Pelvic Region Anatomy Notes PDF

Pelvic Region Anatomy  Pelvis o Split in 2 parts by pelvic brim  Aka linea terminalis  Components (P->A)  Sacral promontory  Ar...

Pelvic Region Anatomy  Pelvis o Split in 2 parts by pelvic brim  Aka linea terminalis  Components (P->A)  Sacral promontory  Arcuate line  Pectineal line  Pubic crest  Superior border of pubic symphysis o Greater/ false pelvis  Superior to pelvic brim  Forms lower part of abdominal cavity o Lesser/ true pelvis  Inferior to pelvic brim  Encloses pelvic cavity & perineum  Contents  Pelvic inlet  Superior  Bound by pelvic brim  Pelvic outlet  Inferior  Boundaries  Anterior angle  Inferior border of pubic symphysis  Posterior angle  Apex of coccyx  Lateral angles  Ischial tuberosities  Anterolateral border  Ischiopubic ramus  Posterolateral border  Sacrotuberous lig.  Pelvic cavity  Space b/w inlet & outlet  Walls  Anterior  Pubic symphysis  Bodies of pubic bones  Posterior  Sacrum  Coccyx  Piriformis mm.  Leaves pelvis via greater sciatic foramina  Lateral  Hip bone inferior to pelvic brim  Obturator membrane & internus m.   Leaves pelvis via lesser sciatic foramen  Inferior  Pelvic diaphragm  Made up of Levator ani m. & Coccygeus m. o Gender differences  Female  Pelvic bones thinner, lighter  Muscular markings not as prominent  Cavity is more cylindrical  Distance b/w ischial spines & tuberosities is greater  Greater sciatic notch is wider  Subpubic angle is wider  Pelvic diaphragm o Divides lesser pelvis into 2 parts  Pelvic cavity  Superior to pelvic diaphragm  Perineum  Inferior to pelvic diaphragm o Incomplete anterior  Urogenital hiatus allows passage to urethra in both (fe)male & vagina o Formed by  Levator ani m. (has 3 parts)  Puborectalis m.  Pubococcygeus m.  Iliococcygeus m.  Coccygeus m.  Aka ischiococcygeus m.  Immediately anterior to sacrospinous lig. o Nerves  Ventral rami S2-S4  Pudendal n. o Actions  Prevents prolapse of pelvic viscera  Sphincteric action (puborectalis m.)  SI joint o Synovial joint o Nerve supply  Superior gluteal n.  Dorsal rami S1 & S1 o Ligaments  Ventral SI lig.  Small anterior strength to SI joint  Interosseous SI lig.  Immediate posterior to SI joint  Major strength & stability to SI joint  Dorsal sacroiliac lig.   Posterior to interosseous SI lig.  Sacrotuberous lig.  PSIS, sacrum, coccyx -> ischial tuberosity  Moves base AI  Sacrospinous lig.  Lower sacrum & coccyx -> ischial spine  Anterior to sacrotuberous lig.  Moves apex AS o Tuberous & spinous ligs. create sciatic foramina's  Greater sciatic foramina  Communicates pelvic cavity w/ gluteal region  Lesser sciatic foramina  Communicates gluteal region w/ perineum  SC joint o Cartilaginous joint connected by small fibrocartilaginous disc o Reinforced via  Anterior SC lig.  Equivalent to ALL  Deep posterior SC lig.  Equivalent to PLL  Superficial posterior SC lig.  Equivalent to ligamentum flavum  Lateral SC lig.  Equivalent to intertransverse lig.  Pelvic cavity arteries o Ovarian a.  Visceral branch of abdominal aorta o Medial sacral a.  Parietal branch of abdominal aorta o Superior rectal a.  Terminal branch of inferior mesenteric a. o Internal iliac a.  Anterior trunk  Umbilical a.  Proximal part gives off Superior vesical aa.  Supplies  Upper part of bladder  Lower ureter  Distal part obliterates, forms medial umbilical lig.  Obturator a.  Leaves via. Obturator canal  Enters medial compartment of thigh  Inferior vesical a.  Present in males  Replaced by vaginal a. in females  Supplies  Lower part of bladder  Prostate   Seminal vesicles  Middle rectal a.  Supplies lower rectum  Internal pudendal a.  Enters gluteal region through greater sciatic foramen inferior to piriformis m.  Supplies perineum  Inferior gluteal a.  Enters gluteal region through greater sciatic foramen inferior to piriformis m.  Uterine a.  Supplies uterus, uterine tube, upper vagina, ovaries  Vaginal a.  Supplies vagina & adjacent bladder & rectum  Posterior trunk  Iliolumbar a.  Iliac branch  Supplies iliacus m. & ilium  Lumbar branch  Supplies psoas major, quadratus lumborum, cauda equina  Lateral sacral aa.  Superior & inferior branches  Supplies sacrum & sacral canal  Superior gluteal a.  Largest branch of II a.  Enters gluteal region through greater sciatic foramen superior to piriformis m.  Internal iliac vein o Posteromedial to II a. o Tributaries same as II a. except for umbilical a. & iliolumbar a. o Pelvic vv. Communicate w/ internal vertebral venous plexus  Tumors of pelvic vv. like ovary, prostate, can reach vertebral column  Sacral plexus o Formed by  Part of ventral rami of L4  Ventral rami of L5 - S4 o Supplies  Muscles & skin of gluteal region, posterior thigh, entire leg & foot, perineum  Skin of medial leg & foot actually supplied via saphenous n. of femoral n.  Autonomic plexus of pelvis o Inferior hypogastric plexus  Main autonomic plexus  Motor & sensory to pelvic organs  Formed by  Hypogastric & pelvic splanchnic nn.   Small contribution from sacral splanchnic nn. o Pelvic splanchnic nn.  Originate from ventral rami S2-S4  Joints inferior hypogastric plexus o Superior hypogastric plexus  Extension of aortic plexus  Divides into L & R hypogastric nn. o Superior rectal & ovarian plexus