Lecture #38a: OMM: Basics of Diagnosis: Sacrum

What are the primary sacral landmarks used for diagnosis?

Sacral base,sacral sulci,inferior lateral angles(ILAs),posterior superior iliac spines (PSIS), and the L5 vertebra

Where are the sacral sulci located and what do they represent?

Slightly medial and superior to the PSIS; their depth reflects the anterior or posterior position of the sacral base

What does a deep sacral sulcus indicate?

The sacral base on that side is more anterior

What does a shallow sacral sulcus indicate?

The sacral base on that side is more posterior

What does a posterior and inferior ILA indicate?

The sacrum is extended on that side

What is the normal lumbosacral angle(Ferguson’s angle)?

Approximately 25–35 degrees between the horizontal plane and the sacral base

How does an increased lumbosacral angle affect the spine?

It increases anterior shear forces and lumbosacral strain

What are the main axes of sacral motion?

Vertical, anteroposterior, superior transverse, middle transverse, inferior transverse, and left and right oblique axes

What motion occurs around the superior transverse sacral axis?

Respiratory and craniosacral motion

What happens to the sacral base during inhalation?

It moves posteriorly and superiorly

What happens to the sacral base during exhalation?

It moves anteriorly and inferiorly

What motion occurs around the middle transverse sacral axis?

Postural motion including sacral nutation and counternutation during forward and backward bending

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 motion occurs around the inferior transverse sacral axis?

Gait-related innominate motion on the sacrum

What motions occur around the oblique sacral axes?

Sacral torsions and sacral rotations

How is a sacral torsion named?

By the direction of sacral rotation on the direction of the oblique axis

What distinguishes sacral torsions from sacral rotations?

In torsions the sacrum and L5 rotate in opposite directions;in rotations they rotate in the same direction

What are physiologic sacral dysfunctions?

Restrictions within normal motion ranges including forward torsions, forward rotations, and bilateral sacral flexions

What are non-physiologic sacral dysfunctions?

Restrictions outside normal motion ranges including backward torsions, backward rotations, unilateral shears, and bilateral sacral extensions

Which sacral dysfunctions should be treated first?

Non-physiologic dysfunctions

What is the purpose of the prone static sacral exam?

To assess L5 position, sacral sulci symmetry, and ILA symmetry

What does a positive lumbosacral spring test indicate?

A non-physiologic dysfunction with an extended sacral base and restricted springing

What does a negative lumbosacral spring test indicate?

A physiologic dysfunction with normal springing motion

What is the sphinx test used to assess?

Whether a sacral dysfunction is physiologic or non-physiologic during lumbar extension

What indicates a positive sphinx test?

Asymmetry of ILAs persists or worsens during lumbar extension

What indicates a negative sphinx test?

ILAs become more symmetric during lumbar extension

What is the seated flexion test used to determine?

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 is the positive seated flexion test used in sacral diagnosis?

It names the side of unilateral dysfunction or the side opposite the oblique axis in torsions and rotations

What does the ASIS compression test assess?

Relative motion restriction at the sacroiliac joints

What does a positive ASIS compression test indicate?

The side with greater resistance to compression is restricted

What is the relationship between deep sulcus and ILA in sacral torsions?

They are found on opposite sides

What is the relationship between deep sulcus and ILA in unilateral sacral dysfunctions?

They are found on the same side

What axis is involved in bilateral sacral dysfunctions?

The middle transverse axis

What axis is involved in sacral torsions and rotations?

An oblique axis

What is the rule of L5 in sacral diagnosis?

L5 rotates opposite the sacrum in torsions and the same direction in rotations

How does L5 sidebending relate to the oblique axis?

L5 sidebends toward the side of the oblique axis

How can sacral torsions be diagnosed if only an L5 diagnosis is given?

Determine whether L5 is neutral or non-neutral, identify axis by sidebending, use opposite rotation for the sacrum, and determine forward versus backward torsion based on lumbar mechanics