Chiou-Tan F Y, Reno S B, Magee K N, Krouskop T A
Department of Physical Medicine and Rehabilitation, Baylor College of Medicine, Houston, Texas 77004, USA.
Am J Phys Med Rehabil. 1998 May-Jun;77(3):243-6. doi: 10.1097/00002060-199805000-00009.
The palmaris brevis (PB) is the only muscle frequently innervated by the superficial branch of the ulnar nerve. It is clinically involved in patients with sensory impairment of the ulnar nerve sparing the deep branch as seen in mild cases of cyclist or crutch palsy. It is also involved in palmaris brevis spasm syndrome. A technique is described that makes it possible to localize the PB distinctly from its neighbors by electromyographic (EMG) pin examination. Methods include prospective (1) anatomic measurement in 10 cadavers and (2) EMG pin examination in 12 normal subjects measuring rise time (ms) and RMS voltage output (microV). Results showed (1) the area of the PB in elderly cadavers was 2.1+/-0.7 x 2.1+/-0.3 cm with a thickness of 0.2+/-.01 cm and (2) in the live subjects, the muscle could be located with identification of motor unit potentials having a rise time <1 ms 100% of the time. In conclusion, the PB can be localized for EMG analysis by using an approach parallel to surface of the palm. Clinically, it could be a useful complement to diagnose neuropathy involving the superficial fibers of the ulnar nerve.
掌短肌（PB）是唯一经常由尺神经浅支支配的肌肉。在自行车手或拐杖麻痹的轻度病例中，临床上可在尺神经深支未受累而出现感觉障碍的患者中见到它。它也与掌短肌痉挛综合征有关。本文描述了一种通过肌电图（EMG）针检查将掌短肌与其相邻肌肉明显区分开来的技术。方法包括前瞻性研究：（1）对10具尸体进行解剖测量；（2）对12名正常受试者进行EMG针检查，测量上升时间（毫秒）和均方根电压输出（微伏）。结果显示：（1）老年尸体中掌短肌的面积为2.1±0.7×2.1±0.3厘米，厚度为0.2±0.01厘米；（2）在活体受试者中，通过识别上升时间<1毫秒的运动单位电位，100%的情况下都能定位该肌肉。总之，通过使用与手掌表面平行的方法，可以对掌短肌进行定位以进行EMG分析。临床上，它可能是诊断涉及尺神经浅支纤维的神经病变的有用辅助手段。
