Pain in the plantar aspect of the metatarsal (MT) heads

Metatarsalgia can be thought of as a symptom rather than a specific disease.

Primary metatarsalgia develops from intrinsic factors, such as a long first ray, hallux valgus, or other congenital deformities.

Secondary metatarsalgia may result from trauma, overuse, or poor footwear.

Repetitive/excessive stress combined with intrinsic and extrinsic factors

The 1st MT head usually carries 30% of the load in weight-bearing. A normal MT arch ensures this balance by providing adequate padding around the 1st MT head. A pronated or splayfoot can disturb this balance, resulting in an abnormally high pressure over the 2nd through 5th MT heads. Over time, reactive tissue can form a callus around the MT heads, which further compounds pain.

Foot deformities: overpronation, pes planus, pes cavus, hallux valgus, prominent MT heads, hammertoe deformity, Morton foot (short 1st MT and a relatively long 2nd MT)

Muscle imbalance or soft tissue dysfunction: tight Achilles tendon or toe extensors, weak toe flexors, laxity in the Lisfranc ligament

Extrinsic factors: obesity, high heels, poorly fitted or worn-down shoes

Dermatologic issues: calluses and warts

Fat pad atrophy or displacement

Iatrogenic changes from surgeries resulting in unequal force distribution

Intrinsic foot muscle weakness

Calluses and warts

Hallux valgus or rigidus

Hammertoe or claw toe

Morton syndrome (long 2nd MT)

Freiberg infraction (aseptic necrosis of a MT head, most commonly the 2nd, as seen in adolescent sprinters)