Presentation on theme: "Anatomy of the Pelvis Amel Ibrahim MBBS BSc"— Presentation transcript:
1Anatomy of the Pelvis Amel Ibrahim MBBS BSc Pelvis is latin for basin
2Contents Intro and definitions Bones et al Muscles Vasculature LymphaticsNervesOrgansSpecial placesQUIZPreviewFurther reading
3Intro & Definitions Pelvic Brim (green line) Imagine a line drawn between promontory of the sacrum, arcuate line of the ilium, pectineal line (pectin of pubis) and pubic crest.Greater (False) pelvisAll of the bony pelvis ABOVE pelvic brimLesser (True) pelvisAll of pelvis BELOW pelvic brim.
4Bones et alBonesIlium (one on each side): crest, anterior superior and inferior iliac spines and greater sciatic notch.Pubic bone (one on each side): lesser sciatic notch, tubercle and symphysisIschium (one on each side): lesser sciatic notch, spine and tuberositySacrum: foramina for spinal nervesCoccyx
5More bonesVertebral column: 5 fused sacral and 3-5 fused coccygeal vertebraeIlium, pubic bone and ischium meet to form acetabulum for hip jointObturator foramen made by articulation of ischium with pubic boneIliumPubic boneIschium
6LigamentsAnterior longitudinal: runs down entire vertebral column. Prevents hyperflexionInguinal ligament: arched fibres of external obliquePubic Symphysis: secondary cartilaginous jointSacroiliac joints anteriorlyPosterior: sacrotuberous, posterior sacrospinous and sacrospinousLigaments provide strengthand stability of hip
7Male Vs FemaleBones: pelvis taller, narrower and more compact. Evolutionary optimised for bipedal locomotion. Acute angle between pubic rami (70 degrees).Contents: rectum, bladder, prostate, anus and male reproductive organsBones: wider and broader with larger inlet. Optimised for childbirth without compromising bipedal locomotion. Wide angle between pubic rami (100 degrees). Wider acetabulum.Contents: rectum, bladder, anus and female reproductive apparatus
8Muscles pubococcygeus iliococcygeus coccygeus Psoas major piriformis Greater Pelvis:Quadratus Lumborum: from iliac crest to insert into 12th rib and L1-4. Lateral flexorPsoas Major: from lumbar veterbrae to lesser trochanter of femur. Hip flexor.Iliacus: from internal iliac fossa to lesser trochanter. Joins with Psoas major = ILIOPSOAS (hip flexor and trunk flexor)Piriformis : from greater sciatic notch and anterior sacrum to greater trochanter. Lateral rotatorLesser Pelvis:MUSCLES CONTROL SPHINCTERSDiaphragm: pubococcygeus, coccygeus, puborectalis, (pubovaginalis) and illiococcygeusLevtor ani = a sling made by puborectalis, pubo- and ilio-coccygeus. Prevents incontinence.Sphincter urethrae(Sphincter prostatae)External anal sphincterpubovaginalis elevates vaginailiococcygeuscoccygeusPsoas majorILIOPSOAS HELPS YOU DO SIT-UPSpiriformisiliacus
9Vasculature: Arteries Gonadal artery (branch of abdo aorta, origin L2)Internal Iliac (anterior + posterior divisions):Superior vesicalInferior vesical (vaginal artery in female)Middle and inferior rectal (superior rectal from inferior mesenteric)Inferior and superior glutealUterine (uterus, vagina, ureter)Internal Pudendal (perineum, penis and urethra)Pudendal from latin for shame as supplies sexual organs...
16Autonomic Sympathetic Parasympathetic Hypogastric nerves: preganglionic fibres travel to hypogastric plexus and synapse there then travel to viscera as hypogastric nerves.Sacral splanchnic nerves: fibres synapse at sympathetic chain and postganglionic fibres travel to hypogastric plexus as a splanchnic nerve.Pudendal nerve: mixed autonomic and sensory. S2-4Pelvic splanchnic nerves: preganglionic fibres from S2-4 travel to hypogastric plexus ad from there nerves travel to and synapse at viscera.Cause erection and sphincter relaxation for micturition/defaecationThe inferior hypogastric plexus is a major meshwork of nerves that are located on either side of the rectum, cervix, and lateral vagina in the female, or on either side of the rectum, prostate, and seminal vesicles in the male.
17Divisions of Lumbar plexus lateral cutaneous nerve: sensory to lateral thighIliohypogastric: motor to transversus and internal oblique, sensory to mon pubisIlioinguinal: motor to internal oblique, transversus and conjoint tendon. Sensory to upper medial thigh, labia majora, scrotum and root of penisGenitofemoral: motor to cremaster. Sensory to scrotum, anterior thigh, spermatic fascia and tunica vaginalis.Femoral (L2,3,4): motor to iliacus, pectineus and quadriceps femoris. Sensory to anterior thigh.Obturator :
19Sacral Plexus Formed by L4, 5, S1-5 Lies on piriformis Branches: 6 nerves from sacral rootsNerve to piriformisPosterior femoralPerforating cutaneousPerineal branch to levator aniPelvic splanchnicPudendalAnterior division:Nerve to Quadratus femorisNerve to Obturator internusTibial branch of sciatic nervePosterior division:Superior glutealInferior glutealCommon peroneal branch of sciatic nerve
20Pudendal Nerve Somatic and autonomic Origins S2-4 Exits through greater sciatic foramen and re-enters pelvis via lesser sciatic foramenTravels with pudendal vessels along ischiorectal fossa in Alcock’s canalSupplies sphincters and genitalia via perineal, dorsal root of penis/clitoris and inferior anal nervesPromotes ejaculation, sexual arousal, anal and bladder sphincter control.
21Coccygeal Nerve 31st spinal nerve Forms coccygeal plexus with S5 Coccygeal plexus gives rise to annococcygeal nerve which supplies sacroccygeal joint and skin over coccyx.
22Organs RENAL TRACT: Ureters: Bladder: Originate at renal hilum at L2 Path initially medial to vertebrae and at pelvic brim take infero-posterior pathOblique entry into bladder avoids urinary refluxCrossed by gonadal artery in pelvisPosterior to it are psoas and genitofemoral nerveUnder it are uterine artery and vas deferensArterial supply via gonadal, renal, vesical, vaginal and aortic branchesAutonomic innervationBladder:Trigonal structure.Wall has 3 layers of smooth muscles: inner circular and middle/outer longitudinal layersArterial supply from superior and inferior vesicalnerves: sympathetic closes bladder neck whilst parasympathetic relaxes detrusor muscle to allow for miturition
23Rectum and anus Rectum Anus: Columnar epithelium Superior 1/3 covered by peritoneum anteriorly and laterally, middle 1/3 anterior peritoneum only and inferior 1/3 bareArteries: superior rectal from inferior mesenteric and middle rectal from internal iliac +inferior rectal from pudendal arteryVeinous drainage from internal venous plexus which drains to:superior rectal which then drains to inferior mesenteric vein, middle rectal which drains to internal iliac vein and inferior rectal vein which drains into pudendal veinAnus:Starts at anorectal junction aka dentate lineSquamous epithelium continuous with skin gradually transforming to columnar as rectum approachedExternal anal sphincter is skeletal muscle with somatic innervation thus voluntaryInternal anal sphincter is smooth muscle and under autonomic controlPortant anal cancers squamous in origin whilst rectal are adenocarcinomas.Note point where each of the rectal veins originates is site for haemorrhoid formation due to eakening of mucosa. Thus haemorrhoids are found at 3, 7 and 11 o’clock positions which is where superior, middle and infderior rectal veins are found.
24Female pelvic viscera Uterus: Ovaries: Fallopian tubes: Vagina: Held at lateral walls by double fold of peritoneum aka broad ligamentUterine arterySympathetic and parasympathetic innervation from pelvic plexusVenous plexus drain to rectal and vesical veinsOvaries:Attached to posterior aspect of broad ligamentOvarian arteryRight ovarian vein drains to IVC whilst left to left renal veinSympathetics from aortic plexus and parasympathetics from pelvic plexusFallopian tubes:Run in free edge of broad ligamentOvarian and uterine arteriesVagina:Opens into vaginal vestibuleVaginal arterySympathetic supply from pelvic plexus and somatic sensory innervation from ilioinguinal and pudendal nervesVenous drainage from pelvic floor plexus to internal iliacClitoris:Female equivalent of penisNerve supply via pudendal
25Male pelvic visceraScrotum:layers are skin, dartos muscle, external spermatic fascia, cremaster muscle, internal spermatic fascia, tunica vaginalis and tunica albugineaTestis:Testicular (gonadal artery)pampiniform plexus drain to testicular veinsTesticular vein drains to IVC on right and left renal artery on leftProstate:Multi-lobar (5) with posterior groove. Apex at the bottom and base at topSmooth muscleEntered by the vasa deferens and seminal vesicalsContains prostatic urethraArterial supply from inferior vesical, middle rectal and occasionally pudendal arteriesDrains to venous plexus and then to internal iliac veinSympathetic nerves promote ejaculation and smooth muscle contraction whilst parasympathetics promote erectionPenis and Urethra:Pre-prostatic, prostatic, membranous and penile urethraReceives ejaculatory ducts, bulbourethral and urethral glandsArterial supply from urethral artery, deep artery to penis and dorsal artery of penisDrainage via superficial and deep dorsal veins of penisNerves are sympathetic and parasympathetics for ejaculation and erection. Sensory supply to skin and glans of penis from pudendal nerveLeft sided renal obstruction by e.g. Tumour causes varicocoeles
27Special places Inguinal canal: Alcock’s canal: Pubic tubercle: 4 cm long running from Anterior superior iliac spine and pubic tubercle.Contains spermatic cord (or round ligament) and ilioinguinal nerve.Spermatic cord contains: 3 structures (vas deferens, cremaster muscle and pampiniform plexus), 3 arteries (artery to vas, artery to cramster and testicular artery) and 3 nerves (sympathetic, parasympathetic and genitofemoral)Floor: fibres of external oblique = inguinal ligamentRoof: transversus abdominis and internal obliqueAnterior: external oblique and internal obliquePosterior: transversalis fascia and conjoint tendonAlcock’s canal:Where pudendal nerve, vein and inetrnal pudendal artery run.Formed by obturator internus fasciaRuns on the lateral wall of ischiorectal fossaFemoral canal:Contains lymphatic vessels and cloquet’s lymph nodeAnterior border is inguinal ligamentPosterior border is pectineal ligamentMedial border is lacunar ligamentLateral border is femoral veinSite of bowel herniationPubic tubercle:Herniae above ad medial are inguinal and those below and lateral are femoral
29Quiz Q1) On the bony pelvis: A) true pelvis lies between iliac crests T/FB) the acetabulum formed by contributions from all parts of hip bone T/FC) male pelvic inlet more oval than female in shape T/FD) angle between pubic rami wider in male T/FE) pelvic out let is between symphysis pubis and sacral tuberosity T/F
30Quiz Q1) On the bony pelvis: A) true pelvis lies between iliac crests T/FB) the acetabulum formed by contributions from all parts of hip bone T/FC) male pelvic inlet more oval than female in shape T/FD) angle between pubic rami wider in male T/FE) pelvic out let is between symphysis pubis and sacral tuberosity T/F
31Q2) Levator AniA) has fibres which assist continence by pulling rectum backwards T/FB) lies inferior to ischiorectal fossa T/FC) is supplied by anterior rami of S1-2 T/FD) Contracts during defaecation T/F
32Q2) Levator AniA) has fibres which assist continence by pulling rectum backwards T/FB) lies inferior to ischiorectal fossa T/FC) is supplied by anterior rami of S1-2 T/FD) Contracts during defaecation T/F
33Q3) On sphincters of the anus A) the anus contains longitudinal and circular muscle T/FB) External sphincter composed of involuntary muscle T/FC) external sphincter continuous with muscle of rectum T/F
34Q3) On sphincters of the anus A) the anus contains longitudinal and circular muscle T/FB) External sphincter composed of involuntary muscle T/FC) external sphincter continuous with muscle of rectum T/F
35Q4) on the inguinal canal: A) contains spermatic cord and splanchnic nerve T/FB) posterior border is transversus abdominis and internal oblique T/FC) floor is inguinal ligament T/FD) carries round ligament in females T/F
36Q4) on the inguinal canal: A) contains spermatic cord and splanchnic nerve T/FB) posterior border is transversus abdominis and internal oblique T/FC) floor is inguinal ligament T/FD) carries round ligament in females T/F
37Q5) on origins of nervesA) lumbar plexus from L1-5 T/FB) pudendal arises from S2-4 T/FC) parasympathetic plexus arises from S2-4 T/FD) hypogastric nerves carry postganglionic fibres T/F
38Q5) on origins of nervesA) lumbar plexus from L1-5 T/FB) pudendal arises from S2-4 T/FC) parasympathetic plexus arises from S2-4 T/FD) hypogastric nerves carry postganglionic fibres T/F
40FinUseful books:Instant anatomy: good for surface anatomy, blood vessels and nervesNetter’s atlas(Anatomy recall)Websites:(down for construction at present)Apps:Gray’s anatomy (2 quid!)Netter’s flash cards (twenty pounds but useful for revision on tube)DVD:Acland’s (AMAZING and free from Warwick University website or youtube. £130 for DVD set)Exam Material:Pastest has over 800 anatomy questions and even more useful when you sit finals Have to pay though :((excellent for uestions on cadaveric dissections)