Anatomy Flashcards
what are the three main parts of the brain?
cerebrum
cerebellum
brainstem
what are the three parts of the brainstem?
midbrain
pons
medulla oblongata
the spinal cord is the inferior continuation of what?
the brainstem (medulla oblongata)
the hypothalmus and the thalmus form what?
diencephalon
what does the diencephalon form?
the central core of the cerebrum
the diencephalon has connections to what parts of the brain?
right and left cerebral hemispheres
the midbrain
the hypothalmus is connecteed to the pituitary by what?
infundibulum or pituitary stalk
what is another anatomical term for the pituiatary?
hypophysis
how is the pituitary divided?
anterior and posterior pituitary
the pituitary is a midline structure found in which bone structure?
pituitary fossa of the sphenoid bone
the pituitary fossa lies within what?
the sella turcica
the pituitary gland lies immediatley inferior to what structure?
the optic chiasm
the optic chiasm is formed from what?
the right and left optic nerves (CNs II)
which cranial bone are the optic canals found in?
the sphenoid bone
the right and left optic tracts pass anteriorly/posteriorly from the optic chiasm
posteriorly
after passing throughthe optic chiasm where do axons from the optic tracts synapse?
the thalamus
after synapsing in the thalamus the next axons pass to the visual cortex via what?
optic radiation
the visual cortex is found where?
the occipital lobe
each retina is divided into what?
nasal and temporal retina
the retina contains what
photoreceptors: rods and cones
light from the temporal side of the visual fieid enters the nasal/temporal retina?
nasal
pituitary tumour causing midline compression of the optic chiasm would result in what?
disruption in transmission of action potentials from the nasal retina bilaterally
disruption of the transmission from the nasal retina would result in what
patient would loose the ability to see structures in the temporal side of the visual field
loss of vision in the temporal side of the visual field bilaterally is called what?
bitemporal hemianopia
what are the two surgical approaches to the pituitary?
transcranial approach
transsphenoidal approach
describe the transcranial surgical approach
subfrontal- under the frontal lobe
describe the transsphenoidal surgical approach
via nasal cavities and sphenoid sinus
what forms the roof of the nasal cavity?
the cribiform plate of the ethmoid bone
what forms the superior part of the nasal septum?
perpindicular plate of the ethmloid bone
what forms teh inferior part of the nasal septum?
the vomer
what are the nasal conchae also termed
turbinates
how are the nasal conchae of the lateral wall of teh nasal cavities divided?
superior nasal concha (of the ethmoid bone)
middle nasal concha (of the ethmoid bone)
inferior nasal concha
describe the paranasal sinuses
air filled spaces within the bones surroundign the nasal cavities
what lines the paranasal sinuses?
mucous secreting respiratory mucosa
what is the function of the paranasal sinuses?
make mucous and drain it into nasal cavities through ostia (bony holes)
reduce weight of skull
add resonance to voice
what are the four groups of paranasal sinuses?
frontal bone- frontal sinuses
maxillae- maxillary sinuses
ethmoid bone- ethmoidal air cells
sphenoid bone- sphenoid sinuses
the ethmoid air cells are further split into how many groups?
three groups between the nasal cavity and the orbit
the trasnsphenoidal transnasal surgical approach to the pituitary requires surgical fracture of which structures?
nasal septum
floor of the septum
roof of the sphenoid sinuses
in more complicated cases which Le Fort fracture approach to the nasal cavities provides better surgical access?
Le Fort 1 down- fracture approach
what lines the entirety of the cranial cavity internally?
dura mater
what is the name given to the tough sheet of dura mater stretched over the cerebellum within the posterioir cranial fossa?
the tentorium cerebelli
what is the name given to the tough sheet of dura mater that forms a roof over the pitutary fossa?
the diaphragm sellae
what within the dura mater drains blood from the cranial cavity?
dural venous sinuses
where do the dural venous sinuses drain into?
internal jugular veins at the jugular foraminae
Note: sinuses not histologically veins but function like them
where inthe cranial cavity are the jugular foraminae found?
the floor of the posterior cranial fossa
what connects the right and left cavernous sinuses to the pituitary?
the anterior intercavernous sinus
the pituitary gland is surrounded by what sinuses?
cavernous
intercavernous
which blood vessels pass through the cavernous sinuses?
the internal carotid arteries
the opthalmic artery is a branch of which major artery?
internal carotid artery
through what does the opthalmic artery enter the orbit?
the optic canal
the internal carotid artery enters the carotid canal in which cranial bone?
temporal bone
what is the function of the optic chiasm?
conducts APs bilaterally from the nasal retinae
damage to the optic chiasm during pituitary gland surgery can result in what functional deficit?
bitemporal hemianopia
what is the function of the oculomotor nerve?
motor to muscles that move the eyeball (globe)
parasympathetic to the sphincter of the iris
damage to the oculomotor nerve during pituitary gland sugery results in what deficit?
problems with several eye movements
dilated pupil
what is the function of the trochlear nerve?
motor to one muscle that moves the globe
damage to the trochlear nerve during piruitary gland sugery can result in what deficit?
probelmes with specific eye movements
what is the function of the trigeminal nerve?
sensory to most of the face
motor to the muscles of mastication
damage to the trigeminal nerve during pituitary gland surgery can result in which deficit?
sensory symptoms on face
difficulty chewing
what is the function of the abducent nerve?
motor to one muscle that moves the globe
damage to the abducent nerve during pituitary surgery can result in what defecit?
problems with specific eye movement
what is the function of the cavernous sinus?
drains venous blood
damage to the cavernous sinus during pituitary surgery can result in what deficit?
venous haemorrhage
what is the function of the internal carotid artery?
supplies arterial blood to brain and orbit
damage to the internal carotid artery during pituitary surgery can result in what?
catastrophic haemorrhage
what is the function of dura mater?
to protect the structures of the cranial cavity
damage to the dura mater during pituitary gland surgery can result in what?
cerebrospinal fluid (CSF) leak
what structures in the anterior neck is the thyroid closely related to?
larynx
tachea
what does the thyroid gland usually consist of?
2 lateral lobes (R&L)
isthmus
where do the lobes of the thyroid attach?
to the lateral aspects of the thyroid and cricoid cartilages and to the trachea
where is the isthmus located?
anterior to the 2nd and 3rd cartilages of the trachea
how will a lump in the gland (or enlarged gland) move during swallowing?
superiorly then inferiorly with the larynx
how many parathyroid glands are there?
four
where are the parathyroid glands located?
posterior surfaces of the thyroid glands lateral lobes
how are the parathyroid glands named?
superior and inferior on right and left sides
what is the name given to the common variant of the thyroid gland in which a thrid lobe is present?
pyramidal lobe
what is the prevelance of a pyramidal lobe?
28-55% (mean 44.6%)
which lobe dese the pyramidal lobe most commonly originate from?
left lateral lobe
where does a pyramidal lobe most commonly attach?
thyroid cartilage
a pyramidal lobe may extend as superiorly as what structure?
hyoid bone
where does the thyroid begin its development? (embryologiically)
the junction between the anterior 2/3rds and posterior 1/3rd of the tongue
what is the name of the embryological origin of the thyroid in adults?
foramen caecum
during development the thyroid migrates _______ attached to the tongue via what?
inferiorly attached to the thyroglossal duct
during which week of development does the thyroid reach its final position?
7th week of development
what can be found at any point along the thyroids migratory path?
thyroglossal duct cysts
ectopic thyroid tissue
what is the name given to the muscles found wihin the superfical fascia of the neck?
Platysma muscles
what ‘group’ of muscles do the platysma muscles belong to?
the muscles of facial expression
which nerve supplies the platysma muscles?
cranial nerve VII (the facial nerve)
what are the four fascial compartments in the neck?
prevertebral (deep) fascia
investing (deep) fascia
2 carotid sheaths
pretracheal (deep) fascia
what are the contents of the prevertebral (deep) fascia?
encloses cervical vertebrae
postural neck muscles
what are the contents of the investing fascia?
trapezius
sternocleidomastoid
what are the contents of the carotid sheaths?
internal jugular veins
carotid arteries
vagus nerves
deep cervical lymph nodes
what are the contents of the pretracheal fascia?
strap muscles
thyroid gland
trachea
oesophagus
recurrent laryngeal nerves
what lies between the pretracheal and prevertebral fascia?
retropharyngeal space
how could infection in the neck spread into the mediasteinum?
between the fascial planes
what is the attachment of the the sternal head of the sternocleidomastoid?
manubrium of the sternum
what is the attachment of the clavicular head of the sternocleidomastoid?
medial end of the clavicle
where do both heads of the sternocleidomastoid attach superiorly?
mastoid process of teh temporal bone
which vessel does the anterior jugular vein drain into?
external jugular vein
which vessel does the external jugular vein drain into?
subclavian vein
where are the carotid sheaths located in the neck in relation to the thyroid?
anterolaterally in the neck either side of the thyroid
where do the carotid sheaths attach superiorly?
base of teh skull around the jugular foramen and teh entrance to the carotid canal
the right subclavian artery gives rise to which artery supllyng the thyroid?
right inferior thyroid artery
what arteries supply the thyroid gland?
inferior thyroid artery
superior thyroid artery
external carotid artery
what vessels drain the thyroid gland?
superior thyroid vein
middel thyroid vein
inferior thyroid vein
what vessels do the thyroid veins drain into?
internal jugular veins
list the sets of lymph nodes involved with the drainage of teh thyroid gland
superior deep cervical nodes
inferior deep cervical nodes
pretracheal node
paratracheal nodes
how is lymph returned on the right side?
via the right lymphatic duct to the right venous angle
how is lymph returned on the left side?
via the thoracic duct to the left venous angle
what part of the brainstem do the vagus nerves connect with?
medulla oblongata
what foramin do the vagus nerves pass through?
jugular foramen
describe the pathway of the vagus nerves?
leave the medulla oblongata
extend through the jugular foramen
descend down the carotid sheaths
what are the branches of the vagus nerve to the larynx in the neck?
superior laryngeal nerve
right recurrent laryngeal nerve
describe the pathway of the right vagus nerve through the chest?
right lateral aspect of the trachea
posterior to right lung root
describe the pathway of the left vagus nerve
left side of arch of aorta
posterior to left lung root
onto which stucture do both the left and right vagus nerves descend to pass through the diaphragm
oesophagus
how do the right and left vagus nerves terminate?
divide into terminal branches on the surface of the stomach
at which point does the right vagus nerve give rise to the right recurrent laryngeal nerve?
in the neck
at which point does the left vagus nerve give rise to the left recurrent laryngeal branch?
in the chest- after descending ast arch of aorta
list the close anatomical features of the thyroid
trachea
pretracheal fascia
oesophagus
carotid sheaths
recurrent laryngeal nerves
list the strap muscles
sternohyoid
omohyoid
thyrohyoid
what are the four surgical approaches to the thyroid gland?
classical thyroidectomy
endoscopicaly assisted thyroidectomy
endoscopic transaxillary approach
endoscopic trans breast approach
define iatrogenically
when structures are damaged by the surgeon
descirbe the classical thyroidectomy incision
‘collar’ incision made wihtin natural skin crease or langers lines
should be just superior to clavicles and jugular notch
made throught the skin and platysma
injury to the recurrent nerve during thyroidectomy would resulyt in what?
paralysis of the vocal cord
unilateral injury of the recurrent nerve results in what?
hoarseness
bilateral injury of the recurrent nerves reults in what?
aphonia- inability to produce sound
inability to close the rima glottidis- fails to prevent aspiration or to produce a cough