Protruding Bone on Outside of Foot 2026 | DPM

Where Exactly Is the Bump? That One Question Narrows It Down Fast

Almost everyone who searches for a bone sticking out on the outside of the foot is describing one of about five things, and the fastest way to tell them apart is not what the bump looks like but where along the foot it sits. Run a finger down the outer edge of your foot from the little toe back towards the heel and note where the prominence is.

• Roughly halfway along the outer edge, level with the middle of your arch. This is by far the most common location, and it is almost always the base of the fifth metatarsal. Usually normal anatomy. Sometimes a fracture.
• Near the front, just behind the little toe. That is a different bone entirely and points towards a tailor’s bunion, also called a bunionette.
• At the back, on or above the heel bone. That is Haglund’s deformity territory rather than a lateral midfoot bump, and it behaves differently.
• Soft, squishy and movable rather than hard. If it does not feel like bone, it very often is not — a ganglion cyst is the usual explanation.
• A bump that is new, on a foot with reduced sensation, and the foot is warm and swollen. Stop reading and call someone today. This one is covered at the bottom of this page and it is the reason we wrote it.

The Usual Answer: The Base of Your Fifth Metatarsal

The fifth metatarsal is the long bone leading to your little toe, and at its back end it flares into a knob called the styloid process. In a lot of perfectly normal feet that knob is prominent enough to see and feel, and people notice it in their thirties or forties and assume something has changed. Two useful checks: look at the other foot, because normal anatomy is usually symmetrical, and ask yourself honestly whether it is genuinely new or whether you simply started paying attention to it.

A prominent styloid becomes a problem rather than a feature for fairly mechanical reasons. People who walk on the outside of the foot, which is called supination, load that edge harder than average. Higher-arched feet sit more on the lateral column. Narrow or stiff shoes press directly on the knob. What hurts in those cases is generally not the bone itself but the tissue caught between the bone and the shoe: a bursa, the peroneal tendons that run right past it, or a callus that has built up over the prominence. That distinction matters because it means the treatment is usually about offloading and footwear rather than about the bump.

A Bump That Appeared Suddenly or After a Twist Is a Different Story

If the prominence showed up after rolling your ankle, stepping off a kerb or landing awkwardly, the working assumption should be a fracture until an X-ray says otherwise. This is one of the most frequently missed injuries in the foot, because the mechanism is identical to a routine ankle sprain and the swelling is in roughly the same neighbourhood.

The clinical distinction is simple to apply. A lateral ankle sprain is tender below and in front of the ankle bone, over the ligaments. A fifth metatarsal base fracture is tender on the bone itself, a couple of inches further forward, at the middle of the outer edge of the foot. If you press there and it is sharply, specifically painful, that needs imaging — not another week of ice and elevation. If that is the spot you are pressing, you can book an evaluation online now in Howell or Bloomfield Township.

Avulsion fracture versus Jones fracture: not interchangeable

Two fractures happen within about an inch of each other here, and they behave completely differently.

An avulsion fracture pulls a fragment off the very tip of the styloid, where the peroneus brevis tendon and part of the plantar fascia attach. It is the more common of the two, it has a good blood supply, and it generally heals well with a stiff-soled shoe or boot and sensible activity limits.

A Jones fracture sits slightly further forward, at the junction where the flared base narrows into the shaft. That precise zone has a notoriously poor blood supply, and as a result Jones fractures have a genuine tendency to heal slowly, to fail to heal at all, or to re-break later. They are treated far more seriously: often a period of not putting weight on the foot, and in active people or athletes, surgical fixation with a screw is frequently recommended as the primary treatment rather than as a rescue. Being told you have “a little fracture in the side of the foot” is not enough information — which of these two it is changes the whole plan.

Tailor’s Bunion: The Bump Nearer the Little Toe

If the prominence is at the front of the outer edge, right behind the little toe rather than back at the arch, it is a bunionette. The name is apt: it is the same process as a bunion but at the opposite side of the foot, with the fifth metatarsal drifting outward and the little toe angling inward. It got the name tailor’s bunion from tailors who sat cross-legged with the outer edge of the foot pressed against the floor all day.

Unlike a prominent styloid, a bunionette is usually progressive, so people describe it as slowly worsening over years rather than as a bump that has always been there. The symptoms come from friction: a hard callus over the bump, redness, an inflamed bursa, and shoes that fit everywhere except across that one point. Wider footwear, padding and offloading handle most cases well. Surgery exists and works, but it is for people whose symptoms persist despite genuinely appropriate shoes, not a first step. One weight-bearing x-ray settles the accessory-bone-versus-fracture question in a single visit, and it changes how the next six weeks go. Book an x-ray visit online.

A Growing Child With a Painful Bump There: Iselin’s Disease

If the person with the prominent, tender bone on the outside of the foot is between about eight and fourteen, the answer is usually different from the adult one — and it is one of the more commonly missed diagnoses in a young athlete’s foot.

The base of the fifth metatarsal has its own growth plate, and it sits at an angle to the shaft rather than across it. The peroneus brevis tendon pulls directly on that growth plate with every push-off and every sideways cut. In an active child — soccer, basketball, dance, gymnastics — that repeated traction irritates the growth plate. The result is Iselin’s disease: a tender, sometimes visibly enlarged prominence on the outer border of the foot that hurts with activity and settles with rest.

Two things make it worth knowing about:

• On X-ray, the open growth plate can be mistaken for a fracture line. It runs obliquely, it is symmetrical with the other foot, and it is normal anatomy. Comparing both feet usually settles it in seconds — a genuine avulsion fracture runs across the bone, not along it.
• It is self-limiting but not self-managing. It resolves as the growth plate closes, but a child who keeps playing through it stays sore for months. Relative rest, activity modification, a stiffer-soled shoe, calf and peroneal stretching, and occasionally a short period in a boot for a bad flare will shorten the whole episode considerably.

A child with pain over the outer midfoot that has lasted more than two or three weeks deserves an examination rather than more rest — partly to confirm Iselin’s, and partly because a stress fracture at that same site is far less forgiving.

Accessory Bones: When the Extra Bone Was Always There

Roughly one person in ten has an extra small bone somewhere in the foot that most people do not. These are normal anatomical variants, present from birth, and they are usually silent for decades — until footwear, a change in activity, or an injury makes one of them announce itself. Two of them sit in exactly the area this page is about.

Os peroneum

A small bone embedded within the peroneus longus tendon as it curves under the cuboid, on the outer border of the foot just behind the fifth metatarsal base. It is present in a substantial minority of feet and is normally symptomless.

It matters when it becomes painful — painful os peroneum syndrome. That can follow a direct blow, an inversion sprain, or a tear of the tendon around it, and it produces pain and tenderness slightly behind and below the fifth metatarsal base, worse when you push the foot outward against resistance. On X-ray, an os peroneum that has fractured or separated will look displaced compared with the other foot, which is why comparison views matter here too.

Os vesalianum

A rarer accessory bone sitting immediately at the tip of the fifth metatarsal base, inside the peroneus brevis tendon. Its main clinical significance is that it is routinely mistaken for an avulsion fracture on X-ray by anyone not looking for it. The distinguishing features: smooth, rounded, corticated edges rather than the sharp irregular margin of a fresh break — and, again, the same appearance on the opposite foot.

Being told you have a fracture that is actually an accessory bone leads to weeks of unnecessary immobilisation. Being told an actual fracture is an accessory bone leads to a non-union. It is worth getting right.

A cuboid prominence

Slightly further back along the outer border, the cuboid itself can feel prominent, particularly in a high-arched foot where the outer column carries more load than it should. This is usually normal bone in an unusual alignment rather than a growth, and it responds to offloading the lateral column with an orthotic rather than to anything surgical.

If the Bump Is on the Inside of the Foot Instead

People search for “a bone sticking out on the side of my foot” from both sides, so it is worth naming the inner-border equivalent briefly.

A prominent bone on the inside of the arch, roughly level with and just below the inner ankle bone, is most often an accessory navicular — an extra bone at the point where the posterior tibial tendon attaches. Like the accessory bones above it is a normal variant, present in perhaps one foot in ten, and often silent until adolescence or until a sprain irritates it.

It matters more than most accessory bones because the posterior tibial tendon is the main dynamic support of the arch. When the attachment is disrupted, arch support can be compromised, and an accessory navicular is a recognised contributor to a painful flatfoot in a teenager. Treatment starts with an orthotic that supports the arch and takes tension off the tendon; surgery to remove the fragment and reattach the tendon is reserved for cases that do not settle.

If you have a bony prominence on either border of your foot that has become painful, changed, or started catching in shoes, it can be identified quickly with an examination and a weight-bearing X-ray — ideally with comparison views of the other foot. Balance Foot & Ankle sees patients in Howell (4330 E Grand River Ave, Howell, MI 48843) and Bloomfield Township (43494 Woodward Ave #208, Bloomfield Township, MI 48302). Call (810) 206-1402.

If It Is Soft and Moves, It Is Probably Not Bone

A ganglion cyst is a fluid-filled sac arising from a joint capsule or tendon sheath, and it turns up on the outside of the foot often enough to be worth knowing. The giveaways are that it feels firm and rubbery rather than rock-hard, it may be slightly movable, and it frequently changes size — larger after a long day, smaller after rest. Old advice to hit them with a heavy book is genuinely a bad idea; they can be aspirated in the office, and the ones that recur can be removed properly.

When a New Bump on the Foot Is a Same-Day Problem

There is one presentation here that is not a nuisance bump, and it is the reason we would rather you read this page than guess. If you have diabetes, peripheral neuropathy or any other cause of reduced sensation in your feet, and a new bony prominence appears on the side or the bottom of the foot, and that foot is warm, swollen and often red, that combination should be assessed immediately. It may be Charcot neuroarthropathy.

In Charcot, the bones and joints of an insensate foot weaken and begin to collapse, frequently without significant pain because the nerves that would normally report it are not working. The affected foot is often noticeably hotter than the other one. It is regularly mistaken for cellulitis, gout, or a sprain, and treated as such for weeks.

The cost of that delay is high, because continuing to walk on a foot in the active phase is what drives the collapse. Caught early and offloaded, the foot can often be preserved in a functional shape. Caught late, the result can be a permanently deformed, rocker-bottomed foot that ulcerates where the new prominence rubs, and those ulcers are how people lose limbs. If this paragraph describes your foot, please do not wait to see whether it settles down on its own.