Case 3 anatomy Flashcards
what does the lateral fissure do? another name?
Slyvian fissure - separates parietal and temporal lobes
what does the calcarine sulcus do?
divides the visual cortex into two - lies between the gyri of the primary visual cortex
what are the fibres called the connect the two hemispheres?
COMMISSURAL fibres
what do the superior and inferior longitudinal fasciculi connect?
- The superior longitudinal fasciculus connects the frontal lobe with the occipital lobe
- The inferior longitudinal fasciculus connects the occipital lobe with the temporal lobe
what is an example of commisural fibres (not corpus callosum) and what does it connect?
anterior commissure
connects the inferior and middle temporal gyri and olfactory regions of each side
describe the most imporant route of the projection fibres
- Corona radiata = fibre bundle that projects to and from the cortex
- Fibres in this bundle converge to form the internal capsule (separates the caudate nucleus and the thalamus from the putamen and the globus pallidus) which passes towards the midbrain
- In the midbrain the fibres of the internal capsule form the crus cerebri (anterior portion of the cerebral peduncle which contains the motor tracts, travelling from the thalamus to the pons and spine)
what does the internal capsule consist of?
anterior limb, posterior limb, genu and retrolenticular part
what does each part of the internal capsule contain?
- Anterior limb – contains connections between the thalamus and prefrontal cortex and frontopontine fibres that connect the frontal cortex to the pontine nuclei (nuclei of the pons involved in motor activity – located in the ventral pons)
- Posterior limb – contains corticobulbar (upper motor neurons of the cranial nerves – bulbar becomes goes to medulla (‘bulbar’)) and corticospinal fibres and also thalamocortical fibres that pass between the ventral posterior nucleus of the thalamus and the primary sensory cortex
- Retrolenticular part – contains fibres that pass from the lateral geniculate nucleus (of thalamus) to the visual cortex and from the medial geniculate nucleus (of thalamus) to the auditory cortex (retrolenticular part is the bit at end of the posterior limb)
how many layers in the cortex? what according to?
- Cerebral cortex consists of neuronal cell bodies, dendrites and axons
- There are 6 layers of cortex according to the arrangement of these components
- The arrangement of these layers differs in different regions of the brain
- Brodman’s numbering system
the primary somatosensory area receives fibres conveying information about what?
course touch and pressure, fine touch and proprioception, pain and temperature
how is the primary somatosensory cortex arranged?
somatotopically
- using sensory homunculus - head first, then arm, then leg (going laterally to medially)
- up the face, up the arm, down the leg
where is the primary auditory cortex?
superior temporal gyrus
where is the sensory cortex for smell?
spread over number of areas:
- uncus
- entorhinal area
- limen insula
how is the primary motor cortex arranged?
- somatotopically
- motor humunculus - same arrangement as sensory basically
what is the frontal eye field? what does it do?
part of the DLPFC
plays an important role in the control of visual attention and eye movements
what is the supplementary (secondary) motor area?
contributes to control of movement, important in planning complex movement (contralateral side)
in the midline just in front of primary motor cortex
premotor cortex is lateral to SMA
what is the auditory association area?
Wernicke’s area - interpretation and understanding of spoken words
which muscles are involved in speech and therefore are coordinated by broca’s area?
the muscles of respiration, larynx, pharynx, tongue, palate, lips and the jaw
what does the arcuate fasciculus form part of?
the superior longitudinal fasciculus
where are blind spots?
15* from central line
what happens to some fibres arising from the inferior colliculus?
• Some fibres arising from the inferior colliculus project directly to the motor nuclei in the brain stem or spinal cord – these fibres initiate auditory reflexes involving muscles of the head, neck and trunk
does the palatine bone contribute to the orbit? does the temporal?
yes - inferior wall - small and at the back
no
where does the optic canal lie?
in the lesser wing of sphenoid
what are the anterior and posterior ethmoidal foramina?
small foramina located on the medial wall of the orbit within the ethmoid bone – they communicate with the lateral wall of the nasal cavity
(they’re where ethmoidal bone meets frontal bone)
what does the lacrimal groove lead to?
nasolacrimal canal -> inferior meatus of nasal cavity
inferior orbital fissure - what between? what communicate with?
- slit-like opening located posteriorly between the maxilla and the greater wing of sphenoid
- it communicates with the pterygopalatine fossa
what do the infraorbital and supraorbital nerves pass through?
- Infraorbital nerve passes through the inferior orbital fissure
- Supraorbital nerve passes through the supraorbital notch
what lines the orbit?
the periorbita - which is periosteum
where does the fascial sheath extend from and to? what does it do?
- extends from optic nerve to the corneoscleral junction
- separates the eyeball from the surrounding periorbital fat
where and what are the medial and lateral check ligaments?
- The medial and lateral check ligaments are triangular expansions of the sheaths of the medial and lateral rectus muscles
- The medial check ligament is attached to the lacrimal bone – this limits abduction
- The lateral check ligament is attached to the zygomatic bone – this limits adduction
what forms the suspensory ligament?
check ligaments blend with the fascia of the inferior oblique and inferior rectus muscles forming a sling to suspend the eyeball
where is the inferior check ligament? what does it do?
- An inferior check ligament arises from the inferior rectus muscle
- The inferior check ligament retracts the inferior eyelid when the gaze is directed downwards
what is enopthalmos?
when eyeballs retracted into orbit
what is the muscle on the top eyelid?
superior tarsal muscle (assists levator palpebae superioris in elevating eyelid)
what is the superior eyelid called?
superior tarsus
what are the two conjuctiva called?
palpebral conjuctiva and bulbar conjuctiva
what are the two glands on eyelid?
- Tarsal glands (at rim of eyelids, supplies meibum (oil substance that prevents evaporation of the eye’s tear film) and to prevent the eyelids from sticking together when closed)
- Ciliary glands (modified sweat glands between the eyelashes – secrete acidic sweat to kill bacteria)
what does the medial palpebral ligament do?
connects the tarsi to the medial aspect of the orbit and provides muscle attachment for the orbicularis oculi muscle
what’s in the middle layer of the eyeball?
the choroid, ciliary body (includes ciliary muscle, which controls shape of lens, and ciliary epithelium, which produces the aqueous humour) and iris
what provides the external surface of the cornea with nutrients and oxygen (as it is avascular)?
lacrimal fluid & aqueous humour
what are the ciliary processes?
folds on the internal surface of the ciliary body, they secrete aqueous humour (they are folds on the inner ciliary epithelium)
what separates the eyeball into anterior and posterior cavities?
lens and suspensory ligaments
what divides the anterior cavity?
iris and pupil
what does the aqueous humour drain into?
the canal of Schlemm where it is removed by the limbal plexus
what does the posterior cavity contain?
contains the vitreous humour, a watery fluid (vitreous humour) enclosed in a transparent gel (vitreous body)
what is the junction between the optic and pigmented parts of the retina called? (junction between retina and ciliary body)
ora serrata
what’s the corneal limbus?
the angle at the junction of the cornea and sclera
what’s the conjuctival sac?
space bounded by the palpebral and bulbar conjuctiva
where does the superior oblique extend from? where is the trochlear?
body of sphenoid (medial to where levator palpebrae superioris originates)
trochlear on medial wall
where does the levator palpebrae superioris originate?
lesser wing of sphenoid
describe the lacrimal apparatus
- The lacrimal glands (just below eyebrow) secrete lacrimal fluid
- The fluid is passed along the excretory ducts
- The fluid enters the superior conjunctival sac (where the bulbar and palpebral conjunctiva meet superiorly)
- Blinking pushes a film of fluid over the cornea
- Fluid accumulates in the lacrimal lake at the medial aspect of the eye
- Drains by capillary action through the lacrimal puncta and lacrimal canaliculi into the lacrimal sac
- Drains via the nasolacrimal duct into the inferior nasal meatus of the nasal cavity
what provides innervation to the lacrimal gland?
parasympathetic innervation by the facial nerve
what sensory nerves are associated with the orbit?
- Optic – CN II = sensory nerve of vision
- Lacrimal – branch of CNV1 (ophthalmic nerve) = general sensation to lateral part of upper eyelid
- Frontal – branch of CNV1, divides into supraorbital and supratrochlear = general sensation to the skin of forehead and frontal nasal sinus
- Nasociliary – branch of CNV1 = general sensation to the ethmoid and sphenoid paranasal sinuses, nasal cavity and skin of medial part of upper eyelid – it also transmits sympathetic innervation to the dilator pupillae muscle
which motor nerves are associated with the orbit?
- Trochlear – CN IV = motor to superior oblique muscle
- Oculomotor – CN III = motor to superior, medial & inferior recti muscles and levator palpebrae superioris, parasympathetic to sphincter pupillae
- Abducens – CN VI = motor to lateral rectus muscle
- Nasociliary – branch of CNV1 = general sensation to the ethmoid and sphenoid paranasal sinuses, nasal cavity and skin of medial part of upper eyelid – it also transmits sympathetic innervation to the dilator pupillae muscle
where is the ciliary ganglion located?
in the orbit
how does the ophthalmic artery enter the orbit? what are its branches?
through optic canal
central artery of the retina, muscular branches, ciliary, lacrimal, supratrochlear and supraorbital arteries
what are the veins of the orbit? what do they communicate with? what do they pass through? what do they both drain into?
- The superior ophthalmic vein communicates with the facial vein
- The inferior ophthalmic vein communicates with the pterygoid venous plexus
- Both veins pass through the superior orbital fissure
- Ophthalmic veins drain into the cavernous sinus
what is the bony part of the septum composed of?
the ethmoid and vomer bones
what does the cartilaginous part of the nose consist of?
- septal cartilage
- pair of lateral cartilages
- pair of alar cartilages
which bones contribute to the nasal cavity?
ethmoid, sphenoid, nasal, maxilla, frontal, vomer, inferior nasal conchae, palatine and lacrimal
(no mandible or zygomatic)
what forms the roof of the nasal cavity?
- Cribriform plate of ethmoid
- Body of sphenoid
- Nasal bone
- Nasal part of frontal bone
(4)
what forms the medial wall of the nasal cavity?
- Vomer
- Perpendicular plate of ethmoid
(2)
what forms the lateral wall of the nasal cavity?
- Labyrinth of ethmoid (superior and middle nasal conchae)
- Lacrimal
- Inferior nasal choncae
- Medial pterygoid plate of sphenoid
- Medial surface of maxilla
- Vertical plate of palatine
(6)
what forms the floor of the nasal cavity?
- Palatine process of maxilla
- Horizontal plate of palatine
(2)
what is formed about the superior concha?
sphenoethmoidal recess
what is the nasal cavity lined by?
pseudostratified ciliated columnar epithelium with goblet cells
where is the olfactory mucosa located?
above the superior nasal conchae
it lines the roof of the nasal cavity and superior nasal conchae and it’s structurally modified to detect odorants
what is the arterial supply of the nose?
- anterior and posterior ethmoidal
- sphenopalatine
- greater palatine
- superior labial
- internal carotid -> ophthalmic -> ethmoidal arteries
- external carotid -> maxillary -> sphenopalatine and greater palatine arteries
- external carotid -> facial -> superior labial
which regions of the nose are supplied by which vessels?
- Chonchae and meatuses – sphenopalatine artery
- Lower part of septum – superior labial, greater palatine and sphenopalatine arteries
- Roof and upper aspect of lateral wall and septum – anterior and posterior ethmoidal arteries
where is a common site of nose bleed? what is the medical name? why?
- lower anterior part of septum
- epistaxis
- site rich in capillaries where all the five vessels supplying the nasal septum anastomose - Kiesselbach’s plexus
what is the venous drainage of the nose?
- sphenopalatine veins
- facial veins
- ophthalmic veins
what is the innervation of the nose?
- The trigeminal nerve supplies general sensation to the nasal cavity
- The maxillary division of the trigeminal nerve supplies the postero-inferior part of the nose
- The ophthalmic division of the trigeminal nerve supplies the antero-superior part of the nose
- The facial nerve provides parasympathetic innervation to the nasal glands
what are the different paranasal sinuses?
- Frontal
- Sphenoid (more posterior in head – just below pituitary gland)
- Ethmoid (between eyes and nose)
- Maxillary
what are the paranasal sinuses lined with?
pseudostratified columnar epithelium
where do the paranasal sinuses drain into?
- Frontal, maxillary and anterior & middle ethmoidal drain into the middle meatus
- Sphenoid sinus drains into the sphenoethmoidal recess
- Posterior ethmoidal drains into the superior meatus
what is the innervation of the hard palate?
the greater palatine nerve provides sensory innervation to much of the hard palate – the nasopalatine nerve assists by innervating the anterior aspect
what is the oral surface of the hard palate covered by?
keratinised stratified squamous epithelium
what passes through the incisive foramen?
nasopalatine nerve
what passes through the greater and lesser palatine foramen?
- Greater palatine nerve and artery pass through the greater palatine foramen
- Lesser palatine nerve and artery pass through the lesser palatine foramen
what does the soft palate do?
its elevated during swallowing to prevent food and fluids from entering the nasopharynx
what does the soft palate consist of?
- muscles
- aponeurotic sheet
- covering mucosa
what are the muscles of the soft palate?
- tensor veli palatini
- levator veli palatini
- palatopharyngeus
- palatoglossus
- muscularis uvulae
tensor veli palatini
- origin - medial pytergoid plate, spine of sphenoid, eustachian tube
- insertion - palatine aponeurosis
- action - tenses soft palate and opens eustachian tube
levator veli palatini
- origin - eustachian tube and petrous part of temporal bone
- palatine aponeurosis
- action - elevates soft palate (and opens eustachian tube?)
(attaches posterior to tensor veli palatini)
palatopharyngeus
- origin - palatine aponeurosis
- insertion - lateral wall of pharynx
- action - elevates pharynx
palatoglossus
- origin - palatine aponeurosis
- insertion - side of tongue
- action - elevates posterior part of tongue and narrows oropharyngeal isthmus
muscularis uvulae
- origin - posterior border of hard palate
- insertion - mucous membrane of uvula
- action - elevates uvula
what is motor innervation of the soft palate?
- pharyngeal plexus all muscles except…
- tensori veli palatini - mandibular nerve
what is sensory innervation of the soft palate?
- nasopalatine nerve
- greater and lesser palatine nerves
- these are all branches of the maxillary division
- glossopharygneal nerve also contributes
