Anatomy of Abdominal Incisions

Abdominal Wall Anatomy (the foundation)

Layers (superficial → deep)

Fiber direction and cross-sectional anatomy of the abdominal wall — above and below the arcuate line (Schwartz's Principles of Surgery, 11e)

The Rectus Sheath and Arcuate Line

• Above the arcuate line: Anterior sheath = external oblique + anterior leaf of internal oblique. Posterior sheath = posterior leaf of internal oblique + transversus abdominis aponeurosis.
• Below the arcuate line: All three aponeurotic layers shift anteriorly, so the posterior sheath is absent — only transversalis fascia covers the rectus posteriorly.

Neurovascular Anatomy

Neurovascular anatomy of the anterior abdominal wall (Schwartz's, 11e)

• Superior epigastric artery — terminal branch of the internal thoracic; enters rectus sheath below the costal margin, travels on the posterior surface of the rectus
• Inferior epigastric artery — arises from the external iliac; these two vessels anastomose at the level of the umbilicus
• Also supplied by subcostal and lumbar arteries; superficial supply from superficial epigastric, superficial circumflex iliac, and superficial external pudendal arteries

• Sensory innervation: afferent branches of T4–L1 (dermatomal pattern)
• Motor innervation: efferent branches of T6–T12 to the abdominal wall muscles
• Lower incisions risk the iliohypogastric (L1) and ilio-inguinal (L1) nerves

Types of Abdominal Incisions

Standard open abdominal incisions: A = Subcostal/midline; B = Paramedian; C = Right subcostal; D = "Saber slash" extension; E = Rocky-Davis; F = McBurney; G = Transverse; H = Pfannenstiel (Schwartz's Principles of Surgery, 11e)

1. Midline Incision

• Direction: Longitudinal through the linea alba
• Access: Most intraabdominal organs and some retroperitoneal structures
• Advantages: Minimal injury to muscles, nerves, and vessels (the linea alba is avascular); rapid entry; extensile
• Closure: Requires reapproximation of the linea alba without undue tension; sutures placed at 5–8 mm intervals with 5 mm width shown to reduce incisional hernia rates

2. Paramedian Incision

• Direction: Longitudinal, lateral to the midline through the rectus sheath (medial paramedian) or in the pararectus location
• Limitation: Restricts access to the contralateral abdomen and pelvis; risks damage to musculature, vessels, and nerves supplying the rectus

3. Subcostal Incision (Kocher)

• Direction: Oblique, parallel and ~2–3 cm below the costal margin
• Right subcostal: Classic approach for cholecystectomy and right liver resections
• Bilateral subcostal (Chevron): Used for liver transplantation and bilateral adrenalectomy; can be extended with a midline ("Mercedes Benz") extension

4. Transverse Incision

• Direction: Horizontal across the abdomen
• Crosses the rectus muscles and oblique muscles
• Advantages over midline: may reduce hernia; incision follows Langer's lines → better cosmesis

5. McBurney / Rocky-Davis Incision

• McBurney: Oblique muscle-splitting incision in the right iliac fossa; centered over McBurney's point (1/3 of the way from ASIS to umbilicus)
• Rocky-Davis: Transverse version at the same location
• Weir extension: lateral extension of the Rocky-Davis for more exposure
• Used for: open appendectomy

6. Pfannenstiel Incision

• Direction: Transverse semilunar, two fingerbreadths above the pubic bone
• Layers divided: Skin → anterior rectus sheath (opened transversely) → linea alba taken down superiorly and inferiorly → rectus muscles bluntly separated from sheath → midline opened into the extraperitoneal space (Space of Retzius) or peritoneum
• Used for: Caesarean section, radical retropubic prostatectomy, pelvic lymphadenectomy, specimen extraction post-nephrectomy
• Closure: Peritoneum and muscle reapproximated; fascia closed with running or figure-of-eight absorbable suture
• Advantages: Low incisional hernia rates; can be extended into a Gibson incision

7. Gibson Incision

• Direction: Oblique/curvilinear, from a few cm medial to the ASIS extending down toward the inguinal fold, terminating lateral to the rectus or continuing to above the pubic symphysis
• A J-shaped ("hockey-stick") modification exists, though some data suggest higher hernia rates
• Layers: External oblique → internal oblique → transversus abdominis split in the same fashion; peritoneum mobilized medially for an extraperitoneal approach
• Used for: Renal transplantation, transplant nephrectomy, access to pelvic vessels, lower ureter, and bladder
• Closure: Two layers with running absorbable sutures

Complications of Abdominal Incisions