What constitutes a lateral chest radiographically? This page considers paravertebral gutter technique as a means of producing a lateral chest position. Irrespective of what you consider a good lateral chest position to be, this technique may have some utility. This page describes a practical approach to lateral chest radiography technique.

adapted from Jannette Collins, Eric J. Stern Chest Radiology: The Essentials Edition: 2, 2007

This graphic illustrates the true lateral chest position. The problem with this position is how to achieve it consistently.

This is an axial CT section through the chest. The arrows point to the paravertebral gutters. Note that the skinline and the posterior ribs are closely related.	This is the true lateral chest position

The paravertebral gutter technique for lateral chest radiography is one of those techniques that is very easy to execute but hard to explain. The general principle is that if you line up the skin adjacent to the paravertebral gutter with the divergent beam (light beam and X-ray beam), in doing so, you are also overlapping the posterior ribs. Position the patient in the true left lateral position with arms folded over his/her head. Rotate the patient's right side forward (anteriorly) until the light from the LBD just skims the left paravertebral gutter (i.e. the left paravertebral gutter is just out of the shadow of the right paravertebral gutter). In this position the posterior ribs are perfectly, or near-perfectly, superimposed.

' Lateral Sternum' Position If you roll the patient's right shoulder backwards off lateral (LPO), you tend to achieve a very lateral looking sternum only.	True Lateral This is the true lateral position- only the mid axillary line structures are superimposed	Paravertebral Gutter Technique This is the position that is achieved using the paravertebral gutter technique (slightly LAO)
This patient was for chest and sternum radiography. The radiographer has deliberately rotated the patient slightly LPO in the hope of achieving a more lateral sternum.		The posterior ribs are perfectly superimposed. (ignore the arrow)

Advantages	Disadvantages
Highly Reproducible	Not a true lateral Can result in an oblique view of the sternum (trauma consideration) Does not work in patients who don't have visible paravertebral gutter surface anatomy (scoliosis, emphysema, obese patients) May superimpose posterior costophrenic angles

	This 50 year old female presented to the Emergency Department with chest pain and was referred for chest radiography. The PA chest image is unremarkable. Multiple artifacts noted.
	The radiographer used paravertebral gutter technique to superimpose the posterior ribs. The patient has pectus excavatum (black arrow). The posterior ribs are well superimposed at the expense of the anterior ribs (white arrows). The pectus excavatum has provided an exaggerated illustration of the tendency to overlap the posterior ribs at the expense of the anterior ribs. If all patients demonstrated their posterior and anterior ribs equally well on lateral chest radiography, how would this change the approach to lateral chest radiography?

Superimposition of the posterior ribs on a lateral chest image is considered by some radiographers as a mark of a good lateral chest X-ray position. Conversely, it is considered a hallmark of bad technique in other institutions. In particular, some paediatric departments require separation of the posterior ribs on the lateral image to assist in separating the posterior costophrenic angles. It must be frustrating for a radiologist to identify a basal lung pathology on a lateral chest image, but not know which side of the chest is involved.

The use of the paravertebral gutter technique to superimpose the posterior ribs allows radiographers to achieve consistent and repeatable lateral chest positioning. This raises the question of whether the ability to reproduce the exact same comparable lateral chest position is of greater utility than producing images that attempt to meet the goal of a true lateral chest position (with unproven diagnostic benefit). Equally, using the paravertebral gutter technique may simply reflect tidymindedness on the part of the radiographer that is of no real benefit to the patient.


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