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MODULE 7: HEAD AND NECK - Coggle Diagram

- - - - EXTERNAL
        
        PNEUMATIZED BONE-
        Contain air spaces (air cells/ large sinuses)
        
        Lined with respiratory mucous membrane
        
        Lighten the skull, give resonance to voice, warm the air we breathe, moisten nasal cavity
        
        FRONTAL SINUS
        
        ETHMOID CELLS
        
        SPHENOID SINUS
        
        MAXILLARY SINUS
        
        SUTURAL / wormian
        
        Commonly found within lambdoid suture.
        
        Arises from separate centres of ossificatioN
        
        BONE
        
        ANTERIOR
        
        FRONTAL B [forehead]
        
        NASAL b
        
        MIDDLE NASAL CONCHA
        
        INFERIOR NASAL CONCHA
        
        MANDIBLE
        
        PARIETAL
        
        SPHENOID
        
        FORAMEN OVALE
        
        Mandibular nerve
        
        Accessory meningeal ARTERY
        
        Lesser petrosal nerve
        
        Emissary vein
        
        FORAMEN SPINOSUM - Middle meningeal artery
        
        MEDIAL PTERYGOID PLATE
        
        LATERAL PTERYGOID PLATE
        
        SPINE OF SPHENOID
        
        TEMPORAL
        
        FORAMEN LACERUM - Closed by fibrous tissue
        
        CAROTID CANAL - Internal carotid artery
        
        JUGULAR FORAMEN - Notches of temporal & occipital bone.
        
        Internal jugular vein & CN IX-XI
        
        STYLOMASTOID FORAMEN - CN VII, stylomastoid artery
        
        MANDIBULAR FOSSA - Upper articular surface of TMJ
        
        STYLOID PROCESS
        
        MASTOID PROCESS
        
        ZYGOMATIC [cheek]
        
        MAXILLA
        
        glabella
        
        superciliary arch
        
        NASION
        
        Intersection of fontal & nasal bone
        
        ALVEOLAR PROCESS
        
        MENTAL PROTUBERANCE [chin]
        
        ANTERIOR NASAL SPINE
        
        POSTERIOR
        
        VOMER
        
        PALATINE
        
        VERTEX- Highest point of skull
        
        LAMBDA - Junction of sagittal & lambdoid sutures
        
        ASTERION
        
        EXT. OCCIPITAL PROTUBERANCE/ inion
        
        Provides attachment to muscles & ligamentum NUNCHAE
        
        LINE
        
        SUPREME NUNCHAL
        
        SUPERIOR NUCHAL - Junction of neck & scalp
        
        INF. NUCHAL L.
        
        LATERALS
        
        TEMPORAL (SQUAMOUS)
        
        OCCIPITAL
        
        OCCIPITAL CONDYLE - Articulate with atlas (C1)
        
        PHARYNGEAL TUBERCLE - Small prominence of basilar part of occipital BONE
        
        CONDYLAR CANAL - chondylar emissary vein
        
        FORAMEN MAGNUM
        
        EXTERNAL OCCIPITAL CREST
        
        EXT. OCC. PROTUBERANCE
        
        TEMPORAL (PETROUS )
        
        ETHMOID
        
        LACRIMAL
        
        TEMPORAL (TYMPANIC)
        
        ASTERION
        
        ZYGOMATHIC ARCH - Inferior limit of cerebrum
        
        LINE
        
        SUPERIOR TEMPORAL L.
        
        INFERIOR TEMPORAL L.
        
        PROCESS
        
        STYLOID P.
        
        MASTOID P.
        
        EXTERNAL ACOUSTIC MEATUS
        
        INFRATEMPORAL FOSSA - Exposed by removal of zygomatic arch & mandible
        
        SUPERIOR
        
        FRONTAL EMINENCE
        
        BREGMA - Junction of coronal & sagittal sutures
        
        VERTEX - Highest point of skull
        
        Midpoint of sagittal suture
        
        PARIETAL EMINENCE
        
        PARIETAL FORAMEN - Inconstant aperture
        
        Transmission of emissary VEIN
        
        VAULT
        
        GROOVE FOR SUP SAGITTAL SINUS
        
        GANULAR PITS - Lateral lacunae &
        arachnoid granulations
      - INTERNAL
        
        ANT. CRANIAL FOSSA
        
        Highest & shallowest.
        
        Lodges frontal lobe of cerebrum.
        
         Forms roof of orbit
        
        formed by
        
        FRONTAL BONE, ETHMOID B., BODY OF LESSER WING OF SPHENOID
        
        FRONTAL CREST, FORAMEN CECUM, CRISTA GALLI, CRIBRIFORM PLATE, OPTIC CANAL, ANTERIOR CLINOID PROCESS
        
        MIDDLE CRANIAL FOSSA
        
        POST CRANIAL FOSSA
        
        Free border of lesser wing of sphenoid bone.
        
        Separates anterior & middle cranial fossae
        
        Upper border of petrous part of temporal bone
        
        Separates middle & posterior cranial fossae
      - DIPLOE
        
        Frontal diploic veins
        
        Anterior temporal diploic veins
        
        DIPLOIC VEIN: Communicate with dural venous sinuses & scalp veins via emissary veins
        
        Route for spread of infection
      - FISSURE
        
        SUPERIOR ORBITAL
        
        INFERIOR ORBITAL
        
        PTERYGOMAXILLARY
        
        Vertical fissure between pterygoid plate & maxilla
        
        Leads medially into pterygopalatine fossa
      - SUTURES
        
        CORONAL
        
        METOPIC
        
        INTERMAXILLARY
        
        SAGITTAL
        
        LAMBDOID
        
        PTERION
        
        H-shaped suture
        
        Thinnest part of lateral wall
        
        Overlies course of ant. division of middle meningeal vessels
        
         Meeting point of frontal, parietal, sphenoid & temporal bones
         Closely related to anterior branch of middle meningeal artery
        
        Severe of artery -> extradural haemorrhage
        
         Blood collected between internal surface of skull & meningeal layer of dura mater
        
        Exerts local pressure on the underlying precentral gyrus
      - FORAMEN
        
        SUPRAORBITAL NOTCH
        
        Supraorbital nerve & vessels
        
        ZYGOMATICOFACIAL
        
        Zygomaticofacial nerve & vessels
        
        MENTAL FORAMEN
        
        Inferior to 2nd premolar teeth
        
        Mental nerve & vessels
        
        INFRAORBITAL
        
        Infraorbital nerve & vessels
    - - Most complex osseous structure
        
        Bony skeleton of the head
        
        Shields the brain, organs of special senses, cranial part of respiratory
        
        Attachments for muscles of the head & neck
      - Cranium + mandible = skull
      - CRANIUM (22 bone)
        
        NEUROCRANIUM/ cranial vault
        
        8 bones
        
        Frontal, parietal (2), occipital, temporal (2), sphenoid, ethmoid
        
        VISCEROCRANIUM/ facial bone
        
        14 bones
        
        Zygomatic (2), maxilla (2), nasal (2), lacrimal (2), vomer, palatine (2), inferior conchae (2), mandible
    - - ORBITOMEATAL PLANE/ Frankfort horizontal plane
        
        Superior margin of external acoustic meatus
        
        Inferior margin of orbit
        
         Anterior view: norma frontalis
        
         Lateral view: norma lateralis
        
         Posterior view: norma occipitalis
        
         Superior view: norma verticalis
        
         Inferior view: norma basalis
  - - - S- SKIN
        
        thick
        
        hairy, contains numerous hair follicles & sebaceous glands
      - C- CONNECTIVE TISSUE
        
        anchors skin to aponeurosis
        
        contain arteries, veins & nerves
      - A- APONEUROSIS
        
        thin, tendon-like structure
        
        unites frontal & occipital bellies of occipitofrontalis muscle
      - *L- LOOSE AREOLAR TISSUE
        
        contain valveless emissary veins >>> connects scalp veins to diploic veins & intracranial venous sinuses
        
        DANGEROUS LAYER
        
        emissary veins devoid of valves & communicates scalp veins with intracranial venous sinuses.
        
        superficial infection from skin spread to deeper structure resulting in osteitis/ meningitis/ venous sinus thrombosis
      - P- PERICRANIUM
        
        periosteum covering external surface of skull bones
    - - FRONT auricle
        
        4 SENSORY
        
        Supratrochlear n.- (branch of ophthalmic n., supplies anteromedial forehead)
        
        o Supraorbital n.- (branch of ophthalmic n., supplies scalp)
        
        o Zygomaticotemporal n.- (branch of maxillary n., supplies temple
        
        o Auriculotemporal n.- (branch of mandibular n., supplies skin ant. sup. to the auricle
        
        1 MOTOR
        
        Temporal branch offacial n.
      - BEHIND auricle
        
        1 MOTOR
        
        Posterior auricular branch of facial n.
        
        4 SENSORY
        
        Great auricular n.- (ant. rami C2 & C3, supplies post. ear skin & angle of mandible
        
        o Lesser occipital n.- (ant. ramus C2, supplies skin post. to ear)
        
        o Great occipital n.- (post. ramus C2, supplies skin of occipital region)
        
        o 3rd occipital n.- (post. ramus C3, supplies skin inferior of occipital region)
    - - FRONT auricle
        
        o Supratrochlear a.
        
        o Supraorbital a.
        
        o Superficial temporal a.
        
        Ophthalmic artery (branch of internal carotid artery)
      - BEHIND auricle
        
        o Posterior auricular a.
        o Occipital a
        
        Branches from external carotid artery
- - - - Orbital process of palatine bone.
        
        orbital surface of maxillary bone.
        
        zygomatic bone
      - Slopes slightly downwards from medial to the lateral wall.
        
        It is crossed by the infraorbital groove, which runs forward from the inferior orbital fissure. Before it reaches the orbital margin, it becomes infraorbital canal, which opens as the infraorbital foramen.
      - RELATION
        
        •Below the floor lies the maxillary sinus, the bone being only 0.5 – 1 mm in thickness
    - - lesser wing of sphenoid bone & orbital plate of frontal bone
      - Fossa for the lacrimal gland – fossa lies in the anterolateral aspect of the roof behind the zygomatic process of the frontal bone
      - Trochlear fossa (fovea) This lies in the anteromedial aspect of the roof
      - Anterior and posterior ethmoidal canals- positioned at the junction of the roof and medial wall above the frontoethmoidal suture.
    - - zygomatic process of frontal bone.
        
        greater wing of sphenoid bone.
        
        orbital surface of zygomatic bone
      - Spina recti lateralis – a small bony spine near apex of the orbit on the greater wing of sphenoid – gives origin to part of the lateral rectus
      - Zygomatic foramen – transmit zygomatic nerve and vessels to temporal fossa and cheek (zygomaticotemporal nerve and zygomaticofacial nerve)
      - Lateral orbital tubercle : the origin of the ligament of the lateral rectus, suspensory ligament of the eye and aponeurosis of levator palpebrae superioris
      - Foramina for small veins that communicate with middle cranial fossa
      - RELATION
        
        •Laterally – skin, temporal fossa and middle cranial fossa in an anterior – posterior sequence
    - - sphenoid bone.
        
        orbital plate of ethmoid bone.
        
        frontal process of maxilla.
        
        lacrimal nerve
      - Oblong in shape, and thin (0.2 – 0.4 mm)
      - The four bones that comprise this wall are separated by vertical sutures
      - Lacrimal fossa for the lacrimal sac : bound by anterior and posterior lacrimal crests and is continuous below with the nasolacrimal canal
      - relations
        
        •thinnest of the walls
        
        •transparent or semitransparent
        
        •Ethmoidal air sinuses can easily be seen through this wall in dried skull
  - - - Between lateral wall and floor of the orbit.
      - Forms communication between orbit and infratemporal fossa and pterygopalatine fossa.
      - Its posterior end lies below and lateral to the optic foramen near the superior orbital fissure.
      - Narrowest in the middle section
      - Covered by periorbita and a sheet of smooth muscle of unknown function – Muscle of Muller
      - Transmits infraorbital nerve, zygomatic nerve and branches from pterygopalatine ganglion
    - - ! ‘a gap’, ‘comma-shaped’, wider at its medial end and narrowest at lateral end
      - ! Lies between the roof and lateral wall of the orbit
      - ! Bounded by lesser and greater wings of sphenoid
      - ! Largest communication between orbital and cranial cavities.
    - - Bony channel in the sphenoid that passes anteriorly, inferiorly and laterally from the middle cranial fossa to the apex of the orbit
      - It is formed by the two roots of the lesser wing of the sphenoid.
      - The two optic canals are 25 mm apart posteriorly and 30 mm anteriorly
      - Funnel-shaped, narrowest anteriorly where opening into the orbit is oval with sharp upper and lower borders and prolonged roof.
      - The opening at cranial aspect is oval with prolonged floor.
      - Transmit optic nerve with its meningeal coverings and ophtalmic artery, which lies below and lateral to the nerve within the dural sheath for part of its course. Sympathetic nerve fibers accompany the artery.
- - - - maxillary artery
        
        Arises in the parotid gland.
        
        Divided into 3 parts by the lateral pterygoid muscle.
        
        BRANCH
        
        1ST-
        
        deep auricular (ext auditory meatus)
        
        anterior tympanic (middle ear)
        
        middle meningeal* (dura mater)
        
        accessory meningeal
        
        2ND
        
        muscular branches to the deep temporal,
        
        pterygoid, masseter and buccal
        
        3RD
        
        posterior superior alveolar
        
        infraorbital
        
        greater palatine
        
        pharyngeal branch
        
        artery to pterygoid canal
        
        sphenopalatine
      - pterygoid venous plexus
        
        Around the lateral pterygoid muscle
        
        Drains into the maxillary vein
        
        Connected to cavernous sinus via:
        
        inferior ophthalmic vein in inferior orbital fissure
        
        deep facial vein
        
        emissary vein in sphenoid bone
    - - mandibular nerve (V3)
      - chorda tympani
      - otiC ganglion
    - - temporalis (inferior part)
      - lateral pterygoid
      - medial pterygoid
- - - - TRAGUS
      - OUTER CANTHUS OF EYE
      - JOINT SPACE
        
        LOWER
        
        UPPER
    - - AURICULAR DISK
        
        FX: to accommodate a hinging action
        as well as the gliding actions OF MANDIBLE
        
        It divides the joint into a larger upper compartment & a smaller lower compartment.
        
        Gliding movements take place in the upper compartment,
        
        Hinging movements take place in the lower compartment
      - GLENOID FOSSA
        
        LOCATION
        
        inferior aspect of squamous part of temporal bone,
        
        anterior to tympanic plate.
        
        CHARAC.
        
        always thin
        
        Overlies it 🡪 is middle cranial fossa
      - ARTICULAR DISK - It is a biconcave fibrocartilaginous structure located between the mandibular condyle and the temporal bone component of the joint.
        
        anterior band = 2 mm in thickness,
        
        posterior band = 3 mm thick,
        
        VASCULAR & MORE CUSHIONED CONSISTENCY
        
        thin in the centre intermediate band of 1 mm thickness
        
        AVASCULAR & DENSER
      - CONDYLE
        
        An ovoid process of mandibular ramus. - wider latero-medially. - Convex in all directions
        
        VARIATIONS
        
        OVAL (60%), BIRD BEAK, DIAMOND, CROOKED FACE
      - SYNOVIAL CAVITY
        
        filled w/ synovial fluid (secreted by synovial mem.)
    - - Arthroscopic - diagnose adhesions and synovitis
      - Arthrocentesis - (the washing out of joint space) procedure
  - - - SPHENOMANDIBULAR L.
      - STYLOMANDIBULAR L.
      - ARTICULAR CAPSULE
        
        Thin sleeve of tissue. & completely surrounding the joint. .
        
        EXTEND FROM circumference of cranial articular surf 🡪 condylar neck
        
        is reinforced more laterally by an external TMJ ligament,
        
        limits the posterior movement of the condyle.
    - - POST L.
      - ANT L.
  - - - O: medial surf of zygomatic arch
        I : lateral aspect of ramus
    - - O: temporal fossa
        I : coronoid process
    - - SUPERFICIAL HEAD
        
        O:maxilla tuberosity
        I: angle of mand
      - DEEP HEAD
        
        O: med surf of lateral pterygoid plate
        I: angle of mand
    - - UPPER HEAD
        
        O: infratemporal crest of the GWS
        I: articular disc
      - LOWER HEAD
        
        O: lat surf of lateral pterygoid plate
        I: pterygoid fovea at condylar neck
    - - SUPRAHYOID & INFRAHYOID
  - - - Superficial temporal artery
      - Maxillary artery [MAIN]
      - Deep auricular artery
      - Anterior tympanic artery
      - Ascending pharyngeal artery [MAIN]
  - - - Dense fibrous CT
        
        Shock absorber.
    - - thin zone of calcified cartilage immediately covering bone
        
        C/cytes, c/blasts & o/blasts ~ Active site for remodeling activity as bone growth proceeds.
  - - - TEMPORAL BLASTEMA
        
        While it still condensed mesenchyme – cleft appear >> inf joint space.
        
        differentiate into CONDYLAR CARTILAGE – 2nd cleft appear in relation to temporal ossification >> u joint space.
      - CONDYLAR BLASTEMA
        
        condylar cartilage [consist of progenitor cell]
        
        chondroblast
        
        differentiate -> chondrocyte
        
        begin to hypertrophy <-> degenerate
        
        endochondral ossification involve [later become condylar bone]
        
        Loss of chondrocytes
        
        Mineralization of cartilage
        
        o/blast 🡪 produce BONE
- - - - Largest, strongest & lowest bone of viscerocranium.
        
        Articulates with skull at temporomandibular joint
      - HORSESHOE- SHAPED
        
        2 surfaces (anterior & posterior)
        
        2 borders (superior & inferior)
      - 2 VERTICALLY PLACED RAMI
        
        2 surfaces (lateral & medial)
        
        4 borders (superior, inferior, anterior & posterior)
        
        2 processes (coronoid & condyloid)
    - - EXTERNAL
        
        BODY OF MANDIBLE
        
        Alveolar part & base
        
        Mental foramen (mental nerve)
        
        Inferior to 2nd premolar teeth
        
        Mental nerve & vessels
        
        Faces upward & backward (adult) Directed laterally (early childhood) Influence direction of needle for mental nerve block
        
        Mental protuberance
        
        Oblique line (buccinator)
        
        RAMI OF MANDIBLE
        
        Coronoid & condyloid processes
        
        Mandibular notch
      - INTERNAL
        
        BODY OF MANDIBLE
        
        Mental spines (genioglossus & geniohyoid)
        
        Superior: genioglossus muscle
        
        Inferior: geniohyoid muscles
        
        Mylohyoid line (mylohyoid)
        
        Mental spines – 3rd molar tooth.
        
        Mylohyoid GROOVE = - Mylohyoid nerve
        
        Digastric fossa (anterior belly of digastric)
        
        RAMI OF MANDIBLE
        
        Mandibular foramen & canal (inferior alveolar nerve)
        
        Lingula (sphenomandibular lig)
        
        Sphenomandibular lig
        
        Landmark for inferior alveolar nerve block
        
        Pterygoid fovea (lateral pterygoid)
      - MUSCLE ATTACHMENT
        
        MYLOHYOID MUSCLE
        
        ANTERIOR BELLY OF DIGASTRIC
        
        MENTALIS
        
        BUCCINATOR
        
        DEPRESSOR LABII ONFERIORIS
        
        DEPRESSER ANGULI ORIS
    - - -related changes of mandible
        
        In children: deciduous teeth, alveolar part poorly developed
        
        In adults: permanent teeth, alveolar part fully developed
        
        Old age: edentulous mandible, resorption of alveolar process
        
        At birth: no teeth, alveolar part not yet formed
      - Position of mental foramen
        
        At birth: lies near to the inferior border
        
        Adult: halfway between superior & inferior border
        
        Old age: lies near to the superior border
    - - Body of mandible (passes through canine tooth socket)
        
        Neck of mandible
        
        Coronoid process
        
        Angle of mandible
  - - - 2nd largest bone of viscerocranium
        
        Forms the
        
        Upper jaw
        
        Roof of oral cavity
        
        Floor of orbital cavity
        
        Floor & lateral wall of nasal cavity
      - BODY - Anterior, posterior (infratemporal), superior (orbital), medial (nasal)
        
        Four sided hollow pyramid
        
        Orbital (infraorbital groove)
        
        Anterior (infraorbital foramen)
        
        Infratemporal (minute canals Æ posterior superior alveolar nerves & vessels)
        
        Nasal (opening of maxillary sinus, nasolacrimal groove)
        
        Houses the maxillary sinus
        
        Horizontal plate forming anterior part of hard palate
        
        Pyramidal-shaped cavity within body of maxilla
        
        Mucosal lining continuous with nasal mucosa
        
        FUNC
        
        Lighten skull
        
        Give resonance to voice
        
        Warm the air we breathe
        
        Moisten nasal cavity
      - PROCESS -
        
        Frontal [- Articulates with nasal (medially) & frontal (superiorly)],
        
        zygomatic [- Articulate with zygomatic (laterally)],
        
        alveolar [- Posses 16 (8X2) sockets for upper teeth] &
        
        palatine processes [- Horizontal plate forming anterior part of hard palate]
    - - MAXILLARY SINUSITIS
        
        Inflammation of mucosa of maxillary sinus [most common].
        
        Opening into nasal cavity located high --> Poor natural drainage
      - INNERVATION- SUPERIOR ALVEOLAR N.
        
        Also supply maxillary teeth
        
        Pain of sinusitis referred to maxillary molars & premolars
      - LeFort classification of maxilla fracture
        
        LeFort 1: separation of maxillae from upper part of viscerocranium.
        
        LeFort 2: separation of central part of face from cranium
        
        LeFort 3: separation of maxillae & zygomatic from cranium
- - - - 1ST- MANDIBULAR
        
        NERVE- CN V2,3 (maxillary & mandibular)
        
        MUSCLE- Mastication, mylohyoid, anterior belly of digastric, tensor palatine, tensor tympani
        
        SKELETON- Mandible, maxilla, zygomatic, part of temporal, incus & malleus
      - 2ND- HYOID
        
        NERVE- CN VII (facial)
        
        MUSCLES- Facial expression, posterior belly of digastric, stylohyoid, stapedius
        
        SKELETON- Stapes, styloid process, lesser horn & upper part of body of hyoid
  - - - OPHTHALMIC
        
        INNERVATE frontonasal process [[Forehead, nose, philtrum of upper lip, frontal bone ]]
      - MAXILLARY
        
        innervate maxillary p. [Upper cheek region, lat. portion of upper lip, maxilla]
        
        ZYGOMATICOTEMPORAL N- Skin over the temple
        
        ZYGOMATICOFACIAL N- Skin over prominence of cheek
        
        INFRAORBITAL N
        
        Direct continuation of CN V2
        
        Skin of cheek, lower eyelid, side of nose & upper lip
      - MANDIBULAR
        
        innervate mandibular p. [Lower lip, chin, lower cheek region, mandible]
      - SUPPLY
        
        SENSORY- mouth, tongue, teeth, nasal cavity & paranasal sinuses
        
        MOTOR [CN V3]- to muscles of mastication, mylohyoid, anterior belly of digastric, tensor veli palatini & tensor tympani.
      - LESION
        
        Widespread anaesthesia of
        
        Corresponding anterior half of scalp
        
        Face, except angle of the mandible, cornea & conjunctiva
        
        Mucous membrane of nose, mouth & anterior part of tongue
        
        Paralysis of muscles of mastication
      - TRIGEMINAL NEURALGIA
        
        Sudden attack of excruciating pain in distribution of CN V2 & V3
        
        Unknown cause (Demyelination of axons in sensory root)
        
        ‘Most severe pain one can imagine’
    - - GREAT AURICULAR N.- angle of mand. & parotid gland
      - LESSER OCCIPITAL N.
- - - - LOCATION
        
        Inferior to external auditory meatus
        • Behind & upon ramus of mandible
        • Anterior to sternocleidomastoid muscle
      - LOBES
        
        SUPERFICIAL LOBE
        
        DEEP LOBE
      - GROSS FEATURE
        
        Largest major salivary gld.
        
        • Pyramidal shape.
        
        • Yellowish, irregular, lobulated appearance.
        
        • Lies within parotid sheath / capsule (part of investing layer of deep cv fascia)
        
        STRUCTURE WITHIN GLAND [lateral to media]
        
        • Parotid lymph nodes
        
        • Facial nerve
        
        • Retromandibular vein
        
        • External carotid artery
        
        • Auriculotemporal nerve
        
        branch of V3.
      - RELATION
        
        LATERAL/ SUP SURF
        
        covered w/ skin & sup. fascia.
        
        great auricular nerve & parotid lymph nodes
        
        ANTEROMEDIAL SURF
        
        grooved by posterior border of ramus of mandible.
        
        masseter & medial pterygoid muscles attached to ramus, TMJ
        
        POSTEROMEDIAL
        
        mastoid process & muscle attached to it (sternocleidomastoid & posterior belly of digastric.
        
        styloid process & muscle attached to it (stylohyoid, stylopharyngeus, styloglossus)
    - - 5cm long, 3mm wide
      - COURSE
        
        emerge from anterior border of gland.
        
        pass forward over lateral surface of masseter.
        
        pierce buccinator
        
        enter vestibule of mout opposite upper 2nd molar
    - - supplied by : maxillary & superficial temporal aa (branches of ECA)
        
        drained into: retromandibular vein & its tributaries
      - EXTERNAL CAROTID ARTERY -> RETROMANDIBULAR VEIN
      - LYMPHATIC DRAINAGE
        
        Parotid lymph nodes – drain into deep cervical lymph nodes
    - - PARASYMPATHETIC SECRETOMOTOR
        
        begin in inf. salivary nucleus
        
        carried by tympanic b. of CN9 >> forms tympanic plexus >> gives off lesser petrosal n. >> carries preganglionic nv fbrs ..
        
        (In short, parasymp innervation to PG : derived from CN9 , via auriculotemporal n).
      - SYMPATHETIC - external carotid nerve plexus
      - SENSORY
        
        Great auricular nerve (C2, C3)
        
        Auriculotemporal nerve ( V3 )
    - - 1-parotid gland infection-Mumps
        
        SWEELLING OF GALND.
        
        is limited by parotid sheath
        results in severe pain.
      - 2-Frey’s Syndrome
        
        During healing, parasymp. secretory fbrs. in auriculotemporal N. grow out & join great auricular N.(C2,3) supplying skin over parotid.
        
        It is caused by damage to auriculotemporal & great auricular nerves.
        
        Thus in the presence of salivary stimulation by smell / taste of food,
        
        sweating, warmth, redness of skin covering PG.
  - - - •Sensory- supply external ear & tympanic m/brane
      - •Special sensory- transmit taste sensation from anterior 2/3rd of tongue via lingual nerve (branch of V3)
      - •Motor- supply mm of facial expression
      - •Parasympathetic secretomotor- innervates lacrimal gland, gld of nose & palate, SMG, SLG.
    - - ORIGIN
        
        junction of pons & medulla
      - WITHIN CRANIAL CAVITY
        
        Tranverse post cranial fossa >> internal acoustic meatus
      - MIDDLE EAR REGION
        
        it forms sharp bend w contains geniculate ganglion >> enters facial canal
      - EXIT CRANIUM
        
        THROUGH stylomastoid foramen.
      - ENTERS- parotid gland.
    - - FACIAL CANAL
        
        nerve to stapedius.
        
        GREATER PETROSAL NERVE- carry parasym. f. to ptherigopalatine ganglion for innervation of lacrimal & nasal
        
        CHORDA TYMPANI N
        
        CARRY PARASYMP. F. TO SUBMAND GANGLION FOR INNERVATIONOF SMG, SLG.
        
        carry special sensory f. to ant 2/3 of tongue via lingual n.
      - AFTER EXIT STYLOMASTOID FORAMEN
        
        POSTERIOR AURICULAR NERVE- auricular posterior & occipital belly of occipitofrontalis
        
        MUSCULAR BRANCH- posterior belly of digastric & stylohyoid
      - IN PAROTID GLD
        
        TEMPORAL, ZYGOMATIC, BUCCAL, MANDIBULAR, CERVICAL
    - - BELL'S PALSY
        
        Facial nerve lesion [INJURY]. - paralysis to some/all facial muscle on affected side
        
        SYMPTOM
        
        no transverse wrinkles.
        
        unable to close eye.
        
        drooping of lower eye lid -> lacrimal fluid not spread [ulceration of cornea]
        
        drooping of angle of mouth -->>> not drwan up while amiling, foord accumulate in vestibula, saliva trickles down
      - RAMSAY HUNT SYNDROME
        
        – paralysis facial expression+ vesicular rash in auditory canal (dt reactivation of latent VZV in geniculate gang within middle ear)
- - - - REFRACTION
        
        The apparent depth of an object in water when viewed from above. This is less than the object's real depth because of refractive effects: the light wave bends as it passes from the denser water into the less dense air.
        
        DEPEND ON:
        
        • angle –the greater the angle the greater the amount of bending.
        • comparative densities of 2 media (Refractive index)
        
        The refraction of light through glass. When the light ray strikes the glass (a denser medium than the air) it is bent towards the normal. When it leaves the glass and re-enters the less dense medium it is bent away from the normal.
        
        The apparent depth of an object in water when viewed from above. This is less than the object's real depth because of refractive effects: the light wave bends as it passes from the denser water into the less dense air.
    - - Light that enters the eye is bent 3 times:
         As it enters the cornea (RI=1.38); enter & leaving the lens (RI=1.40).
        
        It is most refracted by the cornea (due to its shape and density of the fluid).
         Refractory power of the humors (FLUID) and cornea is similar.
        
        The lens make a fine adjustment to focus an image on the retina.
         The lens is highly elastic. It curvature & light-bending power can be adjusted.
        
        Light enters the eye is focused on the retina by the lens.
        
        Photoreceptors of the retina transduce light energy into electrical signals.
        
        The electrical signals are processed through neural pathways.
        
        Interpretation of object seen – occipital lobe (cerebral cortex)
      - FOCUS
        
        DISTANT VISION
        
        •The far point of vision = distant at which the lens does not need to change its shape for focusing.
        
        •For normal (emmetropic) eye, the far point is 6 m (20 feet).
        
        •The ciliary muscles relax, the lens is stretched flat and at its lowest refractory power.
        
        CLOSE VISION
        
        Light from objects less than 6 m away diverges as it approaches the eyes.
        
        For close vision, the eyes need to make active adjustment:
        
        • Accommodation of the lenses.
        
        • Constriction of pupils
        
        • Convergence of the eyeballs
        
        •Near point of vision = the closest point on which we can focus clearly.
        
        Emmetropic eyes of young adults, the near point is 10 cm (4 inches) from the eye.
      - ACCOMODATION - The mechanism by which the shape of the lens in the eye is changed so that clear images of objects can be focused on the retina.
    - - HYPEROPIA/ hypermetropia
        
        far-sightedness.
        • unable to focus on close objects
        • caused by the failure of the lens to return to its normal rounded shape, or by the eyeball being too short, with the result that the image is focused on a point behind the retina.
        
        corrected by wearing glasses fitted with converging (convex) lenses.
      - MYOPIA
        
        NEAR-SIGHTEDNESS.
        • see clearly only those objects that are close up
        • caused either by the eyeball being too long or by the cornea and lens system of the eye being too powerful, both of which cause the images of distant objects to be formed in front of the retina instead of on it.
        
        corrected by suitable glasses concave lenses.
      - ASTIGMATISM
        
        • Unequal curvature in different parts of the cornea / lens.
        • the vertical and horizontal cannot be in focus at the same time.
        • correction - use of a cylindrical lens that reduces the overall focal length of one plane so that both planes are seen in sharp focus (other procedures: corneal implants, laser).
      - PRESBYOPIA
        
        • an increasing inability with advancing age to focus on near objects (non-accommodating).
        • caused by thickening and loss of elasticity in the lens, which is no longer able to relax to the near-spherical shape required for near vision.
      - COLOUR
        
        BLINDNESS
        
        Hereditary defect of vision that reduces the ability to discriminate certain colours, usually red and green.
        
        It is sex-linked and affecting men more than women.
        
        In the most common types of colour blindness there is confusion among the red–yellow–green range of colours
        
        for example, many colour-blind observers are unable to distinguish red from yellow, yellow from green or blue and yellow
        
        VISION
        
        Absorption spectra overlap.
        
        Blue - Respond maximally to wavelengths of 420 nm
        
        Green - Respond maximally to wavelengths of 530 nm
        
        Red- Respond maximally to wavelengths of 560 nm
      - VISUAL FIELD
        
        Total blindness (anopia)
        
        Bitemporal hemianopia
        
        Left homonymous hemianopia
        
        Right homonymous superior quadrantanopia
        
        Right homonymous inferior quadrantanopia
        
        Right homonymous macula sparing hemianopia
      - PUPILS FAIL TO RESPOND TO LIGHT
        
        Visual signals to Edinger-Westphal nucleus are blocked.
        
        CNS syphilis, alcoholism, encephalitis.
        Argyll Robertson (pupils show small response to accommodation).
        
        Horner’s syndrome:
        
        Sympathetic nerves to the eyes are interrupted.
        
        Pupils persistently constricted.
        
        Superior eyelid droops.
    - - Phototransduction = The process by which light energy is converted into a graded receptor potential.
        
        IN DARK
        
         11-cis-retinal
        
         Increase [cGMP].
        
         cGMP binds to Na+ channels to keep them open.
        
         Na+ influx leads to membrane depolarization.
        
         Ca2+ channels open in the synaptic terminal.
        
         Increase inhibitory neurotransmitter release.
        
         Bipolar cells are inhibited (IPSP).
        
         No action potetial formed in the axon of ganglion cell.
        
        IN LIGHT
        
         All-trans-retinal cause activation of phosphodiesterase
        
         Reduce [cGMP].
        
         Na+ channels close.
        
         Photoreceptor hyperpolarized.
        
         Ca2+ channels closed
        
         No neurotransmitter released.
        
         Bipolar cells depolarized (EPSP) – neurotransmitter released.
        
         Action potential formed in the axon of ganglion cell.
      - PHOTORECEPTORS.
        Outer segments- receptor region contain photopigments
        Inner segment – connect to the cell body
        
        RODS
        
        • very sensitive to light (respond to dim light) – best suited for night vision and peripheral vision.
        • contain a single kind of photopigment (rhodopsin / purple pigment).
        
        Rods are concentrated in the periphery.
        Many rods converge to a ganglion cell.
        
        IMPAIRED
        
        • Prolonged vit A deficiency leads to rod degeneration.
        • Retinitis pigmentosa – pigment epithelial cells are unable to recycle the tips of the rods as they are destroyed.
        
        CONES
        
        • have low sensitivity for light
        • used for colour vision & high acuity
        
        Cones are abundant in the fovea.
        
        1 cone connects to 1 ganglion cell.
      - ADAPTATION
        
        LIGHT
        
        •When we move from darkness into bright light, we are momentarily dazzled.
        
        • Large amount of photopigments (rods & cones) are broken down which causes glare.
        
        •Within 60 s, cones are sufficiently recover.
        
        •Within 5-10 min. visual acuity and colour vision improve.
        
        DARK
        
        When we go from well-lit area into a dark area, we can’t see things for a while.
        
        Time-course of dark adaptation is biphasic:
        
         Cones stop functioning in low- intensity light but adapt fast.
        
         Rod pigments have been bleached out by bright light and adapt slowly.
        
         In the dark, rhodopsin accumulates and retinal sensitivity increases.
    - - ISHIHARA CHART
  - - - HEARING- detect sound.
        
        COCHLEA- organ of corti.
        
        RECEPTOR: hair cell
      - EQUILIBRIUM- detect position of head wrt gravity & motion of head.
        
        SEMISIRCULAR CANAL & OTOLITH ORGAN.
        
        RECEPTOR - hair cell
    - - EXTERNAL
        
        •Pinna & Auditory canal
        •Fx: Protection & provide directional sensitivity to the ear for sound waves
      - MIDDLE
        
        •Air-filled cavity , •Tympanic memb. & •Auditory ossicles
        
        to amplify the sound
        
        impedance matching device
      - INNER
        
        •Bony labyrinth filled with perilymph
        
        •Membranous labyrinth filled with endolymph
        
        •Cochlea - fluid- filled, coiled tube
        
        •Vestibular system
- - - - EXTERNAL
        
        ● Root of the nose (attached to the forehead)
        
        ● Dorsumof the nose (part between root & apex)
        
        ● Apex/tip of the nose
        
        ● Nasal septum (separate nostrils)
        
        ● Naris/nostrils (bounded by ala & nasal septum)
      - INTERNAL
        
        NASAL CAVITY
        
        N. VESTIBULE
        
        o supported by nose cartilage
        o lined with tissues contain hair
        
        N. C. PROPER
        
        o lined by mucosa
        o functions: Ø olfactory area – for smell & respiratory area – for breathing
        
        WALL
        
        LATERAL
        
        § Separates the nasal cavity from: ORBIT & MAXILLARY SINUS.
        
        FEATURES: § Inferiorly – vestibules (anterior portion lined by skin with soft hair)
        § Posteriorly – choanae (opening between nasal cavity & nasopharynx)
        § Medially – 3 bony projections àconchae (/turbinates)
        
        FLOOR
        
        formed by - o palatine process of maxilla
        o horizontal plate of palatine bone
        
        MEDIAL [septum]
        
        § Divides nasal cavity into half
        § Consists of: o bony part: vomer & perpendicular plate of ethmoid & cartilaginous part: septal cartilage
      - ARTERIAL SUPPLY
        
        INTERNAL CAROTID ARTERY
        
        ANTERIOR ETHMOIDAL ARTERIES
        
        POST. E. A.
        
        EXTERNAL CAROTID ARTERY
        
        MAXILLA ARTERY
        
        SPHENOPALATINE A.
        
        GREATER PALATINE A.
        
        FACIAL ARTERY
        
        SUP. LABIAL ARTERY
        
        LAT. NASAL ARTERY
      - NERVE SUPPLY
        
        OLFACTORY N. [CN1]- provides smell sensation
        
        INT. NASAL BRANCH OF ANT. ETHMOIDAL N [Br. OF V1]- provides general sensory to anterosuperior part of nasal septum
        
        NASOPALATINE N. [Br. V2]- provides general sensory to
        posteroinferior part of nasal septum
        
        OF LATERAL WALL [N. cavity]
        
        ANT ETH. N (Br. V1)
        
        provides general sensory to anterosuperior part
        
        (Br V2)
        
        ANT SUP ALVEOLAR NERVE
        
        provides general sensory to anteroinferior part
        
        POST. LAT. NASAL N
        
        provides general sensory to posterosuperior part
        
        GREATER PALATINE N
        
        provides general sensory to posteroinferior part
        
        Secretomotor innervation of glands in the mucosa is by:
        Ø preganglionic fibres from superior cervical ganglion
        Ø Postganglionic fibres from pterygopalatine ganglion
    - - EPISTAXIS [nosebleed]
        
        § the most common site – anterior third of the nose.
        [or known as Kiesselbach’s plexus/ Little’s area ]
        
        due to the anastomosis of branches from 5 different arterial sources:
        
        o Sphenopalatine artery (maxillary artery)
        
        o Anterior & posterior ethmoidal artery (ophthalmic artery)
        
        o Greater palatine artery (maxillary artery)
        
        o Superior labial artery (facial artery)
        
        o Lateral nasal branch (facial artery)
      - RHINITIS
        
        § Nasal mucosa becomes swollen & inflamed
        § Causes: o upper respiratory infections
        o allergic reactions (hay fever)
  - - - Air-filled cavities within the nasal cavity
        
        Paired but asymmetrical.
        
        Lined with respiratory epithelium
        
        Functions: resonating voice, reduce weight of skull, and as air-conditioning chambers
      - BONE
        
        o frontal
        
        o maxilla
        
        o sphenoid
        
        o ethmoid
    - - Paired, asymmetric cavities located inside the sphenoid body
        
        Separated by a bony septum.
        
        Age 6: size of a small pea
        
        Arterial supply: posterior ethmoidal artery
      - RELATION
        
        SUPERIORLY
        
        optic chiasma
        
        pituitary gland
        
        LATERALLY
        
        cavernous sinus
        
        internal carotid artery
        
        BEHIND
        
        pons & medulla oblongata
    - - o 3-18 small interconnected air spaces
        o Contained within the ethmoid bone, between nose and orbit.
        o 3 groups: anterior, middle & posterior
        o Separated from orbit by a thin bone plate
        --> so that infection can readily spread from sinuses into the orbit
        o Relations: laterally --> orbital plate of ethmoid
        
        Arterial supply: anterior & posterior ethmoidal branches of ophthalmic a.
    - - o There are two
        o Absent at birth, appear during the 2nd year of life
        o Contained within the frontal bone, separated by a bony septum
        o Roughly triangular
        o Arterial supply: supraorbital vessels
        o Nerve supply: supraorbital nerve
      - EXTEND INTO
        
        Ø Upward and above the medial end of the eyebrow
        Ø Backward into the medial part of the roof of the orbit
    - - o Largest sinuses, and 1st to formed
        o Pyramidal shaped
        Arterial supply: anterior, middle & posterior alveolar vessels of maxillary artery
        Nerve supply: similar to teeth (anterior, middle & posterior superior alveolar nerves)
      - BOUNDARY
        
        § Roof – orbital surface of maxilla (transversed by infraorbital nerve & vessel)
        
        § Floor – alveolar process of maxilla (closely related to roots of premolar & molar)
        
        § Posterior wall – ant. wall of infratemporal fossa (pierced by posterior superior alveolar vessels & nerves)
      - RELATION
        
        SUPERIOR - • orbit
        • infraorbital nerve & vessels
        
        INFERIOR - roots of molars & premolars
        
        LATERALLY & ANTERIORLY - cheek
        
        MEDIALLY- nasal cavity
      - LARGE MAX. SINUS --> SMALL OSTIUM
        
        LACRIMAL B.
        
        UNCINATE PROCESS OF ETHMOID
        
        PERPENDICULAR PLATE OF PALATINE B.
        
        INFERIOR CONCHA
      - ARTERIAL SUPPLY
        
        ANT. SUP.ALVEOLAR ARTERY
        
        MIDDLE. SUP ALV. A.
        
        POST. SUP. ALV. A.
      - NERVE SUPPLY
        
        ANT. SUP. ALV. N.
        
        MIDDLE SUP. ALV. N.
        
        POST. SUP.ALV. N.
    - - SPHENOETHMOIDAL RECESS- o above superior concha
        o opening of the sphenoid sinus
      - MIDDLE MEATUS - lies beneath the middle concha
        
        receive opening from: maxillary sinus, ant. & middle ethmoidal sinus, frontal sinus
      - SUP. MEATUS - o shortest
        o lies beneath the superior concha
        o opening of the posterior ethmoidal sinus
      - INF. MEATUS - o largest
        o lies beneath the inferior concha
        o opening of the nasolacrimal duct
    - - semilunar hiatus with opening of anterior ethmoidal sinus.
        
        Opening of maxillary sinus
        
        Opening of nasolacrimal DUCT
        
        Opening of posterior ethmoidal sinus
        
        Opening of middle ethmoidal sinus
      - MIDDLE MEATUS - opening for
        [ Frontal sinus, Maxillary sinus, Ant. & middle ethmoidal air cells]
      - INF MEATUS- opening for nasolacrimal duct
  - - - The uncinate process is a small piece of bone and tissue in the sinuses forming an outlet for part of the sinuses. Swollen (inflamed) tissue in this area block drainage of mucus. Removal of uncinate process will restore the mucus drain
- - - - a small pyramidal space situated deeply, below the apex of the orbit
      - BOUNDARY
        
        ant. : post surface of maxilla
        
        post : pterygoid process & GWS
        
        superior: body of sphenoid
        
        inferior : pyramidal process of palatine bone
        
        lateral : infratemporal fossa
        
        medial: perpendicular plate of palatine bone
      - CONNECTION
        
        anterosuperior : orbit via inf. orbital fissure
        
        posterosuperior : middle cranial fossa via f/rotundum & pterygoid canal
        
        medial : nose via sphenopalatine foramen
        
        lateral : infratemporal fossa via pterygomaxillary fissure
      - ANT. VIEW
        
        foramen rotundum, pterygoid canal, inf. orbital fissure, sphenopalatine foramen, nasal sptum
      - CONTENT
        
        3rd part of maxillary a.
        
        Arises from trigeminal ganglion in middle cranial fossa.
        
        Passes forward in lat. wall of cavernous s.
        
        Leaves cranial fossa via foramen rotundum
        
        enter pterygopalatine fossa.
        
        Enters orbit by passing thro’ inferior orbital fissure & continues as the infraorbital nerve.
        
        Appears in face by emerging thro’ infraorbital foramen.
        
        Maxillary n.
        
        Nerve to pterygoid canal
        
        Pterygopalatine ganglion
    - - MAX. N.
        
        MENINGEAL B.- supplies dura mater.
        
        ZYGOMATIC N. - two branches to skin.
        
        INFRAORBITAL N
        
        MIIDLE SUP. ALV. N - Upper premolar teeth.
        
        ANT SUP ALV N. - upper canine & incisor teeth, lateral wall & floor of nose.
        
        POST. SUP. ALV. N - upper molar teeth, gums & cheeks, max sinus.
        
        GANGLIONIC B.- Sensory fibres (no synapsis) from nose, palate and pharynx
        
        Postganglionic parasympathetic fibres to lacrimal gland