Pia Mater - Anatomy - Kenhub

Pia mater

Author: Nicola McLaren, MSc • Reviewer: Dimitrios Mytilinaios, MD, PhD Last reviewed: November 22, 2023 Reading time: 3 minutes

Recommended video: Meninges of the brain [11:40] Meninges and superficial vessels of the brain. Pia mater 1/9 Synonyms: none

Pia is the innermost layer of the meninges, the connective tissue layers that surround the central nervous system. It is a thin, transparent, delicate layer that hugs the surface of the brain and spinal cord, closely following its contours. The pia and arachnoid layers of the meninges are collectively called the leptomeninges. Located between these two layers is the cerebrospinal fluid containing subarachnoid space.

The pia is highly vascularized by a network of fine blood vessels. In the cranium, the pia extends for a short distance along the surface of blood vessels as they travel to and from the meninges to enter and exit the cerebral cortex. This pia extension is called a pial coat. Similar extensions are seen in the spinal cord where the pia follows spinal nerves and spinal blood vessels for a short distance as they travel away from the central cord. Fingers of vascularized pia covered by epithelial cells form invaginations into ventricles called choroid plexuses. Choroid plexuses function to secrete cerebrospinal fluid.

In the spinal cord, the pia forms tiny ligaments called the denticulate ligaments. These ligaments suspend the spinal cord within the dural sac. The inferior most aspect of the spinal meninges is anchored to the coccyx by a thin strand called the filum terminale. This filum has internal and external parts, the internal being formed by a strand of pia.

Terminology	English: PiaLatin: PiaSynonym: Pia mater
Definition and function	The thin delicate pia is the innermost of three connective tissue meningeal layers that surrounds, supports and protects the central nervous system (brain and spinal cord).Cranial pia combines with epithelial cells to form choroid plexuses. Spinal pia forms denticulate ligaments and the filum terminale internum.

Learn more about the meninges of the brain with this study unit:

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Sources

All content published on Kenhub is reviewed by medical and anatomy experts. The information we provide is grounded on academic literature and peer-reviewed research. Kenhub does not provide medical advice. You can learn more about our content creation and review standards by reading our content quality guidelines.

Moore, K. L., Dalley, A. F., & Agur, A. (2017). Clinically oriented anatomy (8th ed.). Lippincott Williams and Wilkins.

Standring, S. (2016). Gray's Anatomy (41st ed.). Edinburgh: Elsevier Churchill Livingstone.

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