Rotation is a segment turned about its vertical axis, as when one hip sits forward of the other.
A pelvis, a ribcage, a head: each can live turned. In 📝Postural / Structural Realignment that turn is a pattern of how the person meets gravity, often the start of an apparent leg-length difference or a shoulder that will not sit. It is not a diagnosis of scoliosis, of a subluxation, or of a joint that is out. The useful question is whether the segment can also find a quieter middle, and whether the turn shows at rest as well as in a task.
Clients feel it as one side that is always "on," or as a twist they see in a photo. Work traces the 📝line of pull that keeps the turn, then asks for a small unwind they can breathe through. Forcing a derotation produces bracing.
Dramatic new asymmetry or trauma is a referral.