A bunionette forms when the bone at the base of your little toe gradually shifts outward, creating a bony bump on the outer edge of your foot. Also called a tailor’s bunion, it’s the mirror image of a standard bunion, just on the opposite side of the foot. About 14% of adults have one, making it far less common than a regular bunion but still a frequent source of foot pain. The causes range from inherited bone structure to everyday footwear choices, and most people have more than one factor at play.
The Bone Shift Behind the Bump
Your little toe connects to a long bone in your foot called the fifth metatarsal. In a healthy foot, this bone sits relatively parallel to the bone next to it (the fourth metatarsal). When the angle between these two bones widens, the head of the fifth metatarsal pushes outward against the skin, forming the visible bump.
In normal feet, the angle between the fourth and fifth metatarsals measures about 6.5 degrees. In feet with bunionettes, that angle increases to roughly 8.7 degrees or more. That two-degree difference sounds small, but at the end of a long bone, it translates into a noticeable protrusion. An angle of 9 degrees or greater is generally considered abnormal.
The bone itself can also develop a curve. Instead of running straight, the fifth metatarsal bows outward along its length. People with bunionettes show an average lateral bowing angle of about 8 degrees, compared to just 2.6 degrees in people without the condition. This bowing pushes the metatarsal head even further to the outside of the foot, worsening the prominence.
Inherited Foot Structure
The most fundamental cause of a bunionette is the shape of the bones you were born with. Some people inherit a fifth metatarsal that naturally splays outward or has a wider-than-average head. Others have a foot shape where the little toe sits lower or further out, placing the metatarsal head in a more exposed position. These structural traits run in families, which is why bunionettes often appear in multiple generations.
The deformity doesn’t always show up in childhood. You can carry the predisposing bone geometry for decades before the bump becomes noticeable. What triggers the visible change is usually some combination of time, body weight, and external pressure gradually making a borderline anatomy worse.
Tight Shoes and Forefoot Compression
Compression of the forefoot is the single most cited external cause. Narrow-toed shoes, pointed dress shoes, and high heels squeeze the toes together and press the outer edge of the foot against rigid material. Over months and years, this repeated pressure irritates the fifth metatarsal head and accelerates the outward drift of the bone.
The name “tailor’s bunion” dates back to a time when tailors sat cross-legged on the floor, grinding the outer edges of their feet against hard surfaces for hours each day. The modern equivalent is simply wearing shoes with a toe box too narrow for your foot. If your little toe feels crowded or pressed inward when you’re wearing shoes, the metatarsal head on the outside is absorbing that force.
This doesn’t mean shoes alone create a bunionette from scratch. In most cases, footwear acts on an already-vulnerable bone structure, speeding up a process that might otherwise take much longer or never become symptomatic.
How You Walk Plays a Role
Abnormal loading on the lateral (outer) side of the foot contributes to bunionette development. If your gait places extra weight on the outside of your forefoot during push-off, the fifth metatarsal head absorbs more ground reaction force than it’s designed for. Over time, that stress can encourage the bone to drift and the surrounding soft tissue to thicken.
Excessive pronation, where the foot rolls inward too much during walking, can paradoxically affect the outer forefoot by changing how forces distribute across the ball of the foot. Research from the Johnston County Osteoarthritis Project found that foot pronation patterns influence bunionette risk, and orthotics that correct excessive pronation may help when they’re part of the cause. Interestingly, the same study found that people with oversupinated (outward-rolling) feet who were also obese were actually less likely to develop bunionettes, suggesting the relationship between gait and this deformity is complex and varies by body type.
Inflammatory Arthritis
Conditions like rheumatoid arthritis and psoriatic arthritis increase bunionette risk. These diseases cause chronic inflammation in the joints, including the small joints of the foot. Over time, that inflammation weakens the ligaments and joint capsules that normally hold the metatarsal bones in alignment. Once those stabilizing structures loosen, the fifth metatarsal can shift outward more easily.
If you have an inflammatory arthritis condition and notice a growing bump on the outside of your foot, the arthritis is likely a contributing factor rather than a coincidence. The joint damage from these conditions tends to affect both feet, so bunionettes in this context often appear on both sides.
What the Bump Actually Feels Like
Not every bunionette causes symptoms. Some people notice the bump visually but never experience pain. When symptoms do develop, they typically include pain and pressure on the outside of the foot near the little toe, especially in shoes. The skin over the bump often becomes red, swollen, or develops a thickened callus from friction against footwear. Corns can form on or between the toes as the little toe gets pushed inward by the protruding bone.
A secondary complication is bursitis, where the small fluid-filled sac that cushions the joint becomes inflamed from repeated irritation. This makes the area tender even without shoe pressure and can cause the bump to appear larger than the bone itself due to swelling of the soft tissue around it.
Multiple Causes Working Together
In practice, a bunionette rarely has a single cause. The typical pattern is an inherited bone structure that creates the vulnerability, combined with years of footwear pressure or abnormal gait mechanics that turn a predisposition into a visible, symptomatic deformity. Inflammatory arthritis or excess body weight can accelerate the process further. Understanding which factors apply to you helps guide the most effective management, whether that’s switching to wider shoes, using orthotic inserts to redistribute pressure, or exploring corrective options if the deformity progresses.