It was Dr Thomas Morton who described first this canal syndrome in 1876. Morton’s syndrome, also called Morton’s disease, Morton’s neuroma, or Morton’s metatarsalgia It is a very common, painful forefoot pathology. Morton’s syndrome mainly concerns the female population (80% of cases).
It is an «irritation» of the medial plantar nerve between the 2nd, 3rd or 4th inter-metatarsal spaces. This nerve divides into 2 branches at this level to ensure the internal sensitivity of one toe, and external of the other. The nerve is trapped under an inter-metatarsal ligament (between the heads of 2 contiguous metatarsals). As it is a tight space (inextensible ligament), there is a compression of the nerve, causing the pain. This can radiate over the entire forefoot.
The diagnosis of Morton’s syndrome is clinical, in its typical form. The treatment is first medical if the symptoms are recent, then surgical in case of failure of this medical treatment, or if the nerve has become voluminous. The term neuroma refers to benign nerve swelling. But it is more schematically a «dilaceration» developed at the expense of the nerve, because of the irritation, that generates a fibrosis.
We’re talking about neuroma, but this is more exactly a perineural fibrosis.
There are various risk factors such as hallux valgus (bunions), claws’ toes, flat or cavus feet, wearing high heels or pumps, neurological disorders.