apophysis of the proximal 5th metatarsal
The apophysis of the proximal 5 metatarsal (plural apophyses) lies laterally and is oriented longitudinally parallel to the shaft.
Apophysis of the fifth metatarsal base appears on plain radiographs at age 12 for boys and 10 for girls. Fusion of the apophysis to the metatarsal base usually occurs within the following 2-4 years .
It should not be confused with an os peroneum or an avulsion fracture. An avulsion fracture at this location is typically extra-articular and oriented transversally as compared to the longitudinal orientation of an unfused apophysis.
- Iselin disease (apophysitis)