The author does not intend to minimize the importance of the anterior approach when the essential element in the operation is the release of the scalenus anterior. It is, perhaps, needless to emphasize, that in undertaking the sectioning of the scalenus anterior, the surgeon must be continuously on his guard not to injure the many important structures lying underneath the sternomastoid muscle. Donald and Morton call attention to a patient operated upon through an anterior approach in whom the thoracic duct was lacerated. They quote Spurling and Bradford, who commented on the occurrence of temporary paralysis of the diaphragm following traction on the phrenic nerve which is in intimate relation with the scalenus anterior. In the lateral approach no such important structures are encountered. The author is not here entering a plea for the exclusive use of the lateral approach in cases with symptoms of the scalenus anterior syndrome, but wishes only to direct attention to the fact that, when it is primarily desired to remove a cervical rib or the band of connective tissue extending downward from it, the lateral approach offers a simple and safe method for its performance, and has the following distinct advantages:
1. Accessibility to the rib in the intermuscular region between the levator scapulae posteriorly and the scaleni anteriorly.
2. The entire rib can be removed by freeing its proximal extremity and elevating it from behind forward from the adjacent muscles.
3. The aponeurotic or fascial band extending downward from the tip of the rib, which itself often causes pressure on the brachial plexus and subclavian artery, can be severed, and its pressure effect removed.
4. The approach is avascular, since no important vessels are encountered.
5. There is little danger of damaging the brachial plexus and subclavian vessels because they are protected by retraction of the scaleni.