Where is the distal trim line of a thumb post typically located?

The distal trim line of a thumb post is typically located at the mid nail bed. This positioning is important as it allows for optimal function of the thumb while providing necessary support and alignment. By trimming the post at the mid nail bed, the orthosis can effectively stabilize the metacarpophalangeal (MCP) joint while allowing for movement at the interphalangeal (IP) joint. This design helps maintain the thumb's range of motion and dexterity, crucial for grip and grasp functions.

Positioning the trim line at the MCP joint would restrict movement too much, adversely affecting function. Placing it at the IP joint would compromise the stability and support needed at the MCP joint, and a location at the wrist joint would not provide the necessary engagement with the thumb. Hence, the mid nail bed is the ideal location for maintaining balance between support and mobility.