Abnormality of the epiphysis of the 1st metatarsal +
Abnormality of the epiphysis of the distal phalanx of the hallux +
Abnormality of the epiphysis of the proximal phalanx of the hallux +
In contrast to the metatarsals 2-5, the first metatarsal is embryologically of phalangeal origin and as such equivalent to the proximal phalanges of the digits 2-5, whereas the proximal phalanx of the big toe is equivalent to the middle phalanges of the other digits. This term applies to abnormalities affecting the proximal phalanx of the hallux.