Week 15 Anatomy

Overview of lymphatic drainage of head & neck.

  • There are no LN in either scalp or face so all drain to submental, submandibular, parotid, mastoid and occipital LN.
  • Deep LN along IJV–> thoracic duct on left and jugular lymphatic trunk on right –> IJV/brachiocephalic vein.



  • Dura mater
    • Sub dural space – venous sinuses
  • Arachnoid Mater
    • Itself is avascular and doesn’t receive nerve supply
    • Sub arachnoid space – CSF, cerebral arteries
  • Pia Mater – on the brain parenchyma intimately



Ventricular system of the Brain

  • Lateral ventricles to 3rd is via foramen munro.
  • CSF generated in mainly 3rd and 4th ventricle by choroid plexus(ependymal cells) but occurs in all. 400ml/d
  • 3rd –> 4th via cerebral aqueduct
  • 4th–> subarachnoid space via lateral foramen
  • CSF reabsorbed by arachnoid granulations –> veins.



Blood supply of the cerebral hemispheres

  • Internal carotid start at C4–> carotid canal –> cavernous sinus –> middle cerebral and anterior cerebral, opthalmic artery and post communicating
  • Middle cerebral splits in to anterior and posterior
  • Anterior then has anterior communicating branch to link to other side
  • Sublcavian medial to ant scalene–> Vertebral arteries–> transverse foramina–> foramen magnum–> meningeal branch, ant and post spinal arteries, PICA–> basilar artery –> posterior cerebral –> posterior communicating artery.


  • ACA – anteromedial brain
  • MCA – lateral brain
  • PCA – occiput


Under pterigion is the ant division of middle meningeal artery – meeting point of 4 bones – frontal, parietal, temporal and sphenoid.




Venous drainage


  • Dural venous sinuses – between periosteal and dural layers of dura mater.
    • Drain brain and meninges
    • Sigmoid sinus –> internal jugular vein –> jugular foramen, deep to SCM, lateral to common carotid–> brachiocephalic vein
    • Superior sagital sinus
    • Inferior sagittal sinus
    • Straight sinus
    • Occipital sinus
    • Superior and inferior petrosal sinus
  • Cavernous sinus:
    • Lateral to body of sphenoid
    • Receives venous drainage from sup and inf opthamic, middle superficial cerebral, sphenoparietal sinus
    • Internal carotid and CN6 crosses this sinus
    • CN3,4,V1and V2 are all in lateral wall.
    • At risk of infection from facial vein(valveless) can lean to Cavernous sinus thrombosis–> blindness and other CN defects.




Osteology of the skull:

  • frontal bone
  • parietal bone
  • occipital bone
  • temporal bone
  • sphenoid bone
  • zygomatic bone
  • lacrimal bone
  • nasal bone
  • palatine bone
  • ethmoid bone
  • maxilla, mandible




  • Roof – frontal bone, lesser wing of sphenoid
  • Medial – lacrimal, ethmoid, sphenoid, maxilla
  • Lateral – zygomatic, greater wing of sphenoid
  • Floor  – maxilla, palatine, zygomatic
  • Apex – optic foramen
  • Optic canal – optic nerve + opthalmic artery
  • Superior orbital fissure – lacrimal, frontal, trochlear (CN IV), oculomotor (CN III), nasociliary and abducens (CN VI) nerves. It also carries the superior ophthalmic vein.
  • Inferior orbital fissure – inferior opthalmic vein, maxillary nerve(CN5), sympathetic nerves.
  • Supraorbital foramen carries – supraorbital nerve(CNV1)



Control of the pupil / pupillary reflexes (Important).

  • Pupillary dilation – sympathetic
  • Pupillary constriction – CN3, via parasympathetic ciliary ganglion
  • Accomodation – CN3 – via sympathetic
  • Levetor palpabrae superioris – CN3



Facial muscles (overview only).

  • All inervated by facial nerve
  • Occipitofrontalis, orbicularis occuli, orbicularis oris, buccinator, levetor labii superioris



Facial nerve (Important):


  • Supplies muscle of facial expression, platysma, auricular muscles, scalp muscles.
  • Extracranial course- Starts at stylomastoid foramen–> posterior auricular nerve–> parotid gland –> parotid plexus–> 5 branches “Two Zulus Buggered My Cat”
  • Temporal – superior part of orbicularis oculi
  • Zygomatic – inferior part of orbicularis oculi
  • Buccal – external to buccinator to supply it and also supplies upper lip muscles.
  • Marginal mandibular – risorius, lower lip and chin. Passes deep to platysma
  • Cervical – platysma supply.


Sensory nerve supply of face.

  • Spinal cutaneous nerves C2, C3 – posterior scalp behind auricles
  • Great auricular nerve – inferior auricle, parotid region
  • V1 Opthalmic – via superior orbital fissure–> frontal, nasociliary, lacrimal nerves.
  • V2 Maxillary – foramen rotundum–> pterygopalatine fossa –> branch to pterygopalatine ganglion–> inferior orbital fissure –> orbit–> infraorbital grove–> infraorbital nerve. Zygomaticotenporal branch gives supply to lacrimal nerve?
  • V3 Mandibular/has motor component.–> foramen ovale–> mental, auricotemporal and buccal branches. Auricotemporal supplies parotid.

Muscles of mastication – motor root of trigeminal

  • Masseter
  • Temporalis, medial and lateral pterygoids.



Blood supply of face

  • Facial is the main. All are from external carotid. All anastamose with each other and across midline.
  • Facial – EC–> deep to submandibular gland, winds around inferior border of mandible to enter face.
  • Occipital – EC–> passes medial to posterior belly of digastric and mastoid process, accompanies optic nerve in occiput region.
  • Posterior auricular – EC–> deep to parotid and along styloid process.
  • Supraorbital and supratrochlear –> from IC via opthalmic artery.face-vasculature

Blood supply of nose (particularly septum).

5 arteries

  • ant and post ethmoid(opthamlic)
  • sphenopalatine(maxiallary)
  • greater palatine(maxillary)
  • superior labial(facial).




Nasal meatus

  • Superior – posterior ethmoidal sinuses open
  • Middle – frontal sinus via ethmoidal infundibulum, maxillary sinus
  • Inferior  – nasolacrimal duct
  • Sphenoethmoidal recess – superoposterior to superior concha receives sphenoidal sinus.


Venous drainage of facevains-of-face

Valveless and all partnering arteries. Drain to cavernous sinus as well as IJV.

Supratrochlea+supraorbital = angular vein at root of nose

Angular becomes facial at inferior margin of orbit

Facial joins IJV opposite or inferior to level of hyoid.


Layers of scalp.

  • Skin
  • Connective tissue – sub cutaneous layer – dense
  • Loose connective tissue
  • Periosteum


Nerve and blood supply of scalp.

  • Arteries in Sub cutaneous layer with anastamoses. Walls stuck to Connective tissue so cant constrict much therefore cuts BLEED!!!
  • IC – superatrochlear and supraorbital
  • EC – posterior auricular, occipital, superficial temporal


What passes through the various foramina of the skull?

  • Anterior cranial fossa
    • Foreamen cecum – nasal emissary vein
    • Cribriform plate – CN1
    • Anterior and posterior ethmoid foramina – vessels and nerves of same name
  • Middle Cranial fossa
    • Optic canal – CN2, opthalmic artery
    • Superior orbital fissure – V1, CN3, CN4, CN6, sympathetic fibres, opthalmic veins
    • Foramen rotundum – V2
    • Foramen ovale – V3, accessory meningeal artery and vein
    • Faramen spinosum – middle meningeal artery and vein, meningeal branch of V3.
    • Foramen lacerum – Internal carotid and accompanying venous plexus and sympathetic plexus.
    • Groove/hiatus of greater petrosal nerve – greater petrosal nerve, petrosal branch of middle meningeal artery\
    • Stylomastoid foramen – CN7
  • Posterior cranial fossa
    • Foramen magnum – medulla, meninges, CNXI, vertebral arteries, dural veins, ant and post spinal arteries.
    • Jugular foramen – IJV, CN 9,10,11, inferior petrosal and sigmoid sinuses, ascending pharyngeal and occipital arteries.
    • Hypoglossal canal – CN12



  • Innervation – V3 branch auriculotemporal, glossopharyngeal(CN9) for parasymp secretomotor via otic ganglion
  • Sym from external carotid plexus



  • V2 zygomatic branch
  • Parasym stim from CN7(greater petrosal nerve) via pterygopalatine ganglion
  • Sym from internal carotid plexus
  • Empties in inferior nasal meatus.



Muscles of mastication and their attachments


  • Temporalis – floor of temporal fossa and fascia –> tip and medial surface of coronoid process and ant ramus of mandible – elevates jaw
  • Masseter – inferior border and medial surface of maxillary process of zygomatic bone and arch –> angle and lateral surface of ramus of mandible – elevate mandible
  • Lateral pterygoid – two heads, infratemporal and crest of greater wing of sphenoid, lateral pterygoid plate–> joint capsule and articular disc of TMJ, pterygoid fovea on mandible – protract mandible and depresses chin. Unilateral contraction causes jaw to swing to contralateral side.
  • Medial pterygoid – 2 headed, medial part of lateral pterygoid, tuberosity of maxilla –> medial surface of ramus of mandible – acts synergistically with masseter to elevate mandible. Protrusion of jaw.



  • Posterior 1/3 – both sensory and taste by CN9
  • Ant 2/3 taste – CN7
  • Ant 2/3 sensory – CN5 via lingual nerve