Anatomy - Pelvis and Pelvic Wall

the pelvis is inferior to what?

abdomen

the pelvis contains, supports, and protects what?

the pelvic viscera, the lower parts of the intestinal tract, the urinary tracts, and the internal organs of reproduction

the pelvic provides attachment for what?

trunk and lower limb muscles

what are the two main regions of the pelvis?

false (greater) and true (lesser) pelvis

what describes the pelvic inlet?

pelvic brim, boundary between greater pelvis and lesser pelvis

what describes the pelvic floor?

fibromuscular, separates the pelvic cavity above from the perineum below

perineum is inferior to what?

floor of the pelvic cavity and forms the pelvic outlet

what is the orientation of the pelvis?

tilted anteriorly, sacrum curved to point downward

what is the anterior boundary of the pelvic outlet?

pubic arch

what are the lateral boundaries of the pelvic outlet?

ischial tuberosities anteriorly and sacrotuberous ligaments posteriorly

what is the posterior boundary of the pelvic outlet?

tip of coccyx

what is the anterior boundary of the pelvic inlet?

pubic symphysis

what are the lateral boundary of the pelvic inlet?

iliopectineal line

what is the posterior boundary of the pelvic inlet?

sacral promontory and wings

what is superior to the pelvic inlet?

false pelvis

the false pelvis contains what?

the distal part of the intestines

the false pelvis is continuous with what?

the inferior part of the anterior abdominal wall

the false pelvis supports what?

the abdominal contents and after the third month of pregnancy helps support the gravid uterus

what is located between the pelvic inlet and pelvic outlet?

true pelvis

the true pelvis contains what?

the internal genitalia, perineum, distal organs of the urinary tract

what describes the true pelvis?

short, curved canal with a shallow anterior wall and deeper posterior wall

the female true pelvis contains what?

bony birth canal

what describes the bony pelvis?

pelvic girdle and pelvic spine form a strong basin-shaped skeletal framework

what is the pelvic girdle composed of?

ilium, ischium, and pubis

the ilium, ischium, and pubis are fused together to form what?

one hip/pubic bone

what is the pelvic spine composed of?

sacrum and coccyx

two pubic bones connect at what?

symphysis pubis

pubic bones articulate with spine at what?

sacroiliac joints

the lateral surface of the hip bone houses the ____________, which is the principal union point of the three bones.

acetabulum

ilium extends where?

superiorly to hop joint

ischium is the ________ portion of the hip bone.

posteroinferior

pubic bone is _________ part of hip bone.

anteroinferior

obturator foramen located where?

inferior to acetabelum

within the ilium, what separates upper and lower parts of ilium?

arcuate line

what is inferior to the arcuate line of the ilium?

true pelvis

within the ilium, what is superior to the arcuate line?

fan-shaped wing (ala) that forms iliac fossa anteriorly and provides attachment for muscles lower limb

what is the thick, superior margin of the ilium?

iliac crest

what are the protrusions of the ilium?

• anterior superior iliac spine (ASIS)

• posterior superior iliac spine (PSIS)

• anterior inferior iliac spine (AIIS)

• posterior inferior iliac spine (PIIS)

the greater sciatic notch is enclosed by what?

sacrospinous ligament superiorly and sacrotuberous ligament posteroinferiorly

greater sciatic notch is enclosed by sacrospinous ligament superiorly and sacrotuberous ligament posteroinferiorly to form what?

greater sciatic foramen

what are the contents of greater sciatic foramen

• 7 nerves

• 3 pairs of blood vessels

• 1 muscle

the ischium consists of what?

a body and a ramus

the ischial spine is the attachment site for what?

the sacrospinous ligament

the lesser sciatic notch is the anterior border of what?

the lesser sciatic foramen

the lesser sciatic foramen is bounded by what?

sacrospinous and sacrotuberous ligament

the lesser sciatic foramen is the passageway for what?

• pudendal nerve and internal pudendal vessels

• nerve to obturator internus and tendon of obturator internus

the sacrotuberous and sacrospinal ligaments do what to prevent the upward tilting of the inferior sacrum?

stabilize the sacrum on the pelvic bones

the sacrotuberous and sacrospinal ligaments also convert what?

the greater and lesser sciatic notches into foramina

the pubis consists of what?

small body and two rami (superior and inferior)

medially, the two pubis bones articulate at what?

the symphysis pubis joint

the pubic tubercle (about 2.5 cm lateral to symphysis pubis) is the attachment point for what?

the inguinal ligament

pubic arch inferior to pubic symphysis is what?

sexually dimorphic

what describes the sacrum?

five fused sacral bones

the pelvic surface of the sacrum is what?

smooth compared to the gluteal surface

the gluteal surface of the sacrum is?

rough due to median sacral crest and roughening for gluteus muscles

the base of the sacrum features a midline projection called what?

sacral promontory

what describes the ala of sacrum?

fused transverse processes of S1/S2

what is found at the lateral surface of each ala of the sacrum?

sacroiliac joint

how many joints can be found in the pelvis?

4

• lumbosacral joint

• sacroiliac joint

• sacrococcygeal joint

• pubic symphysis

what describes the lumbosacral joint?

movement of the torso in respect to the pelvis and lower limbs

what describes the sacroiliac joint?

ligaments soften during pregnancy to increase pelvic diameter; otherwise limited mobility due to joint surfaces interlocking with each other

what 3 ligaments stabilize the sacroiliac joint?

anterior, posterior, and interosseous sacroiliac ligaments

what describes the function of the sacrococcygeal joint?

flexion and extension of the coccyx

what describes the pubic symphysis?

no movement except during pregnancy

the muscles (obturator internus and piriformis) contribute to what?

the lateral walls of the pelvic cavity

what describes the obturator internus?

flat, fan shaped muscle that originates from around the obturator foramen; leaves pelvis through the lesser sciatic forament

what describes piriformis?

originates between four anterior sacral foramina and leaves pelvis through greater sciatic foramen

both the obturator internus and the piriformis originate where and connect where?

in the pelvic cavity and attach to the greater trochanter of femur

the pelvic inlet in women is ____________ compared with the heart-shaped pelvic inlet in men.

circular

who has a larger sub-pubic angle, women or men?

women

ischial spines generally do not do what in women compared to men?

project as far medially into the pelvic cavity

the sacrum is more curved in ________. 

men

what four features make the female pelvis distinguishable from the male pelvis?

1. inlet shape

2. arch angle

3. sacrum concavity

4. ischial spine projection

what describes the pelvic floor?

main pelvic cavity above and perineum below

the pelvic floor is formed mainly by what?

the pelvic diaphragm

the pelvic diaphragm is formed by what?

levator ani, coccygeus muscles and tehir fascial coverings

what are the two gaps in the pelvic floor that have great significance?

urogenital hiatus and rectal hiatus

what is the the perineal body?

fibrous node that connects the pelvic floor to the perineum

what describes the levator ani muscles?

broad sheet of 3 separate paired muscles

• pubococcygeus

• pubrorecctalis

• iliococcygeus

what is the most important muscle of the levator ani group for maintaining fecal continence?

puborectalis

what describes the puborectalis?

originate from one side of the pubis and attaches to the other side; forms a sling around the rectal hiatus

some pre-rectal fibers from the puborectalis do what?

form a sling around urogenital hiatus (pubovaginalis or sphincter urethrae/vaginae)

the pubococcygeus muscle is what?

the bulk of the complex of levator ani muscles

the pubococcygeus originates from where?

posterior surface of pubis

the pubococcygeus blends with what?

the contralateral muscle in the midline of the pelvic floor

the iliococcygeus originates from what?

the ischial spinesthe i

the iliococcygeus inserts into what?

the coccyx, perineal body, and anococcygeal ligament

all three levator ani muscles are innervated by what?

nerve to levator ani and branches of pudendal nerve

what describes the coccygeus muscle?

small triangular muscle located posterior to the levator ani muscle group

what supports the pelvic viscera and flexes the coccyx?

coccygeus muscle

the coccygues muscle originates where?

ischial spines

the coccyx muscle inserts onto what?

the inferior end of the sacrum and coccyx

the coccygeus muscle is innervated by what?

anterior rami of S4 and S5