Diagnosis of the Occipito-Atlantal (OA) Joint

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Diagnosis of the Occipito-Atlantal (OA) Joint

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The OA joint – motion/position of the occiput on C1

The OA joint diagnosis is a triplanar diagnosis and includes: Rotation; Sidebending; Flexion/Extension


  • Palpating the Occipital Sulcus – the space between the occiput and C1 – is how you determine the rotational component of the OA diagnosis
    • The easiest way to find the occipital sulcus is slide your fingers down the occiput until you feel them drop off the bone, then move your fingers more cephalad. Your fingers should be in the sulcus 
    • The deeper sulcus is the side the occiput is rotated.  The occipital condyle is more posterior, producing a deeper sulcus. Remember, you are naming for the occiput’s rotation on the atlas vertebrae.
      • Deep right sulcus = OA rotated right


Translate entire head to determine sidebending – use the pt’s nose to determine which side the head translates better towards. Translation to the left means that segment is sidebent right (and vice versa)​. Do not sidebend the neck far enough to engage the inferior vertebral segments.


With your finger in the occipital sulci, flex and extend the head.  The position in which the sulci “even-out” is the freedom of motion, and we always name for freedom of motion!

Very little motion is required to isolate this joint

Putting the triplanar diagnosis together:

Example: A deep sulcus on the R, translates easier to the R, gets better with flexion → OA FRRSL

Note that…

  • Flexion/Extension is the primary motion → makes up 50% of flexion and extension of the cervical spine
  • Very little motion is needed to observe the OA compared to the rest of the C-spine (“Subtle movements”)

Sidebending and rotation “almost always” in opposite directions — Like a Type I Fryettes but remember Fryette did NOT write about the cervical spine

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