Anatomy Flashcards
what are the 3 parts of the brain stem?
midbrain, pons and medulla
what makes up the diencephalon
thalamus and hypothalamus
whats the purpose of the diencephalon
the central core of cerebrum, has connections to the right and left cerebral hemispheres and the midbrain
what connects the hypothalamus and the pituitary
the infundibulum
what are the 3 fossae of the skull
anterior, middle and posterior
boundaries of the anterior fossa
frontal bone and lesser wing of the sphenoid bone
what are the boundaries of the middle fossa of the skull
lesser wings of the sphenoid and the peatrus parts of the temporal bone
boundaries of the posterior fossa of the skull
peatrus parts of the temporal bone and the occipital bone
where is the pituitary fossa located
in the middle part of the sphenoid bone within the sella turcica
what lies inferior to the pituitary gland
optic chasm
what makes up the optic chasm
right and left optic nerves (CNII)
what passes posteriorly from the optic chiasm
the optic tracts
where do the neurones from the optic tract synapse
the thalamus
from the thalamus where do the neurones pass to
visual cortex in the occipital lobe through the optic radiation
what is the roof of the nasal cavity
cribriform plate of the ethmoid bone
what forms the inferior part of the nasal septum
the vomer bone
what forms the superior part of the nasal septum
the perpendicular plate of the ethmoid bone
locations of the 4 paranasal sinuses
frontal bone, maxillae, ethmoid bone, sphenoid bone
what does the pituitary gland lie immediately inferior to
the optic chiasm
what is the optic chiasm formed from
the right and left optic nerves
the right optic canal lies in what bone
the sphenoid bone
early clinical effect of a pituitary tumour on the visual pathway
disrupts the transmission of APs from the nasal retina bilaterally, patients loses ability to see structures in the temporal side of the field = bitemporal hemianopia
describe the transcranial approach to the pituitary fossa
sub frontal, enter under the frontal lobe
describe the transsphenoidal approach to the pituitary fossa
via the nasal cavities and sphenoid sinus
what is dura matter?
adheres to all the internal aspects of the bones of the cranial vault
what is the tentorium cerebelli?
a tough sheet of dura matter which forms a tent over the cerebellum. lies within the posterior cranial fossa but has a central gap for the brain stem to pass through
what is the diaphragm sellae?
a tough sheet of dura matter forming a roof over the pituitary fossa
what are the dural venous sinuses?
venous channels within the dura matter that drain most of the venous blood from the canal cavity into the internal jugular being
what is the purpose of the anterior inter cavernous sinus?
connects the right and left cavernous sinuses, anterior to the pituitary
what is the pituitary gland surrounded by?
cavernous and inter cavernous sinuses
where does the internal carotid pass?
through the cavernous sinuses
where do the dural venous sinuses drain, at what location?
into the internal jugular veins at the jugular foraminae in the floor of the posterior cranial fossa
function of the optic chiasm
conducts APs bilaterally from the nasal rentinae
consequence of injury to the OPTIC CHIASM
bitemporal hemianopia
function of the oculomotor nerve
motor to muscles that move the globe, parasympathetic to the sphincter muscle of the iris
consequence of injury to the oculomotor nerve
problems with eye movements dilated pupil
function of the trochlear nerve
motor to one muscle that moves the globe
consequence of injury to the trochlear nerve
problems with specific eye movement
function of the trigeminal nerve
sensory to most of the face, motor to the muscles of mastication
consequence of injury to the trigeminal nerve
sensory symptoms on the face itself, difficulty chewing
function of the adbucent nerve
motor to one muscle that move the globe
consequence of injury to the abducent nerve
problems with specific eye movement
function of the cavernous sinus
drains venous blood
consequence of injury to the cavernous sinus
venous haemorrhage
function of the internal carotid
supplies arterial blood to the brain and the orbit
consequence of injury to the internal carotid
catastrophic haemorrhage
function of the dura matter
protects the cranial cavity
consequence of injury to the dura matter
CSF leak
what is the connecting band of the thyroid called
isthmus
what surface of the thyroid are the parathyroids found
posterior surfaces
what is the anatomical variant of the thyroid gland?
an extra lobe, the pyramidal lobe
how does the thyroid begin?
a midline epithelial proliferation at the junction between the anterior 2/3rds and the posterior 1/3rd of the tongue.
embryologically, once the gland is formed, then what happens?
migrates inferiorly whilst remaining attached to the tongue via the thyroglossal duct
when does the gland reach its final destination
in the 7th week of development
where are the platysma muscles
deep to the skin within the superficial fascia of the neck
what group of muscles do the platysma muscles belong
muscles of facial expression
what is the nerve supply to the platysma muscles
the facial nerve (CN VII)
what is the blood supply to the thyroid
right inferior thyroid artery, left superior thyroid artery
describe the venous drainage from the thyroid
right superior, middle and inferior thyroid veins
what is the lymphatic drainage of the right side of the thyroid
right superior and inferior cervical nodes -> right lymphatic duct -> right venous angle
what is the lymphatic drainage of the left side of the thyroid
left superior and inferior cervical notes -> thoracic duct -> left venous angle
the vagus nerves CN X, connect to what part of the brain
medulla
the vagus nerves descend through the neck enclosed within what?
the carotid sheath
the vagus nerves give two somatic branches to the larynx, what are they?
superior laryngeal nerve, right recurrent laryngeal nerve
unilateral injury of the recurrent nerve would cause
hoarseness or weakness of the voice and weak cough
bilateral injury of the recurrent nerve causes
aphonia, inability to close the rima glottidis
