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OMM Question of the Day: OA Joint Motion Testing

Osmosis Team
Published on Apr 20, 2022. Updated on Apr 20, 2022.

Today's OMM question involves a 27-year-old woman with neck pain. Physical examination of the occipitoatlantal joint shows a deep left sulcus, the occiput translates more easily to the left. Which is the most likely somatic dysfunction of the patient’s occipitoatlantal joint?

A 27-year-old woman presents to the clinic for neck pain. She has experienced several episodes of this neck pain since it started two weeks ago. She describes it as a dull ache at the upper part of the back of her neck, extending into the bottom of her scalp. It goes away with gentle stretching and hot showers, but often returns the next day. She has no medical problems and takes no medications. She does not have any photophobia. Her vital signs are within normal limits. Physical examination of the occipitoatlantal joint shows a deep left sulcus, the occiput translates more easily to the left. On flexion of the neck, the sulci seem to even out. Which of the following is the most likely somatic dysfunction of the patient’s occipitoatlantal joint?

A. OA Neutral, Sidebent Right, Rotated Left

B. OA Flexed, Sidebent Right, Rotated Left

C. OA Flexed, Sidebent Right, Rotated Right

D. OA Extended, Sidebent Left, Rotated Right

E. OA Extended, Sidebent Right, Rotated Left

Scroll down for the correct answer!


The correct answer to today's OMM Question is...

B. OA Flexed, Sidebent Right, Rotated Left

Before we get to the Main Explanation, let's look at the incorrect answer explanations. Skip to the bottom if you want to see the correct answer right away!

Incorrect answer explanations

The incorrect answers to today's OMM Question are...

A. OA Neutral, Sidebent Right, Rotated Left

The sidebending and rotation are correct, but the patient’s findings improved with flexion, indicating it is a flexion somatic dysfunction. While neutral dysfunctions exist, most patients will be either flexed or extended.

C. OA Flexed, Sidebent Right, Rotated Right

The patient does have a flexed somatic dysfunction, but her OA joint is rotated left, as indicated by the deep sulcus on the left. In addition, sidebending and rotation are always in opposite directions at the OA joint.

D. OA Extended, Sidebent Left, Rotated Right

Since the patient’s sulci even out on flexion, we know it is a flexion somatic dysfunction. This would be the correct answer if the patient had the opposite findings (deep right sulcus, easier translation to the right, sulci even out on extension).

E. OA Extended, Sidebent Right, Rotated Left

Since the patient’s sulci even out on flexion, we know the ease of motion is flexion, so it is a flexion somatic dysfunction. The sidebending and rotation in this question are correct.

Main Explanation

Remember that rotation and sidebending always go in opposite directions at the OA joint.

1. On palpation of the suboccipital sulci, the side with the deeper sulcus indicates the side of rotation of the OA joint. As the occiput rotates on its OA joint, your hand and fingers will be in contact with more of the occiput on that side, causing the sulci to feel deeper on palpation.

2. On translation of the OA joint to one side, you are assessing its sidebending motion to the opposite side. If the OA joint translates more easily to the left, it means the OA joint sidebends more easily to the right. Think of the occiput sidebending down to touch your finger as you translate it toward the opposite side.

3. On either flexion or extension, the sulci will usually even out while you are palpating them. If they feel more even on flexion, then that is the ease of motion and the type of somatic dysfunction. If the sulci feel more even on extension (or the difference is even more pronounced on flexion), then it is an extension somatic dysfunction.

Major Takeaway

Remember the three components of the occipitoatlantal (OA) examination – rotation, sidebending and flexion/extension. Somatic dysfunctions are named for the ease of motion. In this patient, the sulci even out on flexion (flexed), translation is easier to the left (sidebent right), and the left sulcus is deep (rotated left).

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