What is the trochlear nerve responsible for?

What is the trochlear nerve responsible for?

The trochlear nerve (CN IV) is responsible for the motor pathway to the dorsal oblique muscles of the eye. The trochlear nucleus originates in a position similar to that of the oculomotor nucleus. The axons of the nerve run dorsally then cross before exiting the caudal colliculus.

Where is nucleus of trochlear nerve?

midbrain
The trochlear nucleus is located in tegmentum of midbrain, at the level of inferior colliculus. The trochlear nerves decussate at anterior medullary velum in the roof of aqueduct before exiting from dorsal aspect of midbrain.

What happens if cranial nerve 4 is damaged?

Fourth Nerve Palsy Problems with these nerves can cause issues with eye position and movement including eyes turning in, turning out, or being vertically misaligned or causing double vision.

What does trochlear mean?

: an anatomical structure that is held to resemble a pulley especially : the articular surface on the medial condyle of the humerus that articulates with the ulna.

What happens if the trochlear nerve is damaged?

Injury to the trochlear nerve cause weakness of downward eye movement with consequent vertical diplopia (double vision). The affected eye drifts upward relative to the normal eye, due to the unopposed actions of the remaining extraocular muscles.

What is the main function of the trochlear?

The primary function of the trochlear nerves (IV) is also motor, controlling eye movements. These nerves originate in the midbrain, passing through the superior orbital fissures of the sphenoid bone, to reach the superior oblique muscles. The trochlear nerves are the smallest of the cranial nerves.

How many trochlear nucleus are there?

The oculomotor nerve and trochlear nerve are the only two cranial nerves with nuclei in the midbrain, other than the trigeminal nerve, which has a midbrain nucleus called the mesencephalic nucleus of trigeminal nerve, which functions in preserving dentition….

What happens if cranial nerves are damaged?

Cranial nerve issues can affect a motor nerve, called cranial nerve palsy, or affect a sensory nerve, causing pain or diminished sensation. Individuals with a cranial nerve disorder may suffer from symptoms that include intense pain, vertigo, hearing loss, weakness or paralysis.

What happens to the trochlear nerve in the brain?

Trochlear nerve. An injury to the trochlear nucleus in the brainstem will result in an contralateral superior oblique muscle palsy, whereas an injury to the trochlear nerve (after it has emerged from the brainstem) results in an ipsilateral superior oblique muscle palsy.

What are the symptoms of trochlear lesion in the eye?

A trochlear lesion is characterized by: diplopia, maximal on looking downwards and inwards, and causing difficulty descending stairs or reading normal pupils. The ability to move each eye down and inward is tested by asking the person to follow a target moved by the examiner. There is often damage to the third and fourth nerves as well.

What causes nerve palsy in the trochlear nucleus?

A peripheral lesion is damage to the bundle of nerves, in contrast to a central lesion, which is damage to the trochlear nucleus. Acute symptoms are probably a result of trauma or disease, while chronic symptoms probably are congenital. The most common cause of acute fourth nerve palsy is head trauma.

Where do axons pass after leaving the trochlear nucleus?

The trochlear nerve is the longest and thinnest of all cranial nerves, making it susceptible to trauma. After leaving the trochlear nucleus, the axons pass dorsolaterally and caudally around the periaquaeductal gray, and decussate almost completely in the anterior medullary velum.

What is the trochlear nerve responsible for? The trochlear nerve (CN IV) is responsible for the motor pathway to the dorsal oblique muscles of the eye. The trochlear nucleus originates in a position similar to that of the oculomotor nucleus. The axons of the nerve run dorsally then cross before exiting the caudal colliculus. Where…