Synostotic anterior plagiocephaly: a cause of familial congenital superior oblique muscle palsy.

Anterior plagiocephaly due to unicoronal craniosynostosis is commonly associated with an ipsilateral hypertropia and a contralateral head tilt. The ipsilateral superior oblique weakness has been attributed to the shortening of the orbital roof with retroplacement of the trochlea, and to heterotopic positioning of the vertical rectus muscles within the orbit. These anatomical aberrations may alter ocular rotations to mimic a true congenital superior oblique palsy. This paper describes two siblings with synostotic plagiocephaly and simulated superior oblique palsy with ocular torticollis successfully managed by strabismus surgery. Synostotic plagiocephaly should be included in the differential diagnosis of familial congenital superior oblique palsy.