The common bunion is a localized area of enlargement of the inner portion of the joint at the base of the big toe. The enlargement actually represents additional bone formation, often in combination with a misalignment of the big toe. The misalignment causes the big toe to move outward (medically termed hallux valgus deformity). The normal position of the big toe (straight forward) becomes outward-directed toward the smaller toes. The enlarged joint at the base of the big toe (the first metatarsophalangeal joint, or MTP joint) can become inflamed with redness, tenderness, and pain. A small fluid-filled sac (bursa) adjacent to the joint can also become inflamed (bursitis), leading to additional swelling, redness, and pain.