A hammer toe is a common foot deformity that causes one of the lesser toes to bend or curl in an unusual way. This condition is progressive, usually beginning subtly and worsening over time, primarily affecting the second, third, or fourth toe. Recognizing a hammer toe involves identifying the specific structural bend, the secondary skin changes it causes, and the degree of stiffness in the affected joint.
The Characteristic Bend
The defining visual feature of a hammer toe is the buckled appearance, which resembles a hammerhead or an upside-down “V” shape when viewed from the side. This characteristic bend occurs specifically at the proximal interphalangeal joint, known as the PIP joint, the middle joint of the toe. The structural change is caused by an imbalance in the muscles and tendons that normally keep the toe straight.
The deformity causes the middle joint to flex downward, while the joint closest to the ball of the foot hyperextends, creating a raised knuckle on the top of the toe. This raised section of the toe often pushes upward against the inside of a shoe. Simultaneously, the tip of the affected toe points downward, sometimes pressing into the ground or the sole of the shoe.
The second toe is the most frequently affected, though the third and fourth toes are also commonly involved. The constant, abnormal position causes the muscles and tendons on the underside of the foot to tighten over time, eventually locking the toe into its bent shape. In severe cases, the toe can look noticeably contracted, sticking out above the neighboring toes.
Associated Skin and Tissue Changes
The abnormal joint position creates areas of intense friction and pressure, leading to distinct secondary changes on the skin and soft tissues. The most common sign is the formation of a corn, which is a localized area of hardened, thickened skin.
Corns typically develop directly over the prominent, raised knuckle of the PIP joint, where the toe rubs constantly against the upper part of the shoe. The skin attempts to protect the underlying bone and joint from repeated pressure, resulting in this dense buildup of dead skin cells. These corns can appear yellow or grayish and are often painful when pressure is applied.
Another common skin change is the development of a callus on the tip of the affected toe or on the ball of the foot just beneath the deformed toe. This callus forms because the downward-pointing toe tip or the metatarsal head beneath the toe bears an excessive amount of weight and friction against the ground or shoe sole during walking. The skin in these areas thickens and hardens into a broader patch compared to the focal point of a corn.
Beyond the thickened skin, the affected toe or the area around the joint may also display signs of inflammation. Swelling and redness can occur due to the constant irritation from footwear rubbing against the bent joint. This can be accompanied by a feeling of warmth in the area.
Flexible Versus Rigid Appearance
The visual presentation of a hammer toe can also be distinguished based on its stage of progression, which determines whether it is flexible or rigid. The flexible stage represents an earlier, milder form of the condition and has a less severe outward appearance. In a flexible hammer toe, the toe is visibly bent when at rest, but it can still be manually straightened out with gentle pressure from a finger.
When the foot is out of a shoe, a flexible hammer toe may appear almost straight or only slightly buckled, maintaining some range of motion in the joint. The ability to passively straighten the toe indicates that the soft tissues, such as the tendons and ligaments, have not yet permanently tightened or shortened.
A rigid hammer toe, in contrast, represents a more advanced stage where the deformity is permanent and fixed, making the visual appearance more severe. In this stage, the joint is stiff and cannot be manually straightened; it remains locked in the bent position at all times. The toe’s characteristic “V” shape is distinctly visible and unchangeable, even when the foot is not bearing weight or in a shoe.
This rigid presentation occurs because the muscles and tendons have tightened severely, leading to bony changes in the joint itself. The hardened tissues and joint fixation cause the prominent knuckle to be more pronounced and consistently pressed against the shoe.