Download Anatomy of anterior abdominal wall and hernia

Anatomy of anterior abdominal wall and
hernia
Dr.Munirah Batarfi
MD, MSc & PhD
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Layers of the Anterior Abdominal Wall
1- Skin.
2- Superficial fascia:
a- Superficial fatty layer, (Camper’s fascia)
b- Deep membranous layer, (Scarpa’s fascia)
No Deep Fascia in the anterior abdominal wall
3- External oblique muscle.
4- Internal oblique muscle.
5- Transversus abdominis muscle.
6- Fascia Transversalis.
7- Extraperitoneal fatty Tissue.
8- Peritoneum.
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Layers of anterolateral
abdominal wall:
1- Skin.
2- Superficial fascia:
a- Superficial fatty layer
(Camper’s fascia).
b- Deep membranous
(Scarp’s fascia).
4- Muscular layers: (External &
internal oblique and transversus
abdominis.
5- fascia transversalis.
6- Space of Bogros, (extra peritoneal
fatty tissue).
7- Parietal peritoneum.
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Layers of the abdominal wall
Its layers consist of skin, superficial fascia (subcutaneous tissue), muscles and their associated
deep fascias, extraperitoneal fascia, and parietal peritoneum.
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External Oblique
• Origin: outer surface of the lower
8 ribs.
(by 8 fleshy digitations which
interdigitate with serratus
anterior and latissimus dorsi.
• Insertion: Xiphoid process,
Linea alba, Pubic crest, Pubic
tubercle, ASIS. & anterior ½
of the outer lip of the iliac
crest.
• Direction of its fibers :
Downward, Forward, and
Medially.
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Internal Oblique
Origin: lateral 2/3 of the inguinal
ligament, anterior 2/3 of iliac
crest, and lumbar fascia.
Insertion: Lower border of lower
3 ribs and their costal cartilages,
xiphoid process, linea alba,
symphysis pubis, pubic crest
and Pectineal line.
Direction of its Fibers: upward
forward and medially (at right
angle with the fibers of the
external oblique).
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Transversus Abdominis
Origin: Lateral 1/3 of
inguinal ligament,
anterior 2/3 of inner lip of
iliac crest, lumber fascia
and lower 6 costal
cartilages.
Insertion: Xiphoid Process,
Linea alba, Pubic crest,
and Pectineal line.
Direction of its fibers:
Horizontally.
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Rectus Abdominis
Origin: By 2 heads from pubic crest, pubic
and front of symphysis pubis.
tubercle
Insertion: Into 5th,6th,and 7th costal cartilages,
and xiphoid process.
It is a strap muscle that extend along the whole
length of the anterior abdominal wall.
It shows a transverse tendinous intersection.
It is enveloped in Rectus Sheath.
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Contents of Rectus Sheath
2 Muscles: Rectus Abdominis & Pyramidalis.
2 Vessels : Superior & inferior epigastric vessels.
2 nerves: Lower 5 intercostal & Subcostal nerves
Lymph Vessels.
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Abdominal wall muscles
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Inguinal Canal
An oblique passage through the lower part of the anterior abdominal
wall
Extends from the deep inguinal ring to the superficial inguinal ring
Present in both sexes
About 4 cm long in the adult ( very short in children as the two rings lie
near each other)
Lies parallel to and above the inguinal ligament
Has anterior, posterior, inferior (floor) and superior (floor) walls
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Superficial inguinal ring
• Triangular aperture in
the aponeurosis of
external oblique muscle
• Base formed by the
pubic crest
• Margins called the
‘crura’ give origin to
external spermatic fascia
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Deep inguinal ring
An oval opening in the fascia
transversalis
Lies about ½ inch above the
midinguinal point
Related medially to the inferior
epigastric vessels
Margins give origin to internal
spermatic fascia in male, and
covering of round ligament of
uterus in female
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Anterior Wall
Formed along its entire length
by the aponeurosis of
external oblique
Reinforced in its lateral third
by the fibers of the origin of
the internal oblique
Anterior wall is strongest in
the lateral part where it lies
opposite the weakest part of
the posterior wall, namely
the deep inguinal ring
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Posterior Wall
Formed along its entire length
by the fascia transversalis
Reinforced in the medial third
by the conjoint tendon
Posterior wall is strongest in
the medial part where it lies
opposite the weakest part of
the anterior wall, namely the
superficial inguinal ring
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Superior Wall (Roof)
Formed by the
arching lowest
fibers of the
internal oblique
and transversus
abdominis
muscles
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Inferior Wall (Floor)
Formed by the
inguinal ligament
and its medial end,
the lacunar
ligament
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Inguinal canal: Mechanics
Though a weak area of the
abdominal wall, but in
normal conditions:
Anterior and posterior walls
are reinforced against weak
areas
When abdominal muscles
contract, superior arched
fibers close the canal
In squatting position, anterior
surface of thigh lies against
the abdomen, thus
supporting the wall
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Contents of the Inguinal canal
Spermatic cord and Ilioinguinal nerve in male
Round ligament of uterus and ilioingunal nerve in female
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Spermatic Cord
Collection of structures that
traverse the inguinal canal
and pass to and from the
testis
Covered by three layers of
fascia derived from the
layers of the abdominal
wall
Begins at the deep inguinal
ring, lateral to inferior
epigastric vessels, and
ends at the testis
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Inguinal hernias (Cont’d)
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Hernia
Hernia is the protrusion of
part of abdominal viscera
beyond the normal
confines of the abdominal
walls
It has three parts:
The sac
Contents of the sac
Coverings of the sac
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Hernia: Types cont’d
Diaphragmatic/Hiatal
Lumbar (Petit’s triangle)
ObturatorEpigastric
Umbilical: congenital (omphalocele) or acquired
Inguinal: direct or indirect
Femoral
Incisional
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Surgical abdominal incisions
• Gridiron (muscle‐splitting) incisions are often used for an appendectomy.
• The oblique McBurney incision is made at the McBurney point,
approximately 2.5 cm
superomedial to the ASIS on the spinoumbilical line. This incision is
currently less popular than an almost transverse incision in the line of a skin
crease.
• Suprapubic (Pfannenstiel) incisions (“bikini” incisions) are used for
most gynecological and obstetrical operations.
• Transverse incisions.
• Subcostal incisions.
High‐Risk Incisions
Pararectus incisions along the lateral border of the rectus sheath are
undesirable because they are likely
to cut the nerve supply to the rectus abdominis. Blood supply from the
inferior epigastric artery also may be compromised. Inguinal incisions for
repairing herniasmay injure the ilioinguinal nerve directly or it may be
inadvertently included in the suture during closure of the incision. In such
cases, people may feel pain in the L1 dermatome region, which includes the
scrotum (or the labium majus).
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Inguinal Hernia
Herniation of the abdominal
viscera (usually small
intestinal coils) through
the inguinal region
It is of two type:
Direct
Indirect
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Indirect Inguinal hernia
Most common form of
hernia
Most common in children
& young adults
About 20 times more
common in male than in
female
1/3rd are bilateral
More common on the
right side
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Indirect Inguinal hernia cont’d
Hernial sac:
Formed of remains of processus
vaginalis
Enters inguinal canal through
deep ring
Lies lateral to the inferior
epigastric artery
Can be complete, extending to
the scrotal sac, or incomplete,
arrested in the inguinal canal
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Direct Inguinal hernia
Comprise about 15% of inguinal hernia,
Rare in females
Common in old men with weak abdominal
muscles
Hernial sac:
Bulges directly anteriorly through the
posterior wall of the inguinal canal
i.e.through the inguinal
(Hasselbach’s) triangle. This
triangle is bounded medially by
lateral edge of rectus abdominis
muscle, laterally by inferior
epigastric artery, infeiorly by
inguinal ligament.
Lies medial to the inferior epigastric
vessels
Usually nothing more than a generalized
bulge
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Femoral Hernia
Protrusion of abdominal
viscera through the
femoral ring into the
upper part of the thigh
More common in women
(wider femoral ring)
Neck of the sac lies below
and lateral to the pubic
tubercle
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Relation of inguinal & femoral hernial sacs to pubic
tubercle
Inguinal: sac lies above
and medial to the pubic
tubercle
Femoral: sac lies below
and lateral to the pubic
tubercle
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Inguinal hernias
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Relation of inguinal hernia to Inferior epigastric vessels
Right inguinal triangle. A. Internal view. B. Laparoscopic view showing the parietal
peritoneum still covering the area.
Other types of Hernias
• Femoral hernias
• Umbilical hernias
• Para-umbilical hernias
• Incisional hernias
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References
Gray's Anatomy for Students- Second edition
Clinically Oriented Anatomy , Keith L. Moore- Sixth
edition
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