Revision as of 01:04, 5 March 2024

Pituitary gland is located within the sella turcica of the sphenoid bone.

Anterior and posterior pituitary lobe

Adenohypophysis	Neurohypophysis
75% of the gland Ectodermal origin from roof of the stomodeum Three components: Pars tuberalis includes Portion of the infundibular stalk Median eminence of hypothalamus Pars intermedia Pars distalis: majority of the gland, has no direct arterial supply	25% of the gland Diencephalic origin Three components: Pars nervosa (posterior lobe) Infundibulum Nuclei (supraoptic and paraventricular)

Hypophyseal portal system is formed by the superior hypophyseal arteries (supraclinoid ICA) and the inferior hypophyseal arteries (branch of cavernous ICA meningohypophyseal trunk).
These arteries join in and around the pituitary stalk and form sinusoids that feed the infundibulum and the anterior pituitary gland.
The superior hypophyseal artery supplies the infundibulum and the median eminence.
The inferior hypophyseal artery supplies the posterior pituitary lobe.

several small arteries arising from the posteromedial portion of the intradural ICA
They course beneath the optic nerve to supply:
- Pituitary (anterior pituitary lobe, pituitary stalk) and tuber cinereum
- Optic nerve and chiasm (inferior surface)

⇒ posterior lobe of pituitary
postpartum occlusion causes pituitary infarcts (Sheehan's necrosis): however, DI is rare because the stalk is spared

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 * The inferior hypophyseal artery supplies the posterior pituitary lobe.
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 == Superior hypophyseal artery ==
 * several small arteries arising from the posteromedial portion of the intradural ICA