Organization of the antero-lateral abdominal wall




  • Xiphoid process.
  • Costal cartilages of the 7th and 10th ribs.


  • Iliac crest.
  • Anterior superior iliac spine.
  • Inguinal ligament.
  • Pubic tubercle, pubic crest and pubic symphysis.

Divided into 4 quadrants i.e

  1. Right and left upper quadrants
  2. Right and left lower quadrants

Divisions of the abdomen

Can be Divided into 9 regions.

  • Two vertical planes- midclavicular
  • Two horizontal planes:
    • Subcostal plane – joining the most inferior points of the costal margins, and passing at L3.

    • Transtubercular plane, joining the tubercles of the iliac crest.
Note the 9 regions.
  • Right and left hypochondrial regions (1and 3)
  • Middle epigastric region (2)
  • Right and left lumbar regions (6 and 4)
  • A middle umbilical region (5)
  • Right and left iliac (inguinal) region (7and 9)
  • A middle hypogastric or suprapubic region (8)

Layers of anterior abdominal wall

  • Skin
  • Superficial fascia: Fatty and membranous
  • Deep fascia
  • Muscles:
  • Extra peritoneal tissue
  • Peritoneum.


  • Shows ‘creases' which represent the lines of orientation of collagen fibres in the dermis- Langer's lines.

  • These lines are surgically important – incisions along them heal better leaving a thin scar; while those across them leave big scars.

  • In pregnant women, obese people and those with abdominal distention from whatever cause, there are dark elongate lines called striae gravidara.

  • The skin is very sensitive to touch, and quickly when touched, the muscles contract.

Superficial fascia

Consists of two layers;

  • Fatty layer (Camper's fascia) containing variable amounts of fat, more in females and in the lower abdomen.

  • Membranous layer (Scarpa's fascia).

    (+) Contains fibrous tissue and very little fat.
    (+) Fuses with fascia lata below inguinal ligament)
    (+) Continuous with the superficial perineal fascia
    (Colle's fascia) and with that investing the scrotum and penis.



Deep fascia



The muscles

There are 4 main muscles to note:

  • External oblique

  • Internal oblique

  • Transversus abdominis

  • Rectus abdominis

Note the attachment and innervation of these muscles.

Functions of the muscles:
  • Support and protection for abdominal viscera

  • Movement of the trunk – flexion, extension, twisting and lateral bending.

  • Maintenance of     posture

  • Increase intra abdominal pressure in functions such as defecation, micturition and parturition etc.

Home | Project Anatomy | Gross Anatomy | Topic Index | Chapter 31

Anterior Abdominal Wall and the Peritoneum