Kimura Seiichi, Amatani Hiromu, Nakai Hikaru, Miyauchi Ren, Nagaoka Tomohito, Abe Mikiko, Kai Masatake, Yamagishi Toshiyuki, Nakajima Yuji
Faculty of Medicine, Osaka City University, Osaka, Japan.
Department of Anatomy, St. Marianna University School of Medicine, Kawasaki, Kanagawa, Japan.
Anat Sci Int. 2020 Sep;95(4):559-563. doi: 10.1007/s12565-020-00541-3. Epub 2020 Apr 24.
The brachial plexus is an important nervous structure from which all major nerves to the upper limb arise. It typically originates from the anterior rami of the C5-T1 spinal nerves. As it passes laterally, the roots are successively organized into three trunks, six divisions, and three cords. The BP is susceptible to injury during the perinatal and postnatal periods, as well as in adulthood. Its structure can show considerable variation, and there is a wealth of literature describing its variations, providing indispensable information to neurosurgeons. Here, we report a novel unilateral variant of the brachial plexus found in an adult Japanese male cadaver. In this case, the middle trunk arose from the C7 and C8 spinal nerves, and the inferior trunk continued from the T1 alone. At the interscalene triangle, the subclavian artery was situated between the C8 and T1 nerves. The posterior cord arose from the posterior divisions of the superior and middle trunks, while the root from the T1 nerve/inferior trunk was absent. The anterior division of the middle trunk gave independent roots to the musculocutaneous and median nerves, without completely establishing the lateral cord. A communicating branch arose from the musculocutaneous nerve to join the median nerve. Some branches from the roots and cords also deviated from typical configurations. This case represents a rare combination of variations in the trunks, divisions, cords, and the median nerve and offers a valuable addition to the literature regarding variations in the brachial plexus.
臂丛神经是一个重要的神经结构，上肢的所有主要神经均由此发出。它通常起源于C5 - T1脊神经的前支。在其向外走行过程中，这些神经根依次组成三个干、六个股和三个束。臂丛神经在围产期、产后以及成年期均易受损伤。其结构可能存在显著变异，有大量文献描述其变异情况，为神经外科医生提供了不可或缺的信息。在此，我们报告在一名成年日本男性尸体中发现的一种新型单侧臂丛神经变异。在该病例中，中干起源于C7和C8脊神经，而下干仅延续自T1。在斜角肌间隙，锁骨下动脉位于C8和T1神经之间。后束由上干和中干的后股发出，而来自T1神经/下干的根不存在。中干的前股分别独立发出肌皮神经和正中神经的根，未完全形成外侧束。肌皮神经发出一个交通支与正中神经相连。来自神经根和神经束的一些分支也偏离了典型形态。该病例代表了干、股、束以及正中神经变异的罕见组合，为有关臂丛神经变异的文献增添了有价值的内容。
