Pelvis I: Bones and Muscles
PELVISPELVIS I:I: BONESBONES ANDAND MUSCLESMUSCLES
IntroductionIntroduction----whywhy isis pelvispelvis soso hard?hard? BonyBony structuresstructures ofof thethe pelvispelvis MusclesMuscles ofof thethe pelvispelvis---- attachingattaching thethe leleggss forfor uuppririgghtht livinlivingg WhyWhy isis thethe pelvispelvis hardhard----#1#1 uprightupright
PelvicPelvic tilttilt oror howhow wewe gotgot toto bebe uprightupright ––CompareCompare withwith quadrupedquadruped (cat(cat forfor instance)instance) BowlBowl conceptconcept ––pelvispelvis spillsspills forwardforward ––HerniaHernia ––““beerbeer bellybelly”” ––InIn humanhuman minorminor pelvispelvis isis behindbehind (posterior)(posterior) toto gutsguts andand abdominalabdominal cavitycavity HumanHuman pelvispelvis stillstill hashas quadrupedquadruped orientationorientation WhyWhy isis thethe pelvispelvis hardhard #2#2 (fig(fig leafs)leafs)
“Private parts” don’t uncover except in most intimate setting (or medical setting!) Not comfortable seeing or talking about (except jokes) Now serious-many medical issues Realize and confront, not dehumanize-- develop professional manner and language--starts with anatomy BonyBony structurestructure ofof thethe pelvispelvis
MAIN STRUCTURES HOLES Hip bone (innominate, False and true pelvis os coxae)--fusion of (major, minor pelvis) – Ilium (“hips”) Pelvic inlet, pelvic – Ischium (“rear”) outlet – Pubis (anterior midline) Sacrotuberous Sacrum and coccyx ligament Acetabulum Sacrospinous ligament Femur--head, neck, Greater, lesser sciatic greater trochanter foramen Obturator foramen
MusclesMuscles ofof thethe pelvispelvis----attachingattaching legslegs forfor uprightupright postureposture
IliopsoasIliopsoas (from(from abdomen)abdomen) GluteusGluteus maximusmaximus (smaller(smaller inin cat)cat) GluteusGluteus minimusminimus (bigger(bigger inin cat)cat) LateralLateral rotatorsrotators (not(not importantimportant inin cat)cat) MuscleMuscle tablestables----exampleexample
NAME ORIGI INSERTI ACTIO INNERV N ON N . Iliopsoas Gluteus maximus Gluteus minimus Lateral rotators FemaleFemale MaleMale
Cavity is broad, shallow Cavity is narrow, deep Pelvic inlet oval + outlet Smaller inlet + outlet round Bones heavier, thicker Bones are lighter, thinner Pubic angle more acute Pubic angle larger Coccyx less flexible, more Coccyx more flexible, curved straighter Ischial tuberosities longer, Ischial tuberosities shorter, face more medially TheThe pelvicpelvic floorfloor MUSCULAR FLOOR MAIN STRUCTURES AND SPHINCHTERS Ischial tuberosity transverse perineal Pubic symphysis m. Coccyx Anal triangle and Sacrotuberous urogentical triangle ligament Levator ani m. Ischipubic ramus Urogenital Perineal body diaphragm Anus EXTERNAL GENITALIA External urethral Clitoris or penis opening Ischiocavernosus Vaginal opening m. Bulbospongiosus m. (and labia majorum) M&M, Fig. 26.14 BloodBlood supplysupply toto thethe pelvispelvis andand lowerlower limblimb
Aorta ends by splitting into right,left common iliac aa. Each common iliac splits into internal and external iliac aa. External iliac passes under inguinal ligament to lower limb Internal iliac a. enters pelvis and supplies muscles, viscera M&M, Fig. 19.14 Umbilical a. comes off of internal iliac in BranchesBranches ofof internalinternal iliaciliac a.a. SOMATIC BRANCHES--TO MUSCLES Gluteal aa. (to gluteal mm.) Internal pudendal (to pelvic floor, external genitalia) VISCERAL BRANCHES Vesicular aa. (to bladder) M&M, Fig. 19.15 Uterine (to uterus)