Ant Abdominal Wall Flashcards
Umbilicus Levels
L3-L4, innervation T10
External Oblique
O: External surfaces of ribs 5-12
I: Linea alba, pubic tubercle, and anterior half of iliac crest
A: compress and support abdominal viscera; flex and rotate trunk
N: thoraco-abdominal nerves (anterior rami of T7-T11) and subcostal nerves
Internal Oblique
O: Thoracolumbar fascia, anterior 2/3 of iliac crest, and connective tissue deep to inguinal ligament
I: Inferior borders of ribs 10-12, linea alba and pubis via conjoin tendon
A: compress and support abdominal viscera; flex and rotate trunk
N: Thoraco-abdominal nerves (anterior rami of T7-T11) and first lumbar nerve (L1)
Above arcuate line internal oblique
tendons split and wrap anteriorly and posteriorly around the rectus abdominus
Below arcuate line internal oblique
tendon fuses and wraps only anteriorly around the rectus abdominus
Transversus abdominus
O: Internal surfaces of ribs 7-12 costal cartilages, thoracolumbar fascia, iliac crest, and connective tissue deep to inguinal ligament.
I: Linea alba with aponeurosis of internal oblique, pubic crest and pectin pubis via conjoin tendon.
A: Compresses and supports abdominal viscera
N: Thoraco-abdominal nerves (anterior rami of T7-T11) and first lumbar nerve (L1)
Rectus Abdominus
O: Pubic symphysis and pubic crest
I: Xiphoid process and costal cartilages 5-7
A: Flexes trunk (lumbar vertebrae) and compresses abdominal viscera (can act as an antagonist to the diaphragm. Stabilizes and controls pelvic tilt (antilordosis)
N: Thoraco-abdominal nerves (anterior rami of inferior six thoracic nerves)
Rectus abdominus above arcuate line
Above the arcuate line the internal oblique fascia split contributing to both anterior sheath fusing with external oblique aponeurosis and posteriorly fusing with transversus abdominus
Rectus abdominus BELOW arcuate line
Below the arcuate line all three aponeuroses pass anteriorly to the rectus and posterior wall is composed of only the transversalis fascia and parietal peritoneum. This makes this area weaker and prone to hernias.
Thoraco-abdominal nerves
T7-T11
O: continuation of lower intercostal nerves
Course: Run between 2nd and 3rd layers of abdominal muscles; lateral and anterior cutaneous branches enter subcutaneous tissue.
N: Muscles of anterolateral wall and overlying skin.
Subcostal nerves
T12
Origin: Anterior ramus of L1 spinal nerve
Course: Inferior border of 12th rib, then onto subumbilical abdominal wall
N: Muscles of anterolateral abdominal wall and overlying skin superior to iliac crest and inferior to umbilicus
Iliohypogastric nerve
L1
O: Anterior ramus of T12 spinal nerve
Course: Pierces transversus abdominus muscle; branches pierce external oblique aponeurosis of most inferior abdominal wall.
N: Skin overlying iliac crest, upper inguinal and hypogastric regions; internal oblique and transversus abdominis.
Ilioinguinal nerve
L1
O: Anterior ramus of L1 spinal nerve
Course: Passes between 2nd and 3rd layers of abdominal muscles, then traverses inguinal canal
N: Skin of scrotum or labia majus and mons pubis, and adjacent medial aspect of thigh; most inferior internal oblique and transversus abdominus.
Musculophrenic artery
O: Internal thoracic artery
Course: Descends along costal margin
Oxygenates: Abdominal wall of hypochondriac region, anterolateral, diaphragm
Superior epigastric artery
O: Internal thoracic artery
Course: Descends in rectus sheath deep to rectus abdominus
oxygenates: Rectus abdominus and superior part of anterolateral wall
