Related Experiment Video
Updated: Jul 16, 2026

The Modified Single-working Portal Technique Using Lasso-loop Stitch with Needle for Arthroscopic Subscapularis Repair
Published on: August 8, 2025
Motor points for the neuromuscular blockade of the subscapularis muscle
Tim P Harrison1, Anna Sadnicka, Deborah M Eastwood
1Department of Anatomy and Developmental Biology, University College London, and Great Ormond Street Hospital, London, UK.
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.
Design:
Anatomic dissection of the innervation of 20 subscapular muscles.
Setting:
University dissecting room.
Cadavers:
Ten formalin-preserved cadavers.
Interventions:
Not applicable.
Main Outcome Measure:
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.
Related Concept Videos
Muscles that Move the Arm
The pectoralis major has two origins. Its clavicular head originates on the medial half of the clavicle. In contrast, the sternocostal head originates on the costal cartilages of ribs 1-6, the sternum, and the aponeurosis of the external oblique of the...
Muscles of the Shoulder
Anterior Thoracic Muscles
The anterior thoracic muscles include the serratus anterior, subclavius, and...
Nondepolarizing (Competitive) Neuromuscular Blockers: Pharmacological Actions
Although all competitive neuromuscular blockers are designed...
Nondepolarizing (Competitive) Neuromuscular Blockers: Mechanism of Action
Competitive antagonists prevent acetylcholine from binding to its receptor, inhibiting membrane depolarization. Without conformational changes or intrinsic...
Neuromuscular Junction And Blockade
Spinal Nerves: Plexus I
The Cervical Plexus
The cervical plexus, formed by the anterior rami of the first four...