Motor points for the neuromuscular blockade of the subscapularis muscle.
OBJECTIVE
To locate the motor points of the subscapularis muscle in relation to palpable anatomic landmarks and hence suggest a technique for botulinum toxin injection into subscapularis applicable to patients of all ages.


METHODS
Anatomic dissection of the innervation of 20 subscapular muscles.


METHODS
University dissecting room.


METHODS
Ten formalin-preserved cadavers.


METHODS
Not applicable.


METHODS
The location of motor points in relation to anatomic landmarks.


RESULTS
The median number of motor points for the subscapularis was 5 (range, 3-6). All motor point measurements were related to surface points and converted into proportional values along reference lines. Motor points from the 20 dissections showed clustering in a band. A line of best fit was calculated (y=1.48x-0.743).


CONCLUSIONS
We describe an injection technique that would deliver botulinum toxin close to the motor points of the subscapularis, a surrogate marker of the motor endplate zones. By using proportional distances, this technique is applicable to an adult and pediatric population. This should lead to an increased efficacy and decreased side-effect profile in clinical practice, although clinical trials will need to confirm this.
Harrison
Tim P
TP
Department of Anatomy and Developmental Biology, University College London, and Great Ormond Street Hospital, London, UK.
Sadnicka
Anna
A
Eastwood
Deborah M
DM
D000368:Aged; D000369:Aged, 80 and over; D018726:Anti-Dyskinesia Agents / Q000008:administration & dosage; D001905:Botulinum Toxins / Q000008:administration & dosage; D002102:Cadaver; D005260:Female; D006801:Humans; D007273:Injections, Intramuscular / Q000379:methods; D008297:Male; D009128:Muscle Spasticity / Q000188:drug therapy; D018482:Muscle, Skeletal / Q000294:innervation*; D019148:Neuromuscular Blockade / Q000379:methods*; D012782:Shoulder / Q000294:innervation*
D018726:Anti-Dyskinesia Agents; D001905:Botulinum Toxins