8. Pelvis and Pelvic Contents Flashcards
(46 cards)
What makes up the BONY PELVIS?
HIp (coxal) bones, sacrum, coccyx
What makes up the hip bone?
ilium
ischium
Pubis
These bone fuse in late adolescence
What forms the SUPERIOR PELVIC APERTURE?? (pelvic brim, inlet)
The superior pelvic aperture (pelvic brim, inlet) is a line formed by the sacral promontory, arcuate line of the ilium and pectin pubis of the pubic bone. It divides the pelvis into the greater pelvis (pelvis major, false pelvis) above and the lesser pelvis (pelvis minor, true pelvis) below.
The true pelvis contains the pelvic contents
What forms the inferior pelvic aperture? (pelvic OUTLET)
The inferior perlvic aperture (pelvic outlet) runs from the inferior part of the pubic symphysis –> ischiopubic ramus —> sacrotuberous ligament –> tip of coccyx. The shape of inlet and outlet is important in childbirth.
*Note unlike between thoracic and abdominal cavities (diaphragm) there is no physical division between abdominal cavity and pelvic cavity
Name the Joints of the pelvis:
Pubic Symphysis: secondary cartilaginous joint (symphysis) with hyaline cartilage on the symphyseal surface and united by fibrocartilage.
Sacroiliac joints: synovial plane joints with a fibrous posterior component.
The ligaments of the SI joints are very strong and allow only limited movement of the pelvic joints. :
- Iliolumbar
- Anterior sacroiliac
- Posterior Sacroiliac
- Sacrospinous
- Sacrotuberous
- Interosseous
What is the ORIENTATION of the BONY PELVIS
When standing the ASIS and pubic tubercles are in coronal plane,
the superior symphysis pubis and coccyx are in horizontal plane
Planes of pelvic inlet about 60 degrees, outlet about 10 degrees above horizontal.
Female Vs. Male Pelvis
The female compared to male pelvis (on average) has wider superior and inferior pelvic apertures, wider pubic arch, wider greater sciatic notch, narrower depth of true pelvis and thinner, lighter bones. A female can sometimes have more ‘male’ like pelvis, and for this reason may need a caesarean.
Measurements may be made of the pelvis:
Superior pelvic aperture:
- Conjugate (anteroposterior) and transverse
Inferior perlvic aperture:
- Anteroposterior and Transverse
The True Conjugate (superior pubic symphysis to sacral promontory)
The True Conjugate (superior pubic symphysis to sacral promontory) can only be measured on radiographic films.
Normal measurement is 11cm or more.
The diagonal conjugate (inferior pubic symphysis to sacral promontory)
The diagonal conjugate (inferior pubic symphysis to sacral promontory) can be estimated using an internal examination; it is normally 11.5cm or more.
The Obstetric conjugate
The obstetric conjugate is the shortest of the three measurement (sacral promontory to the thickest part of the pubic symphysis) and measures 10cm or more. The inlet is said to be contracted when diameters are smaller than normal
The PELVIC VISCERA:
Male Main contents
Male Main Contents:
- Bladder
- Prostate
- Genital ducts- ductus deferens,
- seminal glands
- rectum
The PELVIC VISCERA:
Female Main contents
Female Main Contents:
- Bladder
- Vagina
- Uterus
- Uterine tubes
- Overies
- Rectum`
THe pelvic viscera and PERITONEUM
The pelvic viscera sit below the peritoneum, so they may be partially covered by peritoneum.
Peritoneum covers the upper parts of rectum (anterolaterally), the superior surface of bladder, most of the uterus, uterine tube and ovary.
POUCHES
The reflection of the peritoneum over the bladder, uterus and rectum creates a number of pouches or recesses.
Males have one pouch; rectovesical.
Females have two pouches: vesicouterine and rectouterine (of Douglas).
*Clinical note: these pouches are the most inferior parts of the peritoneal cavity, fluid etc can accumulate here.
Overview of blood vessels in the pelvis
Internal Iliac ::: pelvic viscera, pelvic wall, perineum and gluteal region
Inferior Mesenteric –> Superior rectal
Aorta –> ovarian artery
Bifurcation of aorta —> median sacral arteries
The RECTUM
Rectum = straight but in fact it is a curved structure.
Function: stores faeces
Starts at the rectosigmoid junction (S3) ends at the rectoanal junction (at level of pelvic diaphragm). It has no haustra, tenaiae coli (complete layer of longitudinal muscle instead), or mesentary.
Characterised by transverse rectal folds which act like valves (better seen on sigmoidoscopy)
Perianal flexure
The perianal (anorectal) flexure is the junction between the anal canal and rectum. It is created by the puborectalis muscle (a pelvic floor muscle)- contributes to incontinence
Anterior relations of the rectum! in the MALE
in the MALE: - SI, - Sigmoid colon - Rectovesical pouch - Genital ducts - Prostate - Bladder Note the proximity of the prostate to rectum for rectal exam of prostate or rectal ultrasound
Anterior relations of the rectum! in the FEMALE
in the FEMALE:
- Sigmoid colon
- Small Intestine
- Rectouterine pouch
- Uterus
- Rectovaginal septum
- Posterior wall of the vagina
BLOOD supply to the rectum
Inferior mesenteric a —-> superior rectal a (supplies most of the rectum)
Internal iliac a —> middle rectal artery
Internal iliac a –> internal pudenal a —> inferior rectal artery(supplies the anal canal)
Venous Drainage of the rectum:
Drainage is mostlyby:
superior rectal vein —> inferior mesenteric vein —-> splenic v (or sup mesenteric v) —> hepatic portal vein.
Middle rectal vein —> internal iliac vein
Inferior rectal vein —> internal pudenal vein —> internal iliac vein .
** important: the internal (above pectinate line) and external rectal venous plexuses (below pectinate line) are sites of anastomoses between the superior, middle and inferior rectal veins (portal- caval anastomosis).
Although haemorrhoids can be caused by portal hypertension they also haev other common causes such as pregnancy, old age, chronic constipation, genetic and anal intercourse
Innervation of the pelvis
Sympathetic: T12- L2 mostly via lumbar splanchnics to pelvic plexus
Parasympathetic: S2-S4 pelvic splanchnics to pelvic plexus.
PAIN travels via P-S nerves
Lymphatic Drainage of the palvis
Follows the arteries;
along the superior rectal and inferior mesenteric aa. —> inferior mesenteric nodes.
Along middle rectal aa –> internal iliac nodes
anal canal –> internal iliac nodes and superficial inguinal nodes
