Mandibular Fractures

11


Mandibular Fractures


Image Anatomy


•   A “U-” shaped bone that contains two hemimandibles


•   Structures unite at midline called symphysis


•   Each hemimandible consists of a (Fig. 11–1)



Image  Body


Image  Angle


Image  Ramus


Image  Coronoid process


Image  Condyle


•   Muscles of mastication



Image  Jaw protrusion



Image   Lateral pterygoid (lateral pterygoid plate to condylar neck)


Image  Jaw elevators



Image   Temporalis (temporal fossa to coronoid)


Image   Masseter (zygomatic arch to the body)


Image   Medial pterygoid (medial pterygoid plate to angle)


Image  Jaw depressor-retractors



Image   Lateral pterygoid


Image   Digastric


Image   Geniohyoid


Image   Mylohyoid


Image   Genioglossus



Image


Figure 11–1 Anatomy of the mandible.


•   Condyle articulates with cranium at the glenoid fossa of the temporomandibular joint (TMJ)


•   Blood supply of mandible



Image  Inferior alveolar artery from the internal maxillary artery enters at mandibular foramen and exits at mental foramen


Image  Branches from the muscles of mastication


•   Nerve supply



Image  Inferior alveolar nerve from V3 enters at mandibular foramen and exits at mental foramen


•   Mental foramen



Image  Located between first and second premolar


Image Dental Relationships


Child:


 


•   20 deciduous or primary teeth labeled A – T



Image  Right A B C D E F G H I J


Image  Left T S R Q P O N M L K


 


Adult:


 


•   32 permanent teeth labeled 1 through 32



Image  Numbering begins with the third right maxillary molar as tooth #1 and the last maxillary molar as #16


Image  Numbering continues onto the mandibular left third molar as #17 and ends with the mandibular right third molar as #32


 


Each hemimandible or hemimaxilla consists of


 


•   One central and one lateral incisor


•   One canine (cuspid)


•   First and second premolar (bicuspid)


•   First, second, and third molar


Angle Classification of Occlusion


Based on the first maxillary molar and its position to the first mandibular molar (Fig. 11–2):



Image


Figure 11–2 Angle classification of occlusion.


 


•   Class I – normal occlusion



Image  Mesiobuccal cusp of the maxillary first molar occludes with buccal groove of the mandibular first molar


•   Class II – overbite



Image  Lower first molar is distal (posterior) to the upper first molar


•   Class III – underbite



Image  Lower first molar is mesial (anterior) to the upper first molar


Image Mandibular Fractures

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Mar 12, 2016 | Posted by in General Surgery | Comments Off on Mandibular Fractures

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