Sacrum

Question 1

Anatomy

Answer 1

•The sacrum consists of 5 fused vertebral segments. •It articulates with the lumbar spine, ilia, and coccyx. •It’s anterior surface is concave and posterior surface is convex •In it’s center is the sacral canal with the cauda equina and 4 sacral spinal nerves which exit from the foramina. •The top of the sacrum is the sacral base (wide and flat like the top of home plate) •The bottom is known as the apex •The sacral promontory is the anterior portion of S1

Question 2

Anatomy (weight bearing)

Answer 2

•The weight of the upper body is transmitted through the sacrum and its ligamentous attachments to the pelvis via the iliolumbar, sacrospinous, &sacrotuberousligaments. •The anterior and posterior sacroiliac ligaments are extremely strong and connect the sacrum to the pelvis.

Question 3

Nutation

Answer 3

Flexion

Question 4

Counternutation

Answer 4

Extension

Question 5

when cranium goes into flexion the sacrum moves

Answer 5

Posteriorly postural is opposite cranial saccral

Question 6

Muscles of the Sacrum

Answer 6

•Piriformis (external rotator) •2nd-4thsacral segments •Iliacus •superolaterally •Pelvic diaphragm (particularly coccygeous) •Anteriorly to sacrotuberous & sacrospinous ligaments •Aponeurosis of the erector spinaeand Latisimusdorsi •Posterior-medial surface •Gluteus Maximus •Inferior Lateral Angle •No muscles move the sacrum directly

Question 7

Piriformis

Answer 7

•Attachments: •S2-4 and inserts into the greater trochanter of the femur •Action: •External rotation of thigh; abductor of the hip when the hip is flexed •Innervation: •S1-2 •Importance: •Sacral dysfunction can lead to piriformis syndrome

Question 8

Lumbosacral angle (Ferguson’s angle)

Answer 8

•The angle is generally between 25-35 degrees •An increase in this angle can increase lumbosacral strain

Question 9

Landmarks for diagnosis of the sacrum

Answer 9

•The sacral sulcimay be found moving medial and slightly superior to the PSIS bilaterally. •Physician places the palm of his/her hand on the sacrum. The most posterior/inferior aspect of the sacrum is the level of theInferior Lateral Angles. The thumbs are then placed on each ILA.

Question 10

The Axes of Sacral motion

Answer 10

•The sacrum has SEVEN axes of motion •1 vertical: allows for left/right rotation •1 Anterior-posterior: allows for sidebending •3 Transverse: Allows for flexion and extension. •2 oblique axes: Combines rotation, sidebending, and flexion/extension.

Question 11

Axes of sacral motion on the ilia

Answer 11

1.Vertical axis 2.Right oblique axis 3.Respiratory axis (superior transverse axis) 4.Sacroiliac axis (middle transverse axis) 5.Iliosacral axis (inferior transverse axis) 6.Left oblique axis 7.Anteroposterioraxis

Question 12

•Superior transverse / (thoracic) Respiratory axis. (S2)

Answer 12

•Flexion and Extension occurs with respiration. •The sacrum flexes with exhalation •The sacrum extends with inhalation craniosacral axis

Question 13

•Middle transverse / Postural/Sacroiliac axis. (S2)

Answer 13

•At the anterior convexity of the upper and lower limbs of SI joint •Flexion and extension occurs with motion of the sacrum on the ilium.

Question 14

•Inferior transverse / Iliosacral axes. (S3)

Answer 14

•At the posterior-inferior part of the inferior limb of SI joint. •Flexion and extension occurs with motion of the ilium on the sacrum.

Question 15

Sacral Side bending via an

Answer 15

AP Axis

Question 16

Sacral rotation about a

Answer 16

Vertical Axis

Question 17

Oblique sacral axes

Answer 17

•Named for the SUPERIORaspect. •The axis that runs from the right superior aspect of the sacrum (right sulcus) to the left inferior aspect of the sacrum (left ILA) is the right oblique axis. •The axis that runs from the left superior aspect of the sacrum (left sulcus) to the right inferior aspect of the sacrum (right ILA) is the left oblique axis.

Question 18

which base is moving when I hve a left axis engaged

Answer 18

the right axis..obvious when you have a left axis the right side is doiong something and vis versa

Question 19

Dynamic sacral motion*

Answer 19

•During the gait cycle •With walking, sacrum alternates: right-on-right, neutral, left-on-left, neutral, etc. •In stance phase, an ipsilateraloblique axis is created, and the sacrum moves anteriorly (obliquely) about this axis. •The lumbar spine sidebends ipsilateral to the weighted foot because of quadratus lumborum contraction. •This motion is physiologic(normal), however, when this motion is limited or fixed in a non-neutral position dysfunction occurs.

Question 20

right on right is rightward rotation about a

Answer 20

right axis

Question 21

•SI joint dysfunction

Answer 21

•Can lead to inhibition of the glut max and medius •This shortens the stride •The hamstrings are the recruited and overused to help extend the hip and leg •The erector spinaeare also recruited and overused •The QL (stabilizer of the L-spine) •This muscle will spasm causing low back pain •It can also be activated by standing on the same leg constantly or by jumping and landing on the same leg multiple times •The “jammed butt syndrome” •Remember the fascial connection from the foot into the TL region •Any disruption in this chain can cause gait abnormalities

Question 22

L5 “rule”

Answer 22

•It is a “rule” (meaning it always occurs on board exams, and sometimes occurs in practice too.) that in a sacral torsion, the sacrum and L5 rotate opposite each other. •Forward sacral torsions occur with NEUTRAL mechanics in the lumbar spine. (Type 1) •Backward sacral torsions occur with NON-Neutral mechanics in the lumbar spine. (Type 2) •So, in a Left on Left sacral torsion, it is expected that L5 is rotated to the RIGHT, and sidebentleft. (type I mechanics)

Question 23

DIAGNOSIS OF THE SACRUM

Answer 23

1. Seated flexion test 2. Combined Sphinx/Spring Test: 3. Static Examination of Sacral Landmarks (Patient Prone) 4. Motion testing

Question 24

1. Seated flexion test

Answer 24

•Seated flexion test determines the motion of the sacrum upon the ilium. This test is performed in the seated position to take away pelvis and lower extremity muscle influences. •The side which moves firstand farthest is the positiveside. •The side which is positive is usuallythe side of dysfunction. False positives exist due to muscle influences. •In sacral torsionsthe side of the positive test is ipsilateralto the dysfunction, but contralateral to the oblique axis. •In sacral sheers, (flexions/extensions) the side of the positive test is ipsilateralto the dysfunction. •This is a lateralizing test—it determines left or right. if positive on right side it means the left axis is activated oblique axis is opposite of the test but the side ofdysfunction is the same side

Question 25

2. Combined Sphinx/Spring Test:

Answer 25

•Backward bending introduces extension of the lumbar spine and flexion of the sacrum (relative to the lumbar spine). (Sphynx position) •Pressure applied from posterior to anterior on the sacral base, near the lumbosacral junction should initiate FORWARD sacral base motion. (spring) •The test is POSITIVEif there is a LACK of spring—i.e. the sacrum will notmove forward, but instead is “stuck” backward. •This test determines anterior or posterior

Question 26

3. Static Examination of Sacral Landmarks (Patient Prone)

Answer 26

•Palpation of the sacral sulci:Physician places thumb pads on the inferior aspects of the gluteal tubercles (dimples). The thumb that is more anterior by palpatory and visual observation is the side of the deep sulcus (anterior sacral base). The sacral sulci may also be found moving medial and slightly superior to the PSIS bilaterally. •Palpation of the Inferior Lateral Angle (ILA’s):Physician places the palm of his/her hand on the sacrum. The most posterior/inferior aspect of the sacrum is the level of the ILA’s. The thumbs are then placed on each ILA. The side on which the thumb is more anterior, according to palpatory and visual observation, is the anterior ILA. Because of sacral biomechanics, the more anterior ILA is usually the more superior. •\*note: in discussing specific dysfunctions, I will describe the dysfunctional landmark as either being anterior or posterior

Question 27

4. Motion testing

Answer 27

•With the patient prone, the DO applies a posterior to anterior pressure over all four corners of the sacrum (bilateral ILA’s and sulci) •Note which corner moves anterior the easiest. •Motion testing, along with landmarks, can confirm your sacral diagnosis.

Question 28

Combined Sphinx/Spring Test:

Answer 28

•A board like resistance or “lack of spring” to the LS junction determines that the sacrum is stuck BACKWARDS. •This is a positive Spring Test. •Able to move sacral base forward with pressure = normalresponse/negativespring test. •Unable to move sacral base forward with pressure = abnormalmotion response/positivespring test. •Also, in this sphinx position: landmarks in an anteriorsacral dysfunction will become softerand more symmetric, while landmarks in a posteriorsacral dysfunction will become harderand more Asymmetric.

Question 29

Naming a Sacral Torsion

Answer 29

•ALL dysfunctions are named for their ease of motion. The reference point for motion is ALWAYS the anterior-superiorcomponent. •We diagnose the sacrum based on the position of ease with the anterior superior aspect of S1as our reference point. •Rotation is stated first with the axis stated 2nd. •For example, a right rotation on a right axis •R on R named off promontory?

Question 30

Sacral torsions

Answer 30

* Seated flexion test determines dysfunctional side—opposite oblique axis * Sphinx/Spring test determines anterior posterior * Landmarks (and motion testing give final diagnosis)

Question 31

Sacral torsions •Example: •Positive seated flexion test on the RIGHT •Denotes a LEFT oblique axis •Negative spring test (there is good, easy anterior spring) •Denotes and anterior dysfunction •Landmarks •Anterior (deep) sulcus right •Posterior ILA left •Diagnosis:

Answer 31

Left of Left Sacral Torsion

Question 32

Unilateral sacral flexion

Answer 32

•The slippage of one sacroiliac joint about a vertical axis with translation of the sacral base (the sacrum appears to be side bending on an A-P axis). •Positive seated flexion test (usually) on dysfunctional side. •Spring test NEGATIVE (forward motion present) •Sulcus deep on same side as positive seated flexion test •ILA posterior on same side as positive seated flexion test get base on onse side goes forward and the ila on the same side goes backward

Question 33

Unilateral sacral extension

Answer 33

•The slippage of one sacroiliac joint about a vertical axis with translation of the sacral base (the sacrum appears to be side bending on an A-P axis). •Positive seated flexion test (usually) on dysfunctional side. •Spring test POSITIVE (forward motion ABSCENT) •Sulcus shallow (posterior) on same side as positive seated flexion test •ILA anterior (deep) on same side as positive seated flexion test

Question 34

Bilateral sacral shear

Answer 34

•Negative (or equivocal) seated flexion test. •Exaggeration of normal flexion or extension. •Sacral sulci equal but excessively deep or shallow. •ILA’s are equal but excessively deep or shallow. •The sphinx/spring test will determine flexion or extension. •Positive spring test (spring is absent) = Extension (Cant stand up stratight) •Negative spring test (spring is present) = Flexion (have to stretch back)