Pelvis and ligaments of pelvis

function of pelvis

support bladder, rectum, anal canal and reproductive organs

anchors root of external genitalia

terminal line of pelvis

false (greater) pelvis

bounded by wings of the iliac and superior margin of pubis

provides support of the lower abdominal viscera

true (lesser) pelvis

forms a bowl containing the pelvic organs: elements of urinary, gastrointestinal and reproductive systems

has an inlet, walls, outlet and a floor

pelvic inlet (brim)

a line from the sacral promontory to the upper part of the pubic symphysis

the junction between the greater and lesser pelvis

pelvic outlet

inferior opening of the true pelvis

a line from the lower border of sacrum to lower part of pubic symphysis

Bones of the pelvis

ilium, ischium, pubis

lumbosacral joint

sacrum S1 articulates superiorly with lumbar spine L5

Pelvic Joints

- lumbosacral

- sacrococcygeal

- sacroiliac (SI)

- pubic symphysis

sacrococcygeal joint

between sacrum and coccyx

sacroiliac (SI) joint

ilium of pelvic bones and facets (articular surfaces) of sacrum

pubic symphysis joint

pelvic bones articulating anteriorly

ilium bone

wing + body

ilium function

expands to form the ala (wing) - provides support for lower abdomen

attachment for lower limb muscles

iliac fossa

anterior concavity surface of ilium wing

iliac crest

upper margin of the ilium

muscle attachment site

auricular surface of ilium

anterior superior iliac spine (ASIS)

anterior inferior iliac spine (AIIS)

Posterior Superior Iliac Spine (PSIS)

posterior inferior iliac spine (PIIS)

arcuate line

ischium bone

(sit bones) the lower, posterior portions of the pelvis

body + ramus

gluteal surface of ilium

ischial spine

ischial tuberosity

greater sciatic notch

lesser sciatic notch

Acetabulum

large socket on lateral surface of the pelvic bone for the head of the femur - forms hip joint

acetabular margin

lunate surface of acetabulum

acetabular fossa

acetabular notch

obturator foramen

opening in hip bone formed by the pubic and ischial rami

Pubis bone

body + 2 rami

pectineal line of pubis

symphysis surface

Sacrum

bone formed from five vertebrae fused together

Wings of the sacrum

sacral promontory

Coccyx

four vertebrae fused together to form the tailbone

auricular surface of sacrum

lateral sacral crest

medial sacral crest

median sacral crest

sacral foramina

holes in sacrum for passage of blood vessels and nerves (S1-S4)

4 pairs anteriorly

4 pairs posteriorly

sacral canal

sacral hiatus of sacrum

inferior opening of the sacral canal

iliolumbar ligament

connects the transverse process of L5 and iliac crest

Lumbosacral ligament

connects transverse process of L5 and wing of ilium

sacroiliac ligament (anterior and posterior)

attaches sacrum to ilium

obturator membrane

covers most of obturator foramen

Pubis symphysis ligaments (superior and inferior)

sacrotuberous ligament

sacrum to ischial tuberosity

C

sacrospinous ligament

sacrum to ischial spine

B

inguinal ligament

ASIS and pubic tubercle

greater sciatic foramen

pelvic opening formed by the greater sciatic notch of the hip bone, the sacrum, and the sacrospinous ligament

lesser sciatic foramen

pelvic opening formed by the lesser sciatic notch of the hip bone, the sacrospinous ligament, and the sacrotuberous ligament

Where does the sciatic nerve exit the pelvis?

greater sciatic foramen inferior to piriformis

Female & Male Pelvis Differences

Static of pelvis

Center of gravity passes through: atlanto-occipital joint, lower lumbar vertebrae, anterior to promontory, head of femur, highest point of plantar arch

Pelvic inclination: 60-65 degrees

ASIS and symphysis are on the same frontal plane, sacrum is nearly vertical

Intragluteal injections