<prompt> The orientation of the SN plane to the FH plane should be:SN plane is 7 degrees upwards anteriorly to FH planeFH plane is 7 degrees upwards anteriorly to SN planeSN plane is 5 degrees upwards anteriorly to FH planeFH plane is 5 degrees upwards anteriorly to SN plane  <response>: An alternative horizontal reference line, easily and reliably detected on cephalometric radiographs, is the line from sella turcica S to the junction between the nasal and frontal bones N. In an average individual, the SN plane is oriented at 6 to 7 degrees upwards anteriorly to the Frankfort plane.Ref: Contemporary orthodontics, William Proffit, 4th edition page 207 