Mandible Flashcards
What is it?
the lower jaw, it moves + shaped like a horse shoe
made up of two bones, joined together in the centre-line at the mental symphysis
Description
its ends bend up into a right angle + each vertical section is called a Ramus
The horizontal section
is called the body of the mandible
The junction of the body + ramus
is called the angle
Two projections at the top of the ramus:
- Coronoid process at the front edge of ramus
- Condyle behind
These are separated from each other by the sigmoid notch
When mouth closed, the coronoid process slots under the zygomatic arch of the face
The condyle + temporal bone of the skull
form the tempo-mandibular joint which allows the lower jaw to move
The ramus
has muscles attached to them which closes the mouth and are called muscles of mastication
Muscles which open the mouth
are attached to the body just below the chin, these pass downwards + attach to the hyoid bone
The first movement in eating
is a hinge-like opening to separate the incisors then moves forwards until the incisors grasp the food
The mandible then
returns backwards + closes this procedure of a shearing action which cuts the foot into smaller pieces ready to chew.
The mandible has an alveolar process running around it
which supports all lower teeth. below this process, on the inner side of the body lies a ridge of bone called the mylohyoid ridge, where the mylohyoid muscles attaches to form the floor of the mouth.
The bony ridge on the outer surface of the ramus
called the external oblique ridge, which marks the base of the alveolar process in this area
Mandibular foramen
halfway up the inner surface of the ramus + protected by the bony lingula, through which the nerve supplying the lower teeth and some of their surrounding soft tissues enters the mandible
Mental foramen
on the outer surface of the body of mandible, between the positions of the premolar teeth, through which the same nerve exits the mandible
