Clinical aspect of anterior abdominal wall

Surface markings and anatomy

Regions of abdomen 1 hypochrondriac (r,l) 2 lumbar  (flank-r, l) 3 paraumbilical  4 Iliac (iliac fossa, r, l)) 5 suprapubic (hypogastric) 6 epigastric 7 left lateral line  or midclavicular line 8 transpyloric plane (L1) 9 subcostal plane 10 transtubercular plane (L5)

1 External oblique muscle of abdomen 2 Tendinous intersections of rectus abdominis

 

 

Surface markings of abdominal organs

Organ

Surface marking

Spleen

9th, 10th and 11th on the left

Liver

From up of 10th rib to below the nipple. Not usually palpable below costal margin

Kidney

Upper pole is deep to 12th rib. Right kidney lies 2.5 cm lower than left

Aorta

Terminates at level of Iliac crest which is about L4

Pancreas

Neck lies at the level of transpyloric plane

Gall-bladder

Lies at tip of 9th costal cartilage where the lateral border of rectus abdominis cuts the costal margin

 

Anterior abdominal wall

This is the gateway to the abdominal cavity anteriorly. It exposes the true intraperitoneal structures such as the small intestine, stomach, distal duodenum, transverse colon and sigmoid colon

It is provided with the following layers

1. Skin

2. Superficial fascia

3. THERE IS NO DEEP FASCIA

4. Layer of muscles which are arranged in three strata

a.  External oblique muscle of abdomen

b.  Internal oblique muscle of abdomen

c.  Transversus abdominis

The three layers correspond to the three layers of muscles in the intercostal spaces which are the external intercostal, internal intercostals and innermost intercostals muscles

5. Transversalis fascia

6. Parietal peritoneum

Hernia

A hernia is an abnormal protrusion through a normal or abnormal space or opening. In the case of the inguinal hernia, it is an abnormal protrusion through the normal inguinal canal opening. It may be congenital and if so, it may extend through the embryological processus vaginalis into the scrotal sac forming the so called congenital inguino-scrotal hernia.

The inguinal canal is formed as  an oblique opening through the muscles of the anterior abdominal wall. It extends from the superficial inguinal ring (external oblique aponeurosis) to the deep inguinal ring (transversalis fascia). It is about 4cm long.  The hernia is usually a viscus, such as small or large intestine, urinary bladder, appendix, omentum etc. It passes through  the deep inguinal ring acquiring the similar covering of internal spermatic fascia. It also acquires the covering of cremasteric fascia in the inguinal canal. In order to separate it therefore from the  spermatic cord, the line of cleavage with  the above fasciae must be sought for. It may extend from the deep inguinal ring to the superficial inguinal ring, in which case it is called the indirect or oblique hernia. If it enters through the posterior wall made up of conjoint tendon (medially) and transversalis fascia (laterally), it is called a direct hernia.

A hernia is repaired by removing the hernial sac after the reduction of the hernia and then reconstructing the inguinal canal using stitches that reduce its size.

Other types of hernia exist in the anterior abdominal wall. All anterior abdominal wall hernias are said to be external hernias as opposed to the internal hernias which occur in the peritoneal and other cavities of the body.

Other external hernia includes

  • Femoral hernia

  • Interstitial hernia (passes through the muscle fibers )

  • Epigastric hernias through linea alba above the umbilicus

  • Paraumbical hernia

  • Umbilical hernia

  • Lumbar hernia (found a the lumbar triangle)

.Blood supply to the anterior abdominal wall

  • Intercostal vessels

  • Internal thoracic artery

  • Musculophrenic artery

  • Lumbar arteries

 

 

 


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Electronic School of Medicine
Creator: Oluwole Ogunranti