Variations of the origin of collateral branches emerging from the posterior aspect of the brachial plexus

Abstract

BackgroundThe frequency of variation found in the arrangement and distribution of the branches in the brachial plexus, make this anatomical region extremely complicated. The medical concerns involved with these variations include anesthetic blocks, surgical approaches, interpreting tumor or traumatic nervous compressions having unexplained clinical symptoms (sensory loss, pain, wakefulness and paresis), and the possibility of these structures becoming compromised. The clinical importance of these variations is discussed in the light of their differential origins.MethodsThe anatomy of brachial plexus structures from 46 male and 11 female cadaverous specimens were studied. The 40–80 year-old specimens were obtained from the Universidad Industrial de Santander's Medical Faculty's Anatomy Department (dissection laboratory). Parametric measures were used for calculating results.ResultsAlmost half (47.1%) of the evaluated plexuses had collateral variations. Subscapular nerves were the most varied structure, including the presence of a novel accessory nerve. Long thoracic nerve variations were present, as were the absence of C5 or C7 involvement, and late C7 union with C5–C6.ConclusionFurther studies are needed to confirm the existence of these variations in a larger sample of cadaver specimens.

Study of Variations in the Branching Pattern and Distance of Origin of Branches of Posterior Cord of Brachial Plexus

“…Ballesteros and Ramirez had reported the origin of the lower subscapular nerve from the axillary nerve in 54.4% of their study of 57 specimens [7]. This also correlates with the current study.…”

“…The Brachial plexus is an intricate network of nerve fibres organized by platuing of ventral rami of C 5,6,7,8 and T 1 . It is divided into Supraclavicular part and infraclavicular parts.…”

“…The posterior cord can be used as a donor fascicle to the suprascapular nerve after its infraclavicular relocation [5].Stimulation of the posterior cord before local anesthetic administration is linked with enhancement of infraclavicular block success compared with stimulation of either the lateral or medial cord [6]. Subscapular nerves are most varied structureand vastly inconsistent in their origin, number, course and supply to the muscles [7]; so their variations become vital as they are used in neurotisation procedure and also help in predicting the area of lesions. The position of the subscapular nerves and the pattern of innervation of the subscapularis is necessary to avoid injury during anterior shoulder surgery [8].…”

Anatomical Variation in Branching Pattern of Brachial Plexus and Its Clinical Significance

“…Earlier, Kerr [18] had come across such a variant origin in 25.4% of his dissections and Fazan et al [19] & Ballesteros and Ramirez [20] had come across such a variant origin in 59% and 50% of their dissections. No explanation can be given for such a wide discrepancy.…”

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“…Variations from this classical branching pattern differ in prevalence between populations [2][3][4]. In clinical practice, injuries to branches of the posterior cord are common and associated with each other [5].…”