Abdominal Wall Ass. Prof. Dr. Saif Ali Ahmed Ghabisha

Abdominal wall divided into:- Anteriolateral abdominal wall Anterior wall Right lateral wall (Right Flank) Left lateral wall (Left Flank) Posterior abdominal wall Abdominal Wall

Landmarks: bony & soft costal arch: formed by 7-10 costal cartilages – infrasternal angle - sharp upward angle at midline, xiphoid process at the apex –epigastric fossa - depression just inferior to xiphoid Three bones fused together ilium: anterior superior iliac spine; iliac crest ischium pubis: pubic symphysis, inguinal ligament (below): indicated at surface by depression separating leg from abdomen

Anterolateral Abdominal Wall This extended from the thoracic cage to the pelvis and bounded : –Superiorly 7 th through 10 th costal cartilages and and xiphoid process –Inferiorly Inguinal ligaments and the pelvic bones.

The body planes The transpyloric plane The subcostal plane The supracrestal plane The intertubercular plane midway between The suprasternal notch & The symphysis pubis It is a transverse line drawn between iliac crests the highest points of the iliac crests tubercles iliac crests the 2 tubercles of the2 iliac crests the the lowest points of the costal margin It is a transverse line drawn between a transverse line a transverse line drawn between The 2 lateral vertical planes vertical line A vertical line drawn from midinguinal point to the midinguinal point midclavicular point the midclavicular point It is a transverse line drawn

The transpyloric plane L1 & The intertubercular plane L5 The Rt. & Lt. lateral vertical planes divisions of the abdomen The anterior abdominal wall 9 regions by is divided into 2 transverse lines and 2 vertical line

Epigastrium Umbilical 3 on the right side & 3 on the left side Divisions of the abdomen Rt. & Lt. Lumbar region The 9 regions are Rt. & Lt. Hypochondrium 3 in the middle Hypogastrium Rt. & Lt. Iliac region From above downward

Anteriolateral abdominal wall A- Lateral: Skin. Subcutaneous tissue. External oblique muscle. Internal oblique muscle. Transversus abdominis m. Fascia transversalis. Peritoneum. B- Medial: Skin. Superficial fascia. Anterior wall of rectus sheath. Rectus muscle. Posterior wall of rectus sheath. Peritoneum. Layer of anterior abdominal wall:

Skin Natural lines of cleavage in the skin are constant and run almost horizontally around the trunk An incision along a cleavage line will heal as a narrow scar, while one that crosses the lines will heal as a wide scar

INCISIONS Longitudinal Midline Paramedian Transrectal Oblique Subcostal McBurney’s Transverse Pfannenstiel Combined Thoracal-abdominal Skin

Antrolateral Abdominal Wall The subcutaneous tissues over most of the wall consists of layer of connective tissues that contains a variable amount of fat. In the inferior part of the wall, the subcutaneous tissue is composed of two layers –Fatty superficial layer (Camper’s fascia) –Membranous deep layer (Scarpa’s fascia) Fascia & Subcutaneous Tissues

Antrolateral Abdominal Wall

InsertionOriginMuscle linea alba, pubic crest & tubercle, anterior superior iliac spine & anterior half of iliac crest lower 8 ribsexternal abdominal oblique lower 3 or 4 ribs, linea alba, pubic crest and pecten lumbar fascia, anterior 2/3 of the iliac crest, lateral 2/3 of the inguinal ligament internal abdominal oblique linea alba, pubic crest and pecten lower 6 ribs, thoracolumbar fascia, anterior 3/4 of the iliac crest, lateral 1/3 of inguinal ligament transversus abdominis xiphoid process of the sternum and costal cartilages 5-7 pubic crest and symphysisrectus abdominis Muscle Anterior Abdominal Wall

3- External Oblique m. A- Lateral Origin: Outer surface of lower 8 ribs. Direction of its fibers: Downward, Forward, and Medially. Insertion: Xiphoid process, Linea alba, Symphysis pubis Pubic crest, Anterior ½ of Pubic tubercle, ASIS. outer lip of iliac crest. External Oblique

External Oblique Muscle Origin Fleshy digitations from the lower 8 ribs

The muscle is inserted by fleshy fibers as well as aponeurosis, as follows: A- Fleshy fibers: Outer lip of the iliac crest B- Aponeurosis: 1.Medial part → linea alba from xiphoid process to symphysis pubis 2.Lateral part → folded upwards & backwards upon itself to form the inguinal ligament (ASIS → pubic tubercle) Insertion Xiphoid Process Symphysis Pubis External Oblique Muscle

Direction of fibers Downward Forwards Medially External Oblique Muscle

Nerve Supply Intercostal nerves (T7 -T11) & Subcostal nerve (T12) External Oblique Muscle

4- Internal Oblique m. Origin: fascia. Lateral 2/3 of inguinal ligament, Anterior 2/3 of iliac crest, Lumbar Direction of its Fibers: upward forward and medially (at right angle with the fibers of external oblique). Insertion:  Lower 3 ribs and their costal cartilages,  Xiphoid process,  Linea alba,  Pubic crest and  Pectineal line. Internal Oblique

Internal Oblique Muscle Origin Insertion 1.Anterior 2/3 of the intermediate line of the iliac crest 2.The lateral 2/3 of the inguinal ligament 3.Lumbar fascia 1.Lower 6 costal cartilages 2.Xiphoid process 3.Linea Alba 4.Pubic crest

Direction of fibers Upwards Forwards Medially Nerve Supply T7-T12 Iliohypogastric n. Ilioinguinal n. Internal Oblique Muscle

5- Transversus abdominis m. Origin: Lateral 1/3 of inguinal ligament, Anterior 2/3 of inner lip of iliac crest, Lumber fascia and Lower 6 costal cartilages. Direction of its fibers: Horizontally. Insertion: alba, PubiXiphoid Process, Linea c crest, and Pectineal line. Transversus Abdominis

Transversus Abdominis MuscleOrigin 1- Lower 6 intercostal cartilages 2- Lumbar Fascia 3- Ant. 2/3 of inner lip of iliac crest 4- Lat. 1/3 of inguinal ligament

Insertion 1- Xiphoid Process 2- Pubic Crest 3- Linea Alba

Direction of fibers Horizontally

Nerve Supply T 7 -T 12 Iliohypogastric n. Ilioinguinal n.

  Is a long fibrous sheath   Encloses the rectus abdominis and pyramidalis muscle (if present)   Formed mainly by aponeurosis of three lateral abdominal muscles Rectus Sheath

Contents: 2 Muscles: Rectus Abdominis & Pyramidalis. 2 Vessels : Superior & inferior epigastric vessels. 2 nerves: Lower 5 intercostal & Subcostal nerves.

Rectus Sheath For description it is considered at three levels: Above the costal margin the anterior wall is formed by the aponeurosis of the external oblique and posterior wall is formed by the thoracic wall That is the 5 th, 6 th and 7 th costal cartilages and the intercostal spaces

Rectus Sheath Between the costal margin and the level of the anterosuperior iliac spine, the aponeurosis of the internal oblique splits to enclose the rectus muscle The external oblique aponeurosis is directed in front of the muscle Transversus aponeurosis is directed behind the muscle

Between the level of the anterosuperior iliac spine and the pubis, the aponeurosis of all three muscles form the anterior wall. The posterior wall is absent. The rectus muscle lies in contact with the fascia transversalis Rectus Sheath

Medially Laterally Linea Alba Linea Semilunaris Arcuate Line

Falciform Ligament External Oblique Internal Oblique Transversus Abdominis Ant. Layer of Rectus Sheath Post. Layer of Rectus Sheath Rectus Abdominis Above Arcuate Line SKIN Peritoneum Transverslais Fascia

External Oblique Internal Oblique Transversus Abdominis Ant. Layer of Rectus Sheath Rectus Abdominis Below Arcuate Line Urachus in Median Umbilical Fold Medial Umbilical Ligament Transverslais Fascia SKIN Peritoneum

Origin: By 2 heads from: Pubic crest, Pubic tubercle and. Front of symphysis pubis. Insertion: Into 5 th,6 th & 7 th 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 lies within the Rectus Sheath. Rectus Abdominis

Rectus Abdominis Muscle Origin From the pubic crest Insertion 7th, 6th, 5th costal cartilages Xiphoid process

RECTUS ABDOMINIS

Rectus Abdominis Muscle Surgical Importance The muscle is divided into segments by tendinous intersections, Which indicate that the muscle arises from a number of myotomes, fused together 1- Segmental nerve supply. 2- Hematoma of rectus m. is localized 2- In paramedian incision  displace m. laterally (n. supply comes from lateral)

Pyramidalis Origin Pubic symphysis, Pubic crest Insertion linea alba Nerve supply: Subcostal nerve (T12). Actions: Tensing the linea alba

Pyramidalis Muscle It is a landmark of linea alba intraoperative

Linea Alba Is a vertically running fibrous band that extends from xiphoid process to the symphysis pubis and lies in the midline. It is formed by the fusion of the aponeurosis of the muscles of the anterior abdominal wall and is represented on the surface by a slight median groove. A B C

5- Post. Wall of Rectus sheath

Linea Alba

Fascia Transversalis m  Transversus aponeurosis is directed behind the muscle

Peritoneum

Actions of Anterior Abdominal Wall Muscles They assist in raising the intra-bdominal pressure (so, they help in vomiting, cough, delivery, etc….) Keep the abdominal viscera in position. Rectus abdominis flexes the trunk, while the 2 oblique muscles bend the trunk laterally. Act as accessory expiratory muscles. Lower midline & paramedian incisions.

Antrolateral Abdominal Wall Arteries Internal Thoracic Artery –Superior Epigastric Artery External Iliac Artery –Inferior Epigastric Artery –Deep Circumflex Iliac Artery Femoral Artery –Superfecial Epigastric Artery –Superfecial Circumflex Artery

Superior epigastric a. Subcostal a. Inferior epigastric a. Deep circumflex iliac a. - I - Internal Mammary a. - III - External Iliac a. - II - Descending Aorta 10th, 11th intercostal a.

lateral thoracic subclavian thoracoepigastric paraumbilical portal S epigastric S circumflex iliac femoral Superficial veins

Lymph Drainage Lymph drainage of the skin of the anterior abdominal wall above the umbilicus is upward to the anterior axillary (pectoral group of nodes) Below the level of umbilicus drains downward and laterally to the superficial inguinal nodes Swelling in the groin is may be due to enlarged superficial inguinal node

Anterolateral Abdominal Wall Nerves T7 – T11 Thoracoabdominal Nerves T12 Sub-costal nerve L1 ilio-hypogastric Nerve. ilio inguinal Nerves

Caput Medusae The superficial veins around the umbilicus and the paraumbilical veins connecting them to the portal vein may become grossly distended in case of portal vein obstruction The distended subcutaneous veins radiate out from the umbilicus, producing in severe cases the clinical picture called Caput Medusae

It is an oblique intramuscular passage in the lower medial part of the Anterior Abdominal Wall. It runs just above and parallel to the medial half of the inguinal ligament. Its length is about 2 inches (5 cm), long in adult. Its gives a passage for the spermatic cord in male, or round ligament of the uterus in female. Also it gives a passage for the Ilioinguinal nerve in both sexes. It connects between the superficial and deep inguinal rings. INGIUNAL CANAL

Superficial Inguinal Ring It’s an oval slit in the lower aponerotic fibers of the external oblique just above & lateral to pubic tubercle. The lateral crus attaches to pubic tubercle & The medial crus attaches to pubic crest.

Deep Inguinal Ring It is an opening in the fascia transversalis 1 cm above the middle of the inguinal ligament (midpoint of inguinal ligament) It lies lateral to the inferior epigastric vessels

Anterior. Wall: External oblique along whole length. Internal oblique along lateral half. Posterior. Wall: Fascia Transversalis along whole length. Conjoint tendon along the medial part. Reflected ligament along the medial part. Superficial inguinal ring Deep ring Walls of the Inguinal canal

Reflected Ligament Intercrural Fibers Conjoint Tendon Cremaster Walls of the Inguinal canal

Ant. Wall: External oblique along whole length

Anterior wall: Internal oblique along lateral half.

Deep Inguinal Ring: Its an opening in the fascia transversalis 1cm above the middle of the inguinal ligament and lateral to the inferior epigastric vessels. Posterior wall

Floor : Inguinal ligament supported medially by the Lacunar ligament. Roof: Arching lower fibers of internal oblique. Floor and Roof

Boundaries of the Inguinal canal Ant. Wall: External oblique along whole length Internal oblique along lateral half. Post. Wall: Fascia transversalis along whole length. Conjoint tendon along the medial half. Reflected ligament along the medial part. Floor: Inguinal ligament supported medially by the Lacunar ligament. Roof: Arching lower fibers of internal oblique.

Mechanics of the Inguinal Canal - It is the site of potential weakness in the anterior abdominal wall in both sexes. - The design of the inguinal canal decrease this weakness by: 1. The canal is an oblique passage: The weakest areas the superficial and deep inguinal rings lying a way from each others. 2. The anterior wall: It is reinforced by the fibers of the internal oblique muscle in front of the deep inguinal ring. 3. The posterior wall: It is reinforced by the strong conjoint tendon behind the superficial inguinal ring. Deep inguinal ring Superficial inguinal ring External oblique Internal oblique Fascia transversalis Conjoint tendon Anterior wall Posterior wall Lateral Medial

4. On coughing and straining (in micturition, defecation and parturition): The arching fibers of the internal oblique and transversus abdominis muscles. contracts leading to flattening of the roof. The roof actually compress the contents of the canal against the floor so that the canal is virtually closed. 5. When great straining efforts may be necessary : The person naturally assume the squatting position so the lower part of the anterior abdominal wall is protected by the thighs.

Shutter Mechanism Mechanics of the Inguinal Canal

Inguinal triangle Region of abdominal wall. Borders: Medial border: Lateral margin of the rectus sheath, also called linea semilunaris Superolateral border: Inferior epigastric vessels Inferior border: Inguinal ligament

Posterior Abdominal Wall

Posterior abdominal wall A musculoskeletal wall between the lower border of the rib cage and the pelvic brim Marks the posterior boundary of the abdominal cavity Anteriorly lie the retroperitoneal organs and the parietal peritoneum Posteriorly lie muscles, fascia and the lumbar spine

Posterior Abdominal Wall Lumbar vertebrae and IV discs. Muscles Psoas, quadratus lumborum, iliacus, transverse, abdominal wall oblique muscles. Lumbar plexus Ventral rami of lumbar spinal nerves. Fascia Diaphragm Contributing to the superior part of the posterior wall Fat, nerves, vessels (IVC, aorta) and lymph nodes.

Posterior Abdominal Wall Fascia Between the parital peritoneum and the muscles The psoas fascia or psoas sheath. The quadratus lumborum fascia. The thoracolumbar fascia.

Anterior layer Middle layer Posterior layer Posoas major muscle Quadratus lumborum Erector spinae Posoas fascia Internal oblique Transversus abdominis Posterior Abdominal Wall (Fascia)

Posterior Abdominal Wall Muscles Three paired muscles Psoas major Iliacus Quadratus Lumborum

Psoas major Originates from bodies of T12 to L5, intervertebral disks and the medial end of transverse processors Inserted into the lesser trochanter of the femur Part above the medial arcuate ligament lies in the thoracic cavity Flexes the hip and laterally flexes the lumbar spine Both muscles acting together flexes the trunk

Quadratus lumborum Originates from transverse process of L5, iliolumbar ligament and iliac crest Inserted into the transverse processes of L4 to L1 and the 12th rib medial half

Iliacus Originates from upper 2/3 of iliac fossa and anterior sacroiliac ligament thereby filling the illiac fossa Inserted into the lesser trochanter of the femur trough a common tendon with the psoas major Flexes the hip Psoas major muscle Iliacus Common attachment

Diaphragm

Lateral arcuate ligament Medial arcuate ligament L1 Arcuate ligaments Median arcuate ligament Formed by tendinous fibres from medial edges of left and right crura of the diaphragm

Organs in the posterior abdominal wall Duodenum 2 nd and 3 rd parts Pancreas Kidneys and ureters Suprarenal glands

Organs in the posterior abdominal wall

Vessels Aorta and its branches Inferior vena cava and its tributaries Portal vein and its tributaries Lymphatics and lymph nodes

Branches of abdominal aorta Main branches are in three categories Single ventral arteries to gut and its derivatives –Coeliac trunk, superior and inferior mesenteric Paired arteries to other viscera –Suprarenal, renal, gonadal Paired arteries to body wall –Inferior phrenic, lumbar

L5 T12 Branches of abdominal aorta Coeliac trunk Superior mesenteric a. Inferior mesenteric a. Median sacral artery R. inferior phrenic art. R. 4 th lumbar art. R. suprarenal art. R. renal art. R. gonadal art.

Branches of abdominal aorta

Related structures Coeliac trunk Superior mesenteric a. Inferior mesenteric a. Splenic vein Body of pancreas L. renal vein Un. pro. pancreas 3 rd part duodenum Median sacral artery L5 T12 T.P.P

Paravertebral gutters lumbar lordosis Forward projection is enhanced by aorta and IVC Floor is formed by psoas and quadratus lumborum above and iliacus below the iliac crest Posterior part of the diaphragm also contributes

Lymph nodes Single ventral arteries Paired arteries to other viscera Paired arteries to body wall Pre-aortic nodes Para-aortic nodes Lymphatics follow arteries

Lymph nodes

Internal iliac nodes External iliac nodes Common iliac nodes Para-aortic nodes Pre-aortic nodes Cisterna chyli Thoracic duct Lymph nodes

Posterior Abdominal Wall Nerves  The sub costal nerves  The lumbar nerves  The lumbar plexus of nerves branchus are: (a) The obturator nerves (L 2 – L 4 ) (b) The femoral nerves (L 2 – through L 4 ) (c) Ilio inguinal and ilio hypogastric nerves (L 1 ) (d) Gentio femoral (L1 – L2) (e) Lateral femoral cutaneous nerves (L2 – L3)

Lumbar plexus 1 st – 4 th lumbar spinal segments Embeded in the psoas Branches related laterally, medially or anteriorly to psoas

Branches of lumbar plexus & psoas muscle

Psoas Abscess Hematogenous spread to the lumbar vertebrae may form an abscess which may spread from the vertebrae into the Psoas sheath producing a Psoas abscess.