SGW - cranial nerves Flashcards
where do the branches of the trigeminal nerve exit the skull?
V1: ophthalmic - SOF into orbit (sensory to cornea)
V2: maxillary - foramen rotundum into ptergopalatine fossa (sensory to soft palate)
V3: mandibular - foramen ovale into infratemporal fossa (sensory + motor)
which cranial nerves pass into orbit?
CN II (optic canal), III, IV, Va, VI (SOF) (cavernous sinus has Vb as well)
where is the pituitary gland found?
within hypophyseal fossa (deepest part of sella turcica within middle cranial fossa)
which anatomical structures lies in close proximity to the pituitary gland?
superior: hypothalamus
anterosuperior: optic chiasm (of optic nerve) just above pituitary gland, in front of infundibulum (pituitary stalk)
what is the optic chiasm?
area where a proportion of the optic nerves from either retina cross over to contralateral (opposite) side before continuing posteriorly as the optic tracts
optic nerve –> optic chiasm –> optic tract
what can pathology affecting the pituitary gland cause? example?
e.g. pituitary adenoma
can cause visual symptoms due to close anatomical relationship with optic chiasm
what is the cavernous sinus?
a type of dural venous sinus
what is a dural venous sinus?
a ‘space’ created when the INNER most layer of the dura (meningeal layer) leaves the periosteal layer (adhered to bone) of the dura
creating a endothelial lined channel between the 2
what are the walls of cavernous sinus?
folds of dura
how many cavernous sinuses are there?
2: one on either side of the sella turcica
what forms the floor of the cavernous sinuses?
sphenoid and part of temporal bone
where is the pituitary gland in relation to the cavernous sinus?
hangs between the 2 cavernous sinus by its stalk
what is the space within cavernous sinus split up by? what does it contain?
multiple fibrous sepa
containing a large plexus of veins
where does the venous plexus of cavernous sinus receive its veinous drainage from?
anteriorly: superior and inferior orbital veins
posterior: receives some minor venous sinuses draining the brain
what are the 2 cavernous sinuses joined by?
joined around and beneath the pituitary gland via intercavernous sinuses