Scroll down for anatomy atlas......



The Anterolateral Abdominal Wall

• The abdomen is the part of the trunk between the thorax and pelvis.
• It has a musculotendinous wall except posteriorly where it includes the lumber vertebrae and intervertebral disks.
• The abdominal cavity is the space bounded by the abdominal walls, diaphragm and pelvis.

• The four planes are: Two Mid-clavicular Plane Transtubercular Plane Subcostal Plane

  The abdominal cavity is divided into nine regions by four planes.
• The nine regions are:

1. Right Hypochondrial
2. Left Hypochondrial
3. Epigastric
4. Right Lumber
5. Left Lumber
6. Umblical
7. Right Iliac
8. Left Iliac
9. Hypogastrium

• The abdominal cavity is also divided into four quadrants by two planes for general clinical description.
• The Quadrants are:

1. Upper Right
2. Upper Left
3. Lower Right
4. Lower Left

• The Planes are:

1. Median Plane
2. Transumbalicus

• The abdominal wall is divided into:
  • Anterolateral wall
  • Posterior wall
• The anterolateral wall is bounded:
  • Superiorly by cartlages of the 7th ~ 10th ribs and the xiphoid process.
  • Inferiorly by the inguinal ligament and pelvic bone.
• The subcutaneous tissue of the anterolateral wall, superficial fascia, is composed out of two layers:
  • Camper's Fascia (Fat layer)
  • Scarpa's Fascia (Membranous layer)
• The anterolateral wall has no deep fascia.
• Muscles of anterolateral abdominal wall:
  • Three flat muscles:
    • External oblique muscle:
      • Most superficial
      • Fiber direction is inferomdially
      • Fibers interdigitate with serratus anterior
    • Internal oblique muscle:
      • Intermediate
      • Fibers are at right angle to external oblique
    • Transverse abdominal muscle:
      • Innermost
      • Fiber direction is horizontal
  • Two vertical muscles:
    • Rectus Abdominis:
      • Enclosed in rectus
      • sheeth has three tendenous intersections
    • Pyramidalis

• The flat muscles are anteriorly in an aponeuroses and each apenuroses interlace at the linae alba from each side to form the rectus sheath.
• The linae alba is a fibrous band running variable distance superior to pelvic symphysis.

• Rectus sheath formation:

• Internal Oblique in the second part splits into two parts which enclose rectus abdominis.
• The 3rd part is a weak point because all three of the apeneurosis of the flat muscles pass anteriorly to rectus abdominis muscle.
• At the level of the anterior superior iliac spine the posterior wall has a free curved lower border called the arcuate line.
• Rectus sheath contents:
  • Rectus abdominis muscle
  • Pyrimidalis
  • Superior epigastric artery
  • Inferior epigastric artery
  • Lymphatic vessels
  • Terminal portions of the anterior primary rami of the spinal nerve from T7 to T12.

• Functions of the Anterolateral Abdominal Muscles:
  • Support for the abdominal wall.
  • Protect abdominal viscera from injuries.
  • Oppose or assist the diaphragm in compressing the abdominal organs.
  • Move the trunk and maintain the posture.
• Nerve Supply of the Anterolateral Abdominal Wall:
  • Thoracoabdominal Nerves
  • Subcostal Nerves
  • Illiohypogastric Nerve
  • Illioinguinal Nerve
• Blood Supply of the Anterolateral Abdominal Wall:
  • Superior Epigstric Vessels branch of the internal thoracic vessels
  • Inferior Epigastric Vessels branch of the external iliac vessels
  • Deep Circumflex Iliac Vessels
  • Superficial Circumflex Iliac Vessels
  • Superficial Epigastric Vessels
  • Anterior & Collateral branches of the posterior intercostals Vessels
  • Branches of the musculopherenic Vessels
• The superficial lymphatic vessels accompany the subcutaneous veins
• Lymphatic vessels superior to the umbilicus drain to the axillary lymph nodes.
• Lymphatic vessels inferior to the umbilicus drain to the superficial inguinal lymph nodes.
• The deep lymphatic vessels accompany the deep veins and drain to the external iliac, common iliac, internal thoracic and lumber lymph nodes.