Head Flashcards
Anterior cranial fossa
Formed by frontal bone, ethmoid, sphenoid bone
Posterior - lesser wing of sphenoid/anterior clinoid process
Content of anterior cranial fossa
Frontal lobe
Olfactory bulb/tract
Crista galli, cribiform plate
Middle cranial fossa
Sphenoid bone - lesser wing
temporal - petrous part
parietal bone
Content of middle cranial fossa
Temporal lobe
Sella turcica - pituitary gland
optic nerve/chiasm, cavernous sinus (CN3, 4, 5i, 6), trigeminal ganglion
Foramina - Optic canal, superior orbital fissure, rotundum (CN5ii), ovale (CN5iii, AMA), spinosum (MMA), lacerum, carotid canal (deep petrosal nerve)
Hiatus for greater/lesser petrosal nerve
Posterior cranial fossa
Sphenoid
Temporal - squamous part,
parietal
Occipital bone
Content of posterior fossa
Cerebellum
Brainstem - midbrain, pons, medulla
foramen - internal acoustic meatus (CN7, 8, labyrinthine), jugular (CN9, 10, 11) , hypoglossal (CN12), magnum
Infratemporal fossa
Deep to the masseter muscle
Lateral - ramus of mandible
Medial - lateral pterygoid plate of the sphenoid
Anterior - posterior surface of maxilla
Posterior - carotid sheath
inferior - medial pterygoid muscle
superior - skull base, sphenoid (foramen ovale/spinosum)
Content of infratemporal fossa
Muscles - lateral/medial pterygoid
Nerve - CN5iii, Chorda tympani (CN7), otic ganglion (parasympathetic nerve)
Artery - maxillary
Pterygopalatine fossa
Anterior - posterior wall of maxillary sinus
posterior - pterygoid process of sphenoid bone
inferior - palatine bone and palatine canal
superior - inferior orbital fissure
lateral - pterygomaxillary fissure
medial - perpendicular plane of the palatine bone
Content of pterygopalatine fossa
CN5ii (infraorbital fissure) pterygopalatine ganglion, CN7 greater petrosal nerve maxillary artery 7 foramina rotundum inferior orbital fissure pterygomaxillary fissure pterygoid canal pharyngeal canal greater palatine canal sphenopalatine foramen
Pterion
H shaped area where 4 bone meets
Frontal, parietal, temporal and sphenoid
it is the weakest part of skull and MMA runs along it
Orbit
Frontal, maxillary, ethmoid, sphenoid, zygomatic, lacrimal, palatine
Superior and inferior orbital fissure
Extraocular muscles
Levator palpebrae superioris
Rectus x4
Oblique x2
Why does infection spreads to skull
connection of venous drainage from facial vein. ophthalmic vein to cavernous sinus
Bones in the ear
Malleus, incus, stapes
Stapes has stapedius muscle
Malleus has Tensor Tympani
Cranial nerves
1 - Olfactroy 2 - optic 3 - oculomotor Midbrain 4 - trochlear Pons 5 - trigeminal 6 - abducens 7 - facial 8 - vestibulocochlear Medulla 9 - glossopharyngeal 10 - vagus 11 - accessory nerve 12 - hypoglossal
Olfactory nerve
Though Cribiform plate
sense of smell
Optic nerve
Vision Covered by dura Nerve to chiasm then to tract then to lateral geniculate nucleus then radiation (lower optic radiation = Meyer's loop)
Oculomotor nerve
Supplies the medial, superior and inferior recti, inferior oblique, levator palpebrae superioris
Parasympathetic nerve supply sphincter pupillae and ciliary muscle (ciliary ganglion)
Travels through the carvenous sinus, medial aspect
Within the sinus, deep petrosal nerve joins in
Trochlear nerve
Supplies the superior oblique muscle
Supplies contralateral as it crosses before exiting the midbrain
Trigeminal nerve
3 main branches - V1 ophthalmic, V2 maxillary V3 mandibular
V1 - superior orbital fissue
V2 - foramen rotundum
V3 - foramen ovale
Mainly sensory but mandibular has motor function (muscles of mastication)
Parasympathetic supply from pterygopalatine ganglion (facial nerve)
Abducens nerve
supplies the lateral rectus
Most lateral in cavernous sinus
Facial nerve
Contains parasympathetic fibres
3 intracranial branches
Chorda tympani, stapedius, greater petrosal nerve (pterygopalatine ganglion)
3 extracranial branches
posterior auricular, stylohyoid, digastric
5 extracranial terminal branches
Temporal, zygomatic, buccal, marginal mandibular, cervical
Pons (initially 2 roots), IAM, Facial canal, Stylomastoid foramen, parotid gland
Vestibulocochlear nerve
hearing and balance
arises from cerebello pontine angle to IAM
Glossopharyngeal nerve
taste, motor function of stylopharyngeus
parasympathetic nerves to parotid
sensation to middle ear, oropharynx
Medulla, jugular foramen
vagus
sensory - EAM, larynx
motor - pharynx, soft palate, larynx, palatoglossus
parasympathetic nerve
medulla, jugular foramen, carotid sheath
Gives off Superior & recurrent laryngeal nerve
Right vagus - anterior to SCA, posterior to SC joint
Left vagus - inferiorly between common carotid and SCA
SLN - cricothyroid
RLN - all others in larynx, RIGHT hooks underneath SCA, LEFT hooks underneath arch of aorta
Accessory nerve
Motor - Sternocleidomastoid, trapezius
Spinal part - originates at C1-C6, then enters through foramen magnum then passes through jugular foramen
Sternocleidomastoid
origin - mastoid process
insertion - 2 heads - manubrim, clavicle
innervation - CN11
action - rotation of head
Trapezius
origin - occipital protuberance/nuchal ligament
insertion - acromion, clavicle, spine of scapula
innervation - CN11
action - elevation of scapula
Pathway of spinal accessory nerve
upper third posterior border of SCM to lower third of anterior border of trapezius
Hypoglossal nerve
Motor - extrinsic and intrinsic muscles to the tongue
genioglossus, hyoglossus, styloglossus
medulla - hypoglossal canal
Joins the C1/C2 nerve root plexus
Extrinsic muscles of the tongue
Genioglossus
Hyoglossus
Styloglossus
Palatoglossus (innervated by vagus nerve)
Muscles of mastication
temporalis
Masseter
Lateral/Medial pterygoid
1st pharyngeal arch
temporalis
origin - temporal fossa
insertion - Coronoid process of mandible
innervation - CN5iii
masseter
origin - maxillary process of zygomatic bone, zygomatic arch of temporal bone
insertion - ramus of mandible
innervation - CN5iii
lateral pterygoid
origin - greater wing of sphenoid and lateral pterygoid plate of sphenoid
insertion - neck of mandible
innervation - CN5iii
medial pterygoid
origin - greater wing of sphenoid and lateral pterygoid plate of sphenoid
insertion - ramus of mandible
innervation - CN5iii
Temporomandibular joint
Articulation between 3 surface - mandibular fossa, articular tubercle and head of mandible
Separated by articular disk
3 Ligaments - lateral, stylomandibular, sphenomandibular
Submandibular gland
Allocated in submandibular triangle
anterior and posterior belly of digastric muscle and mandible
In relations to mylohyoid muscles
Hypoglossal (deep), lingual, marginal mandibular nerve
Sublingual gland
almond shaped
under the tongue, laterally on mandible, medially by genioglossus muscle
around lingual frenulum
Parotid gland
Superior & deep gland separated by facial nerve, ECA Superior - zygomatic arch inferior - inferior border of mandible posterior - external ear/SCM anterior - masseter Stensen duct - 2nd upper molar Sensory nerve - CN9, otic ganglion
Parasympathetic nerve in head
CN3 - ciliary ganglion
CN7 - greater petrosal nerve = pterygopalatine ganglion
CN7 - Chorda tympani = submandibular ganglion
CN9 - otic ganglion
CN10 - rest of body
Sympathetic nerve
Sympathetic nerve - T1-T6 - sympathetic chain - cervical ganglia (superior/middle/inferior)
Superior cervical ganglion - C1-C4 - ICN, ECN, nerve to pharyngeal plexus, superior cardiac branch, nerves to CN2, 3, 4, 6, 9
External Carotid artery
Bifurcates from CCA at C4 Superior thyroid Ascending pharyngeal Lingual Posterior auricular Occipital Facial Maxillary Superficial temporal
Internal carotid artery
Bifurcates from CCA at C4 no extracranial branch enters via carotid canal Gives off ACA, ophthalmic artery, PCom, MCA Forms the Circle of Willis
Vertebral artery
Arises from the Subclavian artery, passes through foramen transversarium of C6
Gives off anterior & posterior spinal arteries
Enters via foramen magnum
Gives off PICA
Forms the basilar artery
Basilar artery
gives off AICA, pontine arteries, Superior cerebellar artery, labyrinthine artery
Forms Circle of Willis
Dural sinus system
Superior sagittal sinus Inferior sagittal - straight sinus Confluence of sinus - Transverse sinus Carvernoous sinus - Superior/Inferior petrosal sinus Sigmoid sinus IJV
CSF drainage system
Lateral - foramen of Monro - third - cerebral aqueduct - fourth ventricle
Cisterns - bath of CSF
Produced by choroid plexus
Drained via subarachnoid cisterns/granulation
Ascending tract
Dorsal column
Spinothalamic
Spinocerebellar
Dorsal column
Medial lemniscal pathway
Fasciculus cuneatus - upper limb
Fasciculus gracilis - lower limb
Decussate in medulla (2nd order neurones)
Spinothalamic tract
Anterior Crude touch & pressure
Lateral - pain and temperature
Decussate at level of spinal cord
Spinocerebellar tract
Proprioception
anterior and Posterior cerebellar - lower limbs
rostral and cunecerebellar - upper limbs
Descending tract
corticospinal tract - cortex - internal capsule - crus cerebri
Corticobulbar - CN7 and CN12 contralateral innervation
Pyrimidal - medullary pyramids
Extrapyrimidal - involuntary movement - vestibulospinal/reticulospinal tract
layers of SCALP
Skin Dense Connective tissue epicranial Aponeurosis Loose connective tissue Periosteum
Pituitary gland
On sella turcica
Anterior - FSH/LH, GH, ACTH, TSH,
Posteriror ADH, Oxytocin
