ANTERIOR ABDOMINAL WALL
The anterior wall is firm but elastic and consists of 8 layers from
3.External oblique muscle and its aponeurosis
4.Internal oblique muscle and its aponeurosis
5.Transversus abdominis muscle and its aponeurosis
6. Fascia transversalis
7.Extra-peritoneal tissue and
Opposite the linea alba, the layers are reduced to six in number.
Embryologically, the 7th layer of the extra-peritoneal tissue is important
because all abdominal visceras virtually lie in this layer; this fact is proved
by the coverings received by the testis during its descent.
DESCRIPTION OF DIFFERENT LAYERS
It is thinner and more sensitive than the skin of the posterior
abdominal wall. The skin presents a number of cleavage lines (Langer’s
lines). The skin presents two parts, an outer epidermis which is non- vascular
and an inner dermis or corium which is highly vascular and presents rich
The skin of the anterior abdominal wall consists of longitudinal
groove overlying the linea alba, and a curved groove on each side with the
convexity directed laterally which corresponds with the lateral border of the
rectus abdominis muscle. A surface depression, the umbilicus, affects the
median groove; It is composed of cicatritial tissue and represents remnant of
the foetal end of the umbilical cord.
Above a line joining the two anterior superior iliac spines it consists of
a single layer. Below that line it splits into superficial fatty layer (Camper’s
fascia) and deep membranous layer (Scarpa’s fascia).
SUPERFICIAL INGUINAL SPACE
It is a potential space in the anterior abdominal wall between the fascia
of Scarpa and the aponeurosis of external oblique.
EXTERNAL OBLIQUE MUSCLE
(OBLIQUUS EXTERNUS ABDOMINIS)
It arises by eight fleshy slips from the outer surfaces and lower borders
of the lower eight ribs.
The most posterior fibres pass almost vertically downwards and are
inserted by fleshy fibres to the anterior half of the outer lip of the ventral
segment of the iliac crest. Its posterior margin is free and forms the anterior
boundary of the lumbar triangle.
The remaining fibres pass downwards, forwards and medially, and end
in a broad aponeurosis.
INGUINAL LIGAMENT (POUPART’S LIGAMENT)
It is the thickened lower border of the aponeurosis of the external
oblique which is folded backwards presenting a grooved upper surface. It
measures about 12 cm. to 14cm. in length in the adult.
INTERNAL OBLIQUE MUSCLE
(OBLIQUUS INTERNUS ABDOMINIS)
1. From the lateral two – third of the upper surface of the inguinal
2. Anterior 2/3 of intermediate lip of the iliac crest.
3. Posterior layer of thoraco lumbar fascia.
1.By forming conjoint tendon it is inserted into pubic crest and
2.Forms rectus sheath and insert into the linea alba.
3. Lower 3 or 4 ribs.
It is a long strap muscle, wider above than below.
Actions of the rectus muscles