Superficial location of the brachial plexus and axillary artery in relation to pectoralis minor: a case report

Abstract

Knowledge of the anatomy of the infraclavicular fossa is important as this region is a target site for anaesthesia of the upper limb during infraclavicular approaches to brachial plexus blocks and in central venous cannulation of the axillary or subclavian veins. The cords of the brachial plexus and the axillary artery and vein are classically described as being located deep to the pectoralis minor and major muscles in the infraclavicular fossa. A rare variation was observed on one side of an individual, out of a total of 170 dissections, in which the brachial plexus and axillary artery were located between the pectoralis minor and major muscles. This variation was observed on the right-hand side of a male cadaver, and resulted in a more superficial position of the cords of the brachial plexus and axillary artery in relation to the skin. This superficial position of these vital structures may lead to an increased risk of complications during clinical procedures, such as infraclavicular brachial plexus blocks, central venous cannulation or surgery. Ultrasound should be used whenever possible to visualise variant positions of arteries, veins, nerves or muscles during these and other procedures.

Anatomical Variations in the Pectoralis Minor Muscle Origin and Insertion: A Systematic Review

“…Still, an earlier study conducted by Low and Tan in 2010 documented a prevalence rate of such variations of nearly 0.1%, even as Lee et al documented a case of PMi insertion at the humerus’ greater tubercle in 1 out of the 74 shoulders [ 34 ]. Also, Keet and Louw, and Lee et al noted anomalous insertion of the PMi in nearly 23% of the total number of dissections they conducted [ 35 , 36 ]. The supraspinatus tendon insertion is likely to result in the imposition of undue tension on the rotator cuff while negatively affecting the repair of the rotator cuff.…”

“…The anomalous insertion of PMi has been observed to vary in prevalence on the basis of gender, equipment utilized, the side of the body involved, and the absence and existence of symptoms [ 8 , 35 ]. For instance, a study conducted in the United States disclosed anomalous PMi insertion in 9.58% of the dissected and evaluated shoulders in 40 patients, including 22 unilateral patients and 18 bilateral patients [ 8 ].…”