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The Antero-lateral Abdominal Wall and Musculature Beth McCullough bmccullough09@qub.ac.ukLearning Outcomes qDescribe and identify the fasciae of the antero-lateral abdominal wall q Describe and identify the cutaneous innervation, arterial supply, venous drainage and lymphatic drainage of the antero-lateral abdominal wall qIdentify the external oblique, internal oblique and transversus abdominis muscles qIdentify the rectus sheath and the rectus abdominis muscles qIdentify and describe the location and boundaries of the inguinal 2 canalLayers of The Antero-later Abdominal Wall 1. Skin 2. Subcutaneous tissue: Superficial fatty layer (Camper’s and Scarpa’s) and deep membranous layer 3. External oblique muscle 4. Internal oblique muscle 5. Transversus thoracis muscle 6. Transversalis fascia 7. Peritoneum 3Borders of the Antero-lateral Abdominal Wall This extends from the thoracic cage to the pelvis and is bounded by: – Superiorly: th th 7 - 10 costal cartilages and xiphoid process – Inferiorly: Inguinal ligaments and the pelvic bones. 4 Fascia is split into camper’s and Scarpa's Superficial Fascia of the only below the level of the umbilicus, above this it’s a Anterolateral Abdominal Wall continuous sheet of fascia Camper’s Fascia Scarpa’s Fascia • Most superficial • deeper • Membranous layer • Fatty layer • Continuous with superficial fascia of • Thins out laterally and above and fades the thigh (ends inf. to inguinal lig) out becoming continuous with the deep fascia of the thigh • Medial and inferior to the pubic • In the midline it forms a tubular sheath tubercle it continues over the scrotum for the penis or clitoris in males to form Dartos Fascia • Continues posteriorly onto the • Below in the perineum it enters the wall peritoneum where it forms Colles of the scrotum or labia majora Fascia 5 • fuses posteriorly with perineal body The superficial vessels and nerves run between campers and scarpas fascia 6Learning Outcomes qDescribe and identify the fasciae of the antero-lateral abdominal wall q Describe and identify the cutaneous innervation, arterial supply, venous drainage and lymphatic drainage of the antero-lateral abdominal wall qIdentify the external oblique, internal oblique and transversus abdominis muscles qIdentify the rectus sheath and the rectus abdominis muscles qIdentify and describe the location and boundaries of the inguinal 7 canal Cutaneous innervation of the Antero-lateral abdominal wall • Derived from the anterior rami of the lower six thoracic spinal nerves and the first few lumbar spinal nerves • Thoracic nerves - the lower 5 intercostal nerves (7-11) and the subcostal nerve • Lumbar nerves – the first lumbar nerve represented by the iliohypogastric nerves and the ilioinguinal nerves 8Arterial supply of the abdominal wall Arterial supply above umbilicus • Posterior intercostal arteries 10-11 • Subcostal arteries • Lumbar arteries 1-4 • Musculophrenic arteries • Superior epigastric arteries • Inferior epigastric arteries 9Arterial supply of the abdominal wall Arterial supply below umbilicus • Superficial epigastric arteries • Superficial circumflex arteries • Superficial external pudendal arteries 10 Venous drainage • Venous blood is collected from a network of veins that radiate from the umbilicus • Above the umbilicus – drains into axillary vein via the lateral thoracic vein • Below the umbilicus – drains into the femoral vein via the superficial epigastric and great saphenous veins • Some small paraumbilical veins form a clinically important portal- systemic venous anastomoses 11 Venous drainage- Clinical Relevance • Caput medusae is the pathological term to describe the gross distension of the superficial veins around the umbilicus and the paraumbilical veins which connect them to the portal veins • This is due to severe portal vein hypertension or obstruction • The distended subcutaneous veins radiate out form the umbilicus 12reating this characteristic signLymphatic drainage – Above the umbilicus: Lymph is directed upwards towards the anterior axillary lymph nodes (pectoral group of nodes) – Below the umbilicus: Lymph is directed downwards and laterally towards the superficial inguinal lymph nodes 13Learning Outcomes qDescribe and identify the fasciae of the antero-lateral abdominal wall q Describe and identify the cutaneous innervation, arterial supply, venous drainage and lymphatic drainage of the antero-lateral abdominal wall qIdentify the external oblique, internal oblique and transversus abdominis muscles qIdentify the rectus sheath and the rectus abdominis muscles qIdentify and describe the location and boundaries of the inguinal 14canal External oblique muscle • Broad, thin sheet of muscle that is aponeurotic anteriorly • Most external, fibers run inferomedially • Origin- lower 8 ribs (5-12) • Insertion- aponeuorosis to linea alba, pubic tubercle and iliac crest (fleshy fibres) • Innervation – T7- T11 and subcostal nerve (T12) • Function- trunk flexion, rotation and compression of abdo wall • The aponeurosis of the external oblique fold back on itself to form the inguinal ligament (ASIS to Pubic Tubercle) • Superficial inguinal ring – a triangle shaped defect in the EO aponeurosis above and medial to pubic tubercle 15 Internal oblique muscle • Smalller and thinner sheet of muscle that is aponeurotic anteriorly • Deep to EO muscle , fibres run superomedially • Origin- lumbar fascia, iliac crest and inguinal ligament • Insertion- ribs 10-12, linea alba, pubic crest and costal margin • Innervation – T7- T11 and subcostal nerve (T12) • Function- trunk flexion, rotation and compression of abdo wall 16 Transversus abdominis muscle • The deepest of the flat muscles, fibers run transversely • Transversalis fascia is deep to this • Origin- inguinal lig, lumbar fascia, cartilage of last 6 ribs (7-12), iliac crest • Insertion- linea alba and pubic crest • Innervation- T7-T11 and subcostal nerves (T12) + branches of the lumbar plexus • Function- compresses abdominal contents 17Learning Outcomes qDescribe and identify the fasciae of the antero-lateral abdominal wall q Describe and identify the cutaneous innervation, arterial supply, venous drainage and lymphatic drainage of the antero-lateral abdominal wall qIdentify the external oblique, internal oblique and transversus abdominis muscles qIdentify the rectus sheath and the rectus abdominis muscles qIdentify and describe the location and boundaries of the inguinal 19canal Arcuate line- horizontal line between linea alba and linea semilunaris. The inferior Rectus abdominis muscle epigastric artery and vein perforate the rectus abdominis here • a long, paired muscle split into two by the linea alba • Lateral borders create the linea semilunaris. • Origin- pubic crest and pubic symphysis • insertion – xiphoid process of sternum and costal cartilage of ribs 5-7 • Innervation – T7- T11 • Action – flexes and rotates trunk, fixes and depresses ribs, stabilizes pelvis, compresses abdomen • Has tendinous intersections 20 Rectus Sheath • Formed by the aponeurosis of the three flat muscles; EO, IO + TA • Contents -the rectus abdominis, pyramidalis muscle(if present), the ant. Rami of lower six thoracic nerves, superior and inferior epigastric vessels and lymph vessels • L1 is not in the rectus sheath • The posterior wall of the rectus sheath is not attached to rectus abdominis • The anterior wall of the rectus sheath is attached to rectus abdominis by the muscles tendinous intersections •21an be divided into three parts…..Rectus sheath- above the costal margin 1- above the costal margin • Anterior wall – formed by aponeurosis of EO • Pthtthior wall – formed by 5 -7 costal cartilages and IC spaces 22Rectus sheath- between the costal margin and arcuate line 2- between the costal margin and arcuate line • Aponeurosis of IO splits into two lamellae • Anterior wall – formed by aponeurosis of EO and anterior lamellae of IO • Posterior wall – formed by post lamellae of IO and aponeurosis of TA 23Rectus sheath- below arcuate line 3 – below arcuate line • Anterior wall – formed by aponeurosis of EO, IO and • Posterior wall – formed only by the fascia transversalis 24Learning Outcomes qDescribe and identify the fasciae of the antero-lateral abdominal wall q Describe and identify the cutaneous innervation, arterial supply, venous drainage and lymphatic drainage of the antero-lateral abdominal wall qIdentify the external oblique, internal oblique and transversus abdominis muscles qIdentify the rectus sheath and the rectus abdominis muscles qIdentify and describe the location and boundaries of the inguinal 26canalThe inguinal canal • What is it? – an oblique passage through the lower abdominal wall. It’s a site of potential weakness • What does it transmit? Males: 1. Spermatic Cord – vas deferens and artery to vas deferens - genital branch of genitofemoral nerve - testicular arteries and veins - Pampiniform plexus - lymph vessels - sympathetic and parasympathetic ns - cremaster artery 2. ilioinguinal nerve (only through superficial ring not deep ring) Females: 1. round ligament of uterus 2. genital branch of genitofemoral nerve 3. ilioinguinal nerve (only superficial ring not deep) 27Inguinal canal – deep inguinal ring • An opening in the fascia transversalis • ½ an inch above the mid inguinal point (1/2 way between ASIS as pubic symphysis) • Structures which pass through the deep ring include thespermatic cord in males and round ligament of uterus in females 2829Inguinal canal – superficial inguinal ring • aponeurosisin the external oblique • Located above and medial to the pubic tubercle • Structures which pass through the deep ring include thespermatic cord in males, round ligament of uterus in females and the ilioinguinal nerve in both 30 Walls of the inguinal canal • Anterior wall: external oblique aponeurosis, reinforced latterly by internal oblique. Strongest where it lies opposite the deep inguinal ring • Posterior wall: conjoint tendon medially and fascia transversalis laterally. Strongest opposite the superficial inguinal ring. • Roof: arching lowest fibers of the internal oblique and transversus abdominis • Floor: inguinal ligament and at the medial end the lacunar ligament 3132 An important clinical risk of hernias is strangulation- the bowel can become Clinical relevance – Hernias gangrenous and need immediate surgery • When contents of the abdomen protrude through the abdominal wall due to a weakness in the wall • This can be due to natural weakness in the wall (e.g. superficial and deep inguinal rings), failure of muscles to overlap, congenital abnormality, increased abdominal pressure, obesity, lifting heavy objects etc. • Types of hernias include inguinal, femoral, umbilical, paraumbilical, incisional and epigastric 33Inguinal hernias Indirect Direct • Passes through the posterior wall of • Passes via deep inguinal ring and out inguinal canal and out the superficial superficial inguinal ring inguinal ring • Descends into scrotum • Follows the embryological descend of • Not through inguinal canal the testis • Rarely descends to scrotum • More common in males • Usually elderly people- weakness in • Passes lateral to hesselbachs triangle abdominal wall with age • Passes medial to hesselbachs triangle 34Learning Outcomes qDescribe and identify the fasciae of the antero-lateral abdominal wall q Describe and identify the cutaneous innervation, arterial supply, venous drainage and lymphatic drainage of the antero-lateral abdominal wall qIdentify the external oblique, internal oblique and transversus abdominis muscles qIdentify the rectus sheath and the rectus abdominis muscles qIdentify and describe the location and boundaries of the inguinal 37canalQuestions 1) The transversalis fascia contributes to which of the following structures on the anterior abdominal wall? a) superficial inguinal ring b) deep inguinal ring c) inguinal ligament d) sac of an indirect inguinal hernia e) anterior wall of the inguinal canal 38Questions 1) The transversalis fascia contributes to which of the following structures on the anterior abdominal wall? a) superficial inguinal ring b) deep inguinal ring c) inguinal ligament d) sac of an indirect inguinal hernia e) anterior wall of the inguinal canal 39Questions 2) Which structure does not enter the inguinal canal through the deep inguinal ring? a) testicular artery b) vas deferens c) ilioinguinal nerve d) genital branch of genitofemoral nerve e) artery to the vas deferens 40Questions 2) Which structure does not enter the inguinal canal through the deep inguinal ring? a) testicular artery b) vas deferens c) ilioinguinal nerve d) genital branch of genitofemoral nerve e) artery to the vas deferens 41 Questions 3)A10 year old boy comes to your clinic at 8 PM for sudden Pain in his inguinal region. He is otherwise healthy. On further questioning you came to know that his Right testis never descended properly. You notice a swelling just medial to deep inguinal ring. You don’t have any facility of surgery in your office at night but you can operate in the morning. What will you do next (A) Give Him Pain medicine andArrange to Operate in the morning for Direct Inguinal hernia (B) Give Him Pain medicine andArrange to Operate in the morning for Indirect Inguinal hernia (C) Give Him Pain medicine and antibiotics to treat Epididymitis (D) Urgently operate for strangulated Indirect Inguinal Hernia (E) Refer to Emergency Surgical Department 42 Questions 3)A10 year old boy comes to your clinic at 8 PM for sudden Pain in his inguinal region. He is otherwise healthy. On further questioning you came to know that his Right testis never descended properly. You notice a swelling just medial to deep inguinal ring. You don’t have any facility of surgery in your office at night but you can operate in the morning. What will you do next (A) Give Him Pain medicine andArrange to Operate in the morning for Direct Inguinal hernia (B) Give Him Pain medicine andArrange to Operate in the morning for Indirect Inguinal hernia (C) Give Him Pain medicine and antibiotics to treat Epididymitis (D) Urgently operate for strangulated Indirect Inguinal Hernia (E) Refer to Emergency Surgical Department 43 Questions 4. Inferior epigastric vessels perforate Rectus abdominis Muscle at the level of (A) First tendinous intersection (B) Second tendinous intersection (C) Third tendinous intersection (D) Umbilicus (E)Arcuate Line ofAnteriorAbdominal Wall 44 Questions 4. Inferior epigastric vessels perforate Rectus abdominis Muscle at the level of (A) First tendinous intersection (B) Second tendinous intersection (C) Third tendinous intersection (D) Umbilicus (E)Arcuate Line ofAnteriorAbdominal Wall 45Thank you and good luck!! bmccullough09@qub.ac.uk