<unk>   is the eponym  for the hepato-renal space, named for British surgeon James R.<unk>  (1853 - 1939).<unk>  is primarily a potential  space, meaning that in  the state of normal function, there is no separation between the  capsules of the liver  and the right kidney. However, this space becomes significant in conditions in which fluid  collects within the abdomen (most commonly, ascites and hemoperitoneum). The intra-peritoneal fluid can be blood, ascites,  or dialysate, and it collects in this space and may be visualized,  most commonly via ultrasound  or Computed Tomography (CT) scanning. As little as 30 or  40 mL of fluid in the abdominal cavity may be visualized in this space. The  medical significance of this space primarily lies in the circumstance  of hemorrhagic shock due to hemoperitoneum. Early visualization of fluid in<unk>  on FAST Ultrasound is an indication for urgent laparotomy.
A normal ultrasonographic view of<unk> . The bright line is the capsule of the kidney; there is  no fluid present and hence no visible space.<unk>  with fluid present (red  arrows).
Morison's pouch
Rathke's pouch
Intestinal villus
Pharyngeal pouch 
Mesenteric glands
Gut-associated lymphoid tissue
Branchial pouch
Villus