Metatarsalgia, literally metatarsal pain and colloquially known as a stone bruise, is any painful foot condition affecting the metatarsal region of the foot. This is a common problem that can affect the joints and bones of the metatarsals.

Metatarsalgia is most often localized to the first metatarsal head – the ball of the foot just behind the big toe. There are two small sesamoid bones under the first metatarsal head. The next most frequent site of metatarsal head pain is under the second metatarsal. This can be due to either too short a first metatarsal bone or to "hypermobility of the first ray" – metatarsal bone and medial cuneiform bone behind it – both of which result in excess pressure being transmitted into the second metatarsal head.

The most common symptom experienced due to Morton's toe is callusing and/or discomfort of the ball of the foot at the base of the second toe. The first metatarsal head would normally bear the majority of a person's body weight during the propulsive phases of gait, but because the second metatarsal head is farthest forward, the force is transferred there. Pain may also be felt in the arch of the foot, at the ankleward end of the first and second metatarsals.

In shoe-wearing cultures, Morton's toe can be problematic. For instance, wearing shoes with a profile that does not accommodate a longer second toe may cause foot pain. A small (80-person) study found no statistically significant difference in the frequency of longer second toes between people with and without ingrown toenails, but tight and ill-fitting shoes are generally considered to increase the risk of ingrown toenails, and shoes are often too tight on the toes.

Symptoms include: pain on weight bearing, frequently after only a short time. The nature of the pain varies widely among individuals. Some people experience shooting pain affecting the contiguous halves of two toes. Others describe a feeling like having a pebble in their shoe or walking on razor blades. Burning, numbness, and paresthesia may also be experienced. The symptoms progress over time, often beginning as a tingling sensation in the ball of the foot.

Morton's neuroma lesions have been found using MRI in patients without symptoms.

Morton's toe is the condition of a shortened first metatarsal in relation to the second metatarsal. It is a type of brachymetatarsia.

The metatarsal bones behind the toes vary in relative length. For most feet, a smooth curve can be traced through the joints at the bases of the toes. But in Morton's foot, the line has to bend more sharply to go through the base of the big toe, as shown in the diagram.

This is because the first metatarsal, behind the big toe, is short compared to the second metatarsal, next to it. The longer second metatarsal puts the joint at the base of the second toe (the second metatarsal-phalangeal, or MTP, joint) farther forward.

If the big toe and the second toe are the same length (as measured from the MPT joint to the tip, including only the phalanges), then the second toe will protrude farther than the big toe, as shown in the photo. If the second toe is shorter than the big toe, the big toe may still protrude the farthest, or there may be little difference, as shown in the X-ray.

As with certain cases of flat feet, high arches may be painful due to metatarsal compression; however, high arches— particularly if they are flexible or properly cared-for—may be an asymptomatic condition.

People with pes cavus sometimes—though not always—have difficulty finding shoes that fit and may require support in their shoes. Children with high arches who have difficulty walking may wear specially-designed insoles, which are available in various sizes and can be made to order.

Individuals with pes cavus frequently report foot pain, which can lead to a significant limitation in function. The range of complaints reported in the literature include metatarsalgia, pain under the first metatarsal, plantar fasciitis, painful callosities, ankle arthritis, and Achilles tendonitis.

There are many other symptoms believed to be related to the cavus foot. These include shoe-fitting problems, lateral ankle instability, lower limb stress fractures, knee pain, iliotibial band friction syndrome, back pain and tripping.

Foot pain in people with pes cavus may result from abnormal plantar pressure loading because, structurally, the cavoid foot is regarded as being rigid and non-shock absorbent and having reduced ground contact area. There have previously been reports of an association between excessive plantar pressure and foot pathology in people with pes cavus.

On weightbearing projectional radiography, pes cavus can be diagnosed and graded by several features, the most important being medial peritalar subluxation, increased calcaneal pitch (variable) and abnormal "talar-1st metatarsal angle" (Meary's angle). Medial peritalar subluxation can be demonstrated by a medially rotated talonavicular coverage angle.

Morton's neuroma (also known as Morton neuroma, Morton's metatarsalgia, Intermetatarsal neuroma and Intermetatarsal space neuroma.) is a benign neuroma of an intermetatarsal plantar nerve, most commonly of the second and third intermetatarsal spaces (between 2nd−3rd and 3rd−4th metatarsal heads), which results in the entrapment of the affected nerve. The main symptoms are pain and/or numbness, sometimes relieved by removing narrow or high-heeled footwear. Sometimes symptoms are relieved by wearing non-constricting footwear.

Some sources claim that entrapment of the plantar nerve because of compression between the metatarsal heads, as originally proposed by Morton, is highly unlikely, because the plantar nerve is on the plantar side of the transverse metatarsal ligament and thus does not come in contact with the metatarsal heads. It is more likely that the transverse metatarsal ligament is the cause of the entrapment.

Despite the name, the condition was first correctly described by a chiropodist named Durlacher, and although it is labeled a "neuroma", many sources do not consider it a true tumor, but rather a perineural fibroma (fibrous tissue formation around nerve tissue).

A neuroma (plural: neuromata or neuromas) is a growth or tumor of nerve tissue. Neuromas tend to be benign (i.e. not cancerous); many nerve tumors, including those that are commonly malignant, are nowadays referred to by other terms.

Neuromas can arise from different types of nervous tissue, including the nerve fibers and their myelin sheath, as in the case of genuine neoplasms (growths) like ganglioneuromas and neurinomas.

The term is also used to refer to any swelling of a nerve, even in the absence of abnormal cell growth. In particular, traumatic neuroma results from trauma to a nerve, often during a surgical procedure. Morton's neuroma affects the foot.

Neuromas can be painful, or sometimes, as in the case of acoustic neuromas, can give rise to other symptoms.

Some of the benign varieties of neuroma, in the broadest sense of the term, are not neoplasms.

- Traumatic neuroma follows different forms of nerve injury (often as a result of surgery). They occur at the end of injured nerve fibres as a form of ineffective, unregulated nerve regeneration; it occurs most commonly near a scar, either superficially (skin, subcutaneous fat) or deep (e.g., after a cholecystectomy). They are often very painful. Synonyms include scar neuroma, amputation neuroma, or pseudoneuroma.

- Morton's neuroma (a mononeuropathy of the foot) is another example of the more general usage of the term "neuroma". Some prefer the term "Morton's metatarsalgia", thus avoiding the term "neuroma" and its association with tumors.