Posterior Abdominal Wall Anatomy PDF

Functional Human Anatomy Posterior Abdominal Wall Deep Pelvis D R. D O N AL M U R R AY PH D C O N T R IBU T IO N S BY: D R. E LLE N C O S T E LLO, PT, P H D Objectives for this Session Identify the structures that comprise the posterior abdominal wall Explain the attachments, muscle actions and ne...

Functional Human Anatomy Posterior Abdominal Wall Deep Pelvis D R. D O N AL M U R R AY PH D C O N T R IBU T IO N S BY: D R. E LLE N C O S T E LLO, PT, P H D Objectives for this Session Identify the structures that comprise the posterior abdominal wall Explain the attachments, muscle actions and neural innervation of musculature in this region Identify the neural structures of the lumbar, Lumbosacral and sacral plexi & their respective motor and sensory responsibilities Identify major branches of the abdominal aorta Explain caput medusa Explain the mechanism of referred pain Posterior Abdominal Wall Comprised of the following: h Lumbar vetebrae, sacrum, Ilium h Posterior aspect of diaphragm, psoas major, iliacus & quadratus lumborum muscles x x x  diaphragm L u Posterior Abdominal QL p m Wall: s b o a Lumbar vertebrae Iliacus &a r Ilium ilium s sacrum Iliacus Sacrum Post diaphragm Psoas major ms Quadratus Lumborum Note: Viscera will be removed Quadratus Lumborum Muscle From the medial 1/2 of inferior border of rib 12 and tips of lumbar transverse processes QL To iliolumbar ligament and internal lip of iliac crest Innervation-ventral rami T12, L1-4 Axn-fixes 12th rib during inspiration h with pelvis fixed, creates ipsilateral sidebending of vertebral column h bilateral axn-may assist in lumbar extension h Ipsilateral elevation of pelvis (hip hiker) hfrom the medial 1/2 of inferior border of rib 12 and tips of lumbar transverse processes hto iliolumbar ligament and internal lip of iliac crest Psoas Major Muscle From transverse processes of all Lumbar Vertebrae; lateral aspect of bodies of TV12 & Lumbar Vertebrae and discs in between To lesser trochanter of the femur Innervation: L2-L4 ventral rami AXN: flexes the hip jt; sidebending of vertebral column if LE fixed; flexes the trunk if pelvis fixed From the transverse processes of all LV; lateral aspect of bodies of TV12-LV and discs in between To lesser trochanter of the femur x Psoas Minor Ms From Lateral aspect of x TV12-LV1 and discs in between To pectineal line and iliopectineal eminence Innervation: L1 & L2 ventral ramus x AXN: assists in hip flexion and hip stabilization Iliacus Ms From the iliac crest, iliac fossa, ala of sacrum and anterior SI ligaments To the tendon of the psoas major, lesser trochanter, and femur just distal to it x Innervation: Femoral Nerve (L2, L3) AXN: acts with the psoas major to flex thigh at the hip; stabilizes hip joint; (reverse action is….) x Lumbar Ventral Rami Lumbar ventral rami descend laterally in the psoas major muscle L1,2,3 and most of L4 form the Lumbar Plexus Part of L4 and all of L5 form the lumbosacral trunk which joins the sacral plexus L1 also receives a branch from T12 ventral rami (subcostal n.) Lumbar Plexus Branches Muscular Branches include: h (T12), L1,L2,L3,L4 supply the following: h quadratus lumborum (T12-L4) h psoas minor (L1, L2) h psoas major (L2,3,4) & h ilacus (L2,3) Sensory Branches include: h Iliohypogastric N. (L1) h arises from upper border of psoas major, crosses the quadratus lumborum h travels between the transversus abdominus and Int Oblique ms. h gives off lateral cutaneous branch-supplies posterolateral gluteal skin h gives off anterior cutaneous branch-supplies suprapubic region Ilioinguinal N. (L1) Arises from lateral border of psoas major caudal to iliohypogastric n., crosses the quadratus lumborum ms. Often runs parallel to the border of iliac crest Pierces the TA, runs between TA and IO & emerges with spermatic cord from superficial inguinal ring Supplies the proximomedial skin of thigh Ilioinguinal nerve Genitofemoral N. (L1,2) Ascends obliquely forward through psoas major ms. emerging near its medial border Divides variably above the inguinal ligament into genital & femoral branches Genital branch-supplies cremaster & scrotal skin Femoral branch-supplies skin to upper part of femoral triangle Lateral Femoral Cut. N. (L2,3) Emerges from lateral border of psoas major, crosses iliacus obliquely Passes deep to the inguinal ligament and divides into ant & post branches Anterior branch-supplies skin of anterior and lateral thigh to the knee Posterior branch-supplies skin lateral surface from greater trochanter to mid-thigh Obturator N. (L2,3,4) Motor & Sensory responsibilities Descends in the psoas major, emerges on its medial border at the pelvic brim Descends forward on pelvic wall Near obturator foramen divides into ant & post branches; goes thru obturator foramen Ant branch-innervates: hip joint, add longus, gracilis, usually add brevis, sometimes pectineus (when not innerv by femoral n.); skin medial thigh Post branch-innervates: obturator externus, adductor portion of add magnus Sensation: medial aspect thigh Femoral N. (L2,3,4) x Motor & Sensory Responsibilities Descends through psoas major, emerges on its lateral border; gives off motor branches to iliacus (in the abdomen) and pectineus (from medial side of N. near inguinal ligament) Passes deep to the inguinal ligament into thigh Splits into ant and post divisions Ant division- medial & intermediate cutaneous femoral nerves, motor branch to sartorius Posterior division-saphenous nerve and motor supply to quadriceps femoris; sensory to knee joint LS trunk & Sacral Ventral Rami LS Trunk=part of L4 ventral ramus and all of L5 ventral ramus joined together LS trunk joins with sacral plexus L4,5 joins with sacral ventral rami S1,2,3 to form sciatic nerve S2,3,4 ventral rami joins to form pudendal n. Structures to Identify Medial & lateral arcuate ligament Median arcuate ligament R & L crura of the diaphragm Hiatus in the diaphragm- aortic, esophageal, vena caval Iliolumbar ligament-LV4-5 transverse process to iliac crest  blood supply: celiac trunk, sup mesenteric, inf mesenteric, paired renal, paired lumbar, common iliac, ext iliac, int iliac, superior gluteal, inferior gluteal, median sacral, lateral sacral, iliolumbar, obturator Caput Medusa Engorged paraumbilical veins as alternate means of venous return to heart from LE Severe ascites Mechanism of Referred Pain Error in perception by the brain as to the source of the painful stimulus An inability of brain to interpret a summation of noxious stimuli from various sources h Pain from neural inflammation h Pain from tendinopathy? h Pain from bursitis? h Pain for skin lesion? h Visceral pain? Example-pain felt in L5 dermatome may be arising from : h L4-5 facet joint h L5 disc h muscles innervated by L5 h visceral structures innervated by L5 h joint capsule supplied by L5 Referred Visceral Pain hHeart (C8-T4) on Left hLungs (T2-5) hEsophagus (T4-5) hLiver (T6-9) right hOvaries & fallopian tubes (T11- L1) hKidneys (T10-T11) hColon (T8-L2) hBladder(T11-L3) hRectum, ovaries, prostate (S2-5) So to recap! Can you identify the structures that comprise the posterior abdominal wall? Can you describe the attachments, muscle actions and neural innervation of musculature in this region? Can you identify the neural structures of the lumbar, Lumbosacral and sacral plexi & their respective motor and sensory responsibilities? Can you identify major branches of the abdominal aorta? Can you explain what causes caput medusa? Can you explain why someone has pain in their back but the physiological source of the pain does not arise from a structure found in their back?