piarachnoid


pia-arachnoid

 [pi″ah-ah-rak´noid] the pia mater and arachnoid considered together as one functional unit; the leptomeninges.

lep·to·me·ninx

(lep'tō-mē'ninks), [TA] The two delicate layers of the meninges, the arachnoid mater and pia mater (vs. the tough pachymeninx or dura mater), considered together; by this concept, the arachnoid and pia are two parts of a single layer, much like the parietal and visceral layers of a membrane or bursa; although separated by the subarachnoid space they are connected via the arachnoid trabeculae and become continuous where the nerves and filum terminale exit the subarachnoid space (the cerebrospinal fluid-filled space bounded by the leptomeninges).
See also: arachnoid mater, pia mater. Synonym(s): leptomeninges [TA], arachnoid mater and pia mater ☆ , meninx tenuis, pia-arachnoid, piarachnoid

lep·to·me·nin·ges

(lep'tō-mĕ-nin'jēz) [TA] The two delicate layers of the meninges, the arachnoid mater and pia mater considered together.
See also: arachnoid, pia mater
Synonym(s): pia-arachnoid, piarachnoid. [lepto- + G. mēninx, pl. mēninges, membrane]