That said, I believe that C-Spine X rays still hold a place in the developing world where cost becomes a significant issue during management of trauma victims. Emergency Physicians often get caught up in financial discussions with patients and their families, therefore we need to choosy while ordering blood investigations and imaging studies. And also, C-Spine X-Rays is a good way to start evaluating low risk injuries. In this three part series, I intend to provide a framework and stepwise interpretation of C-Spine X-Rays.
- Open Mouth (Peg View)
- Swimmer's view: It is named after the swimming stroke referred to as freestyle. This view can be requested in addition to standard 3 trauma views to demonstrate the upper thoracic and the seventh cervical vertebrae.
Look at the images below to visualise C1-C2 anatomy. Peg (labelled as odontoid process of C2 in the image below) sits between the Anterior Arch of Atlas (C1 vertebra is also called as Atlas) and transverse ligament.
|See how peg (also known as odontoid/dens) fits into the ring of C1 vertebra seen from the lateral view|
Lateral View (STEPS)
|Inadequate film (C7-T1 not visualised)|
|Adequate (C7-T1 junction seen)|
Image of Left - Not the that the anterior cortex of peg continuous with the body of C2 and the posterior cortex of the peg is in continuation with the posterior cortex of body of C2. Image on Right- Obvious step in the continuity of C1-2 indicating peg #. This finding may not be very prominent.
Harris Ring, Marked with black Arrow heads. Look at all the above images now and try to localise the harris ring.
- Each line should run smoothly without any steps.
- The anterior and posterior heights of vertebra should be approximately same
- Any swelling on the soft tissues shadows anterior to the vertebra indicates haemorrhage. However, the absence of swelling cannot exclude an injury. So be worried if you increase in the width of pre-vertebral soft tissues but don't be reassured completely if it looks normal. Remember these numbers (3x7=21)
Pre-dental space - < 3mm in adults
Pre-vertebral Soft tissues width at C1-4 - < 7mm
Images taken from: