What anatomical landmark guides the position of the lateral trim line for a TLSO?

The position of the lateral trim line for a Thoraco-Lumbo-Sacral Orthosis (TLSO) is guided by the axilla. This anatomical landmark is crucial because it defines the superior lateral edge of the torso, ensuring that the orthosis fits snugly without restricting upper body movement excessively. Using the axilla as a reference helps in achieving an effective balance between support and mobility, allowing the TLSO to provide the needed stabilization while maintaining comfort for the patient. Proper positioning relative to the axilla also helps in avoiding pressure points that could lead to skin irritation or discomfort during wear.

In contrast, the other anatomical landmarks—such as the greater trochanter, pubis, and scapula—serve different purposes in orthotic design and may influence other aspects of a brace, but do not dictate the lateral trim line of a TLSO specifically. The greater trochanter relates more closely to hip alignment and function, the pubis is more relevant for pelvic alignment, and the scapula plays a role in upper extremity movement. Thus, the axilla is the most relevant landmark in determining the optimal positioning of the lateral trim line for effective TLSO design and functionality.