According to the text, Hallux valgus is caused by the deterioration of the joint in the big toe, resulting in decreased mobility and weakened support from surrounding muscles. The condition leads to pain, inflammation, and the formation of bunions. Lesser metatarsophalangeal instability can also cause joint damage and instability in one or multiple joints, with potential trauma or neuromuscular origin. Additionally, tailor bunions may form near the MTP joint, though they are less common than those at the base of the big toe. The big toe has three joints and can experience pain and discomfort, potentially for an extended period.