The subject of intra-abdominal pressure falls naturally under four heads, namely:
Pressure on solid viscera (liver, kidney, spleen), which cannot be other than that existing in the free peritoneal cavity.
Pressures within hollow viscera; which have been fairly established under a variety of conditions, and may be wholly independent of the pressure in the abdominal cavity.
Pressures within blood and lymph spaces which have been accurately determined, and are modified by the pressure in the abdominal cavity.
Pressures within the peritoneal space proper.
EMERSON H. INTRA-ABDOMINAL PRESSURES. Arch Intern Med (Chic). 1911;VII(6):754-784. doi:10.1001/archinte.1911.00060060036002