Ren Chen; Hong Chen;Jun Zhao & Shengbo Yang

This study aims to examine the intramuscular nerve distribution pattern of the sternocleidomastoid muscle (SCM) in children and to identify the center of the intramuscular nerve-dense region (CINDR), offering morphological guidance for Botulinum neurotoxin type A (BoNT-A) injections in the treatment of pediatric muscular torticollis. A total of 24 Chinese pediatric cadaveric specimens were analyzed. The intramuscular nerve distribution of the SCM was visualized using a modified Sihler’s staining technique. Spiral computed tomography was employed to determine the surface puncture location and depth of the CINDR. A percutaneous longitudinal reference line was defined from the lowest point of the jugular notch of sternum to the chin tip of the mandible, and a transverse reference line was established from the lowest point of the jugular notch of sternum to the acromion. A band-shaped, intramuscular nerve-dense region was identified in the middle portion of the SCM, oriented obliquely from superoposterior to inferoanterior. The CINDR projected at (38.29 ± 1.39)% along the transverse reference line and at (68.62 ± 1.46)% along the longitudinal reference line. The puncture depth of the CINDR was measured as 10.18 ± 1.68 mm. Defining the surface location and depth of the CINDR in the pediatric SCM aids in precise target localization and enhances the efficacy of BoNT-A injections for treating pediatric muscular torticollis.

KEY WORDS: Pediatric muscular torticollis; Sternocleidomastoid muscle; Innervation; Botulinum neurotoxin type A; Neuromuscular blockade.

CHEN, R.; CHEN, H.; ZHAO, J. & YANG, S. Target localization for botulinum neurotoxin type A injection in the treatment of pediatric muscular torticollis. Int. J. Morphol., 44(1):92-98, 2026.