Lecture #38b: OMM Lab 18 Prep Lecture

What is an axis in sacral motion?

An axis is the line around which sacral motion occurs; movement happens around an axis and never on the axis itself

What are the two main types of sacral axes?

Transverse axes and oblique axes

What are the three transverse sacral axes and their levels?

Superior transverse axis through S2 attachment of dura, middle transverse axis through S2 vertebral body, inferior transverse axis through S3

What motion occurs around the superior transverse sacral axis?

Primary respiratory motion and gross respiratory sacral motion

What motion occurs around the middle transverse sacral axis?

Sacral motion on the pelvis including bilateral sacral flexion and extension

What motion occurs around the inferior transverse sacral axis?

Innominate motion relative to the sacrum during gait

How is the oblique sacral axis oriented?

From the superior SI joint on one side to the inferior SI joint on the opposite side

What motions occur around the oblique sacral axes?

Sacral torsions and sacral rotations

How are sacral torsions named?

By the direction of sacral rotation relative to the oblique axis

What defines a sacral torsion biomechanically?

The sacrum rotates in the opposite direction of L5

What defines a sacral rotation biomechanically?

The sacrum and L5 rotate in the same direction

What are the L5 rules for sacral torsions?

L5 rotation is opposite sacral rotation,sidebending is toward the oblique axis, and Type I corresponds to forward torsions while Type II corresponds to backward torsions

What is sacral nutation?

Anterior movement of the sacral base relative to the ilia

What is sacral counternutation?

Posterior movement of the sacral base relative to the ilia

What characterizes physiologic sacral dysfunctions?

The sacrum is restricted in a forward direction such as bilateral sacral flexion or forward torsions and rotations

What characterizes nonphysiologic sacral dysfunctions?

The sacrum is restricted in a backward direction such as bilateral sacral extension, backward torsions, backward rotations, or unilateral shears

Which sacral dysfunctions should be treated first?

Nonphysiologic sacral dysfunctions

What is the purpose of the spring test?

To determine whether the sacrum is stuck in a forward or backward position

What does a positive spring test indicate?

The sacrum is stuck posteriorly indicating a nonphysiologic dysfunction

What does a negative spring test indicate?

Normal anterior springing consistent with a physiologic dysfunction

What is the purpose of the sphinx test?

To distinguish forward versus backward sacral dysfunctions during lumbar extension

What does a positive sphinx test indicate?

Asymmetry worsens with extension indicating a backward dysfunction

What does a negative sphinx test indicate?

Asymmetry improves with extension indicating a forward dysfunction

What is the seated flexion test used for?

To identify the side of sacral or innominate dysfunction

How is the seated flexion test interpreted?

The side whose PSIS moves first and farthest is the positive side

How does the seated flexion test relate to sacral axes?

The axis lies on the side opposite the positive seated flexion finding

What does a deep sacral sulcus represent?

The sacral base on that side is more anterior relative to the opposite side

What does a shallow sacral sulcus represent?

The sacral base on that side is more posterior relative to the opposite side

What does an anterior ILA indicate?

The sacrum is flexed on that side

What does a posterior ILA indicate?

The sacrum is extended on that side

How are sulci and ILAs interpreted clinically?

They are relative findings and must be compared bilaterally to determine asymmetry

What is the relationship between sulci and ILAs in sacral torsions?

The deep sulcus and posterior ILA are found on opposite sides

What is the relationship between sulci and ILAs in unilateral sacral dysfunctions?

The deep sulcus and posterior ILA are found on the same side

What information is required to make a full sacral diagnosis?

Direction of dysfunction(forward or backward), axis location, and relative sulcus and ILA findings

What are the four classic sacral torsion diagnoses?

Right on Right, Left on Left, Right on Left, and Left on Right

What does a Right on Right sacral torsion represent?

A forward sacral torsion rotating right on a right oblique axis

What does a Left on Right sacral torsion represent?

A backward sacral torsion rotating left on a right oblique axis

Why is sacral motion considered relative?

Because palpatory findings are based on side-to-side comparisons rather than absolute positions

What is the key principle for accurate sacral diagnosis?

Determine forward versus backward motion,identify the axis,and then apply palpatory findings logically