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
What SI ligament is a broad flat ligament on the anterior pelvic surface, that connects the ala and pelvic surface of the sacrum to the auricular surface of the ilium?
Anterior sacroiliac ligament
What are the two parts of the posterior sacroiliac ligament?
Short posterior ligament and long posterior ligament
Which posterior ligament runs vertically b/t PSIS and the lower portion of the sacrum? What sacral movement does it prevent?
Long posterior sacroiliac ligament
Prevents downward sacral movement
Which posterior ligament runs obliquely b/t the ilium and upper portion of the sacrum? What sacral movement does it prevent?
Short posterior sacroiliac ligament
Prevent forward sacral movement
What 3 accessory ligament help to reinforce the sacroiliac joint?
Sacrotuberous
Sacrospinous
Iliolumbar
Which accessory ligament connects the transverse process of L5 w/ the ala of the sacrum?
Iliolumbar ligament
Which accessory ligament runs from the PSIS and PIIS of the ilium, from posterior and lateral side of the sacrum inferior to the auricle surface, and from the coccyx?
Sacrotuberous ligament
Where do the sacrotuberous ligament fibers comes together to attach? What other structures attach here?
Ischial tuberosity
Glute max
What motion does the sacrotuberous ligament prevent?
Prevents forward rotation of the sacrum
Which accessory ligament lies deep to the sacrotuberous ligament and has a broad attachment from the lower lateral sacrum and coccyx on the posterior side?
Sacrospinous ligament
What structure is formed when the left and right pubic bones are joined?
Pubic symphysis
What type of joint is the pubic symphysis?
Amphiarthrodial joint
What ligaments hold together the pubic symphysis?
Superior and inferior pubic ligament
Where does the superior pubic ligament attach?
Attaches to the pubic tubercles on each side of the body and strengthens the superior and anterior portions of the joint
Where does the inferior pubic ligament attach?
Attaches b/t the 2 inferior pubic rami
Increases the strength of the inferior portion of the joint
What structure is the superior projection of the pubic body?
Superior ramus
Name the structure that projects anteriorly on the superior ramus near the midline and provides attachment for the superior ligament?
Tubercle
What structure is the main portion of the pubic bone, b/t the superior and inferior projetions?
The body
What structure is an inferior projection of the pubic body that provides an attachment for the inferior pubic ligament?
Inferior ramus
What articulation makes up the Lumbosacral joint?
What type of joint does it function like?
L5 and S1
Hinge joint
What two ligaments hold the lumbosacral joint together?
Iliolumbar and lumbosacral ligament
Iliolumbar ligament location
Attaches to the transverse process of L5 and run laterally to the posterior portion of the iliac crest
What movement does the iliolumbar ligament limit?
Limits rotation of L5 on S1
Assists the articular processes in preventing L5 from moving anteriorly on S1
Lumbosacral ligament location?
Attaches to the transverse processes of L5 and runs inferiorly and laterally to attach on the ala of the sacrum
*its fibers intermingle w/ the fibers of the anterior sacroiliac ligament
How is the lumbosacral angle determined?
By drawing one line parallel to the ground and another line along the base of the sacrum. (L5-S1 angle)
An anterior tilt will cause the lumbosacral angle to….
Increase
A posterior tilt will cause the lumbosacral angle to…
Decrease
What is the optimal lumbosacral angle?
30 degrees
What are the pelvic girdle motions?
Anterior pelvic tilt
Posterior pelvic tilt
Lateral tilt
Pelvic rotation
What structures allow pelvic girdle motions to occur?
Hips, lumbar joints, lumbosacral articulation
In a trendelenburg position what muscles are weakness leading to a pelvic drop?
Gluteus medius and minimus
What is seen in a trendelenburg position?
When standing on one leg the unweighted side displays a pelvic drop b/c the weak gluteus medius and minimus can not keep the pelvis level
What pelvic movements occur in the sagittal plane?
Anterior and posterior pelvic tilt
Describe the movement that takes place during an anterior pelvic tilt?
ASIS moves closer to the pubic symphsis, tilts pelvis forward
Describe the movement that takes place during a posterior pelvic tilt?
ASIS moves away from the pubic symphsis, titls pelvis backward
What muscles initiate a posterior pelvic tilt?
Hamstring pull on ischial tuberosity
What happens to the lumbar curve during a ppt?
it flattens
Frontal plane pelvic motions
Lateral tilt of pelvis that occurs during walking
May cause hip hiking
At what phase in the gait cycle does the pelvis drop?
During the swing phase the pelvis drops on the unsupported side
What motion does the pelvis perform in the transverse plane?
During walking pelvic rotation occurs because the pelvis moves on the weight bearing femoral head.
Rotation occurs when one side moves forward or back in relation to the other side
Anterior pelvic tilt force couples
Trunk extensors (erector spinae)pulling up- posteriorly Hip flexors pulling down- anteriorly
Posterior pelvic tilt force couples
Trunk flexors (abdominals) pulling up- anteriorly Hip extensors (glute max & hamstrings) pulling down- posteriorly
In what plane of motions does a reversal of muscle action occur during a lateral tilt?
Frontal plane
Lateral pelvic tilt force couples
During unsupported stance on left side:
Lateral trunk flexors pull up on the left side of the pelvis while glute med and min pull down on the right side of the pelvis to keep it leveled
Why are pelvic and trunk control needed?
To provide a stable foundation upon which the head and the extremities can move
