Anterior abdominal wall

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Anterior abdominal wall
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Layers of Anterior Abdominal Wall

• In human anatomy, the layers of the abdominal
  wall are (from superficial to deep)
• Skin
• Fascia
• Camper's fascia - fatty superficial layer.
• Scarpa's fascia - deep fibrous layer.
• Muscle
• -Rectus abdominis
• -External oblique muscle
• -Internal oblique muscle
• -Transverse abdominal muscle
• Pyramidalis muscle
• Cremasteric
• Fascia transversalis
• Parital Peritoneum

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Fascia of Ant. Abdominal Wall

• 1- there is no deep fascia
• 2-the superficial fascia is formed of a single
  layer above the ambilicus , but below the
  ambilicus it differentiated into 2 layers
• a- superficial fatty layer (Campers fascia)
• - contains variable amount of fat .
• b- deep membranes layer (Scarpas fascia)
• -continuous with the superficil perineal
  fascia (colles fascia)

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Linea Alba

• An extensive aponeurosis which extend from the
  xiphoid process to the symphsis pubis .

Linea Semilunaris
the lateral margin of rectus abdominis is
marked by a line on the anterior abdominal wall
called linea semilunaris
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Muscles of the anterior abdominal wall
Classified into 2 groups 1- paramedian
muscles -Rectus abdominis muscle -
Pyramidalis muscle 2- anterolateral flat muscles
-external abdominal oblique m. -internal
abdominal oblique m. -transversus abdominis
m.
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Abdominal external oblique muscle

• the largest and the most superficial of the three
  flat muscles of the lateral anterior abdomen.

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• Origin
• lower 8 ribs (outer surface)
• Direction of the fibers
• downwards , forwards medialy
• Insertion
• -iliac crest ( anterior half of the outer lip)
• -anterior superior iliac spine
• -pubic tubercle
• -pubic crest
• -linea alba
• .

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Inguinal ligament

• -It is the infolded lower border of the external
  oblique m.
• -The inguinal ligament runs from the anterior
  superior iliac spine to the pubic tubercle.

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Abdominal internal oblique muscle

• Origin
• 1- iliac crest (ant. 2/3 of its intermediate
  line)
• 2- inguinal ligament
• ( lateral 2/3 of its inner surface).
• 3- lumbar fascia .
• Direction of the fibers
• upwards , forwards and medialy
• Insertion
• 1- linea alba
• 2- lower 4 or 5 ribs
• 3- the lower fibers forms an arched fibers
  called the conjoint tendon.

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Conjoint tendon

• -Formed by the lower arched fibers of both
  internal oblique and transversus abdominis
  muscles where the fiberous pass directly from
  origin to insertion
• -Function
• The contraction of the conjoint tenden leads to
  closure of the inguinal canal
• (shutter mechanism )
• -So , it prevent passage of intestine through the
  canal (Indirect inguinal hernia) .

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Transversus abdominis muscle

• Origin
• -the lateral third of the inner surface of
  inguinal ligament
• -anterior 2/3 of the medial lip of the iliac
  crest
• -the inner surfaces of the cartilages of the
  lower 8 ribs
• -the thoracolumbarl fascia.
• Direction of the fibers
• -horizontaly .
• Insertion
• a- linea alba
• b-the lower fibers form an arched fibers
  together with the lower fibers of internal
  oblique muscle (conjoint tendon)

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Rectus abdominus m.
Site it lies in the middle part of the
abdominal muscle layer inside the tendinous
sheath called rectus sheath. Origin symphysis
pupis and pubic crest. Insetion 5th, 6th 7th
costal cartilages- -The muscle is divided by 3
tendinous intersections as follows -These
tendentious intersections are present on the
anterior surface of the muscle and indicate that
the muscle arises from different myotomes .
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Action -flexion of the trunk . Surface
anatomy the lateral margin of rectus
abdominis is marked by aline on the anterior
abdominal wall called linea semilunaris .
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Cremastric muscle

• It is formed by loops of muscle fibres from the
  lower part of the internal oblique
• it extends down through the spermatic cord
  return behind it to be attached to the pupic
  tubercle
• its n. supply is the genital branch of the
  genitofemoral n.
• action
• elevation of testis upwards in the cold
  weather.
• Cremastric reflex
• Scratching of the upper medial parts of the
  thigh (L1) leads to elevation of the testis.

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Pyramidalis muscle

• origin
• pubic crest and symphysis pubis
• insertion
• into the lower part of the linea alba
• nerve supply
• subcostal nerve
• action
• it stretches the linea alba

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Action of the anterior abdominal wall muscles

• 1-support the viscera and keep them in their
  position
• 2-contract to increase the intra-abdominal
  pressure during urination and defection (mainly
  the trunsversus abdominis).
• 3-expiratory action
• -the abdominal muscles contract during
  expiration and relax during inspiraion .
• 4-movement of the trunk
• a-contraction of rectus abdominis muscle
  ..forward flexion.
• b-contraction of one side of the oblique
  muscles .lateral flexion .
• c. combined action of external oblique with the
  oppisite internal oblique rotation of the trunk
  .
• 5- elevation of the testis ..by the cremastric
  m .

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Inguinal canal

• Definition
• It is an oblique inter-muscular canal
  (4cm) above the medial part of the inguinal
  ligament.
• Openings
• -it starts at the deep inguinal ring and
  ends at the superfascial inguinal ring.

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a-Superfascial Inguinal Ring

• Site
• it is a triangular or inverted V shaped opening
  in the external oblique aponeurosis.
• its margins give the external spermatic fascia to
  cover the spermatic cord.
• Surface anatomy
• It lies just above the pupic tubercle.
• Structures passing through it
• -illio-inguinal nerve.
• -Spermatic cord ( in male) or round ligament ( in
  female)

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B -Deep Inguinal Ring

• Site
• It is a small opening in the lower part of
  fascia transversalis.
• Its margins give the internal spermatic fascia to
  cover the spermatic cord.
• Surface anatomy
• - It lies ½ an inch above the mid-point of the
  inguinal ligament.
• Structures passing through it
• -Spermatic cord (in male) or round ligament ( in
  female).

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Arteries of the Anterior Abdominal wallA- Above
the umbilicus

• 1-superior epigastric artery
• 2-musculo-phrenic artery
• 3-lower two posterior intercostal and subcostal
  arteries

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B- Below the umbilicus

• 1-Inferior epigastric artery
• 2-Deep circumflex iliac artery
• 3-Superficial branches of femoral artery

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Veins of Anterior Abdominal Wall

• The anterior abdominal wall is drained by veins
  corresponding to the arteries

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Nerves of the Anterior Abdominal Wall

• 1-Lower five intercostal and subcostal nerves
• 2-Illio-hypogastric and illio-inguinal nerves
• ..

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Lymphatics of Anterior Abdominal Wall

• A-Above the umbilicus into pectoral lymph nodes
• B- Below the umbilicus into superficial inguinal
  lymph nodes

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