Botulinum toxin injection on the trapezius is safe if it's done by a trained medical practitioner. Botulinum toxin type A is a neurotoxin that "relaxes" muscle through inhibition of acetylcholine release at the neuromuscular junction [1].
Botulinum toxin was first used to treat patients with strabismus by an American ophthalmologist and approved by US FDA in 1989 for the treatment of blepharospasm and strabismus [2]. Since then, Botulinum toxin type A has been used to treat multiple conditions, including cervical dystonia, juvenile cerebral palsy stroke (for rehabilitation therapy) and subsequently extended the use in the aesthetic field for wrinkle reduction.
Indications for Botulinum toxin injection over the trapezius mainly include:
- Cervical dystonia
- Trapezius muscle spasm
- Feminine shoulder lines
- Some cases of migraine
Although a thick and large trapezius muscle may be desirable to bodybuilders, for the general public, especially women, a well-developed trapezius makes the neck appear shorter with an unattractive shoulder line, and the face appears relatively larger. The continuous crouching posture often witnessed in computer or smartphone users aggravates the contraction of the trapezius muscle, which not only brings about hypertrophy of the trapezius muscle but also may induce myalgia and migraines.
When Botulinum toxin A is injected into the trapezius, the muscle volume decreases in size and produces a slimmer shoulder line [3]. In addition, it helps improve the symptoms of myalgia or migraines by relaxing the lumped muscles.
Please consult your medical doctor for any indication of Botulinum toxin injections.
References:
1. Women’s and Children’s Hospital, Adelaide. Sa.gov.au.
2. Chen S. Clinical Uses of Botulinum Neurotoxins: Current Indications, Limitations and Future Developments. Toxins.
3. Lee JH, Lee KY, Kim JY, et al. Botulinum Toxin Injection-Site Selection for a Smooth Shoulder Line: An Anatomical Study. BioMed Research International.
