What is the action of the superior oblique muscle?
The superior oblique muscle’s primary action is eye intorsion, with secondary and tertiary actions being eye depression and abduction, respectively.
Which movement is mediated by superior oblique muscle?
The primary (main) action of the superior oblique muscle is intorsion (internal rotation), the secondary action is depression (primarily in the adducted position) and the tertiary action is abduction (lateral rotation). The extraocular muscles rotate the eyeball around vertical, horizontal and antero-posterior axes.
Is superior oblique palsy hereditary?
Four pedigrees, each with two or more cases of congenital superior oblique palsy among immediate family members, are presented. Except for a single case report in 1926, this disorder has not been known to occur in a hereditary manner.
What causes Trochlear nerve palsy?
The most common cause of congenital trochlear nerve palsies is congenital cranial dysinnervation syndrome, followed by an abnormal superior oblique tendon.
What causes damage to the trochlear nerve?
In some people, it’s congenital, meaning they are born with this condition. It may also be due to trauma from rapid head movements, like during motor vehicle accidents. The trochlear nerve is one of the more fragile cranial nerves because it’s thin and long. Cranial nerve palsy sometimes occurs after minor injuries.
How is trochlear nerve palsy diagnosed?
The diagnosis of unilateral trochlear nerve palsy is based on acute onset vertical deviation which increases in contralateral side gaze, down gaze and ipsilateral head-tilt together with excyclodeviation which also increases in both down gaze and ipsilateral head-tilt.
What is Trochlear nerve palsy?
Dysfunction of the fourth cranial nerve (trochlear nerve), which innervates the superior oblique muscle, is one cause of paralytic strabismus and can result from lesions anywhere along its path between the fourth nerve nucleus in the midbrain and the superior oblique muscle within the orbit.
What is the superior oblique?
The superior oblique is a fusiform (spindle-shaped) muscle belonging to the extraocular group of muscles. It originates near the nose. Along with the other extraocular muscles, it performs the role of controlling eye movements. This muscle’s movement of the eye downward is most effective when the eye is abducted.
How does the superior oblique move the eye?
The belly of superior oblique muscle is located posterior to the eye. When the eyeball is in a neutral position, superior oblique is responsible for abduction (directed laterally from the nose), depression (inferiorly) and internal rotation (movement of the superior pole of the eye medially) of the eyeball.
