Anterior Abdominal Wall Flashcards
(21 cards)
What are the 5 muscles of the anterior abdominal wall?
- External oblique, 2. Internal oblique, 3. Transversus abdominis, 4. Rectus abdominis, 5. Pyramidalis (absent in 20%).
What is the nerve supply of the anterior abdominal wall?
Thoracoabdominal nerves (T7-T11), Subcostal nerve (T12), Iliohypogastric/Ilioinguinal nerves (L1).
What is the arcuate line?
Level below which all 3 muscle aponeuroses (EO, IO, TA) pass ANTERIOR to rectus abdominis (no posterior sheath).
What structures lie within the rectus sheath?
Rectus abdominis, pyramidalis, superior/inferior epigastric vessels, thoracoabdominal nerves.
What are the borders of Hesselbach’s triangle?
Inguinal ligament (inferior), rectus abdominis (medial), inferior epigastric vessels (lateral).
What is the key difference between direct and indirect inguinal hernias?
Direct: Medial to inferior epigastric vessels (through Hesselbach’s). Indirect: Lateral to epigastric vessels (through deep inguinal ring).
What action does the external oblique perform?
Trunk flexion + contralateral rotation (e.g., right EO rotates left).
What is the blood supply to the anterior abdominal wall?
Superior epigastric (internal thoracic), inferior epigastric (external iliac), superficial epigastric (femoral).
What is the mnemonic for abdominal wall layers?
‘Some Englishmen Called It The Perfect Spot’: Skin, External oblique, Camper’s fascia, Internal oblique, Transversus abdominis, Peritoneum.
What is the clinical significance of the arcuate line?
Weak point for Spigelian hernias; below it, only transversalis fascia covers rectus abdominis posteriorly.
What encloses the rectus sheath?
Fibroaponeurotic sleeve formed by EO, IO, and TA muscle aponeuroses
What are the contents of the rectus sheath?
Rectus abdominis, pyramidalis (20% absent), superior/inferior epigastric vessels, thoracoabdominal nerves (T7-T11)
What is the arcuate line (linea semicircularis)?
Level where all 3 muscle aponeuroses pass ANTERIOR to rectus abdominis (no posterior sheath below this)
What forms the anterior layer ABOVE the arcuate line?
External oblique (EO) + 1/2 internal oblique (IO) aponeuroses
What forms the posterior layer ABOVE the arcuate line?
1/2 internal oblique (IO) + transversus abdominis (TA) aponeuroses
What changes BELOW the arcuate line?
All 3 aponeuroses (EO, IO, TA) pass ANTERIOR; posterior layer = only transversalis fascia
What clinical condition is associated with the arcuate line?
Spigelian hernia (through defect in IO aponeurosis near linea semilunaris)
What vessels run in the rectus sheath?
Superior epigastric (from internal thoracic) and inferior epigastric (from external iliac) - they anastomose
Why is the inferior epigastric artery important surgically?
Landmark for differentiating direct (medial) vs indirect (lateral) inguinal hernias
What happens to the rectus sheath in midline incisions?
Linea alba (avascular) is incised; risk of postoperative weakness/herniation
