Abdominal Wall Anatomy PDF

EN: PART I THE ABDOM THE ABDOMINAL WALL  O F TH E AN T ERIOR STRUC TURE IN A L W AL L ABDOM made up of skin, superficial fascia, deep fascia, muscles, extraperitoneal fascia, and parietal peritoneum. Skin -loosely attached to the...

EN: PART I THE ABDOM THE ABDOMINAL WALL  O F TH E AN T ERIOR STRUC TURE IN A L W AL L ABDOM made up of skin, superficial fascia, deep fascia, muscles, extraperitoneal fascia, and parietal peritoneum. Skin -loosely attached to the underlying structures except at the umbilicus, where it is tethered to the scar tissue. Umbilicus -a scar representing the site of attachment of the umbilical cord in the fetus  NERVE SUPPLY The cutaneous nerve supply to the anterior abdominal wall is derived from: The lower six thoracic nerves The 1st lumbar nerve Key dermatomes: T7: Epigastrium over the xiphoid process T10: Umbilicus L1: Just above the inguinal ligament and the symphysis pubis  BLOOD SUPPLY ARTERIES The skin near the midline is supplied by: - Branches of the superior and inferior epigastric arteries. The skin of the flanks is supplied by: - Branches of the intercostal, lumbar, and deep circumflex iliac arteries. The skin in the inguinal region is supplied by: - The superficial epigastric, superficial circumflex iliac, and superficial external pudendal arteries (branches of the femoral artery).  BLOOD SUPPLY VEINS Venous drainage above the umbilicus: - Mainly passes into the axillary vein via the lateral thoracic vein. Venous drainage below the umbilicus: - Passes into the femoral vein via the superficial epigastric and great saphenous veins.  IAL FASCIA FASCIA SUPERFIC DEEP The superficial fascia is divided into: - The deep fascia in the anterior abdominal wall is a thin layer of Fatty layer (Camper's fascia): connective tissue covering the muscles. - It lies just beneath the membranous layer of the superficial fascia. - Continuous with body fat, can be very thick in obese individuals. Membranous layer (Scarpa’s fascia): - Thin, fades laterally and above, continues with the fascia of back and thorax. - Fuses with deep fascia below the inguinal ligament and forms a sheath for the penis (or clitoris). - In the scrotum or labia majora, becomes Colles’ fascia, attaching to the pubic arch and perineal body. In the scrotum: - The fatty layer becomes the dartos muscle. - Membranous layer remains separate.  MUSCLES Ex.In.Tra.Re.P. OF THE ANTERIOR ABDOMINAL WAL A External Oblique Muscles B Interal Oblique Muscles C Transversus Abdominis D Rectus Abdominis E Pyramidalis  EXTERNAL OBLIQUE MUSCLE (E0M) ○ Characteristics: Largest ○ Location: Most superficial abdominal muscle ○ Fiber Direction: Run diagonally downward and medially (like hands in pockets) ○ Origin: Lower 8th rib ○ Insertion: Xiphoid process Linea alba Pubic crest Pubic tubercle Anterior half of the iliac crest EXTERNAL OBLIQUE MUSCLE (E0M) ❖ Structure that derive from the EOM’s aponeurosis: Superficial Inguinal ring & External Spermatic Fascia ❖ Anatomical structure of the Inguinal & Femoral Regions: - Inguinal Ligament - Lacunar Ligament - Femoral Ring - Pectineal Ligament (Ligament of Cooper) - Fascia Lata ❖ Posterior border: Free  INTERNAL OBLIQUE MUSCLE (I0M) ○ Location: Deep to EOM ○ Fiber Direction: Run perpendicular to EOM ○ Origin: Lumbar fascia Anterior ⅔ of the Iliac Crest Lateral ⅔ of the Inguinal Ligaments ○ Insertion: Lower borders of the lower 3 ribs & their c costal cartilages Xiphoid process Linea Alba Symphysis Pubis INTERNAL OBLIQUE MUSCLE (I0M) ○ Structure that derive from the IOM & Transversus Abdominis’ aponeurosis: - Conjoint tendon ○ Structures associated with the inguinal region and the spermatic cord in males: - Cremaster Muscle - Cremasteric Fascia ❖ Posterior border: Attached to the lumbar vertebrae by the lumbar fascia  TRANSVERSUS ABDOMINIS ○ Location: Deep to IOM ○ Fiber Direction: Run horizontally/transversely ○ Origin: Deep surface of the lower 6 costal cartilages The lumbar fascia The anterior 2/3 of the iliac crest The lateral third of the inguinal ligament ○ Insertion: Xiphoid process Linea alba Symphysis pubis Conjoint Tendon - fixed to the pubic crest and the pectineal line ❖ Posterior border: Attached to the lumbar vertebrae by the lumbar fascia  RECTUS ABDOMINIS (RA) Characteristics: Long strap muscle - paired muscle separated by a linea alba - enclosed in a fibrous sheath formed by the aponeuroses of the other abd. muscles. ○ Location: Midline ○ Origin: By two heads From the front of the symphysis pubis From the pubic crest ○ Insertion: 5th, 6th, 7th costal cartilages, & the Xiphoid process  RECTUS ABDOMINIS (RA) ❖ Linea semilunaris: Lateral margin of RA ❖ Three (3) Transverse Tendinous Intersections: One at the level of the xiphoid process One at the level of the umbilicus One halfway between the xiphoid process and umbilicus ❖ The rectus abdominis is enclosed between the aponeuroses of the: External oblique Internal oblique Transversus abdominis These aponeuroses form the rectus sheath  PYRAMIDALIS - For stabilization, often absent ○ Origin: Base from the anterior surface of the pubis ○ Insertion: Linea alba ○ Location: Anterior of the lower part of the RA Rectus Sheath ○ Characteristics: Long fibrous sheath Above the costal margin: ○ Encloses: Anterior wall: Formed by the aponeurosis of Rectus abdominis muscle the external oblique Pyramidalis muscle (if present) Posterior wall: Formed by the thoracic wall ○ Contains: (5th, 6th, and 7th costal cartilages and Anterior rami of the lower six thoracic nerves intercostal spaces) Superior and inferior epigastric vessels Lymph vessels Between the costal margin and the level of Below the level of the anterior superior iliac the anterior superior iliac spine: spine and the pubis: Anterior wall: Formed by the aponeuroses Anterior wall: Formed by the aponeuroses of the external oblique (in front of the muscle) of all three muscles and the transversus abdominis (behind the Posterior wall: Absent; the rectus muscle muscle) lies in contact with the fascia transversalis The aponeurosis of the internal oblique splits to enclose the rectus muscle ❖ Arcuate Line - Curved lower boundary of the posterior rectus sheath. ❖ Linea alba - Vertical fibrous band down the midline that separates the Rectus Sheat  OF THE ANTERIOR FUNCTION ABDOMINAL WALL Oblique Rectus Transversus Pyramidalis Muscles Abdominis Abdominis contributes flexes trunk and compresses keeps the to trunk stabilizes pelvis abdominal linea alba flexion and assists in viscera, assist in “taut”/tense rotation compressing expiration, and during the abdominal viscera ipsilateral process (Fig. 4.14_nxt slide) and forced rotation expiration during breathing  OF THE ANTERIOR FUNCTION ABDOMINAL WALL Anterior and Lateral Abdominal Wall Muscles Function during Breathing Assist diaphragm in inspiration by relaxing to accommodate abdominal viscera Aid in forced expiration by pulling down ribs and sternum during coughing and sneezing Abdominal support Tone supports and protects abdominal viscera Contraction increases intra-abdominal pressure for micturition, defecation, vomiting, and parturition Anterior and lateral abdominal wall muscles play a vital role in breathing, abdominal support, and bodily functions. Coordinated action with diaphragm crucial for maintaining intra-abdominal pressure and supporting organs.  OF THE ANTERIOR NERVE SUPPLY ABDOMINAL WALL MUSCLES NERVE SUPPLY lower 6 thoracic nerves; Oblique Muscles iliohypogastric & ilioinguinal nerves (L1) lower 6 thoracic nerves; Transversus Muscles iliohypogastric & ilioinguinal nerves (L1) Rectus Abdominis lower 6 thoracic nerves Pyramidalis 12th thoracic nerves  M O I N A OF THE ANTERIOR ABDOMINAL WALL  FASCIA TRAN SVERS ALIS Transversalis Fascia (Fascia Transversalis) thin layer of connective tissue lines the inner surface of the abdominal wall deep to the transversus abdominis muscle act as a barrier between the Transversalis Fascia (Fascia Transversalis) abdominal muscles and the contents of the abdominal cavity  ERITONEAL Camper’s fascia EXTRAP Scarpa’s fascia FAT Muscles&fascia also known as Endoabdominal Transversalis fascia or Preperitoneal fascia Extraperitoneal fat consist of connective tissue (adipose tissue) Parietal peritoneum variable amount of fat that separates the transversalis fascia from the parietal peritoneum and anchors the peritoneum to the abdominal wall particularly abundant on the posterior wall of Extraperitoneal the abdomen fat/fascia protects abdominal organs, provides insulation, & contributes to the overall body fat distribution  PARIETAL External oblique muscle Internal oblique muscle PERITO NEUM Transversus abdominis muscle Transversalis fascia composed of thin serous membrane of mesothelial cells Extraperitoneal fat Parietal peritoneum innermost layer of the abdominal wall lines the abdominal cavity and reflects over the organs within the cavity Parietal act as a support structure and peritoneum protective layer for the abdominal organs secretes peritoneal fluid for the abd. organs to glide against each other sensitive to pain, temperature, and touch Parietal peritoneum NERVES OF THE ANTERIOR Anterior rami of lower six thoracic and 1st lumbar nerves ABDOMINAL WALL Passes forward in the interval between internal oblique and transversus muscles. Thoracic nerves lower five intercostal and subcostal nerves and 1st lumbar nerve. represented by iliohypogastric and ilioinguinal nerves (branches of the lumbar plexus). supply the skin of the anterior abdominal wall, the muscles, and the parietal peritoneum. Lower six thoracic nerves supply the rectus muscle and pyramidalis (T12 only). They terminate by piercing the anterior wall of the sheath and supplying the skin. 1st lumbar nerve it does not enter the rectus sheath. supplies skin above inguinal ligament and symphysis pubis. Represented by: Iliohypogastric nerve pierces the external oblique aponeurosis above the superficial inguinal ring. Ilioinguinal nerve which emerges through the ring. DERMATOMES T7 Located in the epigastrium over the xiphoid process T10 includes umbilicus L1 Above inguinal ligament and symphysis pubis  ARTERIES OF THE ANTERIOR ABDOMINAL WALL Superior Epigastric Deep Circumflex Artery Iliac Artery Terminal branch of internal thoracic artery Branch of external iliac artery Enters the upper part of the runs upward and laterally toward rectus sheath between the the anterosuperior iliac spine sternal and costal origins of the continues along the iliac crest. diaphragm supplies lower lateral abdominal descends behind the rectus wall. muscle supplies the upper central anterior abdominal wall o s t e r io r In t e r c o s t al Low er T w o P eries Inferior Epigastric Arteries & F o u r L u m b a r A r t Artery branches of the descending thoracic aorta, and the four Branch of external iliac artery lumbar arteries Runs upward and medially along branches of the abdominal the medial side of the deep inguinal aorta, ring pass forward between the ascends behind the rectus muscle muscle layers supplies lower central anterior Supply lateral part of abdominal abdominal wall. wall. VEINS OF THE ANTERIOR Superficial Veins ABDOMINAL WALL Forms a network that radiates out from the umbilicus. Drained into the axillary via the lateral thoracic vein and below into the femoral veins via the superficial epigastric and great saphenous veins. Paraumbilical veins few small veins connect the network through the umbilicus and along the ligamentum teres to the portal vein forms an important portal–systemic venous anastomosis Deep Veins superior epigastric, inferior epigastric, and deep circumflex iliac veins follow the arteries of the same name drain into the internal thoracic and external iliac veins The posterior intercostal veins drain into the azygos veins The lumbar veins drain into the inferior vena cava LYMPH DRAINAGE OF THE Superficial Lymph Vessels ANTERIOR ABDOMINAL Above the level of the umbilicus is upward to the WALL anterior axillary (pectoral) group of nodes can be palpated just beneath the lower border of the pectoralis major muscle. Below the level of the umbilicus the lymph drains downward and laterally to the superficial inguinal nodes Above the level of the iliac crests Is drained upward to the posterior axillary group of nodes palpated on the posterior wall of the axilla Below the level of the iliac crests It drains downward to the superficial inguinal nodes Deep Lymph Vessels Follow arteries draining into internal thoracic, external iliac, posterior mediastinal, and para-aortic (lumbar) nodes.  INGUINAL CANAL a passage in the lower anterior abdominal wall located just above the inguinal ligament. 1.5 in (4cm) long in the adult present in both sexes In males, it allows structure of the spermatic cord to pass to and from the testis and abdomen In females, the smaller canal allows the round ligament of the uterus to pass from the uterus to the labium majus Boundaries: Thigh inferiorly Pubic tubercle medially Anterior superior iliac spine laterally  INGS (OPENINGS): INGUINAL R Deep (internal) ring: Marks the internal opening of the inguinal canal Found above the midpoint of the inguinal ligament (lateral to the epigastric vessels). The ring is created by the transversalis fascia, which invaginates to form a covering of the contents of the inguinal canal. Superficial (external) ring: Marks the external end of the inguinal canal Lies just superior to the pubic tubercle. It is a triangle shaped opening, formed by the invagination of the external oblique, which forms another covering of the inguinal canal contents. It contains intercrural fibres, which run perpendicular to the aponeurosis of the external oblique and prevent the ring from widening.  WA LLS OF TH E INGUI N AL CA NA L: Anterior Wall: Formed by the oblique muscles Posterior Wall: Formed by the conjoint tendon and transversalis fascia Superior Wall (Roof): Formed by the arching lowest fibers of the internal oblique and transversus abdominis muscles Inferior Wall (Floor): Formed by inguinal and lacunar ligament  INGUINAL CANAL FUNCTION MECHANICS 1. In Males: Canal Structure: The inguinal canal is an oblique - Spermatic Cord Passage: Allows the passage with weak points (superficial and deep rings) spermatic cord to pass between the testis spaced apart, except in newborns. and the abdomen. Anterior Wall: Reinforced by the internal oblique muscle - Spermatogenesis: Essential for normal spermatogenesis, as the testis must be in the fibers near the deep ring. cooler environment of the scrotum, not in the Posterior Wall: Supported by the strong conjoint abdominal cavity. tendon behind the superficial ring. Effect of Straining: Coughing and straining make the 2. In Females: internal oblique and transversus abdominis muscles - Round Ligament Passage: Permits the contract, flattening the canal roof and compressing its passage of the round ligament of the uterus from the uterus to the labium majus. contents. Protection During Straining: Squatting during intense straining helps protect the abdominal wall by using the thighs to shield it.  SPERMATIC CORD Collection of structures that pass through the inguinal canal to and from the testis. Begins at the deep inguinal ring lateral to the inferior epigastric artery and ends at the testis. STRUCURES: Vas Deferens Testicular Artery Testicular Veins (Pampiniform Plexus) Testicular Lymph Vessels Autonomic Nerves Remains of the processus vaginalis Genital branch of the genitofemoral nerve  SPERMATIC CORD STRUCTURES Vas Deferens Testicular Veins Autonomic Nerves cordlike structure extensive venous plexus that Sympathetic fibers can be palpitated between leaves the posterior testis border runs with the testicular artery finger and thumb in the upper of reduces size as plexus ascends from renal or aortic sympathetic the scrotum runs up: posterior abdominal wall plexuses thick-walled muscular duct drains: left renal vein (left) & into Afterent sensory nerves transports spermatozoa from the inferior vena cava (right) accompany the efferent the epidermis to the urethra sympathetic fibers Testicular Lymph Remains of the Testicular Artery Vessels processus vaginalis Present within the cord a branch of the abdominal aorta ascend through the inguinal (2nd lumbar vertebra level) canal long and slender pass up over the posterior descends on the posterior abdominal wall to reach lumbar Genital branch of abdominal wall al nerve (para-aortic) lymph nodes on the the genitofem or transverse the inguinal canal side of the aorta at the level of supplies the testis and the the 1st lumbar vertebra Supplies the cremaster muscle epidermis COVERINGS OF THE SYMPATHETIC CORD (THE SYMPATHETIC FASCIAE) Derived from the layers of the anterior abdominal wall. External spermatic fascia derived from the external oblique aponeurosis attached to the margins of the superficial inguinal ring. Cremasteric fascia derived from the internal oblique muscle Internal spermatic fascia derived from the fascia transversalis attached to the margin of the deep inguinal ring  DEVELOPMENT OF THE INGUINAL CANAL FORMS DURING THE WHAT DEVELOPMENT? internal spermatic fascia cremaster muscle cremasteric fascia external spermatic fascia gubernaculum under the traverses through the through lower arching reaching the fascia inguinal part of the fibers of the aponeurosis of transversalis canal to the internal transversus the external at deep labioscrotal oblique muscle abdominis oblique inguinal ring swelling muscle  FEMALE ·the ovary descends into the pelvis following the gubernaculum gubernaculum persists as the round ligament of the uterus into the developing labium majus only structures that pass through the inguinal canal from the abdominal cavity are the round ligament of the uterus and a few lymph vessels MALE Testis descends through the pelvis and inguinal canal Stimulus: testosterone, which is secreted by the fetal testes spermatic cord is covered by three concentric layers of fascia external spermatic fascia, the cremasteric fascia, and the internal spermatic fascia  SCROTUM outpouching of the lower part of the anterior abdominal wall. It contains the testes, the epididymides, and the lower ends of the spermatic cords ridge in the midline fusion of the two lateral labioscrotal swellings Skin dartos muscle sympathetic nerve Superficial Colles’ fascia Scarpa’s fascia fascia External Spermatic Fascia Cremasteric Fascia Spermatic Internal Spermatic Fascia The cremaster muscle (cremasteric reflex) fasciae genitofemoral nerve (L1 and 2) a closed sac, invaginated Tunica from behind by the testis vaginalis  TESTIS Location: The testis is a firm, mobile organ within the scrotum. Asymmetry: The left testis usually lies lower than the right. tunica fibrous capsule albuginea Fibrous septa divide the interior lobules lobule contains one to three seminiferous tubules a network of channels that tubules connect to rete testis links the rete testis to the Efferent upper end of the epididymis ductules  EPIDIDYMIS Location: Firm structure lying posterior to the testis with the vas deferens lying on its medial side Components: Head, Body and Tail Blood Supply testicular artery is a branch of the abdominal aorta testicular veins emerge from the testis and the epididymis (pampiniform plexus) Lymph Drainage Lymph vessels ascend in the spermatic cord. They end in the lymph nodes on the side of the aorta (lumbar or para-aortic nodes).  LABIA MAJORA are prominent hair-bearing folds of skin formed from fetal genital swellings. large amount of adipose tissue and the terminal strands of the round ligaments of the uterus. MALES Structure of the Posterior Abdominal Wall Formed in the midline by the five lumbar vertebrae their intervertebral discs and laterally by the 12th ribs the upper part of the bony pelvis the psoas muscles the quadratus lumborum muscles the aponeuroses of origin of the transversus abdominis muscles. The iliacus muscles lie in the upper part of the bony pelvis.  Lumbar Vertebrae is massive and shaped like a kidney, bearing most of the body's weight. The fifth lumbar vertebra articulates with the sacrum's base at the lumbosacral joint. The intervertebral discs in the lumbar region are thicker than in other regions of the vertebral column. wedge shaped responsible for the normal posterior concavity in the curvature of the vertebral column in the lumbar region (lordosis).  TWELFTH PAIR OF RIBS the head of the 12th rib has a single facet for articulation with the body of the 12th thoracic vertebra. the anterior end is pointed and has a small costal cartilage, embedded in the musculature of the anterior abdominal wall. Forms the hip bone along with ischium and pubis, meeting at the Ilium acetabulum. Medial surface of the ilium is divided into two parts by the arcuate line. Above this line is a concave surface called the iliac fossa below this line is a flattened surface, continuous with the medial surfaces of the pubis and ischium.  OF THE POSTERIOR M O I N A ABDOMINAL WALL  FASCIAL LINING OF THE ABDOMINAL WALLS Abdominal walls- the parietal peritoneum connected to muscles. ▪︎Fascial lining contains blood, nerves. ▪︎Fascial lining vital in abdomen. ▪︎Rectus sheath posterior.  PERITIONEAL LINING OF THE ABDOMINAL WALLS Posterior wall: aponeuroses of internal muscles. Cells in mesothelium from mesoderm. Space between visceral and parietal peritoneum layers. Smooth, transparent membrane.  MEN: PART I THE ABDO THE ABDOMINAL WALL presented by : DDM2-B4 DEN 015 - lecture