Purpose: This is a rare case of a post-traumatic rectus abdominis muscle tear in an adolescent female diagnosed by ultrasonography (US). Conservative management is also described.Methods: A 14-year-old female presented to a chiropractic clinic with extreme pain and tenderness in the right lower quadrant (RLQ) after post-plyometric power kneel box jumps. Movement aggravated her pain and she demonstrated active abdominal guarding with RLQ palpation. Ultrasonography revealed a subacute Grade 2 right rectus abdominis muscle tear, without evidence of hyperemia or a hematoma. Following the diagnosis of a right rectus abdominis muscle tear, she was treated with spinal manipulation and a course of musculoskeletal rehabilitation directed at truncal stabilization.Results: After treatment, the patient was able to return to play 5 week post-injury without any pain or discomfort. A follow-up US at 3 months provided evidence of muscle healing without complications.Conclusion: This case demonstrates the diagnosis of a rare rectus abdominis muscle tear managed conservatively. To our knowledge, less than a dozen cases are reported using US in the evaluation and diagnosis of a rectus abdominis tear.