Anatomy of Temporomandibular Joint in a Nutshell

Anatomy of Temporomandibular Joint (TMJ)

• Mandibular head: aka Mandibular condyle
• Mandibular Fossa: on the temporal bone
• Temporal bone has 2 tubercles
  • Anterior tubercle (Articular tubercle)
  • Posterior Glenoid tubercle

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• Articular Disc:
  • Divides the joint into 2 joint spaces

1. 1. • Superior Joint space between disc and mandibular fossa
      • Inferior Joint space between disc and mandibular head

• • Is bound to mandibular head by many ligaments
• Ligaments of TMJ:
  • Temporomandibular ligament
  • Sphenomandibular ligament
  • Stylomandibular ligament.
• Mechanism of Opening mouth:
  • Starts with rotation in the inferior joint space

1. 1. • Head of the mandible moves on the articular disc
      • Very small amount of rotation is not enough to open mouth to full extent.
      • Only opens wide enough to make 25 mm of space between teeth

1. • The remainder of mouth opening

1. 1. • Requires Translation in which the head of mandible along with the disc glide forward and onto articular tubercle.
      • Once on the articular tubercle, have wider range of motion

1. • Dislocation:

1. 1. • The mandibular head has gone anterior to the articular tubercle
      • Muscles of mastication go into a spasm

• Mechanism of Closing mouth
  • Rotation to start
  • Posterior translation
  • Rotation once more
• Clinical TMJ:
  • the articular disc and head of mandible have become detached
  • Causes “clicking” which is where head glides forward / back
• Muscles that move the TMJ:
  1. Elevation: Medial pterygoid, Masseter & Temporalis.
  2. Depression: Lateral pterygoid (Most part!) & digastric.
  3. Protrusion: Lateral and Medial pterygoid, Masseter.
  4. Retraction: Temporalis, Masseter.

• Blood supply: 
  • Superficial temporal artery
  • Maxillary artery
• Nerve supply: 
  • Auriculotemporal nerve
  • Masseteric nerve.

Also read:

1. The Temporomandibular Joint @ TeachMeAnatomy
2. Practice Anatomy tests for free!
3. Best Anatomy books for Medical students
4. Best Anatomy websites & journals
5. Anatomy syllabus in (CBME) in India
6. Anatomy syllabus in Russia & Other CIS
7. Anatomy syllabus in China

Also Watch:

• Temporomandibular Joint (TMJ) Anatomy @ Geeky Medics