What Is the Trochlear Nerve?

The pulley nerve, the fourth pair of brain nerves, namely the fourth pair of brain nerves, is a motor nerve and is composed of somatic motor fibers originating from the midbrain pulley nerve nucleus.

The pulley nerve, the fourth pair of brain nerves, namely the fourth pair of brain nerves, is a motor nerve and is composed of somatic motor fibers originating from the midbrain pulley nerve nucleus.

Chinese name

Block nerve

Foreign name

Trochlear nerve

Definition

4th pair of brain nerves

Numbering

F

Belong to

Motor nerve

Overview of the tackle nerve

The brain emerges from below the inferior hypothalamus of the midbrain, bypasses the brain feet forward, penetrates the dura mater behind the posterior process, enters the lateral wall of the cavernous sinus, finally enters the orbit through the supraorbital fissure, and enters the The orbital surface and innervates the muscle, causing the eyeball to turn outward and downward.

Neuroanatomical characteristics of the tackle

The pulley nerve is a brain nerve connected to the dorsal side of the brainstem. It has a small outer diameter and is complex to walk and adjoin.

1. Stroke of the pulley nerve and distance from adjacent structures

The pulley nerve is 4.5 ± 0.6 (3.5 to 5.4) mm from the median line and starts from the lower and outer sides of the inferior colliculus; then it goes around the foot of the brain in the outer ring pool forward and penetrates from the lower edge of the cerebellum into the curtain. The posterior posterior process was 13.7 ± 3.8 (8.4 to 18.5) mm outside; 6.8 ± 1.9 (5.2 to 12.5) mm sneaked into the curtain and entered the cavernous sinus. In the cavernous sinus, the pulley nerve is between the oculomotor nerve and the ophthalmic nerve: most of them approach the upper oculomotor nerve after entering the sinus; parallel to the middle of the sinus, approach forward and down to the lower ophthalmic nerve and follow it The upper edge enters the supraorbital fissure. Three nerves form the lateral superior triangle and lateral inferior triangle of the cavernous sinus (Parkinos's triangle) on the outer side of the cavernous sinus. On the outer wall of the sinus, the pulley nerve is located between the oculomotor nerve and the ophthalmic nerve, and the distance from the upper oculomotor nerve and the lower outer ophthalmic nerve is 4.5 ± 2.1 (2.0 10.4) mm and 4.2 ± 1.4 (1.5 ~ 7.4) mm. Subsequently, the trochlear nerve travels along the lateral side of the sinus wall to the outside of the anterior bed process, and is in close contact with the oculomotor nerve and the optic nerve into the supraorbital fissure. After reaching the orbital cavity, the trochlear nerve runs on the inner side of the frontal nerve, slanting across the levator levator muscle at a distance of 9.1 ± 1.0 (7.7 to 11.0) mm from the total key ring, and inward to the upper edge of the superior oblique muscle, in the middle and rear of the The / 3 junction divides 2 branches into the muscle.

2. Length and outer diameter of each segment of the pulley nerve

project	Cranial segment	Cursive sneak	Cavernous sinus segment	Supraorbital fissure	Orbital segment
length	32.4 ± 4.7 (23.5 39.2)	6.8 ± 1.9 (5.2 12.5)	22.9 ± 4.5 (16.3 32.4)	12.7 ± 2.8 (8.3 18.6)	10.8 ± 2.9 (6.3 16.3)
width	1.2 ± 0.2 (0.8 2.0)	1.1 ± 0.2 (0.8 1.9)	1.0 ± 0.3 (0.5 1.8)	0.9 ± 0.3 (0.5 1.8)	1.3 ± 0.4 (0.6 1.9)
thickness	0.8 ± 0.1 (0.6 1.2)	0.8 ± 0.1 (0.6 1.1)	0.7 ± 0.2 (0.3 1.3)	0.7 ± 0.3 (0.3 1.5)	0.6 ± 0.2 (0.3 1.2)

Length and outer diameter of each segment of the pulley nerve [(x ± s (min max), mm)]

The ratio of the length of the cranial segment, the latent segment, the cavernous sinus, the supraorbital fissure, and the orbital segment of the trochlear nerve was 4.8: 1: 3.7: 1.9: 1.6. Nerve thickness gradually becomes thinner from cranial segment to orbital segment. Nerve width also gradually narrowed from cranial segment to supraorbital fissure segment, but the orbital segment widened at the branch.