Okwumabua Ebubechi, Thompson Johnathan H.
Meharry Medical College
The Hughston Clinic
The brachial plexus is the network of innervation to the upper limb. It originates in the neck and passes between the anterior and middle scalene muscles. It courses beneath the transverse cervical artery in the posterior triangle of the neck and continues underneath the clavicle and first rib. Finally, it travels toward the axilla where the terminal branches arise to provide motor and sensory innervation to the upper limb. The brachial plexus is comprised of ventral rami of C5 down to T1, providing nervous stimulation for muscular actions including flexion, extension, pronation, supination, abduction, adduction, external and internal rotation at the shoulder, arm, forearm, and hand. It also provides sensory innervation to the upper limb. This nerve network begins as roots then continue to divide into trunks, divisions, cords, and lastly terminal branches. The 5 terminal branches are the musculoskeletal nerve, median nerve, ulnar nerve, radial nerve, and the axillary nerve. Each terminal branch has an area where it provides motor and sensory innervation in the upper limb. The regional orientation of each branch assists with understanding the actions which take place secondary to stimulation of specific muscles. When the body is in the anatomical position, the muscles of the arm and forearm which face anteriorly are mostly flexors, as opposed to muscles that are positioned posteriorly, which are primarily extensors. Muscles that cross joints and positions from anterior to posterior or posterior to anterior will participate in pronation or supination, respectively. The axillary nerve is the terminal branch and will be our area of focus to be discussed in this article.
臂丛神经是上肢的神经支配网络。它起源于颈部，在斜角肌前肌和中斜角肌之间穿过。它在颈部后三角内横行颈动脉下方走行，并在锁骨和第一肋下方继续延伸。最后，它向腋窝走行，在那里发出终末分支，为上肢提供运动和感觉神经支配。臂丛神经由C5至T1的前支组成，为包括肩部、手臂、前臂和手部的屈伸、旋前、旋后、外展、内收、内外旋转等肌肉动作提供神经刺激。它还为上肢提供感觉神经支配。这个神经网络最初是神经根，然后继续分为干、股、束，最后是终末分支。5个终末分支是肌皮神经、正中神经、尺神经、桡神经和腋神经。每个终末分支在上肢都有一个提供运动和感觉神经支配的区域。每个分支的区域定位有助于理解特定肌肉受刺激后发生的动作。当身体处于解剖位置时，手臂和前臂前面的肌肉大多是屈肌，与之相对的是位于后面的肌肉，主要是伸肌。从前向后或从后向前穿过关节和位置的肌肉将分别参与旋前或旋后。腋神经是终末分支，将是本文重点讨论的区域。
