What is the functions of trochlear nerve?
The trochlear nerve is one of 12 sets of cranial nerves. It enables movement in the eye’s superior oblique muscle. This makes it possible to look down. The nerve also enables you to move your eyes toward your nose or away from it.
What eye movements does the trochlear nerve control?
Cranial nerve 4, also called the trochlear nerve, controls the movement of the superior oblique muscle. This muscle moves the eye down and rotates the top of the toward the nose. It also helps pull the eye outward when the eye is looking downward.
How do you test for trochlear nerve damage?
To detect excyclotropia one must ask the patient whether there is a tilted double image in down gaze. Bilateral trochlear nerve palsy causes a change of vertical deviation between right and left gaze and between head-tilt to the right and to the left shoulder.
What are the symptoms of trochlear nerve lesion?
Thus, a trochlear nerve palsy causes an ipsilateral higher eye (i.e., hypertropia) and excyclotorsion (the affected eye deviates upward and rotates outward). Patients may report vertical and/or torsional diplopia that is usually worse on downgaze and gaze away from the affected side.
How do you test trochlear nerve?
To assess the trochlear nerve, instruct the patient to follow your finger while you move it down toward his nose. Cranial nerve V covers most of the face. If a patient has a problem with this nerve, it usually involves the forehead, cheek, or jaw—the three areas of the trigeminal nerve.
What causes trochlear nerve damage?
The most common cause of congenital trochlear nerve palsies is congenital cranial dysinnervation syndrome, followed by an abnormal superior oblique tendon. The most common cause of acquired isolated fourth nerve palsy, after idiopathic, is head trauma.
Where is trochlear nerve located?
midbrain
The Trochlear Nerve (IV) The fourth nerve nucleus is located in the tegmentum of the midbrain at the level of the inferior colliculus, ventral to the periaqueductal gray matter, inferior to the oculomotor nucleus, and superior to the medial longitudinal bundle.