Development of children’s feet begins in utero and is derived from Mesenchyme (embryological tissue). Beginning as cartilaginous buds, blood flows to the tarsal bones within the foot and begins the early stages of turning cartilage to bone (ossification).
At approximately 37 weeks gestation, ossification of the cuboid occurs and is used as a symbol of foetal maturity.
By birth, a child’s foot remains only partially ossified with much of the contents of the hindfoot, excluding the Calcaneus and Talus, remaining cartilaginous. At this stage, there is evidence of some development of bone in the cuboid and primary centres in all of the bones of the forefoot.
The lateral cuneiform develops during year one, followed by the intermediate cuneiform in the late second to the third year. The Navicular is the last bone to ossify, occurring at around the age of 2-5 years.
During this time, the bones of the forefoot begin to develop secondary centres at their base (excluding the 2nd, 3rd, 4th and 5th Metatarsals whose secondary centres are at their head).
Over time and with continued growth, cartilage begins to develop and separates the bones from one another. As the point of fusion draws near, the cartilage will diminish, and one complete bone will form.
The only bone to have a secondary centre in the hindfoot is the calcaneus, appearing around years 5 to 8. Full fusion with the main bone occurs around age 14 to 15. We refer to the secondary centres as epiphyses. The muscles in the posterior compartment of the leg (calf muscles) attach to the calcaneal epiphysis via the tendo Achilles – or Achilles tendon, on its posterior surface. Some of the intrinsic muscles attach to its inferior surface meaning it can be subjected to significant tension or traction.
Children who are particularly active, especially boys, may present complaining of heel pain which is particularly prevalent after vigorous activity. This could be a condition known as Severs disease. Severs disease is caused by excessive traction being placed on the calcaneal epiphysis as the combination of growing bone and consequently increased tension causes minute damage to the bone. There are treatment options including the use of Orthotic insoles with a slight heel raise to offload the Achilles tendon or rest. Persistent or significant pain should always be checked out by a medical professional.
Complete ossification of the bones of the foot occurs by the age of 25 and can be slightly earlier in females.