Anterior Abdominal Wall & Inguinal Region - ANAT30008 2024 PDF

Anterior Abdominal Wall & Inguinal Region Dr Rex Barton-Smith BSc (Clin Sci), MHSc (Osteo), Grad.Cert.Tert.Ed 1  Learning Outcomes Identify and describe the layers of the anterior abdominal wall Describe the attachments, fibre orientat...

Anterior Abdominal Wall & Inguinal Region Dr Rex Barton-Smith BSc (Clin Sci), MHSc (Osteo), Grad.Cert.Tert.Ed 1  Learning Outcomes Identify and describe the layers of the anterior abdominal wall Describe the attachments, fibre orientation and basic actionof the anterior abdominal wall muscles Describe origins and pathways of basic neurovasculature contributing the anterior abdominal wall Comprehend and describe the male and female inguinal canal formation and distinct features Outline the openings, boundaries and contents of the inguinal canal Comprehend basic clinical examples relating to the abdominal wall anatomy 2  Anterolateral Abdominal Wall Layers Camper’s Fascia Fatty layer Rich vasculature Scarpa’s Fascia Membranous layer Continuous with perineal fascia Drake RL, Vogl AW, Mitchell AWM. Gray’s Anatomy for Students. 3rd Ed. Churchill Livingstone Elsevier, 2015 Fig 4.24 3  Anterolateral Musculature Review External Oblique Internal Oblique Transverse Abdominis Expected prior knowledge for each muscle… Order of depth EO TA Fibre direction IO Basic attachments 4  Anterolateral Musculature Review External Oblique Internal Oblique Transverse Abdominis Expected prior knowledge for each muscle… Order of depth Fibre direction Basic attachments 5  Bony Framework for Abdominal Musculature Adjacent cavities (thorax and pelvis) have a greater bony contribution to their walls than the abdomen. Abdominal muscles use some of the Costal bony landmarks in these adjacent margin regions for attachment. Iliac Antero-lateral abdominal muscles crest anchor to: ASIS Costal margin & ribs Iliac crest & ASIS (anterior superior iliac spine) Pubic tubercle, crest and symphysis Pubic tubercle Pubic symphysis Pubic crest 6 Netter, FH. Atlas of Human Anatomy. 3rd Ed. New Jersey, Icon Learning Systems Plate #240  External Oblique (EO) EO is the outer muscular layer with an inferomedial fibre direction. Pectoralis Costal Major Margin Proximal Attachment/Origin Ribs 5-12 (external surfaces) Serratus Anterior Skin Distal Attachment/Insertion Pelvic bone External Superficial fascia (Iliac crest, ASIS, Pubic tubercle and symphysis) Oblique Linea alba (via external oblique aponeurosis) External Oblique Aponeurosis 7 Netter, FH. Atlas of Human Anatomy. 3rd Ed. New Jersey, Icon Learning Systems Plate #241  External Oblique (EO) – Inguinal Ligament Anterior view Saggital section of Anterior view External Oblique External Oblique ASIS Inguinal ligament Inguinal ligament Pubic tubercle The inguinal ligament attaches from the The inguinal ligament is the inferior free edge of the external oblique muscle. ASIS to the pubic tubercle. 8 Moore KL, Dalley AF & Agur AMR. Clinically Oriented Anatomy. 7th Ed. Wolters Kluwer, 2014, Fig 2.15 Drake RL, Vogl AW, Mitchell AWM. Gray’s Anatomy for Students. 3rd Ed. Churchill Livingstone Elsevier, 2015 Fig 4.17  Internal Oblique (IO) IO is the middle muscular layer with a superomedial fibre direction*. *Fibre direction typically opposite external oblique but it is a little more complex. Proximal Attachment/Origin Thoracolumbar fascia (posteriorly) Internal Iliac crest & inguinal ligament (Lat. ~1/3 to 1/2) Oblique Distal Attachment/Insertion Ribs 10-12 & costal margin Linea alba (via aponeurosis) Pubic crest (via conjoint tendon) 9 Netter, FH. Atlas of Human Anatomy. 3rd Ed. New Jersey, Icon Learning Systems Plate #242  Transverse Abdominis (TA) TA is the deepest muscular layer with a transverse fibre direction. Different fibre direction than innermost intercostals Continuous with transverse thoracis anteriorly Proximal Attachment/Origin Thoracolumbar fascia Transverse Abdominis Iliac crest and inguinal ligament Costal cartilages 7-12 (internal surface) Distal Attachment/Insertion Linea alba (via aponeurosis) Pubic crest (via conjoint tendon) 10 Netter, FH. Atlas of Human Anatomy. 3rd Ed. New Jersey, Icon Learning Systems Plate #243  Which muscles will fire most? During the large and powerful throwing motion shown in this image (right handed javelin), significant torso/abdominal rotation will occur. Which of the following groups of muscles will fire most to aid this throwing and torso rotation movement? A – Right (both) external oblique and internal oblique B – Right external oblique and left internal oblique C – Left (both) external oblique and internal oblique D – Left external oblique and right internal oblique 11 https://www.reuters.com/lifestyle/sports/world-champion-barber-hoping-javelin-will-sing- through-chorus-cheers-2021-04-28/  Rectus Abdominis Most anterior muscle of the abdominal wall Vertically oriented fibres divided by tendinous intersections known as linea semilunaris “Rectus” = straight Linea Rectus Alba Abdominis Most muscle fibres are enclosed by the rectus sheath Linea Semilunaris Proximal Attachment/Origin Rectus Sheath Pubic symphysis and crest Distal Attachment/Insertion Xiphoid process 5th-7th costal cartilages 12 Netter, FH. Atlas of Human Anatomy. 3rd Ed. New Jersey, Icon Learning Systems Plate #242  Rectus Sheath Rectus Sheath is comprised of anterior and posterior layers. Arcuate line indicates the termination of the posterior layer. Drake RL, Vogl AW, Mitchell AWM. Gray’s Anatomy for Students. 3rd Ed. Churchill Livingstone Elsevier, 2015 Fig 4.32 13  Cross Section Above Arcuate Line Rectus Sheath Cross Section Below Arcuate Line 14 Rohen JW & Yokochi C, Color Atlas of Anatomy, A Photographic Study of the Human Body. 7th Ed. Lippincott Williams & Wilkins 2010 p213 Drake RL, Vogl AW, Mitchell AWM. Gray’s Anatomy for Students. 3rd Ed. Churchill Livingstone Elsevier, 2015 Fig 4.33  Major Arteries of the Anterior Abdominal Wall Internal Thoracic Inferior Epigastric Musculophrenic Superior Epigastric Superficial Epigastric Inferior Epigastric Femoral artery External iliac 15 Netter, FH. Atlas of Human Anatomy. 3rd Ed. New Jersey, Icon Learning Systems Plate #245 Netter, FH. Atlas of Human Anatomy. 3rd Ed. New Jersey, Icon Learning Systems Plate #247  Arterial and Venous Supply Can you identify the corresponding veins? 16 Netter, FH. Atlas of Human Anatomy. 3rd Ed. New Jersey, Icon Learning Systems Plate #247 Netter, FH. Atlas of Human Anatomy. 3rd Ed. New Jersey, Icon Learning Systems Plate #248  Innervation of Anterior Abdominal Wall Anterior cutaneous branches of intercostal nerves T7-11 Lateral cutaneous branches of intercostal and subcostal nerves Anterior cutaneous branches of subcostal nerve T12 Anterior cutaneous branch of iliohypogastric nerve 17 Netter, FH. Atlas of Human Anatomy. 3rd Ed. New Jersey, Icon Learning Systems Plate #249  Innervation of Anterior Abdominal Wall Anterior Lateral branch branch Netter, FH. Atlas of Human Anatomy. 3rd Ed. New Jersey, Icon Learning Systems Plate #249 Moore KL, Dalley AF & Agur AMR. Clinically Oriented Anatomy. 7th Ed. Wolters Kluwer, 2014, Fig 2.10 Netter, FH. Atlas of Human Anatomy. 3rd Ed. New Jersey, Icon Learning Systems Plate #250 18  Inguinal canal Male Inguinal Canal Short (4cm) oblique passage through the Deep inguinal abdominal wall layers ring Deep inguinal ring – outpouching of transversalis fascia Superficial inguinal ring – medial opening of external oblique aponeurosis Superficial inguinal Provides pathway for relocation of gonadal ring structures during fetal development Spermatic cord in males Round ligament of the uterus in females Spermatic cord Neurovasculature for external genitalia Netter, FH. Atlas of Human Anatomy. 3rd Ed. New Jersey, Icon Learning Systems Plate #253 19  Inguinal Canal Formation Gubernaculum INGUINAL CANAL FORMATION Gonads begin on the posterior abdominal wall Gubernaculum connects the gonads to the labioscrotal folds Processes vaginalis occurs - peritoneum herniates through abdominal wall FEMALE Gubernaculum will aid ovary descent but won’t shorten/pull the ovary through the canal Round ligament of Gubernaculum becomes the round ligament of the uterus uterus 20 Moore KL, Dalley AF & Agur AMR. Clinically Oriented Anatomy. 7th Ed. Wolters Kluwer, 2014, Fig 2.17  Inguinal Canal Formation INGUINAL CANAL FORMATION Moore KL, Dalley AF & Agur AMR. Clinically Oriented Anatomy. 7th Ed. Wolters Kluwer, 2014, Fig 2.16 Gonads begin on the posterior abdominal wall Gubernaculum connects the gonads to the labioscrotal folds Processes vaginalis occurs - peritoneum herniates through abdominal wall MALE Gubernaculum will shorten, testes descend through the inguinal canal During relocation, testes become ensheathed by layers of the anterolateral wall – forming spermatic cord 21 Anterolateral Wall  Spermatic Cord Layers Transversalis fascia Internal oblique and investing fascia External oblique External Spermatic fascia Cremasteric muscle and fascia Internal spermatic fascia 22 Moore KL, Dalley AF & Agur AMR. Clinically Oriented Anatomy. 7th Ed. Wolters Kluwer, 2014, Fig 2.15  *Note that green, orange and blue correlate to both images Inguinal Canal Boundaries EO IO TA Floor Inguinal ligament Deep inguinal ring Roof TA (arching fibres) IO (arching fibres) Conjoint Conjoint tendon tendon Anterior Wall IO (more laterally) Inguinal canal EO aponeurosis contents Posterior Wall Transversalis fascia Superficial Inguinal Conjoint tendon inguinal ring ligament 23 Moore KL, Dalley AF & Agur AMR. Clinically Oriented Anatomy. 7th Ed. Wolters Kluwer, 2014, Fig 2.15 Moore KL, Dalley AF & Agur AMR. Clinically Oriented Anatomy. 7th Ed. Wolters Kluwer, 2014, Fig 2.15  Inguinal Hernia DIRECT INGUINAL HERNIA INDIRECT INGUINAL HERNIA Bowel passes medial to Bowel passes lateral to inferior epigastric inferior epigastric vessels vessels Bowel enters canal via Bowel enters canal by deep inguinal ring pushing through More common and peritoneum and congenital transversalis fascia Less common and acquired 24 Moore KL, Dalley AF & Agur AMR. Clinically Oriented Anatomy. 7th Ed. Wolters Kluwer, 2014, Fig B2.3  Indirect Inguinal Hernia Moore KL, Dalley AF & Agur AMR. Clinically Oriented Anatomy. 7th Ed. Wolters Kluwer, 2014, Fig 2.16 Indirect inguinal hernias are predisposed by an incomplete closure of the processus vaginalis from the abdominal peritoneum These hernias are much more common in males Image to the right is typical development demonstrating proper closure of processus vaginalis 25 Moore KL, Dalley AF & Agur AMR. Clinically Oriented Anatomy. 7th Ed. Wolters Kluwer, 2014, Fig B2.3  Abdominal Incisions 26 Moore KL, Dalley AF & Agur AMR. Clinically Oriented Anatomy. 7th Ed. Wolters Kluwer, 2014, Fig I.7 Moore KL, Dalley AF & Agur AMR. Clinically Oriented Anatomy. 7th Ed. Wolters Kluwer, 2014, Fig B2.1  Revision Suggestions Below are images that may be useful references and activities suggested for your revision When revising, consider what activities help you understand the content to be able to reproduce your knowledge 27  Anterolateral Abdominal Wall Layers Test yourself by annotating these layers  28 Drake RL, Vogl AW, Mitchell AWM. Gray’s Anatomy for Students. 3rd Ed. Churchill Livingstone Elsevier, 2015 Fig 4.24 Moore KL, Dalley AF & Agur AMR. Clinically Oriented Anatomy. 7th Ed. Wolters Kluwer, 2014, Fig 2.4 What is structure ‘A’? Justify your answer A Rohen JW & Yokochi C, Color Atlas of Anatomy, A Photographic Study of the Human Body. 7th Ed. Lippincott Williams & Wilkins 2010 p217 29 Rectus Sheath – Revision labelling pictures Moore KL, Dalley AF & Agur AMR. Clinically Oriented Anatomy. 7th Ed. Wolters Kluwer, 2014, Fig 2.6 30  Revision – Inguinal Canal Boundary Labelling Floor Inguinal ligament Roof TA (arching fibres) IO (arching fibres) Anterior Wall IO (more laterally) EO aponeurosis Posterior Wall Transversalis fascia 31 Conjoint tendon Netter, FH. Atlas of Human Anatomy. 3rd Ed. New Jersey, Icon Learning Systems Plate #251  Inguinal Canal Formation – Reference images Male Female 32