Objective: To evaluate the safety and accuracy of ultrasound (US)-guided needle insertion into the subscapularis using fresh cadavers. Design: A needle was inserted into the subscapularis of adult human cadavers under US guidance using a lateral approach from the posterior axillary fold. An anatomist dissected the cadavers to evaluate the effectiveness of this injection method. Setting: University dissecting room. Participants: Fresh cadavers (N=5). Interventions: US-guided dye injections targeting the motor points of the subscapularis. Main Outcome Measure: Accuracy of the injections and prevalence of complications. The presence of dye within 1.0cm of the motor points was defined as reaching the target. The injection procedure was considered a success if two-thirds of the injected dye reached the target. Results: We did not identify any neurovascular structures at risk of injury in the injection route. All subscapularis muscles were injected successfully using the US-guided lateral approach. Conclusions: US-guided needle insertion into the subscapularis using this lateral approach was accurate and had the minimal risk of neurovascular or lung injuries.