anatomy Flashcards
what is the anterior lobe of the pituitary gland called? what is it responsible for?
adenohypophysis
- pars distalis
- pars tuberalis
- pars intermedia
syntheis + release of most pituitary hormones
what is the posterior lobe of the pituitary gland called? what is it responsible for?
neurohypophysis
- pars nervosa
releases ADH + oxytocin (synthesised in hypothalmus)
describe the location of the pituitary gland
midline structure in the pituitary fossa of sphenoid bone
pituitary fossia lies in sella turcica
what cranial nerve innervates the platysma muscles?
CN VII (facial nerve)
in what week of development does the thyroid gland reach its final position?
7th week
where are the 4 parathyroid glands located?
the posterior surfaces of thyroid gland lateral lobes
-> superior + inferior on each side
the immediate superior relation to the pituitary gland is?
diaphragma sella
–> tough sheet of dura matter forming roof (diaphragm) over pituitary fossa
(also optic chiasma)
how do axons from the optic tract get to the visual cortex? where is the visual cortex?
axons in chain pass via optic radiation to visual cortex in occipital lobe
bilateral loss of temporal visual field
bitemporal hemianopia
–> can be caused by pituitary tumour crpressing optic chiasma
how can the pituitary fossa be surgically accessed?
transcranial approach - subfrontal (inferior to frontal lobe)
transsphenoidal approach - via nasal cavities + sphenoid sinus
what are paranasal sinuses? name them
air-filled sacs within bones surrounding nasal cavities
- frontal sinuses
- maxillary sinuses
- ethmoid air cells
- sphenoid sinuses
function of paranasal sinuses
no real function - reduces weight in skull, adds resonance to voice
lined by mucus-secreting respiratory mucosa - drains into nasal cavities through ostia
how are hypothalmic hormones transported to the pituitary
hypophyseal portal veins
–> to 2nd capillary bed in the anterior pituitary
what hormones does the anterior pituitary secrete?
Growth hormone (GH) prolactin (milk production)
thyroid stimulating hormone (TSH)
adrenocorticotrophic hormone (ACTH)
luteinising hormone (LH)
follicle stimulating hormone (FSH)
what does functional deficiet to the optic chiasma lead to?
bitemporal hemianopia
function = conducts AP bilaterally from nasal retinae
what does functional deficit to the trochlear nerve cause?
difficulty looking inferiorly and laterally
function = motor to one muscle that moves globe
where do the superior, middle and inferior thyroid veins drain?
superior + middle = internal jugular -> brachiocephalic
inferior = directing into brachiocephalic
brachiocephalic -> SVC
which nerve supplies the sternocleidomastoid and trapezius?
CN XI - spinal accessory nerve
which muscle lies between the anterior and posterior trainagles of the neck?
sternocleidomastoid
sternal head - manubrium of sternum
clavicular head - medial end of clavicle
both attach to mastoid process of temporal bone
which vein passes over sternocleidomastoid and can be seen superficially?
external jugular vein
what muscles are found immediately deep to the skin of the neck? how are they innervated?
platysma muscles
belong to “muscles of facial expression”
CN VII = facial nerve
what do the carotid sheaths contain?
internal jugular vein
common carotid artery
vagus nerve
deep cervical lymph nodes
(x2 carotid sheaths)
which fascial compartment is the thyroid found in? what else is contained in this compartment?
pretracheal fascia
oesophagus trachea thyroid gland strap muscles recurrent laryngeal nerves
which fascial compartment is the trapezius muscles found in? what other muscle is found in here?
INVESTING FASCIA
sternocleidomastoid
what does the prevertebral (deep) fascial compartment contain?
postural neck muscles
cervical vertebra
where is the retropharyngeal space? what is it’s clinical importance?
between pretracheal + prevertebral sheath
passes down to mediastinum - any infection that gets to this space has potential to track down
where do the superior and inferior thyroid arteries branch from respectively?
superior - external jugular artery
inferior - subclavian artery
what does unilateral injury to the recurrent laryngeal nerve cause?
“hoarseness” or weakness of voice + weak cough
what does bilateral injury to the recurrent laryngeal nerve cause?
aphonia = inability to produce sound
inability to close rima glottidis (opening between vocal cords) - prevent aspiration, produce good cough (requires closure of rima glottidia)
where does the recurrent laryngeal nerve lie in relation to the thyroid gland?
in the groove between trachea and oesophagus
?vagus more lateral
course of travel of vagus nerve (CN X) superior to thorax
emerge from medulla oblongata
exit cranium via jugular foramen
descend in carotid sheath
how does the vagus nerve descend through the thorax?
right CN X = lateral to trachea
left CN X = left side of aortic arch
both - POSTERIOR to lung hilum + plexus around oesophagus
whats the difference between the route of the left and the right recurrent laryngeal nerves?
left - wraps around arch of aorta
right - wraps around subclavian artery
which structure is at risk of haemorrhaging in a surgery to access the pituitary?
internal carotid artery
which cranial nerves could be affected by a pituitary tumour?
CN III - eye movement deficit, dilated pupil
IV - difficulty looking inferior + laterally
V1, V2 - parathesia of face
VI - difficulty abducting eye
which bones must be fractures in a transsphenoidal approach?
nasal septum + floor
roof of sphenoid sunuses
(to access pituitary tumour)
clinical term for enlargement of thyroid
goitre
how does a swollen thyroid move in degluitition? why?
moves superiorly then inferiorly with larynx
due to relationship with trachea and larybx
from which embryological remnant is a pyramidal lobe from?
thyroglossal duct
name the 4 strap muscles
sternohyoid
thyrohyoid
sternothyroid
omohyoid (fascial sling)
A 34-year-old lady undergoes a thyroidectomy for Graves disease. Post operatively she develops a tense haematoma in the neck. In which of the following fascial planes will it be contained?
pretracheal fascia
The pretracheal fascia encloses the thyroid and is unyielding. Therefore tense haematomas can develop.
what is colloid in the thyroid gland?
It is a high molecular weight protein that acts as a storage form of thyroid hormones.
main component = thyroglobulin
