| 释义 | DictionarySeecloacalEncyclopediaSeemembrane cloacal membrane
 clo·a·cal mem·branea transitory membrane in the caudal area of the embryo, separating the proctodeum from the cloaca; it is divided into anal and genitourinary membranes that break down during the eighth to ninth week of human development to establish the external opening for the alimentary and genitourinary tracts.clo·a·cal mem·brane(klō-ā'kăl mem'brān) A transitory membrane in the caudal area of the ventral wall of the embryo, separating the endodermal from the ectodermal cloaca; it is divided into anal and genitourinary membranes that break down during the eighth to ninth weeks to establish the external opening for the alimentary and genitourinary tracts. |