Anatomy of Anterior Abdominal Wall Mohammed El-Matary Lecturer of General Surgery Ain Shams University

Anterior Abdominal Wall Layer of anterior abdominal wall: A- Lateral: 1- Skin. 2- Subcutaneous tissue. 3- External oblique muscle. 4- Internal oblique muscle. 5- Transversus abdominis muscle. 6- Fascia transversalis. 7- Peritoneum.

Anterior Abdominal Wall B- Medial: 1- Skin. 2- Superficial fascia. 3- Anterior wall of rectus sheath. 4- Rectus muscle. 5- Posterior wall of rectus sheath. 6- Peritoneum.

A- Lateral Side

A- Lateral 1- Skin

A- Lateral 2- Subcutaneous tissue

A- Lateral 3- External Oblique m.

A- Lateral 4- Internal Oblique m.

5- Transversus abdominis m. A- Lateral 5- Transversus abdominis m.

6- Fascia Transversalis m A- Lateral 6- Fascia Transversalis m

A- Lateral 7- Peritoneum

B- Medial Side

Anterior Abdominal Wall Layer of anterior abdominal wall: B- Medial: 1- Skin. 2- Superficial fascia. 3- Anterior wall of rectus sheath. 4- Rectus muscle. 5- Posterior wall of rectus sheath. 6- Peritoneum.

B- Medial 1- Skin

B- Medial 2- Subcutaneous tissue

3- Ant. Wall of Rectus sheath B- Medial 3- Ant. Wall of Rectus sheath

B- Medial 4- Rectus Muscle

5- Post. Wall of Rectus sheath B- Medial 5- Post. Wall of Rectus sheath

B- Medial 6- Peritoneum

External Oblique Muscle

External Oblique Muscle Origin Fleshy digitations from the lower 8 ribs

External Oblique Muscle Xiphoid Process Insertion The muscle is inserted by fleshy fibers as well as aponeurosis, as follows: A- Fleshy fibers: Outer lip of the iliac crest B- Aponeurosis: Medial part → linea alba from xiphoid process to symphysis pubis Lateral part → folded upwards & backwards upon itself to form the inguinal ligament (ASIS → pubic tubercle) Symphysis Pubis

External Oblique Muscle Direction of fibers Downward Forwards Medially

External Oblique Muscle Nerve Supply Intercostal nerves (T7 -T11) & Subcostal nerve (T12)

Internal Oblique Muscle

Internal Oblique Muscle Origin Anterior 2/3 of the intermediate line of the iliac crest The lateral 2/3 of the inguinal ligament Lumbar fascia Insertion Lower 6 costal cartilages Xiphoid process Linea Alba Pubic crest

Internal Oblique Muscle Direction of fibers Upwards Forwards Medially Nerve Supply T7-T12 Iliohypogastric n. Ilioinguinal n.

Transversus Abdominis Muscle

Transversus Abdominis Muscle Origin 1- Lower 6 intercostal cartilages 4- Lat. 1/3 of inguinal ligament 2- Lumbar Fascia 3- Ant. 2/3 of inner lip of iliac crest

Transversus Abdominis Muscle Insertion 1- Xiphoid Process 3- Linea Alba 2- Pubic Crest

Transversus Abdominis Muscle Direction of fibers Horizontally

Transversus Abdominis Muscle Nerve Supply T7-T12 Iliohypogastric n. Ilioinguinal n.

Rectus Abdominis Muscle

Rectus Abdominis Muscle Insertion 7th, 6th, 5th costal cartilages Xiphoid process Origin From the pubic crest

Rectus Abdominis Muscle The muscle is divided into segments by tendinous intersections, Which indicate that the muscle arises from a number of myotomes, fused together Surgical Importance 1- Segmental nerve supply. 2- Hematoma of rectus m. is localized 2- In paramedian incision  displace m. laterally (n. supply comes from lateral)

It is a landmark of linea alba intraoperative Pyramidalis Muscle It is a landmark of linea alba intraoperative

Actions of Anterior Abdominal Wall Muscles They assist in raising the intra-bdominal pressure (so, they help in vomiting, cough, delivery, etc….) Keep the abdominal viscera in position. Rectus abdominis flexes the trunk, while the 2 oblique muscles bend the trunk laterally. Act as accessory expiratory muscles. Lower midline & paramedian incisions.

Rectus Sheath

Rectus Sheath Medially Laterally Linea Alba Arcuate Line Linea Semilunaris Laterally

Rectus Sheath Above Arcuate Line SKIN Peritoneum External Oblique Ant. Layer of Rectus Sheath Internal Oblique Transversus Abdominis Rectus Abdominis SKIN Falciform Ligament Peritoneum Transverslais Fascia Post. Layer of Rectus Sheath

Rectus Sheath Below Arcuate Line SKIN Peritoneum External Oblique Ant. Layer of Rectus Sheath Internal Oblique Transversus Abdominis Rectus Abdominis SKIN Transverslais Fascia Peritoneum Urachus in Median Umbilical Fold Medial Umbilical Ligament

Arterial Supply of Anterior Abdominal Wall

Deep circumflex iliac a. - II - Descending Aorta - I - Internal Mammary a. Superior epigastric a. 10th, 11th intercostal a. Subcostal a. - III - External Iliac a. Deep circumflex iliac a. Inferior epigastric a.

Thanks You Mohamed Noman