Head & Neck

HEAD & NECK M.Sc. Students College of Dentistry Dr. Fareed Hanna Assistant professor

• Facial Bones : Mandible , Maxilla ,Zygomatic , Sphenoid • Infratemporal fossa • Pterygopalatine fossa • Facial muscles • Cranial nerves • Brain stem • Oral cavity • Tongue • Salivary glands • Face:blood supply , nerve supply

Mandible Accessory foramina: may be present for passage of branches of facial ,myelohyoid ,buccal & other nerves for supply of teeth ,these may be significant in dental blocking techniques

Maxilla Largest pneumatic facial bone ,forms whole upper jaw , most of buccal roof ,floor & lat walls of nose ,orbital floor , in part infratemporal ,pterygopalatine fossae & inferior orbital & pterygomaxillary fissures Body & 4 processes : zygomatic , frontal , alveolar & palatine

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Maxillary body: pyramidal ,4 surfaces Anterior:faces anterolaterally Incisive fossa Canine eminance Canine fossa Infraorbital formaen Orbital inferior border separates it from orbital surface Medially is concave nasal notch Anterior nasal spine

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Infratemporal surface: concave ,faces posterolaterally , forms ant wall of infratemporal fossa 2,3 alveolar canals in center –post sup alveolar nerves & vessels Maxillary tuborosity-superomedially attached to it is pyramidal process of palatine bone Above forms ant surface of pterygopalatine fossa grooved by maxillary nerve as it passes upward to infra orbital groove

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Orbital surface : forms orbital floor smooth triangular Infraorbital groove passes forward into canal Infraorbital canal near its midpoint has a small lat branch for ant sup alveolar nerve & vessels is canalis sinuous curves medially in ant wall of maxillary sinus ,it opens near nasal septum in front of incisive canal Nasal surface: maxillary sinus opening forms part of walls of nasolacrimal duct

• Processes of maxilla: • Zygomatic :is pyramidal where orbital ,infratemporal & ant surfaces coverge , above is serrated articulating with zygomatic bone • Frontal; projects superiorly , joints apically with frontal bone , its ant border with nasal bone ,ita post border with lacrimal bone

• Alveolar process: is thick & arched, wide behind & socketed for teeth roots ,sockets vary according to teeth roots , for canine is deepest , for molars widest & divided into 3 by septa ,for the rest is single. The buccinator is attached to external alveolar aspect as far as forwards as 1st molar . Occasionally a longitudinal maxillary torus variably prominent appears on palatal aspect of process near molar sockets • Palatine process: thick ,strong ,horizontal projects medially from lowest part of medial surface, forms most of nasal floor & palate, is thicker in front. Its inferior surface is concave ,uneven

Maxillary sinus: large pyramidal cavity, its lat apex extends into zygomatic process, its base is medial forming lateral wall of nasal cavity with maxillary hiatus in it. Its posterior wall contains alveolar canals conducting post sup alveolar nerves & vessels to molar teeth Radiating septa usually spring from sinus floor between adjacent dental roots , sometimes is perforated by molar roots Extraction of molar tooth may damage the floor Impact may fracture its walls

• Vascular foramens , depressions for palatine glands , posterolaterally contains 2 grooves for greater palatine nerves & vessels • Incisive fossa: 2 lat incisive canals . • ant & post median incisive f. for nasopalatine nerves • Incisive suture: fine groove extends anterolaterally from incisive fossa to interval between lat incisor & canine • Superior surface: is concave transversely smooth , anteriorly near its median margin is incisive canal • Medial border: is thicker in front ,is raised into nasal crest which with its fellow forms a groove for vomer.the front of ridge rises higher as incisive crest prolonged forward into a sharp process with its fellow forms ant nasal spine • Posterior border: serrated for palatine horizontal plate

Palatine bone: post placed between maxilla & pterygoid process of sphenoid resembles letter L with horizontal & vertical plates , 3 processes: pyramidal , orbital & sphenoidal Horizontal plate: is quadrilateral , 2 surfaces ,4 borders ,forms posterior one fourth of palate & nasal floor Lateral border is continuous with perpendicular plate & is grooved by greater palatine v. Perpendicular plate:

Temporomandibular joint Type: synovial , ellipsoid (condyler) , the 2 joints form a bicondyler articulation Articular parts: above: temporal tubercle & ant part of mandibular fossa below:mandibular condyle (head) Articular surfaces are covered with fibro cartilage An intraarticular disc divides usually completely the joint into upper & lower parts Fibrous capsule: each part can be considered to be covered by short capsular fibers as if it has two capsules ,from condyle to disc , from disc to temporal bone true capsular fibers are present only on lateral side passing from condyle to temporal bone Post, ant & med the upper & lower laminae of disc are attached separately either to temporal bone of mandibular condyle Capsule : is attached above to articule tubercle ,lips of squamotympanic fissure, to edges of mandibular fossa , below to mandibular neck Synovial membrane : lines capsule

Ligaments: 1-lateral temporomandibular ligament: close to capsule ,is attache above to tubercle on zygoma root , below to lat surface & post border of neck ,fibers slop downward & backward deep to parotid gland 2-The sphenomandibular ligament: medial to & separate from capsule, passes from spine of sphenoid as a thin band to lingula , structures related to it are: superolateral, lat pterygoid muscle & auriculotemporal nerve , is separated from neck by maxillary vessels , Inf alveolar vessels & nerve ,a lobule of parotid separates it from ramus Is crossed by chorda tympani Nerve & vessels to myelohyoid pierce it at lower end 3-Stylomandibular ligament: a thickened band of deep cervical fascia ,streches from apex & ant aspect of styloid process to angle of mandible , is accessory to joint Articular disc: oval plate of fibrous cartilage like a peaked cap,completely divides joint, upper surface is sagittaly concavoconvex to fit articular tubercle & fossa Its inferior is concave to fit mandibular head Its circumference belds with capsule & ant with lat pterygoid

Vessels : arteries: superficial temporal , maxillary Nerve supply: auriculotemporal , masseteric nerves Movements: both joints always act together but may differ in actual movement Mandible can be: depressed , elevated protruded , retracted rotation: gliding , spin , roll & angulation In position of rest: upper & lower teeth are slightly apart Occlusal position : teeth are apposed In open mouth:mandibular condyles rotate on a common horizontal axis , glide forward & downward on inf surface of articular disc In closure: movements are reversed

• Muscles producing movements: • Protrusion: lateral & medial pterygoids • Retraction:temporalis (post fibers) aided by middle & deep parts of masseter ,digastric ,geniohyoid • Elevation: temporalis ,masseter medial pterygoid of both sides , temporalis maintains position of rest. • Depression: lateral pterygoids aided by digastric ,geniohyoid & myelohyoid • Lateral movements: medial & lat pterygoids of each side acting alternately • Clinical anatomy: • Dislocation of mandible is only forward: with open mouth ,condyles are on articular eminances& sudden violence ,even muscle spasm ,a convulsive yawn, may displace one or both heads into infratemporal fossa

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INFRATEMPORAL FOSSA: Irregular post maxillary space Ant wall: infratemporal surface of maxilla Med wall : lat pterygoid plate Roof: lat communicates with temporal fossa between zygomatic arch & lower temple , medially is infratemporal surface of greater wing of sphenoid (contains foramen ovale & spinosum) Post ,lat & inf fossa is opened The medial & ant walls converge inferiorly but are separated sup by pterygomaxillary fissure which communicates it with pterygopalatine fossa , the fissure is continuous above with post end of infraorbital fissure connecting ithem to orbital cavity Contents: muscles; temporalis ,lat & medial pterygoids vessels: maxillary artery(2nd part & branches), pterygoi plexus of veins Nerves: mandibular & its branches , chorda tympani , ant wall is pireced by spost superior alveolar nerves & vessels Pterygomaxillary fissure: admits maxillary artery to pterygopalatine fossa(3rd part) , uppermost part contains maxillary nerve

• PTERYGOPALATINE FOSSA: • Small pyramidal space below orbital apex • Boundaries: behind, root of pterygoid process, ant surface of greater wing of sphenoid • Medially ;palatine perpendicular plate • Ant; upper part of post surface of maxilla • Lat; pterygomaxillary fissure connecting it with infratemporal fossa • Communications: with a-infratemporal fossa • b-middle cranial fossa via foramen rotendum ,pterygoig canal c-orbit via infraorbital fissure • d-pharynx via pharyngeal(palatovaginal ) canal enasal cavity ,via sphenopalatine foramen f-oral cavity via greater palatine canal • Contents: pterygopalatyine ganglion , maxillary nerve , 3rd part maxillary artery

THE FACE Basic shape of face is determined By underlying bones Buccal fatpads :Skin , hair distribution skin wrinkles , Landmarks Orbital orifices Nasal orifices Oral orifce

Superficial fascia: subcutanous tissue contain Facial muscles which arise from skull bones & Inserts into skin Skin is connected to bones by skin ligaments (retinaculae cutis) vessels & nerve , lymph nodes & lymphatics Facial muscles: muscles of expression Deep fascia : no deep fascia in face

Muscles of face: are subcutaeous , move skin change expression of face to convey mood& All develop from 2nd pharyngeal arch All are innervated by facial nerve All arise from bones or fasciae All insert in skin They are: muscles of forehead muscles of mouth ,lips & cheeks muscles around orbit muscles around nose :Facial lacerations & incisions lacerations tend to gap widely following bruising of face fluid or blood usu ally accumulates in subcutaeous tissue Muascles of mouth ,lips & cheeks )orbicularis oris( compound sphinctor elevators ,retractors & evertors of upper lip depressors ,retractors & evertors of lower lip The buccinator in cheek

Orbicularis oris: is sphinctor of mouth, fibers encircle mouth & are within lips , aid in mastication , speech Closes mouth Origin: median plane of maxilla & mandible ,deep surface of skin Insertion: mucous membrane of lips Zygomaticus major: from zygoma to angle of mouth draws angle of mouth superolaterally Zygomaticus minor: from zygoma to orbicularis oris helps raise upper lip when showing contempt deepen nasolacrimal sulcus when showing sadness Levator labii superioris: infraorbital margin to upper lip , raises upper lip Levator anguli oris: from infraorbital margin to angle of mouth ,elevates corner of mouth Levator labii superioris alaque nasi: from maxilla, two slips ,one to alar cartilage of nose Other to lip , elevates both

Mentalis: small arising from mandible , inserts to skin of chin raises skin of chin in expression of doubt , Depressor anguli oris: from mandible to angle of mouth depress angle of mouth Depressor labii inferioris: lat to mentalis ,arise from mandible ,, merges with orbicularis oris draws lip inferiorly & laterally as in impatience Risorius: variable ,arises from platysma , attaches to angle of mouth & fascia over parotid it draws corner of mouth laterally when grinning Platysma: superficial muscle in neck

Buccinator: thin ,flat ,rectanaugular .Origin: alveolar process of maxilla ,mandible opposite molars Pterygomandibular raphe Insertion: in orbicularis oris ,middle fibers cross at modulus , Action : aids mastication ,act in smiling , keeps cheek taught whistling ,sucking . Relations: is pirecerd by parotid duct , inner surface lined by m . m , Outer surface: parotid duct , buccal branches of facial nerve Buccal branch of mandibular , parotid gland , facial vessels

Nerve supply of face: sensory, sympathetic & motor Sensory supply: trigeminal nerve branches: 1-ophthalmic : a-supraorbital b-supratrochlear c-lateral palpebral d-infratrochlear e-external nasal 2-Maxillary: a-infraorbital: 1-nasal 2-palpebral 3-labial b-zygomatico temporal c-zygomaticofacial 3-mandibular: a-buccal b-mental c-auriculotemporal Sympathetic supply: accompany sensory nerves ,derived from sup cervical Sympathetic ganglion

Motor supply: facial nerve is motor supply for all facial & scalp muscles Emerging from stylomastoid foramen , enters within parotid gland Divides into terminal branches which emerge from deep surface of parotid 7 spread to supply facial muscles. Posterior auricular: supplies posterior auricular ,occipital belly of occipito frontalis Temporal branches: two or three, supply superior ,anterior auricular , frontal belly of occipitofrontalis Zygomatic branches: one or two , supply orbicularis oculi ,zygomaticus major & minor

Buccal branches: one or two ,some times three ,accompany parotid duct supply buccinator , orbicularis oris ,muscles of upper lip Marginal mandibulr: along base of mandible , supplies lower lip muscles , mentalis , orbicularis oris , risorius Cervical : descends into neck ,supplies platysma Facial palsy: Facial nerve paralysis: Injury of branches of facial nerve: buccal

Nerve block in face: Infraorbital block: in repairing maxillary incisor teeth site of injection is infraorbital foramen Inferioralveolar block: site is mandibular foramen , is most difficult to perform if needle goes more far ,may enter parotid gland , anaesthetizes facial nerve branches leading to transient unilat facial palsy Mental & incisive nerve block: site in mental foramen Buccal nerve block: site is into mucosa covering retromolar fossa located posterior to 3rdmandibular molar Trigeminal neuralgia: (tic douloureux): sudden attacks of excruciating , lightening like jabs of facial pain ,maxillary nerve is most frequently involved is usually due to pressure of a vessel on the nerve causing demyelination of nerve op go

Dermatomes of face

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Blood supply of face: 2 sources , External carotid artery :Facial superficial temporal maxillary posterior auricular Facial: branches; inferior labial Pulsations felt superior labial At base of mandible lateral nasal angular Superficial temporal : is smaller terminal branch of external carotid :Pulsations felt anterior to auricle , branches transverse facial , auricular glandular for parotid frontal ,temporal maxillary: infraorbital , zygomaticofacial , zygomaticotemporal Posterior auricular: auricular , occipital :Internal carotid: ophthalmic artery branches supraorbital , supratrochlear dorsal nasal , infratrochlear , lateral palpebral

Venous drainage of face: supra orbital + supratrochlear =angular vein at medial angle of eye communicate with superior ophthalmic vein Facial vein: continuation of angular vein ,runs posterior to facial artery tributaries: external nasal , palpebral , deep facial draining pterygoid plexus upper & lower labial , Inferior to mandibular base is joined by anterior division of retromandibular vein terminates in internal jugular vein in carotid triangle of neck Superficial temporal vein: Accompanies artery , near auricle enters parotid gland to unite with maxillary vein forming retromandibular within parotid gland Retromandibular vein: formed within parotid gland , passes deep & post to ramus deep to facial nerve , divides into ant & post divisions , ant unites with facial , post with posterior auricular to form external jugular vein Thrombophlebitis of facial vein: connections with pterygoid plexus through inferior ophthalmic & deep facial veins , cavernous sinus through superior ophthalmic vein Danger triangle of face

Lymphatic drainage of face: lymphatics accompany vessels superficial with veins , deep with arteries All lymph from face drains into deep cervical lymph nodes

-lymph from lateral part of face +eye lids drains inferiorly into parotid lymph nodes -lymph from deep parotid nodes drains into upper deep cervical nodes -lymph from upper lip & lateral parts of lower lip drains into submandibular lymph nodes -lymph from the chin & central part of lower lip drains into submental lymph nodes parotid nodes : superficial & deep submental nodes: in submental triangle submandibular nodes : in digastric triangle ,superficial to submandibular gland Efferents from all above pass to upper deep cervical nodes in carotid triangle along internal jugular vein Squamous cell carcinoma of lip: usually involves lower lip may spread to submental , submandibular nodes

ORAL REGION: includes oral cavity , teeth , gingiva(gums) tongue ,palate & region of palatine tonsils Oral cavity (buccal cavity): 2 parts , oral vestibule ,Cavity proper vestibule: narrow ,bounded by: externally lips, cheeks , internally gums & teeth communicates with exterior through oral fissure above & below is limited by reflexion of mucosa to gums forming a horse shoe shaped trough, posteriorly is continuous with cavity proper behind last molar tooth , is formed of 2 parts : labial sulcus & buccal sulcus Lips: 2 fleshy folds surrounding oral orifice , externally is skin , internally by mucosa enclosing orbicularis oculi , labial vessels & nerves ,fibroadipose connective tissues , numerous small labial salivary glands secreting into vestibule Vermilion (transitional border): reddish zone depending on degree of melanization covered by thin keratinized epithelium with c t papillae its color is due to proximity of blood vessels to surface , is devoid of salivary glands but often contains sebaceous glands Upper lip : philtrum , tubercle , lateral ridges Each lip internally is connected by a median frenulum to gum , lateral frenula crosses vestibule in the region of canine or premolar Cleft Lip: harelip Carcinoma of lip: usually lower lip involvement Cyanosis of lips: Large labial frenula: may cause large labial space bet incisors Large lower frenula may contribute to gingival recession leading to exposure of ro

Cheeks: limited by nasolabial sulcus & nasolabial fold lateral to it contents : skeletal muscles ,variable amount of adipose tissue(buccal pad of fat) fibrous CT nerves ,vessels ,buccal salivary glands outer : is skin inner is mucous membrane , parotid papilla marks opening of parotid duct opposite upper 2nd molar The mucous salivary glands : 4-5 lie over buccinator around parotid duct , their ducts piercing buccinator to open near last molar most lie between buccinator & mucosa Sebaceous glands also occur in buccal mucosa often in large numbers can be seen as yellowish maculae(Fordyce spots) especially if cheek is streched, their number increases at puberty Gums:Gingiva: composed of dense vascular fibrous tissue ,covered by orthokeratinized stratified squamous epithelium,pink stippled firmly attached to cement at neck of teeth(marginal gingiva, not stippled) & to bone of alveolar process melanocytes producing melanosomes , Langerhan cells are present Gingivits: inflammation of gingiva Periodentitis: inflammation of alveolar bone & periodental membrane Dentoalveolar abscess: may drain into oral cavity & lips

ORAL CAVITY PROPER: is bounded by alveolar arches , palate ,& floor comunicates posteriorly through isthmus of fauces with orophrynx Communicates with vestibule behind 3rd molar teeth Palate: 2 regions: hard & soft palate Hard palate: palatine process of maxilla & horizontal plate of palatine bone Is covered by thick mucosa bound tightly to underlying periosteum A submucosa in lateral regions containing mucus glands & adipose tissues Orthokeratinized stratified squamous epithelium Palatine raphe: in midline , its ant extremity is incisive papilla Ruges: transverse folds of CT running laterally from palatine raphe Post half: contains numerous mucus palatine salivary glands ,they secrete through numerous ducts ,although bilaterally a large duct collect these to open At paired palatine fovea situated at post border of hard palate at midline

Soft palate: is a mobile flap suspended from post border of hard palate is a thick fold of mucosa enclosing : muscles ,aponeurosis neurovascular tissues & mucous glands Inferior(oral surface is concave with median raphe Superior(nasal) surface convex forms floor of nasopharynx Anterior: is attached to hard palate post border Post:is free hanging between mouth & pharynx Sides: blend with pharyngeal walls Uvula: median conical process projects from its post border

Palatal arches: 2 curved folds of mucosa with muscles palatoglossal arch; ant ,contains palatoglossal muscle , descends to sides of tongue palatopharyngeal arch: post ,contains palatopharyngeal muscle , descends to Lateral wall of oropharynx Superficial features of palate: mucosa is tightly bound to bone consequently submucus injections are extremely painful lingual gingiva; is continuous with that of palate mucus palatal glands:opening of their ducts gives a pitted or orange peel appearance Incisive papilla: elevation of mucosa lie directly ant to incisive fossa 7 is the site of anaesthetizing nasopalatine nerve Structure of soft palate: Muscles: 5 Tensor veli paalatini : from scaphoid fossa , spine of sphenoid , cartilage of auditory tube , passes inferiorly , tendon hooks around pterygoid hamulus to spread out as palatine aponeurosis ,it tenses soft palate , opens auditory tube Levator veli palatini: from cartilage of auditory tube ,petros part of temporal to attach to superior surface of palatine aponeurosis , elevates soft palate Palatoglossus: descends from palatine aponeurosis to the side of post 3rd of tongue , it depresses soft palate ,elevates post 3rd of tongue Palatopharyngeus: from hard palate & palatine aponeurosis to lateral wall of oropharynx , tenses soft palate ,pulls walls of pharynx superiorly

Musculus uvulae: from post nasal spine & palatine aponeurosis to fade in mucosa Of uvula ,free post end , it shortens uvula & pulls it superiorly. Innervation: all muscles of soft palate are supplied by vagoaccessory complex ( cranial part of accessory nerve & vagus) except tensor veli palatini which is supplied by mandibular nerve through its medial pterygoid nerve vis otic ganglion Blood supply of palate: rich blood supply from greater palatine ,lesser palatine from maxillary ascending palatine from facial The veins drain into pterygoid venous plexus Sensory nerve supply : is accompanied by post ganglionic sympathetic & postGanglionic parasympathetic from pterygopalatine ganglion as follows greater palatine nerve , nasopalatine , lesser palatine Nasopalatine nerve block: injection into incisive fossa just posterior to incisive Papilla Greater palatine nerve block: injection into greater palatine foramen between 2nd & 3rd molars Cleft palate: primary & or secondary cleft uvula:

Floor of oral cavity: is a mobile but stable floor formed by meylohyoid muscle: a suprahyoid muscle & a muscular sling inferior to tongue origin; myelohyoid line insertion: myelohyoid raphe in median line , body of hyoid bone Posterior free border Nerve supply : nerve to myelohyoid from inferior alveolar of mandibular Action: suprahyoid muscle elevating hyoid bone ,support tongue & elevate it when swallowing ,speaking or protruding it. Geniohyoid muscle: form a slip on each side , parallel to post belly of digastric origin: inferior mental spine (genial tubercle) of mandible insertion: anterior aspect of body of hyoid bone above myelohyoid attachment Nerve supply: hypoglossal nerve Action: elevates & retracts hyoid bone , thereby elongating floor of mouth The tongue lies over oral floor Floor is covered by mucosa , non kearatinized ,

Sublingual fold: sublingual salivary duct , openings of ducts Sublingual papilla: anterior end of fold , opening of submandibular Salivary gland Frenulum of tongue Mucosa : non keratinized stratified epithelium continuous with: lingual gingiva mucosa of the tongue

The tongue: a mobile muscular organ can assume a variety of shapes & positions Is partly in oral cavity & partly in pharynx At ,rest occupies all oral cavity proper Action: involved in: mastication , taste , deglutition , & oral cleansing but mainly it: Forms words during speaking Squeezes food into pharynx Parts: Root: post third , relatively fixed Body: ant two thirds , mobile Apex: pointed ant part of body , mobile Dorsum: posterosuperior surface includes; sulcus terminalis foramen cecum lingual papillae Inferior(sublingual)surface: lingual frenulum deep lingual vein

Dorsum of tongue: ; divided by sulcus terminalis into : Anterior(presulcal): lies in oral cavity proper (oral part) Posterior(postsulcal): lies in oropharynx (pharyngeal part) The mucous membrane of anterior part : is rough because of presence of lingual papilla: A-vallate papillae: large ,flat topped ,lie directly ant to terminal sulcus, surrounded by deep furrows , walls of contain taste buds, openings of serous glands B-foliate papillae: small lat folds of mucosa ,poorly developed C-filiform papillae: long ,numerous contain afferent nerve endings sensitive to touch Scaly threadlike ,pinkish grey lying parallel to terminal sulcus D-fungiform papillae: mushroom shaped, pink or red spots ,most numerous at apex & sides of tongue

Taste buds: present in vallate ,foliate & most of fungiform papillae , some in epithelium covering surface , post wall of orpharynx , & epiglottis The mucus membrane is thin & closely attached to underlying muscles Midline sulcus: divides tongue into right & left sides , Lingual septum : deep to midline groove ,a fibrous septum divides tongue into right & left halves Posterior part of tongue: located post to sulcus terminalis & palatoglossal arch Mucus membrane is thick & freely mobile Lingual tonsil:nodules of lymphatic follicles givies this part irregular coblestone appearance The posterior part is attached to ant surface of epiglottis by three mucus folds: a- median glossoepiglotic fold b-2 lat glossoepiglottic folds c-enclosed between folds are two valleculae: depressed fossae Muscles of the tongue: two groups ; 4 extrinsic & 4 intrinsic The muscles in each half of tongue are separated by lingual septum Extrinsic muscles: originate outside tongue & insert to it , mainly alter position but may change its shape Intrinsic muscles: are entirely within tongue & not attached to bone All intrinsic & extrinsic muscles are supplied by hypoglossal nerve Except palatoglossus (muscle of soft palate originally)

Extrinsic muscles: Muscle

Origin

Insertion

Genioglossus

Sup mental spine

Dorsum of tongue body of hyoid bone

Hyoglossus

Body & greater horn Side & inferior of hyoid bone aspect of tongue

Styloglossus

Styloid process & stylohyoid ligament

Palatoglossus

Palatine aponeurosis Side of tongue

Side & inferior aspect of tongue

Action Depresses tongue pulls tongue ant for protrusion

Depresses & retracts tongue

Retracts tongue & draws it up to create a trough for swallowing Elevates post part

Intrinsic muscles: Muscle

Origin

Insertion

Action

Superior longitudinal

Submucus fibrous layer & fibrous median septum

Margins of tongue Curls tip & sides & mucus membrane of tongue sup. & shortens tongue

Inferior longitudinal

Root of tongue & body of hyoid

Apex of tongue

Curls tip of tongue inferiorly & shortens it

Transverse

Median fibrous septum

Fibrous tissue at margins of tongue

Narrows & elongates tongue

Vertical

Sup surface of borders of tongue

Inferior surface of borders of tongue

Flattens & broadens tongue

Nerve supply of tongue: Motor: hypoglossal nerve supplies all muscles Except palatoglossus which is supplied by vagoaccessory complex General sensory : mucosa of ant two thirds supplied by lingual nerve mucosa of post third supplied by glossopharyngeal nerve mucosa of tongue just ant to epiglottis is supplied by internal laryngeal nerve ,branch of vagus Taste sensation: ant two thirds Except vallate papillae supplied by chorda tympani ,branch of facial nerve accompanying lingual nerve post one third + vallate paillae by glossopharyngeal nerve area ant to epiglottis by internal laryngeal nerve from vagus Parasympathetic : from submandibular ganglion accompany lingual , are secretomotor to glands Taste sensations are detected on tongue as follows: sweetness: apex(tip) saltiness: lateral margins sourness : posterior part bitterness: posterior part

Blood supply of tongue: Arterial supply: lingual artery arising from external carotid ,passes deep to hyoglossus , main branches are: Dorsal lingual : supply post part ,send branch to palatine tonsil Deep lingual; supplies ant part Sublingual : supplies sublingual gland & floor of oral cavity Venous drainage: Dorsal lingual veins: accompany lingual artery Deep lingual : begin at apex ,join sublingual vein Venae commitants of hypoglossal nerve: drains most of the veins to end in internal jugular vein Lymph drainage: takes four routes as follows; Lymph from post third drains into upper deep cervical nodes Lymph from medial part of ant two thirds drains directly to lower deep cervical nodes( jugulomohyoid ) Lymph from lateral parts of ant two thirds drains to submandibular nodes Lymph from apex drains into submental nodes __ The posterior third & area near midline drain bilaterally

Clinical Notes: Gag reflex: touching post third of tongue ,IX nerve provides afferent limb, IX , X nerves provide efferent leading to contraction of pharynx muscles Paralysis of genioglossus: tongue has tendency to fall posteriorly ,obstructuing airway & risk of suffocation ( occurs in general anaesthesia with need to airway intubation to prevent tongue relapse Injury to hypoglossal nerve: paralysis & atrophy of paralyzed half ,deviates to paralyzed side during protrusion Sublingual absorption of drugs: quick absorption of drugs : are dissolved & enter in sublingual vein in less than one minute( nitroglycerin) Lingual carcinoma: may spread along lymphatic drainage to different nodes Frenectomy: large lingula frenulum may interfere with tongue movements Thyroglossal duct cyst: Aberrant thyroid tissue : at foramen caecum , may undergo metaplasia & malignant changes

Salivary glands: 2 groups ; main salivary glands which ; parotid , submandibular & sublingual minor accessory glands ; scattered over palate , lips ,cheeks , tonsils & tongue They are exocrine compound tubuloalveolar glands secreting SALIVA: Ducts of all glands open into oral cavity Saliva: is a clear , tasteless , odorless , viscid fluid , it: a-keep mucus membrane of mouth moist b-lubricates food during mastication c-begins digestion of starches d-serve as an intrinsic mouth wash e-play important role in prevention of tooth decay f-play important role in the ability of taste( material dissolve init)

:Major salivary glands PAROTID GLAND: largest of the 3 pairs , has an irregular shape , occupies gap between ramus of mandible & styloid process , it has no capsule ,but is enclosed by deep investing layer of cervical fascia with the thickened stylomandibular ligament separating it from submandibular gland , it projects on masseter , a small or detached part lies above its duct , is composed of almost entirley serous glandular tissues Is like an inverted flat 3 sided pyramid , having a small superior , superficial ,anteromedial & posteromedial surfaces , apex directed downward Superior surface: related to cartilagenous part of external acoustic meatus , post aspect of TMJ ,here auriculotemporal nerve curves around neck of mandible inside the gland Apex: overlaps post belly of digastric Superficial surface : skin ,superficial fascia , containing branches of auriculo -temporal nerve ,superficial parotid nodes ,investing layer of cervical fascia Anteromedial surface: grooved by post border of ramus , covers part of masseter , lat aspect of TMJ Posteromedial surface: is moulded to mastoid process , sternocliedomastoid , post belly of digastric & styloid process & its muscles, is grooved by external carotid artery

Intraglandular structures: several structures traverse gland partly or wholly: Vessels: external carotid artery terminates init to two branches , maxillary & supe rficial temporal arteries , posterior auricular artery maxillary vein , superficial temporal vein , unite to form retromandibular vein , divides into ant & post divisions within gland Nerves: auriculotemporal ,facial & its terminal branches emerge from its ant border Lymph nodes: parotid nodes embedded in it

Parotid duct: 5 cm long, 3mm diameter , begins by confluence of 2 main tributaries within ant part crosses masseter & at its ant border curves medially at almost right angle traversing buccal pad of fat & buccinator , then runs for a short distance between buccinator & oral mucosa to open upon a small papilla opposite upper 2nd molar tooth Relations: buccal branches of facial nerve lie above & below it accessory gland , transverse facial artery lie above it buccal branch of mandibular is just below duct at ant border of masseter Blood supply: glandular branches of external carotid , superficial temporal veins drain to external jugular Lymph: to parotid nodes – upper deep cervical nodes Nerve supply: sympathetic from external carotid plexus , is inhibitory parasympathetic : from otic ganglion ,is secretomotor sensory : auriculotemporal nerve

SUBMANDIBULAR GLANDS: irregular in shape , size of a walnuts 2 parts , superficial large ,deep small , continuous with each other at post border of myelohyoid muscle , is mixed seromucus Superficial part: lie in digastric triangle ,is partially enclosed by deep cervical fascia with stylomandibular ligament separating it from parotid ,one layer covers its inferior surface attached to base of mandible ,other covers its medial surface attached to myelohyoid line Surfaces: 3 inferior , lateral & medial Inferior surface: covered with skin ,platysma ,deep fascia , is crossed by facial vein & cervical branch of facial nerve , submandibular lymph nodes lie on it or embedded within gland Lateral surface: related to submandibular fossa , medial pterygoid attachment , facial artery grooves its posterosuperior part Medial surface: related anteriorly to myelohyoid , with meylohyoid nerve & vessels & submental vessels branches intervening , posteriorly related to styloglossus , stylohyoid ligament ,glossopharyngeal nerve , in its middle part is related to hyoglossus , lingual nerve , hypoglossal nerve , deep lingual vein Deep part: extends forward to post end of sublingual gland , lies between myelohyoid inferolaterally & hyoglossus & styloglossus medially above it runs lingual nerve , submandibular ganglion , below it hypoglossal Nerve & deep lingual vein The gland is palpable between an index finger placed on floor of mouth & a thumb Placed below the floor, anteromedial to angle of mandible

Submandibular duct: 5 cm long ,begins in superficial part ,emerges from it behind Post border of myelohyoid , it traverses deep part ,passing up & slightly back then Forward between myelohyoid & hyoglossus , passing between sublingual gland & Genioglossus it opens in floor of oral cavity on summit of sublingual papilla at the Sides of lingual frenulum On hyoglossus : lingual nerve & submandibular ganglion lies above it hypoglossal nerve lies below it at anterior border of hyoglossus is crossed by lingual nerve

Blood supply: arteries are branches of facial & lingual arteries veins correspond to arteries lymphatics drain to submandibular nodes – upper deep cervical nodes(jugulodigastric) Nerves : sympathetic: plexus around facial & lingual arteries ,inhibitory parasympathetic : submandibular ganglion, secretomotor sensory : lingual nerve

Sublingual glands: smallest ,lie beneath oral mucosa ,each in contact with sublingual fossa of mandible. Is narrow ,flat ,shapped like an almond , 3-4 g are mucus in type. Relations: above is oral mucosa raised as sublingual fold below is myelohyoid in front is ant end of its fellow behind lies deep part of submandibular gland medial is genioglossus ,separated from it by lingual nerve & submandibular duct

Sublingual ducts: has 18-20 excretory duct small ducts mostly open on summit of sublingual fold separately few open in submandibular duct from ant part small rami sometimes form a major sublingual duct opening in or near to the orifice of submandibular duct Vessels : arteries: sublingual , submental arteries veins: correspond to arteries Nerves: sympathetic : sympathetic plexus around facial & lingual arteries is inhibitory parasympathetic : submandibular ganglion ,is secretomotor sensory : is lingual nerve Sialography: identifies calculi , inflammation , tumors of ducts & glands Mumps: viral infection of salivary glands , mainly parotiditis Abscess in parotid gland: could result from extremely poor dental hygiene Excision of submandibular gland: incision should be made at least 2.5cm below angle of mandible to avoid mandibular branch of facial nerve

CRANIAL NERVES: 12 pairs arising from ventral surface of brain EXCEPT the 4th All of them arise from nuclei in brain stem Except 1st & 2nd which arise from cerebral hemisphere Components of cranial nerve: Motor: General somatic efferents (GSE) supply skeletal muscles Special somatic efferents (SSE) supply skeletal muscles derived from pharyngeal arches Special visceral efferents (SVE) , preganglionic parasympathetic fibers for parasympathetic ganglia Sensory : General somatic afferents (GSA) general sensations (touch ,temp..) Special somatic afferents (SSA) somatic special senses(vision,hear) Special visceral afferents (SVA) visceral special senses (Taste) General visceral afferents (GVA) general visceral sensations All above components are represented by nuclei in brain stem Motor: GSE : occulomotor , trochlear , abducent , hypoglossal nuclei SSE : motor n. of trigeminal , facial n. , nucleus ambiguus SVE : Edinger Westphal n. , superior salivatory n. , inferior salivatory n. , dorsal motor nucleus of vagus Sensory: GSA : mesencephalic n. of trigeminal , main sensory n. of trigeminal spinal tract n. of trigeminal SSA : vestibular n. , cochlear nuclei , SVA : gustatory nucleus GVA : nucleus of tractus solitarius

Trigeminal nerve: 5th cranial nerve components: GSA , SSE Supplies sensory fibers to orbit ,face ,oral cavity & nasopharynx supplies motor fibers for muscles derived from 1st pharyngeal arch Origin: brain stem nuclei sensory root : arise from mesencephalic n. , main sensory n. spinal tract n. motor root : arise from motor n, of trigeminal Course: emerges from lateral side of pons – pass to trigeminal ganglia in middle cranial fossa , motor root bypasses ganglion , sensory root rely divides into 3 branches: ophthalmic (sensory) ,maxillary (sensory) & mandibular (sensory & motor)

Ophthalmic nerve: enters in lateral wall of cavernous sinus , at its ant end divides into 3 terminal branches : Nasociliary , frontal ,& lacrimal the three branches pass through superior orbital fissure into orbit ,they supply orbital contents ,& some emerge on the face to supply it Lateral palpebral ; from lacrimal Supra orbital & supratrochlear from frontal External nasal & infratrochlear from nasociliary

MAXILLARY NERVE: emerges from trigeminal ganglion to enter in lateral wall of cavernous sinus , leaves ant half of cavernous sinus , pass in foramen rotendum to pterygopalatine fossa ,gives a branch to pterygopalatine ganglion & zygomatic branch , then leaves the fossa as infraorbital nerve through infraorbital fissure to pass in the floor of orbit in infraorbital groove , enters infraorbital canal in ant half of orbital floor to emerge from infraorbital foramen & divides into a labial ,nasal & palpebral branches supplying face Generally it carries sensations from: Skin of face over maxilla Upper lip Maxillary teeth Mucosa of nose Maxillary sinus Palate nasopharynx

Branches of maxillary nerve: 1-meningeal: dura mater of middle cranial fossa within pterygopalatine fossa: 2-zygomatic nerve: enters lateral wall of orbit through inferior orbital fissure carry with it a branch from pterygopalatine ganglion (postganglionic parasymp -athetic fibers ) which leaves it to join lacrimal nerve for supply of lacrimal gland It divides into zygomatico facial & zygomaticoorbital for supply of face emerging from corresponding foramina in lateral wall of orbit 3-posterior superior alveolar : emerge in anterior aspect of fossa descend along infratemporal surface of maxilla to enter a canal in posterior wall of maxillary sinus supplying molars & share in formation of superior dental plexus 4-branch to pterygopalatine ganglion which bypasses it & distribute with branches of ganglion as follows: 4 groups of nerve emerge from ganglion (sensory-maxillary , sympathetic –deep petrosal nerve , parasympathetic from ganglion): a-orbital : supply floor of orbit b-pharyngeal: pass through pharyngeal canal for nasopharynx c-palatal: greater & lesser palatine d-nasal: nasopalatine & sphenopalatine __maxillary nerve leaves fossa through inferior orbital fissure as 5-infraorbital nerve: pass in infraorbital groove gives rise to a-middle superior alveolar: descends along lateral wall of maxillary sinus to form upper dental plexus above roots of premolars ,supplying them

b-anterior superior alveolar : arise within infraorbital canal ,descends in anterior wall of maxillary sinus to reach above incisors roots supplying them , shares in formation of upper dental plexus c-emerging from infraorbital foramen into face it divides into 1-labial 2-nasal 3-palpebral supplying skin MANDIBULAR NERVE: is the largest branch , the only mixed (motor & sensory) Arises from main sensory nucleus of trigeminal & main motor nucleus of Trigeminal in brain stem , enters trigeminal ganglion with motor root bypassing it Leaves middle cranial fossa by passing through foramen ovale to enter in upper Deep part of infratemporal fossa lying medial to lateral pterygoid muscle & Anterior to otic ganglion & middle meningeal artery, terminates by dividing into anterior & posterior divisions each of which carry both sensory & motor fibers Generally the nerve carries sensations from: Skin over mandible , lower lip , temple ,anterior aspect of auricle, mandibular teeth , TM joint , mucosa of mouth & anterior two thirds of tongue Motor supply for all muscles derived from 1st pharyngeal arch Branches : from trunk, A-meningeal :dura mater of middle cranial fossa B-nerve to medial pterygoid : supplying medial pterygoid , from it arises a branch to supply tensor veli palatini muscle C-nerve to tensor tympani: passes through otic ganglion

D-Anterior division: smallest , mainly motor ,gives rise to: 1-two deep temporal nerves; ascend deep to zygomatic arch to deep surface of temporalis muscle 2-masseteric nerve: one or two nerves cross along mandibular notch to deep Surface of masseter supplying it 3-nerve to lateral pterygoid : supply lateral pterygoid 4-buccal : is only sensory branch descends on lateral surface of lateral pterygoid to appear on superficial surface of buccinator supplying skin

E-posterior division: largest , mainly sensory , branches 1-auriculotemporal: arises by two roots from posterior aspect , surrounding middle meningeal artery , enters posteromedial surface of parotid gland supplying it to appear on face ascending anterior to auricle toward temple passing superficial to zygomatic arch ,divides into frontal & temporal branches for supply of skin It carries with it postganglionic parasympathetic fibers from otic ganglion to parotid gland , 2-lingual nerve: descends in infratemporal fossa lateral to lateral pterygoid ,emerges below its inferior border to pass medial to medial pterygoid , crosses over mandible behind last molar tooth where is covered only by mucosa Enters in digastric triangle passing Superficial to hyoglossus ,deep to Myelohyoid , is crossed by duct of submandibular gland , pass to floor Of oral cavity , supplies floor & ant two thirds of tongue In infratemporal fossa is joined by chorda tympani nerve.

3-inferior alveolar: descends medial to lat pterygoid to enter mandibular Foramen passing in mandibular canal in ramus descends to body giving dental branches for molars , reaching at the level of 1st or between 1st & 2nd premolars it divides into : a-incisive: supplying canine & incisors b-mental : emerging from mental foramen to face supplying skin 4-nerve to myelohyoid : the only motor component of posterior division ,arises from inferior alveolar just above mandibular foramen , perforates sphenomandibular ligament , descends in myelohyoid groove to inferior surface of myelohyoid muscle supplying it & gives a branch to supply anterior belly of digastric muscle

FACIAL NERVE : VII CRANIAL NERVE: components: sensory , special motor(2nd pharyngeal arch) , preganglionic parasympathetic , taste (GSA , SSE , SVE , SVA) ORIGIN: In brain stem nuclei , sensory nucleus of trigeminal , motor nucleus of facial , superior salivatory nucleus , gustatory nucleus , Course: fibers from above nuclei emerge between pons & medulla , accompanied by VIII Nerve enters internal acoustic meatus in petros part of temporal bone , passing in the facial canal (an S shaped canal in posterior wall of middle ear) forming the geniculate ganglion (sensory fibers rely) turning downward in the canal to descend in stylomastoid canal emerging from stylomastoid foramen posterior to styloid process, enters in posteromedial surface of parotid gland , within gland it divides into its terminal branches for supply of facial muscles Generally facial nerve supplies: 1-Sensory from auricle near external acoustic meatus 2-Motor for all muscles derived from 2nd pharyngeal arch 3-Preganglionic parasympathetic to submandibular & Pterygopalatine ganglia 4-Taste fibers from anterior two thirds of tongue

Branches of facial nerve: From geniculate ganglion: 1-Greater petrosal nerve: carries preganglionic parasympathetic to Pterygopalatine ganglion & some taste fibers from palatal mucosa Emerges from a hiatus in anterior wall of petros part to enter middle cranial fossa passing forward along foramen lacerum , it joins with deep Petrosal nerve (postganglionic sympathetic from internal carotid sympath -etic plexus) to form nerve of pterygoid canal ,enters the canal to reach Pterygopalatine fossa to terminate in pterygopalatine ganglion , taste fibers bypass ganglion & distribute with its palatal branches .

In the facial canal: 2-nerve to stapedius: arises behind pyramidal eminence of posterior wall of middle ear ,passing through a small canal to supply stapedius muscle 3-Chorda tympani: carries preganglionic parasympathetic fibers to submandibular ganglion & taste fibers from anterior two thirds of tongue Emerges 5mm above stylomastoid foramen , ascends to enter middle ear cavity , emerges through petrotympanic fissure to enter infratemporal fossa , it joins lingual nerve , reaching with lingual to submandibular region ,parasympathetic fibers leave it to rely on submandibular ganglion Taste fibers continue with lingual to distribute to taste buds in anterior two thirds of tongue

At exit from stylomastoid foramen: 4-posterior auricular: arises near stylomastoid foramen ,ascends between mastoid process & external acoustic meatus to divide into auricular branch supplying posterior auricular muscle & occipital branch supplying occipital belly of occipitofrontalis muscle 5-digastric : supplies posterior belly of digastric muscle 6-stylohyoid branch: frequently arise with digastric branch , is long supplies stylohyoid muscle 7-sensory branch: accompany auricular Branch of vagus , supply external Acoustic meatus

On the face: 8-temporal 9-zygomatic 10-buccal 11-marginal mandibular 12-cervical They supply muscles of face frontal belly of occipitofrontalis anterior & superior auricular muscles orbicularis oculi zygomaticus muscles nasal orbicularis oris buccinator mentalis risorius platysma

Hypoglossal nerve: XII cranial nerve (GSE) , is a pure motor nerve arising from hypoglossal nucleus in medulla oblongata , emerging lateral to pyramid leaves cranial cavity through hypoglossal canal to enter carotid Sheath at base of skull , here is joined by a branch from cervical plexus conveying motor fibers from C1 ,2 spinal nerves & sensory fibers from C2 It passes inferiorly leaving carotid sheath medial to angle of mandible & curves anteriorly to pass over hyoglossus to enter tongue , it terminates in many branches that supply all intrinsic & extrinsic muscles of tongue Except palatoglossus Branches: 1-meningeal : returns to cranial cavity through hypoglossal canal to supply dura of posterior cranial fossa 2-descending branch: superior root of ansa cervicalis ( fibers from C1,2 leaves nerve & join posterior root of ansa cervicalis from C2,3 to form ansa cervicalis which supply infrahyoid muscles 3-nerve to thyrohyoid & geniohyoid: from C1 to supply thyrohyoid & geniohyoid muscles 4-terminal branches : supplying hyoglossus ,genioglossus styloglossus & all intrinsic muscles of tongue

Blood supply of the alveolar arches & teeth Main supply : External carotid artery branches: Maxillary artery: larger terminal branch of external carotid , arises behind Mandibular neck embedded within parotid gland , passes medial to neck then superficial or deep to lateral pterygoid ,passing through pterygo -maxillary fissure into pterygopalatine fossa Is divided into 3 parts : 1st part : mandibular related to bone 2nd part : pterygoid related to muscle 3rd part : pterygopalatine ,inside pterygopalatine fossa Generally the artery is distributed to : Mandible Maxilla Teeth Muscles of mastication Palate Nose Dura mater Branches: form 3 groups corresponding with its parts

Branches of 1st part: is horizontal passes between mandible neck & Sphenomandibular ligament , parallel with auriculotemporal nerve ,it Crosses inferior alveolar nerve to lower border of lateral pterygoid 1-Deep auricular : supplies external acoustic meatus ,exterior of tympanic membrane &TM joint 2-Anterior tympanic : enters tympanic cavity through petrotympanic Fissure supplies tympanic cavity 3-Middle meningeal : ascends between two roots of auriculotemporal nerve to foramen spinosum to enter middle cranial fossa ,dividing into frontal & parietal branches , in cranial cavity has following branches: a-ganglionic for trigeminal ganglion b-petrosal branch ; supplies facial & greater petrosal nerves c-superior tympanic for supply of tensor tympani muscle d-temporal branches e-anastomosing branch with lacrimal 4-Accessory meningeal artery: enters cranial cavity through foramen ovale supplies dura mater 5-Inferior alveolar (dental ) artery: descending post to inferior alveolar Nerve to mandibular foramen , here is between bone laterally & sphenoMandibular ligament medially , then it traverses canal with nerve & divides Into

A-incisor : continues below incisor teeth to midline where it anastomose With its fellow B-mental branch: leaves mental foramen supplies chin & anastomose With submental & inferior labial arteries In the canal the inferior alveolar artery supply mandible , tooth sockets & teeth with branches entering minute hole at apex of root to supply pulp Branches of inferior alveolar artery outside canal: a-myelohyoid: arise just before artery enters canal , pierces sphenoman -dibular ligament to descend with myelohyoid nerve in its groove in ramus It ramifies on muscle surface & anastomose with submental of facial b-lingual branch: arises near its origin ,it descends with lingual nerve passing behind last molar tooth to supply the buccal mucus membrane Branches of 2nd part: muscular part , within infratemporal fossa , A-deep temporal : ant & post ascend between temporalis & bone B-pterygoid branches : irregular in number & origin supply pterygoids C-masseteric : small passes through mandibular notch to deep surface of masseter D-buccal : runs obliquely forward with buccal nerve ,supplies external Surface of buccinator & through it the mucosa

Branches of 3rd part: within pterygopalatine fossa lies anterior to ganglion A-posterior superior alveolar : leaves maxillary artery as it enters the fossa It descends on maxillas infratemporal surface , it then divides ,some branches entering alveolar canals to supply molar & premolar teeth & the Maxillary sinus , others continuing over alveolar process to supply gingiva B-infraorbital artery: enters orbit posteriorly through inferior orbital fissure To run in infraorbital groove & canal with corresponding nerve both emerging on face via infraorbital foramen deep to levator labii suoperioris In the canal it has following branches: 1-orbital : supply rectus inferior , inferior oblique ,lacrimal sac 2-anterior superior alveolar(dental) : descends via anterior alveolar canals to supply upper incisor ,canine & mucus membrane of maxillary sinus On the face: 1-labial 2-nasal 3-palpebral C-greater(descending) palatine: from it arises lesser palatine D-pharyngeal E-artery of pterygoid canal F-sphenopalatine

MUSCLES OF MASTICATION: 4 pairs : temporalis ,masseter , lateral & medial pterygoid: All arise from bones of face All insert on mandible All are derived from 1st pharyngeal arch All are supplied by mandibular nerve(V cranial nerve) Temporal fascia : covers temporalis ,is strong fascia overlapped by ant & sup auricular muscles , epicranial aponeurosis & part of orbicularis oculi , above is a single layer attached to sup temporal line , below is of two layers ,one attached to lat & other to medial borders of superior border of zygomatic arch enclosing between them are zygomatic branch of superficial temporal artery , zygomaticotemporal nerve & fat The deep surface of it gives rise to superficial fibers of temporalis 1-Temporalis : origin: whole of temporal fossa , deep surface of temporal fascia insertion: fibers converge & descend into a tendon which passes in gap between zygomatic arch & side of skull & attaches to medial surface , apex , ant & post borders of coronoid process & ant border of ramus almost to last molar tooth .

The ant fibers are oriented vertically the most post fibers almost horizontally Intervening fibers with intermediate degree of obliquity , in a manner of fan -Because of tough temporal fascias is difficult to palpate it ,but its contr action can be easily felt. Its upper limit can be made out along inferior temporal line when teeth are firmly clinched Relations: Superficial : skin ,auricular muscles , temporal fascia ,auricul -otemporal nerve , temporal branch of facial ,zygomatic arch , masseter zygomaticotemporal nerve , epicranial aponeurosis Deep : temporal fossa , lateral pterygoid medial pterygoid buccinator ,maxillary artery , deep temporal arteries , nerves & buccal nerve Posteriorly : masseteric nerve & vessels Anteriorly : separated from zygomatic bone by a mass of fat Nerve supply: deep temporal branches of anterior division of mandibular Action: Elevates mandible so closes mouth & approximates teeth Contributes to side to side grinding movement Post fibers retract mandible

2-Masseter: is quadrilateral consisting of 3 layers which blend anteriorly A-superficial layer : largest origin: maxillary process of zygomatic bone , anterior two thirds of inf border of zygomatic arch insertion: fibers pass downward & backward to insert to angle & lower Post half of lat surface of ramus B-middle layer: origin: medial aspect of ant two thirds of zygomatic arch , lower border of post third insertion: central part of mandibular ramus C-deep layer: origin: from deep surface of zygomatic arch insertion: upper part of ramus , coronoid process Middle + deep parts = form cruciate muscle Relations: superficial: skin ,platysma ,risorius , parotid gland & duct , facial nerve branches , transverse facial artery deep: temporalis , ramus masseteric nerve & vessels lie deep to it posterior: overlapped by parotid gland anterior: projects over buccinator & is crossed by facial vein Nerve supply: masseteric nerve from anterior division of mandibular

Action: elevates mandible to occlude teeth minimal effect in side to side movements ,protraction & retraction Lateral pterygoid : is a short thick muscle with two heads upper head: origin: infratemporal surface & infratemporal crest of greater wing of sphenoid lower head : origin: lateral surface of lateral pterygoid plate insertion: fibers of both heads pass backward & laterally to be inserted into pterygoid fovea , articular capsule & disc of TM joint Relations : superficial : ramus ,maxillary artery (may be deep) tendon of temporalis & masseter deep : upper part of medial pterygoid , sphenomandibular ligament middle meningeal artery & mandibular nerve upper border : temporal & masseteric branches of mandibular lower border : lingual & inferior alveolar nerves , maxillary artery passes between two heads of muscle Nerve supply: branch from anterior division of mandibular Action: upper head mainly involved in chewing lower head mainly involved in protrusion assists in opening mouth

Medial pterygoid: is a thick quadrilateral , with a deep & superficial parts Deep part ; origin: medial surface of lateral pterygoid plate , grooved surface of pyramidal process of palatine Superficial part: origin: lateral surface of pyramidal process & maxillary tuborosity Insertion : lies at 1st on inferior aspect of lateral pterygoid , fibers descend posterolaterally & attaches by a strong tendinous lamina to posteroinferior part & medial surface of ramus & angle as high as mandibular foramen & almost as forward as myelohyoid groove Relations: laterally: ramus ,from which is separated above its insertion by lat pterygoid ,sphenomandibular ligament , maxillary artery , inferior alveolar vessels & nerve ,lingual nerve & a process of parotid gland medially : tensor veli palatini , styloglossus ,stylopharyngeus separating it from superior constrictor of pharynx Nerve supply: mandibular nerve trunk Action: assists in elevating mandible , with lateral pterygoid it protrude it alternating activitiy in right & left muscles produces side to side movements which are used to triturate food