Disc helps keep this motion smooth.
There are three extracapsular ligaments that assist to stabilize the Temporomandibular Joints.
The extracapsular ligaments are:
- The Lateral Ligaments
These ligaments run from the beginning of the ArticularTubercle to the Mandibular neck. It is a thickening of the joint capsule and helps prevent posterior dislocation of the TMJ.
- Sphenomandibular Ligament:
It originates from the Spina angular (spine) of the Sphenoid bone and attaches to the lingula of the Mandibular foramen.
- Stylomandibular Ligament:
It is a thickening of the fascia of the Parotid gland. Along with the facial muscles, it acts to support the weight of the jaw.
Protrusion and retraction
During protrusion and retraction, the mandibular condyle and disc Translate anteriorly and posteriorly, respectively, relative to the Mandibular fossa. The Condyle and Articular disc follow the downward slope of the articular eminence. The Mandible slides slightly downwards during protrusion and upward during retraction. The path of movement varies depending o the degree of opening of the mouth.
The Lateral Pterygoid muscle is responsible for protrusion while the Posterior Fibers of the Temporalis assist to achieve retraction of the Mandible. The lateral excursion involves primarily a side-to-side translation of the Condyle and Articular disc within the Mandibular fossa.
Elevation and Depression
The lower part of the TMJ (between the Condyle and Articular disc) permits elevation and depression of the Mandible, in addition to opening and closing of the mouth. During the opening of the mouth, the Mandible hinges downward and is pulled anteriorly, causing both the Condyle and the Articular disc to glide forward from the Mandibular fossa (depression in the temporal bone that articulates with the Mandible) onto the downward projecting Articular tubercle (bony eminence on the temporal bone in the skull).
This results in a forward and downward motion of the Condyle and the resultant depression of the Mandible. However, the Digastric, Geniohyoid, and Mylohyoid muscles act synergistically to assist with depression of the Mandible. Elevation of the Mandible is caused by the contraction of the Temporalis, Masseter, and Medial Pterygoid muscles.
Blood supply to the TMJ is provided by the branches of the External Carotid artery, mainly by the Superficial Temporal branch. Other contributing branches include the Deep Auricular, Ascending Pharyngeal, and Maxillary Arteries. The TMJ is innervated by the Auriculotemporal and Masseteric Branches of the Mandibular Nerve.
Temporomandibular Disorders (TMD)
The common signs and symptoms of TMD are -Pain around the jaw, ear, and temple (the lateral aspect on either side of the head, above the zygomatic arch where four skull bones fuse together: the Frontal, Parietal, Temporal, And Sphenoid).
- Clicking, popping, or grinding noise in the jaw when the mouth is opened or closed
- In opening the mouth widely Locking of the jaw joints
Self-care and lifestyle changes may be enough to handle mild-to-moderate symptoms of TMD. Recommended self-care treatment may involve reducing the movements of the jaw. When a Doctor recommends resting for your jaw, it could involve avoiding chewing gums /clenching of the teeth and jaws and eating only soft food.
A Doctor may send the patient to an Oral and Maxillofacial Specialist, Otolaryngologist, also called an Ear, Nose, and Throat (ENT) Specialist, or a Dentist specialized in TMD to confirm a diagnosis. Sometimes a Health Care Professional may order Magnetic Resonance Imaging (MRI) of the Temporomandibular Joint to detect the damage to the cartilage of the TMJ. If TMD is caused by tooth grinding or clenching during sleep, a Mouthguard may help ease the problem. In cases where TMD is caused by degenerative conditions, such as Osteoarthritis, steroid injections may be a recommended treatment option. In more severe cases, Surgery may be the most efficient option to relieve pain and/or ease the restricted movements of the jaw.
Mild-to-moderate symptoms of TMD can be relieved with self-care and necessary lifestyle changes. If the symptoms are severe, consult a Doctor specialized in TMD. People should always seek professional medical help before choosing a treatment option even if it involves self-care and basic lifestyle changes.
DR. AKHIL GUPTA
BDS, MDS Endodontist & Cosmetic Dentist (Root Canal Specialist)
The beautiful smiles created at our practice are principally the work of Dr.Akhil. His commitment to the utmost in quality and attention to detail has made him a highly regarded cosmetic dentist.