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pterygoid plate and inserts onto the neck of the mandibular condyle.
Fractures of the condyle are pulled anterior-medially by this muscle.
Three paired muscles close the mandible. The medial pterygoid muscle
from the medial portion of the lateral pterygoid plate and the masseter
muscle from the zygomatic process of the maxilla, and anterior
two-thirds of the lower border of the zygomatic arch, insert on the
medial and lateral vertical mandible forming a tendinous “pterygomas-
sitric sling.” The temporalis muscle arises from the temporal fossa and
the deep part of temporal fascia and passes medial to the zygomatic
arch and inserts onto the coronoid process of the mandible.
C. Temporomandibular Joint
The TMJ’s articular eminence and superior condyle are covered with
fibrocartilage. The articular disk is dense collagenous connective tissue
and is without sensation. The retordiscal loose connective tissue that
anchors the disk posteriorly is well innervated, and when torn, allows
the disk to displace anteriorly.
The jaw opens in two steps: (1) the condyle rotates in the inferior joint
space for an interincisor opening of 20–24 millimeters (mm), and (2)
the condyle and disk translate down the articular eminence, allowing
the interincisor opening to exceed 40 mm.
II. Indications of the Presence of Mandibular Fracture
A. Symptoms (Subjective)
y
y Pain.
y
y Bite abnormality.
y
y Numbness.
y
y Bleeding.
y
y Swelling.
y
y Dyspnea.
B. Signs (Objective)
1. Deformity
External deformity is often difficult to see clinically due to swelling.
Intraoral exam may show displacement creating a step deformity, open
bite deformity, and malocclusion. Many patients can have significant
preexisting malocclusion, which must be documented in preoperative
notes and considered during treatment planning.