Anterior Abdominal Wall

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What are the layers of the anterior abdominal wall from superficial to deep?

Skin
Camper’s fascia
Scarpa’s fascia
External abdominal oblique
Internal abdominal oblique
Transversus abdominis
Rectus abdominis
Pyramidalis
Preperitoneal fat
Parietal peritoneum

Which structures comprise the rectus sheath between the costal margin and the anterior superior iliac spine?

Anterior: External abdominal oblique aponeurosis and the anterior half of the internal abdominal oblique aponeurosis.
Posterior: Posterior half of the internal abdominal oblique aponeurosis and the transversus abdominis aponeurosis.

Which structures comprise the rectus sheath between the anterior superior iliac spine and the pubis?

Anterior: External abdominal oblique, internal abdominal oblique, and transversus abdominis.
Posterior: Transversalis fascia.

What are the boundaries of the abdomen?

Superior: Diaphragm
Inferior: Pelvic inlet
Anterior: Anterior abdominal wall
Posterior: Lumbar vertebrae, upper bony pelvis, psoas, and quadratus lumborum

Which dermatome is responsible for innervation of the skin over the epigastrium?

T7

Which dermatome is responsible for innervation of the skin over the umbilicus?

T10

Which arteries are responsible for the arterial supply of the skin of the anterior abdominal wall?

Superior and inferior epigastric arteries
Intercostal and lumbar arteries

Extended question
Which of the above incisions might commonly be used for the following open procedures, and why?

Appendicectomy
Incision: Gridiron
Reason: The Gridiron incision, also known as the McBurney's incision, is commonly used for appendectomy. It provides excellent access to the right lower quadrant of the abdomen, where the appendix is located. The incision is placed along the line between the anterior superior iliac spine and the umbilicus.

Cholecystectomy
Incision: Kocher
Reason: The Kocher incision is typically used for open cholecystectomy. It is a subcostal incision placed on the right side of the abdomen, under the ribs, which allows easy access to the gallbladder and biliary structures. It provides good exposure for dissection of the gallbladder from the liver.

Hysterectomy
Incision: Pfannenstiel
Reason: The Pfannenstiel incision is commonly used for abdominal hysterectomy, especially for elective procedures. It is a transverse incision made just above the pubic symphysis, providing good access to the pelvic organs while minimizing cosmetic concerns and avoiding damage to major abdominal muscles.

Emergency Laparotomy
Incision: Midline
Reason: The midline incision is commonly used for emergency laparotomy due to its rapid and wide access to the entire abdominal cavity. It allows the surgeon to quickly evaluate and address multiple abdominal issues such as trauma, bowel obstruction, or internal bleeding. The midline incision is versatile and can be extended if necessary.