Anterior Abdominal Wall & Surface Anatomy PDF

RCSI Royal College of Surgeons in Ireland Coláiste Ríoga na Máinleá in Éirinn Course GIHEP Title Anterior Abdominal Wall & Surface Anatomy Lecturer Dr Caroline Curtin Email [email protected] Date 12/09/2024 Learning Outcomes Describe the...

RCSI Royal College of Surgeons in Ireland Coláiste Ríoga na Máinleá in Éirinn Course GIHEP Title Anterior Abdominal Wall & Surface Anatomy Lecturer Dr Caroline Curtin Email [email protected] Date 12/09/2024 Learning Outcomes Describe the anterior abdominal wall Understand the anatomy of the inguinal canal Demonstrate an understanding of how inguinal hernias develop & explain the anatomy and clinical findings Describe the layers and contents of the scrotum Explain the embryology of testicular descent, and why this is clinically relevant Surface Anatomy  Surface Anatomy - Four Quadrants Xiphoid process to pubic symphysis Trans-umbilical line The umbilicus - usually midway between the xiphoid process and the pubic symphysis Surface Anatomy - Nine Regions  Transpyloric Plane –L1 Midway between jugular notch and pubic symphysis, (or Xiphoid and Umbilicus) at 9th costal cartilage – Pylorus of stomach – Gall bladder (fundus) – Body of Pancreas – Hila of Kidneys – Origin of superior mesenteric artery  Lumbar Vertebrae Transpyloric plane – L1 Umbilicus – L3/4 intervertebral disc Transtubercular plane– L4-5  Layers of the abdominal wall Skin Superficial fascia (or subcutaneous tissue) Muscles and associated fascia Parietal peritoneum  Superficial Fascia Consists of fatty connective tissue. The composition of this layer depends on its location: Two layers: – fatty superficial layer (Camper’s fascia) – membranous deep layer (Scarpa’s fascia) – superficial vessels and nerves run between these two layers of fascia  Muscles of the abdominal wall 5 muscles in the abdominal wall (on each side) Can be divided into two groups: Flat muscles – 3 flat muscles, situated laterally 1. External oblique 2. Internal oblique 3. Transverse abdominis Vertical muscles – 2 vertical muscles, situated near the mid-line 1. Rectus abdominis 2. Pyrimdalis  Muscles of the abdomen: The Flat muscles 3 flat muscles; 1. External oblique 2. Internal oblique 3. Transversus abdominis Located laterally in the abdominal wall, stacked upon one another Act to flex, laterally flex and rotate the trunk Fibres run in differing directions and cross each other – strengthening the abdominal wall and decreasing the risk of herniation Muscles of the abdomen: The Flat muscles External Oblique Origin Ribs 5-12 Insertion Iliac crest and linea alba Innervation Thoracoabdominal T7-11 and subcostal nerve T12 Blood Lower intercostal arteries and Supply branches of either the deep circumflex iliac artery or the iliolumbar artery Action Compresses abdomen contents, contralateral rotation of the torso External Oblique- Inguinal Ligament Inguinal ligament (rolled-in free lower border of external oblique aponeurosis) ASIS – pubic tubercle Medial half of inguinal ligament forms floor of inguinal canal Inguinal Canal – Canal between peritoneal cavity and abdominal wall M) External Oblique - Ligaments Lacunar ligament – Cresent shaped extension of medial fibres Pectineal Ligament – Extended fibres along pelvic brim v  Muscles of the abdomen: The Flat muscles Internal Oblique Origin Lateral 2/3 inguinal ligament, iliac crest and thoracocolumbar fascia Insertion Linea alba, pectineal line, pubic crest, inf border of ribs 9- 12 Innervation Thoracoabdominal T7-11 and subcostal nerve T12, iliohypogastric (L1) and ilioinguinal (L1) Blood Subcostal arteries Supply Action Compresses abdomen contents, ipsilateral trunk rotation Muscles of the abdomen: The Flat muscles Transversus Abdominis Origin Iliac crest, lateral 1/3 inguinal ligament, thoracolumbar fascia and ribs 7-12 Insertion Linea alba, pubic crest and pectineal line Innervation Thoracoabdominal T7-11 and subcostal nerve T12, iliohypogastric (L1) and ilioinguinal (L1) Blood Subcostal arteries Supply Action Compresses abdomen contents  Muscles of the abdomen: Vertical muscles Rectus Abdominis Origin Pubic crest, tubercle & symphysis Insertion Costal cartilage of ribs 5-7, xiphoid process Innervation Thoracoabdominal T7-11, subcostal T12 Blood Inferior epigastric artery Supply Action Compresses abdomen contents, tense abdominal wall Pyramidalis Origin Pubic symphysis and pubic crest Insertion Linea alba Innervation Subcostal nerve (T12) Blood Inferior and superior epigastric Supply artery Action Tense linea alba  Rectus Sheath Formed by aponeuroses of the 3 flat muscles Anterior wall by aponeuroses of external oblique and half of internal oblique Posterior wall by aponeuroses of half internal oblique and of the transversus abdominus Upper Abdomen ~ midway between umbilicus and pubic symphysis, all the aponeuroses move to the anterior wall of rectus sheath – Arcuate line Lower Abdomen  Nerve Supply Motor and sensory Nerve Supply Dermatomes Umbilicus T10 – Referred pain from appendix, testis Shoulder tip pain – “C3,4,5 keeps the diaphragm alive” – Dermatome = shoulder area Arterial Supply Surgical Incisions Fascia layers inferiorly  Inguinal Canal Boundaries & Contents Boundaries Anterior wall – aponeurosis of the external oblique, reinforced by the internal oblique muscle laterally Posterior wall – transversalis fascia Roof – transversalis fascia, internal oblique, and transversus abdominis Floor – inguinal ligament, thickened medially by the lacunar ligament Contents Male Female – Ilioinguinal nerve - Ilioinguinal nerve – Spermatic cord - Round ligament of the uterus  Spermatic cord 3 Layers Internal spermatic fascia (transversalis fascia) Cremasteric layer (internal oblique) External spermatic fascia (external oblique) 3 Arteries Testicular – from Aorta at L2 Cremesteric – from Inferior Epigastric Artery of Vas – from Superior Vesical 3 Nerves Nerve to cremaster – from Genitofemoral nerve Sympathetics – deep pain sensation (Ilioinguinal – separate) 3 other things Vas deferens Pampiniform plexus of veins – asymmetric, variocosities Lymphatics to para-aortic nodes at L2  Hernia -Definition A protrusion of an organ in part or in whole through a defect in the cavity that normally contains it Groin Hernias – Common: 75% of hernias – 25% of males and 2% of females have inguinal hernias in their lifetime Adductor longus attaches to the pubic tubercle Inguinal – Neck is above & medial to pubic tubercle Femoral Canal – Neck is below and lateral to pubic tubercle Inguinal Hernia - Indirect – Inguinal canal – Congenital – Through deep ring, along inguinal canal, superficial ring to scrotum – If reduced, can be controlled at deep ring  Inguinal hernia - Direct Through weakness in transversalis fascia & superficial ring Acquired – Heavy lifting – Constipation – Sports e.g. Rugby Descent of Testes  Testis anatomy In scrotum – (Undescended/ retractile/ectopic) Fibrous capsule – tunica albuginea Serous covering – tunica vaginalis Epididymis – posterolateral Sinus epididymis - groove  Testis Blood supply – Testicular artery (from lateral aspect of aorta L1-2) Venous drainage – Pampiniform plexus - renal veins – Right to inferior vena cava – Left to left renal vein Lymph – with arteries to para- aortic nodes NB: skin of scrotum drains to inguinal nodes Nerves – visceral sensory to T10 Scrotum anatomy Testis Clinical Undescended testis Torsion Testicular carcinoma Swellings – Hydrocoele Collection of fluid in tunica vaginalis – Varicocoele Enlarged dilated veins Pampiniform plexus L>R..Renal Vein – Spermatocoele Fluid-filled sac that grows in the epididymis Thank you for your attention Questions?