Abstract:

Objective This study is aimed to accurately localize the nerve entry point (NEP) of the subscapalaris muscle, and to provide guidance for implementing the chemical neurolysis of the ethanol or phenol injection for the treatment of subscapalaris muscle spasticity. Methods Twenty Chinese adult cadavers in the supine position were examined. The joining lines from the most inferior point of the jugular notch to the apex of the acromion and from the most inferior point of the jugular notch to the junction of sternal body and xiphoid process were designated as the horizontal (H line) and the longitudinal (L line) reference lines of the NEP, respectively. The cadavers were dissected to expose the NEPs of muscular branches of subscapalaris muscle.The NEPs were marked by barium sulfate. Spiral CT scanning and three-dimensional reconstruction were performed. The body surface projection points (P) of the NEPs were determined under Syngo system, P by N projecting to the back skin was designated as P’. The intersections after the vertical P and the H line, after the horizontal P and L line were designated as P_H and P_L, respectively. The percentage location of P_H and P_L points on H line and L line and depth of NEPs were measured respectively. Results The points P_H of the upper branch and lower branch of subscapular muscle were located at (78.49±5.48)% and (86.17±1.68)% of the H line, and at (21.94±3.59)% and (30.00±1.79)% of the L line, respectively. The depth of NEPs was located at (46.65±2.74)% or (45.87±2.39)%, respectively. Conclusion These results provide guidance for improving the efficacy and efficiency of the chemical neurolysis of the subscapalaris muscle spasticity.

Key words: Subscapalaris muscle, Spasticity, Nerve entry points, Localization, Spiral computed tomography, Human