Mandible Study Notes

MANDIBLEINTRO/DEFINITION: The mandible, or the lower jaw- is thelargest and the strongest bone. ofthe face. It has a horseshoe. - shaped body which lodges theteeth, and a pair of rami which project upwands from thethe muscles of mastication.posterior ends of the body The rami provide attachment toDIPANRARRAYMandible consists of 3 pants - A Horizontally -oriented bodyTwo Vertically -oriented ramiBODY :The body of the mandible is U- Shaped and itpresents:TWOSURFACES = (a) EXTERNAL SURFACE Two BORDERS 2 (a) SUPERIOR(b) INTERNAL SURFACE (b) INFERIOR BORDER OF BASEBORDEROR BODYSUPERIOR BORDER OF THE BODY It is called alreolar process Itbears suckets of lower 16 teeth.INFERIOR BORDER OR BASE OF MANDIBLE Presents a small depression(Digastric fussa) on either side near the median plane. It givesanachment to the anterior belly of the digastric.OUTER SURFACE OF THE BODY It presents the followingfeatures-DIPANKAR_RAYSYMPHYSIS MENTIIz is a faint median ridge on the externaltriangular eleration termed Mental Procuberance. It forms chinsurface of body. It expands below into athe point of Chin, the base of which is limited on each side.possesses four tubercles called Genial Tubercles Mental Spines)by the Mental Tubercle The inner aspect of Symphisis mentiarranged provides into attachment two pairs Upper and lower The upper pairto to genioglossus muscles and loweer pairgenioryoid muscles.MENTAL FORAMEN :Lies teeth. below the interval between premolarOBHQUE LINE:Continuation of anterior border of ramus,Runs downwards and forwards towardsthe mental tubercle.INCISIVE FOSSA:Shallow depression just below the incisor teeth. MANDIBLECITALITHE INNER SURFACE OF THE BODY Eaach half of themandible presents the following features.MYLOHYOID LINE:Prominent oblique ridge that runs obliquelydownduards and forwards from behind the 3rd molar teethto the symphysis menti below the genial tubencle.MYLOHYOD GROOVE:Lies below the posterior end of the mylohyoidline.DIPANIRAR RAYSUBLINGUAL FOSSA:Shallow area above the anterior part ofmylohyoid lineSUBMANDIBULAR FOSSA :Slightly hollowed out area below theposterior part of the mylohyoid lineMUSCLES ATTACHED: BODY OF MANDIBLE Human AnaromyFor ExamThe various museles attached to the body of mandible.(1) BUCCINATOR(2) MYLOHYOID(3) GENPOGLOSSUS(4.) GENIOHYOID(5) ANT BELLY OF DIGASTRICS(6) PLATYSMA.(7) SUPERIOR COSTRICTOR MANDIBLE3RAMUS OF THE MANDIBLE:It is more or less a quadrangular vertical plate of bone thatprojects upwards from the posterior part of the bodyRamus presents the following features :-Two ProcessesTwo SurfacesFour bordersLateral SurfaceAnteriorCondylarSuperiorCoronoid ProcessMedial Surface.InferiorHuman AnatomyPosteriorFor Exam.a DARAYCONDYLAR PROCESS A strong upwand projection fromposterosuperior part, Its upper end is expanded to from head.Neck is constricted part below head and presents a depressionon its anterior surface called Prerygoid FoveaDIPANIAARCORONOD PROCESS A flattened (Side to Side) triangular projectionfrom anterosuperior past. Its anterior borderis continuous bounds with the the anterior border of ramus. The posteriorborder mandibular notchUPPER BORDER Upper border of the ramus is thin and is curreddownwards farming the Mandibular NotchLOWER BORDER Backwand continuation of the base of mandiblePosteriorly it ends by becoming continuous with the post borderat the angle of mandibleDIPANKAR RAYANTERIOR BURDER is thin, while the POSTERIOR BORDER is thick.ANGLE OF MANDIBLE The meeting point between posterior andinferior borders of the ramus of mandible is called Angle of MandibleLATERAL SURFACE OF RAMUS It is flat and bears a number ofoblique ridges produced by masseter muscle. MANDIBLE4MEDIAL SURFACE OF RAMUS It presents the followingfeatures 1MANDIBULAR FORAMEN:Located a little above the centre oframus and leads into mandibular canal which runs.external surface as Mental Faramendownwards and forwards into the body to open on itsDIDANKAR RAYLINGULA Small tongue-shaped projection on the anteriormargin of the mandibular frearren.MYLOHYOIDGROOVE : Begins just below the mandibular foramen.and runs downwards and forwards to reach the body ofmandible below the posterior part of mylohyoid line.MUSCLES ATTACHED : RAMUS OF THE MANDIBLEvamus of mandible as under.-All the muscles of mastication are attached (Inserved) into the(1) MASSETER2 TEMPORALISODH3RAY Human Ancrory For Exam.f LATERAL PTERYGOID(4) MEDIAL PTERYGODLIGAMENTS ATTACHED : MANDIBLEDIPANKARRAYThe following ligaments are attached to the mandible 1(2) (1) STYLOMANDIBULAR LIGAMENT - Attached to angle of mandibleTEMPOROMANDIBULAR LIGAMENT 1 Attached to lateral cupect ofneck of mandible.(3) SPHENOMANDBULAR LIGAMENT - Attached to lingwa of mandible.(4) PIERYGOMANDIBULAR LIGAMENT - Attached behind the last molartooth to the upper end ofmylohyoid line.