A high-back orthopedic office chair is designed to provide additional support and comfort. Particularly for the lumbar (lower back) region and the entire spine. 

1. Lumbar Support: One of the key features is lumbar support, which is a firm cushion or mechanism designed to support the natural curve of the lower spine. This helps maintain proper alignment and reduces stress on the lumbar discs.
2. Adjustable Height: The chair should have an adjustable height mechanism to allow users to set the chair at a level where their feet can comfortably rest on the floor, promoting proper posture.
3. Adjustable Armrests: Ergonomic chairs often come with adjustable armrests. Allowing users to position them at a height that supports their arms comfortably while typing or performing other tasks.
4. High Backrest: The high-back design provides support not only to the lumbar region but also to the upper back and shoulders. This helps maintain a neutral spine position and reduces strain on the entire back.
5. Seat Depth Adjustment: Some chairs offer the ability to adjust the depth of the seat, ensuring that users can sit with their backs against the backrest while leaving a small gap between the back of their knees and the seat edge.

When shopping for a high-back orthopedic office chair, it’s essential to try out the chair if possible and consider your specific ergonomic needs. Keep in mind that individual preferences vary, so finding a chair that suits your body and work habits is crucial for optimal comfort and support.