The spring ligament is a vital component of the foot's arch structure that supports the foot's bone structure. This ligament is also known as the plantar calcaneonavicular ligament, and it provides support and stability to the foot. There are several synonyms for this ligament that are used interchangeably, depending on the context of the discussion. These synonymous terms include the calcaneonavicular ligament, the inferior calcaneonavicular ligament, the internal calcaneonavicular ligament, and the sustentaculum tali. These terms refer to the same ligament that forms an essential part of the spring-like mechanism that allows the foot to absorb shock and maintain balance during walking and other physical activities.