title: Differences between motor point and innervation zone locations in the biceps brachii. An exploratory consideration for the treatment of spasticity with botulinum toxin.
abstract: BACKGROUND
  Botulinum toxin (BTX) acts on the neuromuscular junction which can be located by the innervation zone (IZ). Clinically, the motor point (MP) is homologous to the IZ and it is used as the injection site of BTX. Differences in the effectiveness of the application of BTX between MP and IZ locations have been determined.
  
  
  OBJECTIVE
  Compare the location of the MP obtained using electrical stimulation and the location of the IZ using a linear surface electrodes array on the biceps brachii muscle.
  
  
  METHODS
  The biceps brachii muscle of twenty men was assessed. The MP was located using the torque measurement generated by electrical stimulation. The IZ was detected using a linear surface electrodes array.
  
  
  RESULTS
  A difference between the MP and the IZ positions (75.8 vs. 86.5mm, delta 10.7 mm; p=0.003, post-hoc power 0.89) was observed.
  
  
  CONCLUSIONS
  The magnitude of the difference between the MP and the IZ may be clinically relevant. The IZ location using surface electromyography as a guide to optimize BTX injection is proposed.
authors.affiliation: Laboratorio Integrativo de Biomecánica y Fisiología del Esfuerzo (LIBFE), Kinesiology School, Faculty of Medicine, Universidad de los Andes, Santiago, Chile.
authors.forename: Rodrigo A
authors.initials: RA
authors.lastname: Guzmán-Venegas
authors.affiliation: Laboratorio Integrativo de Biomecánica y Fisiología del Esfuerzo (LIBFE), Kinesiology School, Faculty of Medicine, Universidad de los Andes, Santiago, Chile.
authors.forename: Oscar F
authors.initials: OF
authors.lastname: Araneda
authors.affiliation: Centro de Estudios del Movimiento Humano, Kinesiology School, Faculty of Medicine, Universidad Mayor, Santiago, Chile.
authors.forename: Rony A
authors.initials: RA
authors.lastname: Silvestre
mesh_terms: D001905:Botulinum Toxins / Q000008:administration & dosage*; D003430:Cross-Sectional Studies; D004550:Elbow / Q000294:innervation / Q000502:physiology; D004576:Electromyography / Q000379:methods; D006801:Humans; D008297:Male; D009128:Muscle Spasticity / Q000175:diagnosis* / Q000188:drug therapy*; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000294:innervation* / Q000502:physiology; D009469:Neuromuscular Junction / Q000187:drug effects* / Q000502:physiology; D055815:Young Adult
chemical_list: D001905:Botulinum Toxins
keywords: Botulinum toxin; Electrical stimulation; Innervation zone; Motor endplate; Motor point