What is the Trochlear?

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 is the function of the trochlear nerve?

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.

What is an oculomotor?

The oculomotor nerve is the third of 12 pairs of cranial nerves in the brain. This nerve is responsible for eyeball and eyelid movement. It follows the olfactory and optic nerves in terms of order. Accommodation is the ability of the eye to keep an object in focus as the object’s distance from the eye changes.

What is superior orbital fissure?

The superior orbital fissure is a bony cleft found at the orbital apex between the roof and lateral wall. It is a communication between the orbital cavity and middle cranial fossa and is bounded by the greater wing, lesser wing and body of sphenoid.

What is the difference between trochlea and capitulum?

The first of these, called the trochlea, is a pulley-shaped surface that accommodates the ulna. The other, called the capitulum, is a small spherical structure lateral to the trochlea that articulates with the head of the radius. The capitulum is on the lateral side, the trochlea is medial.

Where is the Trochlear bone?

The trochlear notch (/ˈtrɒklɪər/), also known as semilunar notch and greater sigmoid cavity, is a large depression in the upper extremity of the ulna that fits the trochlea of the humerus (the bone directly above the ulna in the arm) as part of the elbow joint. It is formed by the olecranon and the coronoid process.

What is unique about the trochlear nerve?

The trochlear nerve is unique among the cranial nerves in several respects: It is the smallest nerve in terms of the number of axons it contains. It has the greatest intracranial length. It is the only cranial nerve that exits from the dorsal (rear) aspect of the brainstem.

Is trochlear nerve parasympathetic?

The trochlear, abducens, accessory, and hypoglossal nerves are only motor nerves; the trigeminal nerve is both sensory and motor; the oculomotor nerve is both motor and parasympathetic; the facial glossopharyngeal, and vagus nerves have sensory, motor, and parasympathetic components (Standring, 2008).

What are the different eye movements?

There are four basic types of eye movements: saccades, smooth pursuit movements, vergence movements, and vestibulo-ocular movements. Saccades are rapid, ballistic movements of the eyes that abruptly change the point of fixation.

Is the oculomotor nerve sympathetic or parasympathetic?

In addition, as discussed in the section on autonomic innervation, the oculomotor nerve carries the parasympathetic preganglionic axons that synapses in the ciliary ganglion, and whose postganglionic axons innervate the pupillary sphincter and ciliary muscles of the eye.