| a narrow, fluid-filled space between the pleural membranes of the lung and the inner chest wall. |
| fluid-filled space between the two layers of the pericardium |
posterior pos·te·ri·or (pŏ-stēr'ē-ər, pō-)
adj.
Located behind a part or toward the rear of a structure.
Relating to the caudal end of the body in quadrupeds or the dorsal side in humans.
Near the tail or caudal end of certain embryos.