“…Dimensions of the fi rst cervical vertebra (C1), atlas, as well as the posture of the head and neck are associated with factors such as craniofacial morphology, including the cranial base ( Solow and Tallgren, 1976 ;Opdebeek et al , 1978 ;Marcotte, 1981 ;von Treuenfels, 1981 ;Solow et al , 1984 ;Hellsing et al , 1987 ;Huggare, 1987Huggare, , 1991Sandikcioglu et al , 1994 ;Huggare and Houghton, 1996 ), upper airway space ( Solow et al , 1984( Solow et al , , 1996Wenzel et al , 1985 ), to some extent, occlusion ( Rocabado et al , 1982 ;Huggare, 1991 ;Huggare and Harkness, 1993 ;Solow and Sonnesen, 1998 ), and temporomandibular disorders ( Kritsineli and Shim, 1992 ;Hackney et al , 1993 ;Watson and Trott, 1993 ;Lee et al , 1995 ;Sonnesen, 1997 ;Sonnesen et al , 2001 ;Visscher et al , 2002 ). Furthermore, head posture is associated with the development and function of the dentofacial structures ( Solow andSiersbaek-Nielsen, 1986 , 1992 ;Sonnesen, 1997 ;Sonnesen et al , 2001 ;Solow and Sandham, 2002 ).…”