Pelvic Girdle Flashcards
What comprises the pelvic girdle?
Sacrum, Coccyx, the two hip bones made up of the ilium, ischium, and pubis
What are the joints of the pelvic girdle?
Sacroiliac joint (posteriolaterally), Symphis pubis (anteriorly), Lumbosacral joint (superiorly)
Pelvic girdle functions
Supports weight of the body through the vertebral column and passes that force on to the hip bones
Receives the ground forces generated when the foot contacts the ground and transmits up toward the vertebral column
Provides attachment for muscles
Supports and protects the pelvic viscera
Makes up the bony portion of birth canals for females
Moves as a unit in all 3 planes
False pelvis
is the boney area b/t the iliac crest and superior to pelvic inlet
No organs within the false pelivs
aka- greater or major pelvis
Pelvic inlet
is found by drawing a line b/t the sacral promontory posteriorly and the symphis pubis anteriorly
True pelvis
lies b/t the pelvic inlet and outlet
Pelvic outlet
is found by drawing a line from the tip of the coccyx to the interior surface of the symphis pubis
Pelvic cavity
composed of the true pelvis
contains the gastrointestinal tract, urinary tract, some reproductive organs, and the birth canal in females
Male pelvis
Superior opening is heart shaped
Long and funnel shaped pelvic cavity
Pelvic arch is more narrow and less rounded
Female pelvis
Superior opening is oval shaped
Short and less funnel shaped pelvic cavity
Walls are not vertical
Wide acetabulum and ischial tuberosity distances
Pelvic arch is wider and more rounded
Sacral base
superior surface of S1
Promontory
ridge projecting along the edge of the body of S1
Superior articular process
located posteriorly on the base of S1
articulates w/ the inferior articular process of L5
SI joint motion
Nutation = sacral flexion
Counternutation = sacral extension
Motion occurring at this joint is minimal and motion must occur w/ other joint motions
When does nutation occur?
during hip extension or trunk flexion
What does counternutation occur?
during hip flexion or trunk extension
*important during child birth
Nutation
Sacral promontory moves anteriorly and inferiorly, inferior portion of the sacrum and coccyx (tip) moves posteriorly
Pelvic outlet becomes larger
Seen during later phases of childbirth when the fetus passes through the birth canal
SI joint diameter must be wide in the A-P direction
Counternutation
Sacral promontory moves posteriorly and superiorly, tip of the coccyx moves anteriorly
Pelvic outlet becomes smaller
Occurs during early phase of child birth
Fetus moves through pelvic inlet, the A-P diameter needs to be wider
What type of joint is the sacroiliac joint?
bicondylar
meaning that movement of one side corresponds to movement on the other side
What are the lateral flared wings that are actually fused transverse processes?
Ala
What structure is located on the lateral surface of the sacrum, inferior and anterior to the iliac tuberosity and articulates w/ the ilium?
Auricular surface
“earlike structure”
What structure serves as the exit for the anterior and posterior division of the sacral nerves?
Foramina
How many foramina are there?
4 pairs
Which foramina are larger dorsal or anterior?
Anterior
What structures comprise the lumbosacral angle?
How many degrees is the it tilted?
Sacrum articulates with L5
30 to 60 degrees
What makes up the greater sciatic notch?
sacrospinosus and sacrotuberous ligaments
Where is the greater sciatic notch located?
Below the PIIS
What passes through the greater sciatic notch?
the piriformis and sciatic nerve
Which SI ligament is the deepest, shortest, and strongest?
Interosseous sacroiliac ligament