Intramuscular Neural Distribution of the Serratus Anterior Muscle: Regarding Botulinum Neurotoxin Injection for Treating Myofascial Pain Syndrome

Abstract

The serratus anterior muscle is commonly involved in myofascial pain syndrome and is treated with many different injective methods. Currently, there is no definite injection point for the muscle. This study provides a suggestion for injection points for the serratus anterior muscle considering the intramuscular neural distribution using the whole-mount staining method. A modified Sihler method was applied to the serratus anterior muscles (15 specimens). The intramuscular arborization areas were identified in terms of the anterior (100%), middle (50%), and posterior axillary line (0%), and from the first to the ninth ribs. The intramuscular neural distribution for the serratus anterior muscle had the largest arborization patterns in the fifth to the ninth rib portion of between 50% and 70%, and the first to the fourth rib portion had between 20% and 40%. These intramuscular neural distribution-based injection sites are in relation to the external anatomical line for the frequently injected muscles to facilitate the efficiency of botulinum neurotoxin injections. Lastly, the intramuscular neural distribution of serratus anterior muscle should be considered in order to practice more accurately without the harmful side effects of trigger-point injections and botulinum neurotoxin injections.

Novel Anatomical Guidelines on Botulinum Neurotoxin Injection for Wrinkles in the Nose Region

“…Although sensitivity to BoNT differs among individuals, there is no effective treatment for ptosis, which persists for several months [ 31 , 32 ]. Accurate BoNT injection points from an anatomical point of view have been suggested in various studies concerning BoNT injection in specific muscles [ 16 , 17 , 18 , 19 , 20 , 21 , 33 , 34 , 35 , 36 , 37 ]. According to the meta-analysis conducted by Camargo et al, most studies had duration of treatment of 5 months [ 38 ].…”

“…Numerous studies on BoNT injection points in muscles have previously been published on external anatomical standards ( Figure 2 ) [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ]. We searched for articles using the following keywords: “botulinum neurotoxin in nose region” and “side effect of botulinum neurotoxin injection in nose wrinkle” on Pubmed and Scopus.…”

Distribution of the intramuscular innervation of the triceps brachii: Clinical importance in the treatment of spasticity with botulinum neurotoxin

“…The subcutaneous tissues of the upper limb were dissected to reveal the triceps brachii muscles. From these 10 cadavers, 16 triceps brachii muscles were harvested and Sihler's staining was performed (Liem & Douwe van Willigen, 1988; Yi, Lee, & Kim, 2022; Yi, Lee, Seo, & Kim, 2022a).…”

Sihler's staining technique: How to and guidance for botulinum neurotoxin injection in human muscles

“…This muscle had the largest arborization pattern from the fifth to the ninth ribs between the 5/10th and 7/10th portions. The first to the fourth rib portions had arborization patterns between the 2/10th and 4/10th portions (Figure 3) (Yi, Lee, & Kim, 2022).…”