The condition “intermetatarsal neuroma” was first described by Thomas G. Morton in 1876, so it is also called “Morton’s neuroma” and belongs to the category of nerve entrapment syndrome. The cause of this disease is complex and may be related to gender, shoe and walking habits, chronic injury and neurodegeneration; among them, the difference in intermetatarsal mobility and abnormal forefoot weight bearing are the main factors. Currently, women wear more popular shoes with narrower heels at the front, so this may be one of the reasons why intermetatarsal neuroma is more common in women. Other disorders of the forefoot, such as bowed feet and bunions, can cause intermetatarsal neuroma due to abnormal function or loss of the medial first metatarsal sequence of the forefoot, resulting in an outward shift of the plantar weight-bearing area and increased weight-bearing of the second and third metatarsal sequences. However, intermetatarsal neuroma is not a real tumor, but a tumor-like pathological change after chronic mechanical stimulation of the common toe nerve such as long-term compression, mainly due to the proliferation of fibrous tissue in and around the nerve and the increase of fibroblasts and collagen fibers, with a tumor-like appearance. [Clinical manifestations] Patients most often present with pain on the metatarsal side of the forefoot, and some patients present with pain in the toes. The pain is mostly burning, but can also be stabbing, swelling, and crushing pain. The pain may radiate to the toes and, rarely, to the dorsum and proximal end of the foot. Walking, wearing narrow shoes and high heels can aggravate the symptoms, while resting, removing the shoes or massaging the area can relieve the symptoms. There is usually no nocturnal pain. Some patients feel a swelling on the metatarsal side between the webs of the toes. Some patients may feel numbness in the toes. The course of the disease is mostly slow, but a very small number of patients may also have acute onset. The affected foot is not deformed or swollen. There is localized pressure pain between the metatarsal heads of the lesion, which sometimes radiates to the toes. The diagnosis is facilitated by the presence of localized pain when the foot is squeezed from the medial or lateral side to the central part of the foot. Sometimes small swellings on the metatarsal side of the foot can be seen, and squeezing the swelling between the toe webs can cause pain. Toe sensation is usually normal, and a few patients may have hypoesthesia. X-rays are of little help in the diagnosis, and their main role is to identify forefoot pain caused by bone and joint lesions. Ultrasound examination has some significance in the diagnosis of interdigital neuroma. The role of magnetic resonance imaging (MRI) in the diagnosis of interdigital neuroma is similar to that of ultrasonography. Imaging findings must be combined with clinical presentation to make a diagnosis. Local closure with anesthetic can be used to help the diagnosis, but the injection should be accurate and the anesthetic should not be too much to avoid blocking the surrounding diseased tissue and affecting the judgment. In the diagnosis, it should also be differentiated from the following diseases: lumbar disc herniation, tarsal tunnel syndrome, peripheral neuritis, metatarsophalangeal joint synovitis and metatarsophalangeal joint lesions caused by rheumatoid, gout, trauma, etc., metatarsal head necrosis and adjacent synovial cysts, lipomas, tendon sheath cysts, etc. [Etiology and pathology] It is more common in women than in men, and the age of onset is usually between 50 and 60 years old. The exact cause of intermetatarsal neuroma is not well understood. It is generally believed to be due to impingement of the toe nerve under the transverse intermetatarsal ligament. Why are interphalangeal neuromas commonly found in the 3rd toe web space? It is thought that the common nerve of the 3rd toe is composed of the medial plantar nerve and the lateral plantar nerve, and is thicker and more susceptible to injury than the other common toe nerves. In addition, the 1, 2, and 3 metatarsals are relatively fixed, while the 4 and 5 metatarsals are more mobile, and the 3 and 4 metatarsal heads are relatively mobile, making it easy to damage the common toe nerve between them. However, autopsy of cadavers revealed that only 27% of specimens with the 3rd common toe nerve were composed of both the medial plantar nerve and the lateral plantar nerve. In addition, the 2nd common toe neuroma is not very rare, which makes it difficult to explain this problem. The explanation for the prevalence of interphalangeal neuromas in women is that women generally wear high heels, which increases the stress load on the forefoot, while the metatarsophalangeal joint is more dorsally extended, making the strained toe nerve more susceptible to injury. In a small number of patients, the nerve can also be damaged by falling from a height or walking long distances suddenly. Synovial cysts, tendon sheath cysts, and lipomas around the common toe nerve can also cause interphalangeal neuroma if they compress or irritate the nerve. [Non-surgical treatment] Firstly, patients should wear loose, low-heeled shoes and use metatarsal pads on the proximal side of the affected area. After 3-6 months of conservative treatment, most patients’ symptoms can be eliminated. To avoid local complications caused by hormones, continuous or multiple injections should not be given, nor should multiple injections be given at the same time. [For patients with interdigital neuroma whose symptoms do not improve significantly with non-surgical treatment, surgery should be used to provide lasting relief of the patient’s symptoms. For significantly deformed nerves a classical surgical approach, namely common toe neurectomy, should be used. However, because the nerve is severed, a stump neuroma can form and irritation can still cause pain. This may be one reason why this procedure still has a 15-20% unsatisfactory rate. For patients with a short history and insignificant nerve thickening, a nerve release procedure can be used. The transverse intermetatarsal ligament is cut and the fibrous adhesions around the common toe nerve are released. Since the nerve is not cut during surgery, the symptoms caused by the formation of a stump neuroma are avoided. Other disorders of the forefoot, such as bowed feet and bunions, should be actively treated along with the treatment of interphalangeal neuromas, and surgery can be performed at the same time if necessary.