Morphological analysis of the fascial lamination of the trunk.

For a fuller understanding of the fascial relationships of the visceral organs and their vessels, a general scheme is presented. According to this scheme, there are four basic layers internal as well as external to the trunk musculature. In the abdomen, the internal layers (numbered outwards) consist of (1) the peritoneum, (2) the deep layer of the subperitoneal fascia, (3) the superficial layer of the subperitoneal fascia and (4) the transversalis fascia, while the external layers (numbered inwards) comprise (1) the skin, (2) the superficial layer of the subcutaneous fascia, (3) the deep layer of the subcutaneous fascia and (4) the investing layer of the abdominal fascia. Each interfascial space between layers 2 and 3 gives passage to the main vessels and nerves and will be referred to as the "neurovascular corridor." By the addition of some slight modifications to the basic scheme, the fascial relationships of some organs is illustrated. Photographs of dissections, substantiating the schemes are also included. The schemes and dissections together demonstrate three points: The mammary gland to be situated within the neurovascular corridor, external to the thorax, That the layers of the renal fascia, comprising layers 2 and 3, continue into the pelvic cavity to form the fascia around the ureter and urinary bladder, An outline arrangement of the vascular sheath in the pelvis.