UNTIL now the significance of head posture has been considered chiefly from the symptomatological point of view. It is common knowledge that changes of head posture occur in general disturbances, such as meningeal or muscular disorders, or as a corrective posture in local lesions producing such disturbances as diplopia, homonymous hemianopsia, or unilateral positional vertigo. Deviation of the head occurs also in posterior fossa tumors and for some time may be the only sign present.
The classic investigations of Magnus1 showed that head posture not only undergoes passive alterations but can, under certain circumstances, effect an active influence. He revealed in his experiments on animals that turning of the head to one side caused extension of the "facial" limbs and flexion of the "occipital" limbs. Tonic neck reflexes were later observed, as is well known, under pathological conditions in human beings too. They appear with certain variations, particularly in
HALPERN L. BIOLOGICAL SIGNIFICANCE OF HEAD POSTURE IN UNILATERAL DISEQUILIBRIUM. AMA Arch NeurPsych. 1954;72(2):160-168. doi:10.1001/archneurpsyc.1954.02330020028003