What Is A Normal Atlanto-Dental-Interspace (ADI)?

A normal adult Atlanto-Dental-Interspace (ADI) is  ≤ 3mm.  A normal child ADI can range from 1-5mm,  (figure 1).

Figure 1

What Is The Most Common Cause For ADI Disruption?

Trauma – This is by far the most common. An accident or injury has occurred that has torn the Transverese Atlantal Ligament (TAL).  (figure 2)

Figure 2

How Is The ADI Measured? 

Typically the Atlanto-Dental-Interspace is measured on a neutral lateral cervical x-ray from the bottom of the anterior tubercle to the anterior surface of the odontoid process of (C2). (figure 3).  

Figure 3

How Is The ADI Tested For Stability?

Typically flexion-extension x-rays are taken with the patient tipping their head forward and back to determine ligament stability or laxity of the Atlanto-Dental-Interspace.  

Figure 4

About the Author

Dr. Dr. Grayson Blom, B.Sc., D.C., U.C.A., C.C.E.P

Upper Cervical Health Centers Boise

Before becoming an​ Upper Cervical Chiropractor, Dr. Blom graduated with honors from the Fountain Head of Chiropractic, Palmer College in Davenport, Iowa. He is an Idaho native returning home to serve the community he grew up in. Dr. Blom has also received a post graduate diplomate from the Upper Cervical Academy through Sherman College of Chiropractic and is also trained and certified in the Upper Cervical procedure through the KCUCS, Blair Upper Cervical Society, and in the Orthospinology procedure. He is one of only a few Doctors trained and certified in the Upper Cervical procedure in the State of Idaho.