ABDOMEN REGION

Introduction to Abdominal Cavity

The abdominal cavity is a hollow, four-walled cavity that contains and protects the abdominal organs. It is a major body cavity that extends from the diaphragm to the pelvic floor.

Regions of Abdominal Cavity

• Upper Abdomen (Thoracoabdominal Region): extends from the diaphragm to the lower border of the last rib.
• Middle Abdomen (Umbilical Region): extends from the lower border of the last rib to the umbilicus.
• Lower Abdomen (Inguinal Region): extends from the umbilicus to the pelvic floor.

Contents of Abdominal Cavity and Pelvic Cavity

• Abdominal Cavity: contains the stomach, small intestine, liver, gallbladder, pancreas, spleen, kidneys, adrenal glands, and the abdominal portion of the large intestine.
• Pelvic Cavity: contains the pelvic portion of the large intestine, urinary bladder, prostate gland, and reproductive organs.

Perineum

• Definition: the diamond-shaped area of skin between the thighs and under the genital area.
• Boundaries:
  • Anteriorly: by the skin of the pubic symphysis and the labia majora in females.
  • Posteriorly: by the skin over the coccyx and the ischial tuberosities.
  • Laterally: by the skin over the ischial tuberosities.
  • Superiorly: by the urogenital diaphragm.
• Contents:
  • Superficial perineal pouch: contains the ischiocavernosus, bulbospongiosus, and superficial transverse perineal muscles.
  • Deep perineal pouch: contains the external urethral sphincter, deep transverse perineal muscle, and the perineal body.

Note:

• The pelvic cavity is bounded by the pelvic girdle and the pelvic diaphragm.
• The pelvic diaphragm is formed by the levator ani and coccygeus muscles.
• The abdominal cavity is bounded by the diaphragm and the pelvic floor.