accessory bone

accessory bone

the os trigonum in the ankle joint - a bone present in only <10% of the population. In practice, rarely injured in sport but can be confused on X-ray with an avulsed fragment of bone or loose body.

supernumerary bone

; accessory bone normally inconstant, small, additional bones noted on radiographs, e.g. os trigonum, os tibiale externum, os vesalianum (see Table 1)
Table 1: Accessory bones in the foot
Accessory bone in the footLocation
Os tibiale externum (accessory navicular)Within tibialis posterior tendon, adjacent to proximal part of navicular tuberosity
Os trigonumPosterior margin of talus
Os peroneumWithin peroneus longus tendon, adjacent to inferior lateral border of cuboid/calcaneocuboid joint
Os vesalianumAdjacent to fifth metatarsal base
Os intermetatarseumBetween bases of first and second metatarsals
Os interphalangeusWithin insertion of flexor hallucis longus tendon, adjacent to plantar area of hallux interphalangeal joint
References in periodicals archive ?
If conservative measures fail, open or arthroscopic surgical excision of the abnormal accessory bone is recommended.
Saxena removed an accessory bone from the foot of U.
Daily contact practice, however, may stimulate accessory bone growth in children's feet and ankles.
This type of condition, an accessory bone in the foot, has never been recognized in the literature.