THORAX ABDOMEN AND PELVIS

Detailed explanation-1: -The diaphragm separates the abdominal and thoracic cavities but does allow certain structures to pass through via its three openings: The inferior vena cava passes through the diaphragm at the vena caval foramen.

Detailed explanation-2: -The diaphragm is an unpaired, dome shaped skeletal muscle that is located in the trunk. It separates the thoracic and abdominal cavities from each other by closing the inferior thoracic aperture. The diaphragm is the primary muscle that is active in inspiration.

Detailed explanation-3: -These planes divide the abdomen into nine regions; right and left hypochondriac regions, epigastric region, umbilical region, right and left lateral regions of abdomen, hypogastric region, and right and left inguinal regions. Another way to divide the abdomen is with one vertical and one horizontal line.

Detailed explanation-4: -The thoracic diaphragm (as described above) descends when contracted to inhale, making room for air in the lungs. The pelvic diaphragm or pelvic floor musculature (PFM) forms a basket at the bottom of the abdominal cavity. It descends downwards with the contraction of the thoracic diaphragm on the inhale.