The<unk>  <unk> , comprises skew deviation, head<unk>  and<unk>  torsion involving structures of the inner ear responsible for maintenance of balance of the body i.e. the semi-circular canals (SCC), utricle and saccule. Each anterior semi-circular canals has excitatory projections to the ipsilateral superior rectus muscle and its yoke i.e., the contralateral inferior oblique while simultaneously inhibiting the ipsilateral inferior rectus muscle and its yoke i.e. the contralateral superior oblique. Also, each posterior semi-circular canals has excitatory projections to the ipsilateral superior oblique and its yoke i.e. the contralateral inferior rectus, while simultaneously inhibiting the ipsilateral inferior oblique and its yoke i.e. the contralateral superior rectus. A head<unk>  causes stimulation of both anterior semi-circular canals and the posterior semi-circular canals resulting in excitation of ipsilateral intorters (superior oblique and superior rectus) and contralateral extorters (inferior oblique and inferior rectus) while their antagonists are simultaneously inhibited. The otoliths (utricle and saccule) probably follow a similar pathway. Normally, a body<unk>  (along with the initial head<unk>  to the right causes a shift of the subjective visual vertical (SVV) to the left resulting in reflex, compensatory orientation of the head to left to realign the SVV to the true vertical. The initial head<unk>  to right will cause stimulation of the right utricle resulting in excitory signals to pass to the SR and SO (right eye), and IO and IR (left eye). Simultaneously, inhibitory signals pass to their antagonists. The stimulated two intorters (right eye) and the two extorters (left eye) have opposite vertical actions i.e., one is an elevator and the other is a depressor. The opposite vertical actions nearly cancel each other and therefore only a small vertical deviation occurs, whereas their identical torsional actions are additive. In case of any lesion from the utricle to the brainstem, diminished input from the affected vestibular pathway, for example the left vestibular is the same as stimulation of right vestibular pathway, resulting in the erroneous interpretation by the brain that the head is<unk> ed to the right and consequently that the SVV is<unk> ed to the left. This causes reflex rotation of the head to the left, thus realigning the eyes and head to a position that is actually<unk> ed but which the brain interprets as vertical. Published literature on<unk>  torsion in physiologic<unk>  counter-roll are usually not very clear on the type of head<unk>  inducing the torsion, i.e., initial head<unk>  causing a<unk>  in the SVV or the compensatory head<unk>  to realign SVV with the true vertical. It has been stated that the<unk>  torsion in physiologic<unk>  counter-roll appears in the opposite direction as that of the head<unk>  in contrast to the same direction of<unk>  torsion as the head<unk>  in pathologic<unk> . If instead of the actual head<unk>  (as compared to true vertical), the direction of the head<unk>  as interpreted by the brain (subjective head<unk>  is given importance, then it is seen that the head<unk>  and<unk>  torsion are actually in the same direction in both the physiologic<unk>  counter-roll and the pathologic<unk> . The subjective head<unk>  as interpreted by the brain in the presence of asymmetric signals from the inner ear neural afferents is the principal factor in determining the direction of<unk>  torsion in<unk> .
Ocular tilt reaction
Corneal reflex
Oculocardiac reflex
Vestibulo–ocular reflex
Intraocular pressure
Pupillary light reflex
Hirtz compass
Acoustic reflex