<unk>  can be divided in two categorizes based on the restriction of movement on the eye itself and how it affects the eye excluding the movement: * Congenital (present at birth)<unk>  results from structural anomalies other than a short tendon sheath but other fibrous adhesions may be present around the trochlear area. * Acquired cases arise from trauma, surgery, sinusitis and inflammation of the superior oblique tendon sheath in rheumatoid arthritis. Orbital floor fractures may trap the orbital tissue in such a way as to simulate<unk> . Intermittent forms of vertical retraction syndrome have been associated with click, which occurs as the restriction is released (superior oblique click syndrome).
Brown's syndrome
Horner's syndrome
Shone's syndrome
Seaver Cassidy syndrome
Nance–Horan syndrome
Pilotto syndrome
Weaver syndrome
Brown-Séquard syndrome