Clinical Anatomy of Anterior Abdominal Wall

Anterior abdominal wall consists of following layers outside to in-

1. Skin:
2. Superficial fascia:
   1. Superficial fatty layer of Camper
   2. Deep fibrous layer of Scarpa
   3. Muscles of Anterior Abdominal wall:
      1. External oblique: Outer surface of lower 8 ribs → Xiphoid, linea alba, Pubic crest, Pubic tubercle, Anterior ½ pubic crest
      2. Internal oblique: Lumbar fascia, Anterior 2/3 iliac crest, Lateral 2/3 inguinal ligament→  Lower 6 costal cartilages, line alba, pubic crest
      3. Transversus abdominis: Lower 6 costal cartilages, Lumbar fascia, Anterior 2/3 iliac crest, Lateral 1/3 inguinal ligament→Linea alba, Pubic crest
      4. Rectus abdominis: 5-7 costal cartilages→ Pubic crest

3 transverse tendinous intersections: Tip of xiphoid, Umbilicus and Halfway between

At each intersection vessels from superficial epigastric artery and vein pierce rectus

Rectus sheath:

1. Above costal margin: External oblique aponeurosis → Costal cartilages
2. Above arcuate line: External and internal oblique aponeuorsis → Internal and Transverse aponeurosis
3. Below arcuate line: All 3 aponeurosis → Fascia transversalis and Peritoneum

–          Arcuate line: Lower border of posterior aponeurotic part of rectus sheath where inferior gastric vessels anastomose with superior epigastric vessels

1. Fascia transversalis
2. Peritoneal fat
3. Peritoneum

Segmental nerve supply of skin and muscles: T7-L1

Ligaments:

1. Inguinal: Inferior edge of external oblique
2. Lacunar: Triangular extension of external oblique before insertion into pubic tubercle
3. Conjoined: Fusion of internal oblique and transverse aponeuroses
4. Pectineal (Cooper): Periosteum and fascia along superior ramus of pubis

 

Inguinal Canal:

Length: 1.5 inch or 4 cm

Course: Oblique; downward and medial from internal inguinal ring to external inguinal ring, parallel and immediately above inguinal ligament

Inferior epigastric vessels demarcate medial edge of internal inguinal ring

Relations:

1. Anterior: External oblique aponeurosis, Internal oblique (Lateral 1/3)
2. Posterior: Conjoined tendon (Medial), Fascia transversalis (Lateral)
3. Above: Arch of lowest fibers of internal oblique and transverse abdominis
4. Below: Inguinal and Lacunar ligament

Contents: Spermatic cord/Round ligament and Ilioinguinal nerve (L1)

Spermatic cord:

1. 3 layers of fascia: External spermatic (External oblique a.) → Cremasteric (Internal oblique a.) → Internal spermatic (Fascia transversalis)
2. Contents:
   1. 3 structures: Vas deferens, Lymphatics of testis (Para-aortic), Patent processus vaginalis (indirect hernia)
   2. 3 arteries: Testicular (aorta), Cremasteric (Inferior epigastric), Artery of vas (Inferior vesical)
   3. 3 veins: Pampiniform plexus (Rt à IVC; LtàLt renal vein), Cremasteric vein, Vein of vas
   4. 3 nerves: Nerve to cremaster (Genitofemoral), T10-11 sympathetic, Ilioinguinal (on and not in)

Myopectineal  orifice of Fruchaud: Simple layer of fascial transversalis

1. Above: arching fibers of internal oblique and transverse abdominus muscles
2. Medially: Rectus muscle and sheath
3. Inferiorly: Coopers or Pectineal ligament
4. Laterally: Iliopsoas muscle

Hesselbach’s triangle:

1. Lateral border of rectus sheath
2. Inguinal ligament
3. Inferior epigastric vessels