CLINICAL ANATOMY OF CLINICAL ANATOMY OF ANTERIOR ABDOMINAL WALL ANTERIOR ABDOMINAL WALL

& RECTUS SHEATH& RECTUS SHEATH

By: Dr. Mujahid KhanBy: Dr. Mujahid Khan

Structure of Abdominal CavityStructure of Abdominal Cavity

Superiorly it is formed by diaphragm which Superiorly it is formed by diaphragm which separates the abdominal cavity from the separates the abdominal cavity from the thoracic cavitythoracic cavity

Inferiorly the abdominal cavity is Inferiorly the abdominal cavity is continuous with the pelvic cavity through continuous with the pelvic cavity through the pelvic inletthe pelvic inlet

Structure of Abdominal WallStructure of Abdominal Wall

Anteriorly:Anteriorly:

The abdominal wall is formed above by The abdominal wall is formed above by lower part of the thoracic cagelower part of the thoracic cage

Below by the rectus abdominis, external Below by the rectus abdominis, external oblique, internal oblique, and transversus oblique, internal oblique, and transversus abdominis muscles and fasciaeabdominis muscles and fasciae

Structure of Ant. Abdominal WallStructure of Ant. Abdominal Wall

It is made up of skin, superficial fascia, It is made up of skin, superficial fascia, deep fascia, muscles, extraperitoneal deep fascia, muscles, extraperitoneal fascia and parietal peritoneumfascia and parietal peritoneum

The abdominal walls are lined by a fascial The abdominal walls are lined by a fascial envelope and the parietal peritoneumenvelope and the parietal peritoneum

SkinSkin

Natural lines of cleavage in the skin are Natural lines of cleavage in the skin are constant and run almost horizontally constant and run almost horizontally around the trunkaround the trunk

An incision along a cleavage line will heal An incision along a cleavage line will heal as a narrow scar, while one that crosses as a narrow scar, while one that crosses the lines will heal as a wide scarthe lines will heal as a wide scar

Cutaneous Nerve SupplyCutaneous Nerve Supply

Is derived from the anterior rami of the Is derived from the anterior rami of the lower six thoracic and first lumbar nerveslower six thoracic and first lumbar nerves

Thoracic nerves are the lower five Thoracic nerves are the lower five intercostal and the subcostal nervesintercostal and the subcostal nerves

First lumbar nerve is represented by the First lumbar nerve is represented by the iliohypogastric and ilioinguinal nerves iliohypogastric and ilioinguinal nerves

Blood SupplyBlood Supply

Skin near the midline is supplied by Skin near the midline is supplied by branches of the superior epigastric artery branches of the superior epigastric artery (br. of int. thoracic artery) and the inferior (br. of int. thoracic artery) and the inferior epigastric artery ( br. of external iliac epigastric artery ( br. of external iliac artery)artery)

Skin of the flanks is supplied by branches Skin of the flanks is supplied by branches from the intercostal, lumbar, and deep from the intercostal, lumbar, and deep circumflex arteriescircumflex arteries

Superficial FasciaSuperficial Fascia

Fatty layer or fascia of camper is Fatty layer or fascia of camper is continuous with the superficial fat over the continuous with the superficial fat over the rest of the body and may be extremely rest of the body and may be extremely thick in obese patientsthick in obese patients

The membranous layer or scarpa’s fascia The membranous layer or scarpa’s fascia is thin and fades out laterally and aboveis thin and fades out laterally and above

Becomes continuous with the superficial Becomes continuous with the superficial fascia of the back and the thoraxfascia of the back and the thorax

Superficial FasciaSuperficial Fascia

Inferiorly the membranous layer passes onto the Inferiorly the membranous layer passes onto the front of the thigh, where it fuses with the deep front of the thigh, where it fuses with the deep fasciafascia

In the midline inferiorly forms a tubular sheath In the midline inferiorly forms a tubular sheath for the penis or clitorisfor the penis or clitoris

Below in the perineum, enters the wall of the Below in the perineum, enters the wall of the scrotum or labia majorascrotum or labia majora

From there it passes to be attached on each From there it passes to be attached on each side to the margins of pubic arch, here it is side to the margins of pubic arch, here it is called Colle’s fasciacalled Colle’s fascia

Superficial FasciaSuperficial Fascia

Posteriorly it fuses with the perineal body Posteriorly it fuses with the perineal body and the margin of the perineal membraneand the margin of the perineal membrane

The fatty layer is represented as a smooth The fatty layer is represented as a smooth muscle in the scrotum, the dartos musclemuscle in the scrotum, the dartos muscle

The membranous layer persists as a The membranous layer persists as a separate layerseparate layer

Deep FasciaDeep Fascia

Deep fascia in the anterior abdominal wall Deep fascia in the anterior abdominal wall is merely a thin layer of connective tissue is merely a thin layer of connective tissue covering the musclescovering the muscles

It lies immediately deep to the It lies immediately deep to the membranous layer of the superficial fasciamembranous layer of the superficial fascia

Muscles Muscles

Consists of Three broad thin sheets that are Consists of Three broad thin sheets that are aponeurotic in frontaponeurotic in front

From exterior to interior they are:From exterior to interior they are:

External oblique, internal oblique, and External oblique, internal oblique, and transversetransverse

A wide vertical muscle, the rectus abdominisA wide vertical muscle, the rectus abdominis

They lie on either side of the midline anteriorlyThey lie on either side of the midline anteriorly

MusclesMuscles

As the aponeurosis of three sheets pass As the aponeurosis of three sheets pass forward, they enclose the rectus forward, they enclose the rectus abdominis to form the rectus sheathabdominis to form the rectus sheath

The cremaster muscle which is derived The cremaster muscle which is derived from the lower fibers of internal oblique, from the lower fibers of internal oblique, passes inferiorly as a covering of the passes inferiorly as a covering of the spermatic cord and enters scrotumspermatic cord and enters scrotum

External Oblique MuscleExternal Oblique Muscle

Is a broad, thin, muscular sheetIs a broad, thin, muscular sheet

Origin: Lower 8 ribsOrigin: Lower 8 ribs

Insertion: Xiphoid process, linea alba, pubic tubercle, Insertion: Xiphoid process, linea alba, pubic tubercle, iliac crestiliac crest

Nerve Supply: Lower 6 thoracic nerves, iliohypogastric & Nerve Supply: Lower 6 thoracic nerves, iliohypogastric & ilioinguinal nervesilioinguinal nerves

Action: Supports abdominal contents, assist in forced Action: Supports abdominal contents, assist in forced expiration, micturition, defecation, parturition, vomiting expiration, micturition, defecation, parturition, vomiting

External Oblique MuscleExternal Oblique Muscle

A triangular shaped defect in the external A triangular shaped defect in the external oblique aponeurosis lies immediately oblique aponeurosis lies immediately above and medial to the pubic tubercle, above and medial to the pubic tubercle, known as superficial inguinal ringknown as superficial inguinal ring

Between the anterosuperior iliac spine and Between the anterosuperior iliac spine and the pubic tubercle, the lower border of the the pubic tubercle, the lower border of the aponeurosis is folded backward on itself, aponeurosis is folded backward on itself, forming the inguinal ligamentforming the inguinal ligament

Internal Oblique MuscleInternal Oblique Muscle

Origin: Lumbar fascia, iliac crest, lateral two-Origin: Lumbar fascia, iliac crest, lateral two-thirds of inguinal ligamentthirds of inguinal ligament

Insertion: Lower three ribs and costal cartilages, Insertion: Lower three ribs and costal cartilages, xiphoid process, linea alba, symphysis pubisxiphoid process, linea alba, symphysis pubis

Nerve Supply: Lower six thoracic nerves, Nerve Supply: Lower six thoracic nerves, iliohypogastric & ilioinguinal nervesiliohypogastric & ilioinguinal nerves

Action: Supports abdominal contents, assist in Action: Supports abdominal contents, assist in forced expiration, micturition, defecation, forced expiration, micturition, defecation, parturition, vomiting parturition, vomiting

Transversus AbdominisTransversus Abdominis

Origin: Lower six costal cartilages, lumbar fascia, Origin: Lower six costal cartilages, lumbar fascia, iliac crest, lateral third of inguinal ligamentiliac crest, lateral third of inguinal ligament

Insertion: Xiphoid process, linea alba, symphysis Insertion: Xiphoid process, linea alba, symphysis pubispubis

Nerve Supply: Lower six thoracic nerves, Nerve Supply: Lower six thoracic nerves, iliohypogastric & ilioinguinal nervesiliohypogastric & ilioinguinal nerves

Action: Compresses abdominal contentsAction: Compresses abdominal contents

Rectus AbdominisRectus Abdominis

Origin: Symphysis pubis and pubic crestOrigin: Symphysis pubis and pubic crest

Insertion: 5Insertion: 5thth, 6, 6thth and 7 and 7thth costal cartilages costal cartilages and xiphoid processand xiphoid process

Nerve Supply: Lower six thoracic nervesNerve Supply: Lower six thoracic nerves

Action: Compresses abdominal contents, Action: Compresses abdominal contents, flexes vertebral column, accessory muscle flexes vertebral column, accessory muscle of expirationof expiration

Lymph DrainageLymph Drainage

Lymph drainage of the skin of the anterior Lymph drainage of the skin of the anterior abdominal wall above the umbilicus is upward to abdominal wall above the umbilicus is upward to the anterior axillary (pectoral group of nodes)the anterior axillary (pectoral group of nodes)

Below the level of umbilicus drains downward Below the level of umbilicus drains downward and laterally to the superficial inguinal nodesand laterally to the superficial inguinal nodes

Swelling in the groin is may be due to enlarged Swelling in the groin is may be due to enlarged superficial inguinal nodesuperficial inguinal node

Venous DrainageVenous Drainage Venous blood is collected into a network of veins Venous blood is collected into a network of veins

that radiate from the umbilicusthat radiate from the umbilicus

The network is drained above into the axillary The network is drained above into the axillary vein via the lateral thoracic veinvein via the lateral thoracic vein

Below into the femoral vein via the superficial Below into the femoral vein via the superficial epigastric and the great saphenous veinsepigastric and the great saphenous veins

Few small veins, the paraumbilical veins form a Few small veins, the paraumbilical veins form a clinically important portal-system venous clinically important portal-system venous anastomosisanastomosis

Caput MedusaeCaput Medusae

The superficial veins around the umbilicus The superficial veins around the umbilicus and the paraumbilical veins connecting and the paraumbilical veins connecting them to the portal vein may become them to the portal vein may become grossly distended in case of portal vein grossly distended in case of portal vein obstructionobstruction

The distended subcutaneous veins radiate The distended subcutaneous veins radiate out from the umbilicus, producing in out from the umbilicus, producing in severe cases the clinical picture called severe cases the clinical picture called Caput Medusae Caput Medusae

NervesNerves

Nerves of the anterior abdominal wall supply the Nerves of the anterior abdominal wall supply the skin, muscles and the parietal peritoneumskin, muscles and the parietal peritoneum

They are derived from the anterior rami of lower They are derived from the anterior rami of lower six thoracic and the first lumbar nervessix thoracic and the first lumbar nerves

Inflammation of parietal peritoneum causes pain Inflammation of parietal peritoneum causes pain in the overlying skin and also a reflex increase in in the overlying skin and also a reflex increase in tone of the abdominal musculature in the same tone of the abdominal musculature in the same area area

Rectus SheathRectus Sheath

Is a long fibrous sheathIs a long fibrous sheath

Encloses the rectus abdominis and pyramidalis Encloses the rectus abdominis and pyramidalis muscle (if present)muscle (if present)

Contains the anterior rami of lower six thoracic Contains the anterior rami of lower six thoracic nerves and the superior and inferior epigastric nerves and the superior and inferior epigastric vessels and lymph vesselsvessels and lymph vessels

Formed mainly by aponeurosis of three lateral Formed mainly by aponeurosis of three lateral abdominal musclesabdominal muscles

Rectus SheathRectus Sheath

For description it is considered at three For description it is considered at three levels:levels:

Above the costal margin the anterior wall Above the costal margin the anterior wall is formed by the aponeurosis of the is formed by the aponeurosis of the external oblique and posterior wall is external oblique and posterior wall is formed by the thoracic wallformed by the thoracic wall

That is the 5That is the 5thth , 6 , 6thth and 7 and 7thth costal cartilages costal cartilages and the intercostal spacesand the intercostal spaces

Rectus SheathRectus Sheath

Between the costal margin and the level of Between the costal margin and the level of the anterosuperior iliac spine, the the anterosuperior iliac spine, the aponeurosis of the internal oblique splits to aponeurosis of the internal oblique splits to enclose the rectus muscleenclose the rectus muscle

The external oblique aponeurosis is The external oblique aponeurosis is directed in front of the muscledirected in front of the muscle

Transversus aponeurosis is directed Transversus aponeurosis is directed behind the musclebehind the muscle

Rectus SheathRectus Sheath

Between the level of the anterosuperior Between the level of the anterosuperior iliac spine and the pubis, the aponeurosis iliac spine and the pubis, the aponeurosis of all three muscles form the anterior wallof all three muscles form the anterior wall

The posterior wall is absentThe posterior wall is absent

The rectus muscle lies in contact with the The rectus muscle lies in contact with the fascia transversalisfascia transversalis

Rectus SheathRectus Sheath

The posterior wall of the rectus sheath is The posterior wall of the rectus sheath is not attached to the rectus abdominis not attached to the rectus abdominis musclemuscle

The anterior wall is firmly attached to it by The anterior wall is firmly attached to it by the muscle’s tendinous intersections the muscle’s tendinous intersections

Linea AlbaLinea Alba

The rectus sheath is separated from its The rectus sheath is separated from its fellow on the opposite side by a fibrous fellow on the opposite side by a fibrous band called the linea albaband called the linea alba

Extends from the xiphoid process to the Extends from the xiphoid process to the symphysis pubis symphysis pubis