Neil M J, Conacher C
J Bone Joint Surg Br. 1984 Jan;66(1):77-80. doi: 10.1302/0301-620X.66B1.6693482.
The condition known as delta phalanx (or longitudinally bracketed epiphysis) is a rare congenital anomaly first described in 1964. The deformity consists of a triangular bone with an epiphysis running along the shortened side of the phalanx in a proximal to distal direction, making longitudinal growth of the digit impossible. Isolated hallux varus congenitus due to a delta phalanx of the proximal phalanges of both great toes is extremely rare: there have been only three such cases reported, two of which were in one family--the only report of a familial occurrence of this deformity. This present report details the occurrence of isolated bilateral hallux varus congenitus in four members of one family, a father and his three eldest children. All three children show bilateral delta phalanx of the proximal phalanges of both great toes. There are associated thumb nail anomalies, but no suggestion of polydactylism.
三角趾骨（或纵向夹附骨骺）是一种罕见的先天性异常，于1964年首次被描述。该畸形表现为一块三角形骨头，其骨骺沿趾骨缩短侧从近端向远端延伸，导致该趾无法纵向生长。因双侧大脚趾近节趾骨的三角趾骨导致的孤立性先天性拇内翻极为罕见：仅报告过3例，其中2例来自同一个家族——这是该畸形家族性发病的唯一报告。本报告详细介绍了一个家族中4名成员（一位父亲及其3个年长子女）出现的孤立性双侧先天性拇内翻情况。所有3名子女均表现为双侧大脚趾近节趾骨的三角趾骨。同时伴有拇指指甲异常，但未发现多指畸形。
