Pelvis Flashcards
The pelvis is divided into true & false by……
Promontry of scarum (post) & linea terminalis (arcuate line, pecten pubis, pubic crest) on both sides & ant
Pelvic surface of symphsis pubis us directed……, while sacrum & coccyx face…….
Upwards & backwards
Downwards & forward
Pelvic inlet shape is….in males &……in females
Describe its bounds
Heart-shaped, transversely oval
1. Promontory & alae of sacrum
2. Arcuate lines on either side
3. Pectineal lines (pecten pubis), pubic crests & upper margin of symphsis pubis (in front)
Describe bounds of pelvic outlet
Diamond shaped
Ant angle: inf pubic ligament
Post angle: tip of coccyx
Lateral angles: ischial tuberosities
Anterolateral sides: ischiopubic rami
Posterolateral sides: sacrotuberous ligaments
The sacrum articulates with other vertebra by……joints & with ilium by…..
2ry cartilagenous joint
Synovial plane joints
Mention structures passing through ant sacral foramina
Exit to ventral rami of upper 4 sacral nerves
Entrace to lateral sacral arteries
List contents of sacral canal
- Roots of sacral & coccygeal nerves (cauda equina)
- Filum terminale
- Arachnoid & dural tubes
- Small branches of lateral & median sacral arteries
- Internal vertebral venous plexus communicating with pelvic venous plexus through lateral & median sacral veins
- Amount of fat
Apex of coccyx gives attachement to….., while pelvic surface to….., while dorsal to…..
Anococcygeal ligament
Coccygeus & levator ani muscles & sacrospinous ligament
Gluteus maximus & filum terminale
Coccyx move backwards during……..
Defecation & labour
Describe origin of levator ani
It has linear origin from:
1. Pelvic surface of pubis
2. Pelvic surface of ischial spine
3. Tendinous arch (white line)
Mention parts of levator ani & insertion of each
- Pubococcygeus;
A. Levator prostatae/pubovaginalis: inserted into perineal body
B. Puborectalis: form a U-shaped sling around anorectal junction
C. Puboccygeus proper: inserted into tip of coccyx & anococcygeal raphe or ligament - Iliococcygeus: inserted into side of coccyx & anococcygeal raphe deep to insertion of pubococcygeus
Pubococcygeus originates from……, while iliococcygeus originates from……
Back of pubis & anterior 1/2 of white line
Posterior 1/2 of white line & pelvic surface of ischial spine
Describe nerve supply of levator ani
- Branches from S4 (sacral plexus) through its pelvic surface
- Inferior rectal nerve or perineal branch of pudendal nerve through its perineal surface
Inferior surface of levator ani froms…..wall of……
Medial
Ischiorectal fossa of perineum
Describe action of levator ani muscle
- Puborectalis fuses with the deep part of external anal sphincter and upper part of internal anal sphincter to form anorectal ring that inc forward angulation of junction imp on rectal continence
- Levatores form most of pelvic diaphragm which supports pelvic viscera & maintains position
- Acting with muscles of ant abdominal wall & diaphragm, the levator ani inc intra-abdominal pressure during expulsive acts
- Sphincter vaginae with perineal body support uterus preventing prolapse
- Levator ani produces mechanical rotation of head of fetus during 2nd stage of labour
……represents posterior border of levator ani muscles
Sacrospinous ligament