Sacrum Flashcards
What common complaints require evaluation of the sacrum
Abdominal pain Pelvic pain Dysmenorrhea Lower back pain Urinary tract complaints Lower GI issues Neuralgia of lower extremities
Anterior sacral landmarks
Sacral base
Sacral promontory
Sacral apex
Sacral ala Coccyx Anterior sacral foramen Pelvic brim landmark Transverse lines
Posterior sacral landmarks
Coccyx
Inferior lateral angle
Superior articular facets Sacral canal Auricular surface Posterior sacral foramina Sacral hiatus Sacral tuberosities Spinous tubercles Sacral cornu Intermediate sacral crest Median sacral crest
Lowest portion of spinal column composed of 4 vertebra that are sometimes fused
Coccyx
The sacrum is formed by the union of ____ modified vertebra from 35 ossification centers as well as additional centers for ______ elements which develop within a cartilaginous model along with the vertebral arch and centrum
There are two _____ _____ for each lateral surface which separate adjacent segments and fuse sequentially after puberty with the lowest segments first
Five; costal
Epiphyseal plates
The dura attaches at the level of the ____ sacral segment
Second
Bony articulations of the sacrum
Fifth lumbar vertebra superiorly
Coccyx inferiorly
Two os coxae through C shaped SI articulations
Sacral joints AP
Right SI joint
Left SI joint
L5-S1 intervertebral disc
Sacrococcygeal joint
SI joint characteristics in males vs. females aftery puberty
Males: SIJ ligaments well developed and strong
Females: SIJ ligaments less developed, allowing mobility required during childbirth
SI joint characteristics in the second decade of life
Crescent shaped ridge develops along iliac surface that interdigitates with a depression on the sacral side, which adds stability and limits mobility
SI joint characteristics in the 3rd decade of life, particularly in males
Crescent shaped ridge becomes more pronounced decreasing ROM
Males: degenerative changes may begin to occur on the iliac side
SI joint characteristics in 4th and 5th devades of life, particularly in males
Males: degenerative changes begin on the sacral side
Fibrous ankylosis may further limit joint motion
SI joint characteristics of sacral surface vs. iliac surface
Sacral surface: generally smooth, hyaline cartilage, decreases in width inferior and is consequently wedged between 2 ilia
Iliac surface: anteriorly smooth, posteriorly fibrous, giving rise to the interosseous ligaments, fibrocartilage
The SI joint is described as either L or C shaped; contoured with a ______ upper arm and a ______lower arm, with a junction occurring at approximately ____
The apex points _____
Shorter; longer; S2
The SI joint is considered to be _____ bc it contains synovial fluid and matching articular surfaces
Diarthrodial
What makes the SI joint different from any other joint in the body?
One side is hyaline cartilage and the other is fibrocartilage
What ligament has inferior fibers from the third and fourth sacral segments ascending to the PSIS and posterior end of the internal lip of the iliac crest?
Posterior sacroiliac ligament
The posterior sacroiliac ligament blends with the _____ and the ____ fascia
STL; thoracolumbar
Which is thicker, anterior or posterior SI ligaments?
Posterior
What ligament connects the third sacral segment to the lateral side of the preauricular sulcus?
Anterior SI ligament
The anterior sacroiliac ligament blends with what other ligament?
Iliolumbar ligament
What ligament forms the major bond between the sacrum and ilium, filling the irregular space posterosuperior to the joint?
Interosseous sacroiliac ligament
What covers the interosseous sacroiliac ligament posteriorly?
Posterior SI ligament
What ligament connects the PSIS to the lateral aspect of the third and fourth sacral segments?
Long dorsal SI ligament
The long dorsal SI ligament is in close anatomic relationship with what 3 structures?
Erector spinae mm group
Posterior layer of thoracolumbar fascia
Sacrotuberous ligament
What effect does nutation have on the STLs and sacrospinous ligaments?
Stretches them
What ligament is stretched in counternutation, such as early stages of pregnancy, aging, or backward torsions or sacral extensions?
Long dorsal SI ligament
What ligaments are stretched by nutation?
STLs
Sacrospinous
What small muscle runs and blends with the STL and sacrospinous ligaments?
Coccygeus m
What ligament extends from ischial spine to lateral margins of the sacrum where it blends with the sacrotuberous ligament and forms part of the origin of the coccygeus m?
Sacrospinous L
What ligament runs from lower sacral tubercles to ischial tuberosity and forms part of gluteus maximus attachement, tendon of biceps femoris attachment, and connects with the fascia of the pelvis?
STL
What ligaments stabilize to limit posterior-superior rotation of the sacral apex around a transverse axis?
Sacrospinous
Sacrotuberous
Origin/insertion/innervation/action of piriformis m
Origin from anterior surface of 2-3-4 lateral masses of the sacrum and sacrotuberous ligament
Insertion upon superior border of greater trochanter
Innervation: ventral rami of 1 and 2 sacral plexus
Action: externally rotates thigh when hip joint is extended; abducts thigh when hip joint is flexed; assists in holding femoral head in acetabulum
Hypertonicity of the piriformis may lead to what condition?
Sciatica
What muscles make up the pelvic diaphragm?
Levator ani (puborectalis, pubococcygeus, ileococcygeus)
Obturator internus
Ischiococcygeus
Piriformis
What 3 plexuses are associated with the sacrum?
Lumbar plexus L1-4
Sacral plexus L5-S4
Coccygeal plexus S5-coccygeal n
What 3 ganglia are important in innervation surrounding the sacrum?
Inferior mesenteric ganglion
Superior hypogastric ganglion
Ganglion impar
What is the significance of the ganglion impar?
It joins the 2 sides of ganglia along the sacrum at the apex
The self-locking mechanism of the sacrum is critical for resistance against ______, the result of:
______ = the specific properties of the articular surfaces of the SIJ requiring the proper size, shape, and attitude of the articulating surfaces
______ = the compression produced by body weight, muscle action, and ligament force
Shear
Form closure
Force closure
____ closure is due to how the joint fits together
____ closure is due to gravity and loading forces - muscles, fascia, and ligaments
Form
Force
How are the 2 oblique axes of sacral motion named?
According to the side of the body toward which the superior end of the oblique axis is located
What are the 3 transverse axes of motion associated with the sacrum?
ST (respiratory) axis - level of S2
MT (postural) axis - level of S2
IT (pelvic/ilial) axis - level of S3
Describe movement of the sacrum (including base vs. apex) in counternutation
Sacral extension
Base moves posteriorly
Apex moves anteriorly
Describe movement of the sacrum (including base vs. apex) in nutation
Sacral flexion
Base moves anterior
Apex moves posterior
All movements of the sacrum on the ilium are _____ movements including flexion, extension, rotation, SB, and upward/downward motion
Gliding
Downward force transmitted from the lumbar region glides the sacrum downward and causes ________
Traction applied from above the LS junction glides the sacrum upwards and causes _____
Nutation
Counternutation
Rotation applied through the lumbar spine causes the sacrum to rotate toward the _____ side and sidebends towards the ____ side
Ipsilateral; contralateral
Sidebending applied through the lumbar spine causes the sacrum to sidebend towards the ______ side…but rotation during sidebending may be inconsistent
Ipsilateral
T/F: flexion/extension and gliding upward/downward ROM is less than rotation or sidebending
False; greater than rotation or sidebending
T/F the ilium always moves in the same direction as the sacrum but to a lesser degree
True
A restricted inferior occipital condylar part is related to what dysfunction of the sacrum?
Lowered sacral base on that side
_____ = a transitional segment in which the first sacral segment becomes like an additional lumbar vertebra articulating with the second sacral segment
Lumbralization
______ = incomplete separation and differentiation of the fifth lumbar vertebra such that it takes on characteristics of a sacral vertebra
OR when transverse proces of the fifth lumbar vertebra are atypically large, causing pseudoarthritis with the sacrum and/or ilia referred to as a batwing deformity if bilateral
Sacralization
Static testing methods for sacrum
Sacral sulcus
L5 rotation
ILA
4 point eval
Active motion testing of the sacrum
Backward bending test
Respiratory motion test
Passive motion testing of the sacrum
Lumbosacral spring test
4 point PROM
Oblique axis passive motion
In a torsion, the lateralization test will be _____ on the opposite side of the axis
Positive
The sacral base should move ____ during inhalation and _____ during exhalation
Posteriorly; anteriorly
Innominate rotation occurs around what sacral axis?
Inferior transverse axis (S3)
How should rotation of the sacrum relate to rotation of L5?
L5 rotates opposite the direction of the sacrum (if not rotated, it is uncompensated and should be tx before the sacral dysfunction)
A flexed sacrum means a _____ L5; an extended sacrum means a _____ L5
Neutral (type 1); non-neutral (type 2)
How does L5 sidebend in relation to an oblique axis of a torsion?
L5 sidebends toward the oblique axis of a torsion
Which side of the SI joint should be gapped to facilitate flexion?
Anterior SI
Which side of the SI joint should be gapped to facilitate extension?
Posterior
For bilateral sacral flexion HVLA, on what respiratory cycle is thrust applied?
Inhalation
