Page 126 - Edited - Webster HEAD AND NECK - part 1

HN 104
THE TEMPOROMANDIBULAR JOINT
LATERAL ASPECT:
A. BONES

1. THE MANDIBLE (LOWER JAW) IS A
U-SHAPED BONE, WITH THE ARMS OF THE
U BENT AT ~90° TO THE CURVE (SI 38)
2. THE CURVE OF THE U IS HORIZONTAL &
ARTICULAR IS THE BODY OF THE MANDIBLE, WITH
TUBERCLE BEARS THE LOWER TEETH IN ITS
ZYGOMATIC MANDIBULAR ALVEOLAR MARGIN (HARD PART OF GUM).
ARCH FOSSA 3. THE VERTICAL PART IS THE RAMUS OF
THE MANDIBLE WHICH ENDS SUPERIORLY
EXTERNAL AS THE FLATTENED CORONDID (“CROW'S
AUDITORY BEAK”) PROCESS ANTERIORLY & THE
MEATUS
MANDIBULAR CONDYLE POSTERIORLY.
4. THE RAMUS IS THIN & FLAT, BUT
MAXILLA
K.E.W.
CONDYLE
BODY OF OF MANDIBULAR FOSSA
MANDIBLE RAMUS MANDIBLE
ANGLE
ARTICULAR INTRA-
MENTAL (“CHIN”) EMINENCE TUBERCLE ARTICULAR
DISC
THE CONDYLE HAS A CYLINDRICAL
PROFILE FOR ARTICULATION WITH THE CORONOLD
MANDIBULAR FOSSA OF THE TEMPORAL PROCESS CONDYLE
(HEAD)
BONE.
5. THE TEMPORO-MANDIBULAR JOINT IS
SYNOVIAL, BUT MADE COMPLEX BY THE BONY
INCLUSION OF A FIBROUS INTRA- RAMUS TUBE:
ARTICULIAR DISC, ATTACHED AT ITS EXTERNAL AUDITORY
PERIPHERY TO THE JOINT CAPSULE. MEATUS
6. THIS DIVIDES THE JOINT INTO UPPER & LOWER PARTS: WHEN THE LONDYLE ROTATES, IT DOES SO ON
THE DISC; WHEN THE CONDYLE SLIDES, THE DISC & CONDLYLE MOVE AS ONE, SLIPPING OVER THE
MANDIBULAR FOSSA SURFACE. 7. THE JOINT CAPSULE IS STRENGTHENED ON ITS
B. CAPSULE & LIGAMENTS LATERAL SIDE BY AN INTRINSIC LIGAMENT.
JOINT CAPSULE 8. THE SPHENO-MANDIBULAR LIGAMENT
ATTACHES THE BODY OF THE SPHENOID BONE TO
WITH INTRINSIC THE MEDIAL SIDE OF THE RAMUS, THERE ARE
LIGAMENT
SPHENO- ANTERIORLY ALSO THE STYLO-MANDIBULAR LIGAMENT &
MANDIBULAR RAPHE BETWEEN BUCCINTOR & SUP.
LIGAMENT PHARYNGEAL CONSTRICTOR MM WHICH, WITH
THE PRIMARY MUSCLES OF MASTICATION
( ) STABILIZE THE JOINT.
9. LIMITATIONS OF MOVEMENT:
(a) SIDE-TO-SIDE: INTRINSIC LIGAMENTS
OF JOINT CAPSULES,
(b) POSTERIOR: INTRINSIC LIGAMENTS OF JOINT
CAPSULES (∵ OF DIRECTION OF COLLAGEN

STYLOID FIBRES) & THE BONE OF THE EXTERNAL
PROCESS AUDITORY MEATUS.

ANGLE. STYLO-MANDIBULAR
LIGAMENT
(c) ANTERIOR: THE ARTICULAR TUBERCLE & STYLOMANDIBULAR LIGAMENT. THE JOINT MOST
READILY DISLOCATES IN THIS DIRECTION: “JUMPING” THE TUBERCLE, THE CONDYLE SLIPS
INTO THE DEPRESSION IMMEDIATELY IN FRONT. SEE ALSO:

K.E.W.