TMJ Conditions

Question 1

Describe a forward head position and its impact on the body.

Answer 1

Forward head position refers to excessive anterior displacement of the head relative to the vertebral column.

This places the upper craniocervial region in excessive extension, and the lower craniocervical region and upper thoracic region in excessive flexion.

In this position:

• the SCM is shortened
• infrahyoid muscles are overstretched
• the mandible is pulled into retrusion and depression
• mandibular condyle is posteriorly displaced, compressing retrodiscal tissues
• protective spasm of lateral pterygoid
• can cause disc derangement

Question 2

Describe the mechanics of overbite and underbite dysfunction

Answer 2

Overbite:

• mandible is retruded
• mandibular incisors not in contact with maxillary incisors

Underbite:

• mandible is protruded
• mandibular incisors on anterior side of maxillary incisors

Pterygoids:

• because pterygoids incisor contact both create stability in lateral movements of mandible, where incisor contact is not present, pterygoids can overwork.
• overuse of pterygoids can pull disc anteriorly, causing disc displacement and increasing wear on joint.

Question 3

Describe the stages of disc derangement of the TMJ

Answer 3

1. Disc displacement with reduction
   - disc stuck at articular eminence
   - as condyle moves forwards and backwards in depression and elevation, it compresses (reduces) disc against eminence, with a click or pop
2. disc displacement without reduction
   - disc is anteriorly displaced forwards of the articular eminence
   - no clicking or popping as the disc is no longer present to be ‘reduced’ in depression and elevation movements
   - usually very limited range opening mouth, pain & inflammation