Temporomandibular joint

 Temporomandibular joint 

 

It is a synovial joint of condylar variety

It connect the mandible with the caverna

Relations

Anterior - lateral pterygoid ,mesenteric vessels and parotid gland

Posterior - superficial temporal vessels and auriculotemporal nerve

Superior - middle meningeal vessels and middle cranial fossa

Inferior - maxillary artery and vein

Lateral - skin, fascia, parotid gland, temporal branches of the facial nerve

Blood supply - superficial temporal and maxillary artery

Nerve supply - auriculotemporal nerve and maxillary nerve.

LIGAMENTAL ATTACHMENTS

 there are 5 ligaments attached to the temporomandibular joint

 

1. Fibrous capsule

1. Lined by synovial membrane.

2. Attached to the auricular tubercle

3. sqamotympanic fissure

 

2. Temporomandibular ligament

1. Attached to the auricular tubercle 

2.  head of mandible

3. Strengthens the lateral part

 

 

3. Spheinomandibular ligament

 

• Attached to the spine of the sphenoid and lingua of the mandibular foramen

• It is a remnant of Meckel's cartilage(embryonic cartilage that contributes to the formation of mandible)

• Pierced by the nerve to mylohyoid in the inferior segment

 

 

4. Stylomandibular ligament

• Attached to the styloid process and the posterior ramus  of the mandible

• It separates the parotid and submandibular region 

 

5. Pterygomandibular ligament

Attached to the pterygoid hamulus and the inner aspect of the mandible near the third molar

Joint capsule:

 

Contains 3 parts

1. Meniscotemporal compartment - upper part, permits gliding movement

2. Meniscomandibular compartment- lower compartment, permits both gliding and rotatory movement

3. Articular disc-

• lies in between the upper two compartment

• Fibrous in nature

• Provides cushioning for the head of the mandible

• Prevents friction in the articulating surface and lowed

• It consists of several parts

         1. bilaminar region

          2. posterior thick region.

          3.Intermediate band.

            4.Anterior thick region.

5. Anterior region

 

Synovium:

Tmj is lined with synovium and synovial fluid

The synovial fluid is a filtrate of plasma and consist of hyaluronic acid

Muscles involved in mandibular movements:

 

Depression- lateral pterygoid digastric geniohyoid and mylohyoid

 

Elevation- masseter, medial pterygoid, temporalis

 

Protrusion - lateral and medial pterygoid

Retraction - horizontal fibres of temporalis and masseter