The big toe is one of five digits located on the front of the foot. It is officially known as the hallux. It is the innermost toe of tetrapods (animals that have four limbs) and is counted as digit number one. The big toe's function is to provide additional leverage to the foot when it pushes off the ground during walking, running, or pedaling. In conjunction with the little toe, it also assists in maintaining the body's balance while standing. The removal of the big toe would require the foot and ankle to be retrained to use different muscles to perform these functions.
The most common problems that afflict the big toe are injury through usage, bunions, and arthritis, particularly gouty arthritis. A bunion is a progressive disorder that causes structural deformity of the bones and forefoot. This, in turn, can cause the hallux to become misaligned from its normal position on the foot. Gout is caused by the deposit of uric acid crystals in the joint, which results in periodic inflammation and pain. Both conditions are treatable.
In some medical cases, microsurgery is used to successfully transplant the big toe to the patient's hand in order to replace a lost thumb.