Choroid Plexus

plexus choroideus

The choroid plexus is a frond-like network of capillaries covered by a specialised epithelium that hangs into the ventricles. It produces most of the cerebrospinal fluid, about 500 mL per day. Its tightly joined epithelial cells form the blood-cerebrospinal fluid barrier.

Anatomical Data

Structure & Connections

Location	In the bodies and temporal horns of the lateral ventricles, the roof of the third ventricle and the lower roof and lateral recesses of the fourth ventricle (not in the frontal or occipital horns or the aqueduct)
Parts	Fenestrated capillaries Choroid epithelium (modified ependyma) Tela choroidea Glomus (enlargement in the atrium of the lateral ventricle)
Connections	Lateral, third and fourth ventricles Internal cerebral and basal veins (venous drainage)
Blood Supply	Anterior choroidal artery; Medial and lateral posterior choroidal arteries; Posterior inferior cerebellar artery; Anterior inferior cerebellar artery

Biomechanics

Function & Actions

Secretes cerebrospinal fluid, regulates its chemical composition and forms a selective barrier between blood and CSF.

Clinical Relevance

Clinical Notes

Choroid plexus calcification is common and normal in adults. Choroid plexus papillomas, mostly in young children, can cause hydrocephalus partly by overproducing CSF. Choroid plexus cysts are a frequent finding on prenatal ultrasound and are usually harmless. Acetazolamide reduces CSF production by acting on choroid epithelium.

Pathology

Common Injuries & Conditions

Choroid Plexus Papilloma

A benign tumour of the choroid plexus, most common in the lateral ventricle of infants, causing hydrocephalus.

Choroid Plexus Cyst

A small fluid cyst in the choroid plexus, usually an incidental prenatal ultrasound finding that resolves without consequence.

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