4. DSA: Sacrum Flashcards
Describe the SI joint after puberty
- males
- females
males: SIJ ligaments are well developed and strong
Females: SIJ ligaments are less developed, allowing the mobility required during childbirth
Describe the sacrum in the second decade of life
Crescent-shaped ridge develops along the iliac surface that interdigitates with a depression on the sacral side, which adds stability and limits mobility
Describe the sacrum in the third decade of life
Crescent-shaped ridge becomes more pronounced decreasing ROM more
Males: degenerative changes may begin to occur on the iliac side
Describe the sacrum in the 4th and 5th decades of life
Males: degenerative changes begin on the sacral side
Fibrous ankylosis may further limit joint motion
The sacrum is described as either c shaped of L shape and are contoured with arms; the _______ is the junction of these arms anteriorly
apex
The SI joint is a _________ joint
diarthrodial joint; contains synovial fluid
***Different from any other joint in the body due to one side being hyaline cartilage and the other being fibrocartilage
This surface is….
- generally smooth
- hyaline cartilage
- decreases in width inferiorly and is wedged between the two ilia
Sacral surface
This surface is.... -Anteriorly smooth • Posteriorly fibrous, giving ligaments • Fibrocartilage
Iliac surface
The ______ ________ _______ is composed of inferior fibers from the third and fourth sacral segments, ascend to the PSIS and posterior end of the internal lip of the iliac crest
Posterior sacroiliac ligament
The ______ SI ligament is thicker than the ________ SI ligament
posterior is thicker than the anterior
The ______ _______ _______ connects the the third sacral ligament to the side of the pre-auricular sulcus
anterior SI ligament
The ______ ________ _______ is the major bond between the bones, filling the irregular space posterosuperior to the joint.
Covered posteriorly by the posterior sacroiliac ligament.
Interosseous sacroiliac ligament
This ligament connects the PSIS to the lateral aspect of the third and fourth sacral segments
Long dorsal SI ligament
What are the landmarks that the long dorsal SA ligament has a nose relationship with?
Erector spinae muscle
Posterior layer of the throacolumbar fascia
Sacrotuberous ligament
The long dorsal SI ligament becomes stretched when the sacrum is rotated in a _____ manner relative to the ilium
posterior
What are reasons that the long dorsal SI ligament would stretch?
- early stages of pregnancy
- aging and degenerative changes
- backward torsions or unilateral/bilateral extensions
The ___________ ligament is from ischial spine to lateral margins of the sacrum where it blends with the sacrotuberous ligament
and
Forms part of the origin from which coccygeus muscle arises
sacrospinous ligament
The _________ ligament
Runs from lower sacral tubercles to ischial tuberosity, has a Gluteus maximus attachment, Tendon of the biceps femoris attachment Connects with fascia of the pelvis
STL
sacrotuberous ligament
What are the functions of the sacrospinous and sacrotuberous ligaments?
stabilize to limit posterior - superior rotation of the sacral apex around a transverse axis
________ hypertonicity can cause sciatica; causing inflammation of the sciatic nerve
Piriformis
What are the posterior pelvic landmarks?
PSIS
AIIS
ILA
The _____ ______ ______ is critical for resistance against shear
self-locking mechanism
______ ______ involves the specific properties of the articular surfaces of the SIJ
Form closure
***requires the proper size, shape, and attitude of the articulating surfaces
______ ______ is the compression produced by body weight, muscle action, and ligament force
force closure
List the muscles that lay posteriorly to the SI and provide a belt like effect
Latisimus dorsi, the thoracolumbar fascia, gluteus maximus, and the ITB.
List the muscles that lay ventrally to the SI and provide a belt like effect
abdominal obliques, the linea alba, and the transverse abdominals.
—- In both standing and sitting, the activity of the oblique abdominal muscles, especially the internal obliques, was found to be significant
the _____ (______) ____ transverse axis about which the sacrum moves during the respiratory cycle and inherently due to PRM in OCMM. It passes from side to side through the articular processes posterior to the point of attachment of the dura at S2.
ST (Respiratory) axis
The _____ (_______) _____ is the functional transverse axis of nutation & counternutation in the standing position, passing through the anterior aspect of S2.
MT (postural) axis
The _____ (______) ____ functional transverse axis at the level of S3 through the inferior auricular surface, and represents the axis for movement of the ilia on the sacrum.
IT (Pelvic/Ilial) Axis
Describe the sacral extension counternutation
What does the base of the sacrum do? What does the apex of the sacrum do?
Base moves posteriorly and the apex moves anteriorly
Describe the sacral flexion nutation
What does the base of the sacrum do? What does the apex of the sacrum do?
Base: anteriorly
Apex: posteriorly
All of the movements of the sacrum on the ilium are ______ movements.
gliding
**This includes flexion/extension, rotation, sidebending (lateral flexion) & gliding upward and downward.
Downward force transmitted from the lumbar region glides the sacrum downward and causes ______.
nutation
Traction applied from above the LS junction glides the sacrum upwards and causes ______.
counternutation
Rotation applied through the lumbar spine causes the sacrum to rotate towards the ______ side and sidebends towards the ______ side.
Ipsilateral
contralateral
_______ is when a transitional segment in which the first sacral segment becomes like an additional lumbar vertebra articulating with the second sacral segment.
Lumbarization
_______ is the
- Incomplete separation and differentiation of the fifth lumbar vertebra (L5) such that it takes on characteristics of a sacral vertebra.
- When transverse processes of the fifth lumbar (L5) are atypically large, causing pseudoarthrosis with the sacrum and/or ilia(um), referred to as batwing deformity, if bilateral.
Sacralization
Review the second to last slide fo this lecture for the common sacral abnormalities
K thanks bye
