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
Describe origin & insertion of coccygeus
O, pelvic surface of tip of ischial spine
I, last piece of sacrum & side of coccyx
Describe nerve supply & action of coccygeus muscle
S4,5
It forms part of pelvic floor & pulls coccyx forward after it has been moved backward during defecation & parturation
The internal iliac art begins at level of……..
Disc between 5th lumbar & 1st sacral vertebra at sacro-iliac joint
List branches of posterior division of internal iliac art
- Superior gluteal art
- Iliolumbar art
- Lateral sacral arts
List branches of anterior division of IIA
Parietal:
Obturator artery, internal pudendal art, inferior gluteal art
Visceral:
Umbilical art & its sup vesical branches, middle rectal art, inferior vesical art (in male) or vaginal art (in female), umbilical artery (in f)
Iliolumbar art supplies……., while lateral sacral artery supplies…….
Psoas major, quadratuslumobrum, iliacus
Contents of sacral canal & pass through posterior sacral foramen & supply muscle & skin of back.
Superior gluteal artery passes between………..
Lumbosacral trynk & ventral ramus of S1
Compare proximal & distal parts of umbilical artery
Proximal: gives 2 or 3 superior vesical arteries supply part of urinary bladder, ureter & vas deferens
Distal: fibrosed formas median umbilical ligament that raises median umbilical fold
Describe abnormal obturator artery
In 30% of subjects, obturator atery is absent and arises from pubic branch of inferior hypogastric which is enlarged,
Descrine the distribution of inferior vesical art (vaginal a)
In male, supplies urinary bladder, seminal vesicles, prostate & lower part of ureter
In female, supplies vagina, urinary bladder & adjacent part of rectum, branches from it anastomose with vaginal branches of uterine artery forming 2 longitudinal vessels known as azygos arteries that ascend one in front & one behind the vagina.
Uterine artery supplies…..& ends by…….
Vagina, uterus, uterine tubes. It ends by anastomosing with ovarian art along uterine tube
Mention vessel(s) passing through greater sciatic foramen:
A. Above piriformis
B. Below piriformis
A. Superior gluteal
B. Internal pudendal, inferior gluteal
…..arises from back of aorta, it gives…….
Median sacral artery
Last pair of lumbar arteries
Internal iliac vein recieves veins corresponding to parietal branches of IIA except…….& visceral except……
Iliolumar vein (ends in common iliac vein)
Umbilical artery (no vein)
List parietal tributaries of IIV
- Superior gluteal v
- Lateral sacral veins
- Obturator vein
- Inferior gluteal
- Internal pudendal
List visceral tributaries of IIV
- Inferior vesical veins
- Prostatic veins
- Vaginal veins
- Uterine veins
- Middle rectal veins
Sacral plexus is formed of………
Lumobsacral trunk (L4,5), ventral rami of upper sacral ventral rami (S1,2,3 & upper part of 4)
List vessels related to sacral plexus with explanation
- Internal pudendal vessels descend in front of plexus
- Superior gluteal artery passes backwards between lumbosacral & ventral ramus of S1 or between S1&2
- Inferior gluteal artery passes backwards between ventral rami of S1 & S2 OR S2 & S3
List branches of sacral plexus arising from roots
-Muscular branches to piriformis (S1,2), levator ani & coccygeus (S4), external anal sphincter (through perineal branch of S4 which supplies also perianal skin)
-Pelvic splanchnic n (S2,3,4): these nerves are preganglionic parasymp.
List branches of sacral plexus arising from:
1. Ventral
2. Dorsal
3. Both
4. Terminal
- N. to quadratus femorus, n. to obturator inetrnus (both L5, S1)
- Sup gluteal (L4,5, S1), inf gluteal (L5,S1,2), perforating cutaneous n (S2,3)
- Posterior cutaneous n of the thigh (S1,2,3)
- Sciatic n (L4,5, S1,2,3), Pudendal (S2,3,4) is the somatic n of perineum
Coccygeal plexus is formed from……., it gives rise to…..
S4,5 & coccygeal nerves
Anococcygeal nerves supply levator ani & coccygeus & pierce sacrotuberous ligamentto supply skin on back of coccyx
Obturator n root value is……., it emerges at……..& supplies…….
L2,3,4
Medial border of psoas major
Adductor group of muscles
Each sacral sympathetic trunk carries……& give branches……, ends as……
4 ganglia
Grey rami communicants to sacral & coccygeal nerves & visceral branches to join hypogastric plexus
Ganglion impar
How is the inferior hypogastric plexus formed?
- Inferior hypogastric n which arises from superior hypogastric plexus (purely sympathetic)
- Sympathetic fibers from sacral sympathetic trunk
- Pelvic splanchnic nerves which represent the preganglionic parasympathetic fibers of S2,3,4
Describe distribution of inferior hypogastric plexus
The plexus divides into 2ry plexuses which accompany branches of IIA to pelvic viscera & perineal organs . Visceral afferent fibers travel with autonomic nerve fibers.
