The
posteromedial central arteries or
paramedian arteries (also
posteromedial perforating arteries, or
posteromedial ganglionic arteries are posteromedial central arteries which supply parts of the
thalamus. of the
posterior cerebral artery (PCA), (though branches arising from the latter may be considered as a distinct anatomical entity'''
Distribution The PMCAs supply a substantial part of the diencephalon. The PMCAs are distributed to: •
globus pallidus • (lateral wall of)
third ventricle, • (parts of the)
thalamus (partially via the
thalamoperforating artery) •
subthalamus •
hypothalamus •
mammillary bodies •
pituitary gland •
optic chiasm and
tracts •
tuber cinereum •
posterior limb of internal capsule •
mesencephalon (midbrain) •
basis pedunculi •
substantia nigra •
mesencephalic tegmentum Clinical significance An
embolus passing along a vertebral artery will typically continue into the basilar artery before finally lodging at the bifurcation of the basilar artery, thus bilaterally obstructing the PMCAs (as well as the
superior cerebellar artery); such occlusion of the PMCAs will swiftly result in infarction of the
reticular formation at the level of the mesencephalon-pons junction (resulting in coma) as well as destruction of the fibers of both
oculomotor nerve (CN III) (resulting in divergence of both eyes, and fixed
mydriasis). An embolism of a single PMCA at mesencephalic levels may result in a small infarction of the mesencephalon, causing
Weber's syndrome.
Uncal herniation can cause compression of the PMCAs, which may result in
Duret haemorrhages. ==Posterolateral central arteries==