According to Northwest Foot & Ankle, the medical name for the big toe is hallux. The big toe is considered to be one of the most essential parts of the body because it provides propulsive force when walking.
Northwest Foot & Ankle explains that a healthy big toe should possess 50 to 90 degrees of extension. Flexing the big toe should never cause pain.
According to Northwest Foot & Ankle, if the hallux is not functioning properly, the joints and tissues of the lower extremity may experience strain and fatigue as they are forced to compensate while walking or running. Northwest Foot & Ankle notes that constricting footwear is a common cause of big-toe problems.