The trochlear nerve, together with the other significant nerves of the lower back known as the internal subdivisions of the median nerve (VI, III, and X), the vena cava (XIV), the sacral nerve (XV), and the annulus fibrosus (IV), runs through the lumbar spine. The primary function of these nerves is to provide the appropriate signals for motor functions such as walking, ambulation, swallowing, and chewing. In fact, these nerves form the motor system of our bodies.
The largest internal chamber of the heart:
The trochlear nerve actually extends up into the chest wall, or coccyx, and is closely connected to the heart by the cardiac muscle. The extension of this nerve includes the extent of the superior vena cava, which is the largest internal chamber of the heart. It also extends to the right side of the sacral ribs on the left side of the body—the abducens run from the margins of both eyes to the rear of the head. Finally, the oculomotor nerves extend from the inferior chest wall and the brain cavity to the anus on the right side of the body.
The trochlear nerve is divided into two branches, the internal and the external branches. The interior unit starts in the area of the brain stem. It extends to the cerebellum, peritoneum, and the several regions of the nervous system, including the adrenal medulla, brainstem, spinal cord, and anterior lumbar region. The external branch of this nerve extends to the abdomen and includes the internal parts of the ears, the colon, lungs, and ovaries. The inner part of this nerve is bounded by the visceral (visceral meaning stomach) wall and the internal organs. Since the internal part of this nerve is so small, it is enclosed in a capsule. The capsule also protects the delicate organs from injury.
Important function of trochlear nerve:
The function of this nerve is to provide a link between the brain and the somatic efferent. This is the link that is essential for coordinating the muscular activities of the body. The muscle fibers contract and relax in response to what the somatic efferent is telling the muscles to do. In fact, many of our major muscle movements are controlled by the actions of our somatic efferents. This nerve carries impulses from the cerebral cortex to the leg and hip flexors, as well as from the foot to the internal organs. The function of these muscles is to enable us to walk, sit, move, talk, swallow, and much more.
There is a big difference between the function of this nerve in humans and in animals. While animals are mostly very much on instinct, humans have developed a remarkable ability to use their extraocular muscles while awake. In fact, many people can carry out very complex eye movements without even knowing they are moving their eyes or their bodies. This is called ocular coordination. People who have good visual coordination are able to perform a number of different tasks, including reading, learning to recognize colors, motion sickness, and even using computers.
The function of this nerve in humans is related to the superior orbital fissure, which is located in the back of the eye. The superior orbital fissure passes through the choroid, which is a small bag of fluid under the eyes that houses blood cells. The choroid also houses the blood supply to the lens. The blood supply to the lens passes through the choroid directly to the retina through the superior orbital fissure.
Trochlear nerve is a bundle of nerve fibers:
The trochlear nerve is basically a bundle of nerve fibers that pass through the dura mater layer of your eyes. The dura mater is made up of the three layers of tissue that make up your eyes-the iris, the cilia, and the macula. The dura mater is the covering over the photoreceptors that allow you to see. The nerve fibers that make up this bundle are called the corpus callosum, which is the primary link in your vision processing system. When this nerve gets damaged due to age, disease, trauma, or a natural occurrence such as an accident, it can be extremely painful.
The Trochlear Nerve starts in the temporal bone of your skull at the base of your skull and extends outward. It passes through the temporal bone and then goes through the middle ear, the ear canal, the ear cavity, the brain stem, the spinal cord, the gastrointestinal tract, and finally, it reaches the external auditory canal. When this nerve becomes inflamed, it causes severe headaches, vomiting, nausea, decreased hearing ability, weakness, numbness, and tingling in the ears. The exact pathway that this nerve supplies to your brain is still not completely understood. Still, thanks to advancements in medicine that have been made over the last hundred years, some scientists are hoping to better understand the inner workings of the human brain through the study of the nerves that are associated with motor function.