The face skeleton serves to safeguard the brain; house and also protect the feeling organs of smell, sight, and also taste; and administer a frame on which the soft organization of the face can act to facilitate eating, facial expression, breathing, and also speech. The major bones the the face are the mandible, maxilla, frontal bone, nasal bones, and zygoma. Facial bone anatomy is complex, however elegant, in the suitability to serve a multitude the functions. The image below provides summary of the anterior attributes of the skull. <1, 2, 3, 4, 5, 6>
The mandible is a U-shaped bone. That is the only mobile bone of the face skeleton, and, due to the fact that it homes the lower teeth, its motion is crucial for mastication. The is created by intramembranous ossification. The mandible is composed of 2 hemimandibles joined at the midline through a upright symphysis. The hemimandibles fuse to kind a single bone by age 2 years. Each hemimandible is written of a horizontal body v a posterior vertical extension termed the ramus. (See the pictures below.) <7>
Body - lateral surface
On the anterior worse midline an ar of the hemimandible body is a triangular thickening that bone termed the mental protuberance. The thickened inferior rim the the psychological protuberance extends laterally native the midline and forms 2 rounded protrusions termed the mental tubercles. Located lateral to the midline ~ above the outside surface are the psychological foramina that transmit the mental nerves and vessels. Castle usually room located below the apex the the second bicuspid and also have 6-10 mm of variation in the anteroposterior dimension.
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The rim of bone lateral to the psychological tubercles expand posteriorly and also ascends obliquely as the oblique line to join the anterior edge of the coronoid process. The worse rim that the posterior human body thickens and also flares laterally whereby it attaches to the masseter muscle.
Body - medial surface
Just lateral to the symphysis on the inner surface ar of the mandible space 2 combine protuberances termed the superior and inferior psychological spines. The genioglossus muscle attaches to the superior mental spines, and also the geniohyoid muscle attaches come the inferior mental spines. Simply lateral come the inferior mental spines on the inferior border that the mandible space 2 concavities dubbed the digastric fossae, where the anterior digastric muscle attach.
Extending obliquely in a posterosuperior direction from the midline is a ridge the bone dubbed the mylohyoid line, i m sorry serves together the attachment website for the mylohyoid muscle. Over and listed below the mylohyoid line on the within mandibular body room 2 shallow convexities versus which the sublingual and also submandibular glands abut, respectively. Medial come the ascending edge of the anterior ramus is the retromolar trigone, located instantly behind the 3rd molar.
Rami - lateral surface
The ramus extend vertically in a posterosuperior direction posterior come the body on each hemimandible. The mandibular angle is developed by the intersection of the inferior rim that the body and also the posterior in salt of the ascending ramus. The superior ramus bifurcates into an anterior coronoid procedure and a posterior condylar process. The concavity between the 2 procedures is called the mandibular notch. The coronoid is thin and triangular. Through the this in occlusion, the superior extent is medial come the zygomatic arch. The coronoid is the site of attachments of the temporalis muscle. Inferiorly, the condylar procedure has a small neck the widens come a globular head the articulates with the glenoid fossa that the temporal bone.
Rami - medial surface
On the medial surface ar of the ramus, just below the mandibular notch, is an aperture termed the mandibular foramen; the inferior alveolar nerve and also blood vessels run with this aperture. Just medial to the mandibular foramen is the lingula, a triangle bony protuberance through its apex pointing posterosuperiorly toward the condylar head. Prolonging anteriorly and also inferiorly native the mandibular notch toward the worse rim of the body is the mylohyoid groove, v which the mylohyoid nerve runs.
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The mandible has actually a big medullary core with a cortical rim 2-4 mm thick. <8> The inferior alveolar canal begins at the mandibular foramen and also courses inferiorly, anteriorly, and also toward the lingual surface ar in the ramus. In adults, the canal come in close proximity come the root of the third molar. In the mandibular body, the canal courses along the inferior border close to the lingual surface. Anteriorly, the canal runs frequently inferior come the level that the mental foramen, come which that ascends at its terminal end.
The mandible homes the reduced dentition, i m sorry in adults is composed of 2 central and 2 lateral incisors, 2 canines, 2 an initial and 2 second premolars, and also 3 set of molars. Interdental septi run in between the buccal and also lingual cortices the the mandible, and also interradicular septi run in between the mesial and also distal root of the molars.