You’ve booked a physiotherapy appointment for your pain. But you’ve also noticed some stranger symptoms – maybe some tingling, numbness, abnormal taste, ringing in the ears, or even vision changes. Your physiotherapist asks you some questions and starts a variety of strange tests that include seeing if you can follow a moving pen with your eyes. Curious about why your physiotherapist is making you do this? They are probably assessing the function of your cranial nerves.

What are the cranial nerves? Let’s dive into it.

There are twelve pairs of cranial nerves that start in the brain and branch out to various parts of the head, neck and body. They all have difference functions. Some are involved in the primary senses – such as seeing, hearing and taste – and others control facial muscles or regulate glands. All cranial nerves are numbered in anatomical organisation, starting from the front of the brain going towards to the back. Let’s talk specifics.

Cranial nerve 1 – the olfactory nerve - controls smell. If it is injured you will have either a diminished or complete loss of smell.

Cranial nerve 2 – the optic nerve – controls vision. If it is injured you will have blurry or even a complete loss of vision.

Cranial nerve 3 – the oculomotor nerve – controls several muscles that move the eye. It also constricts the pupil. If it is injured your eye may be turned out and down.

Cranial nerve 4 – the trochlear nerve – controls one of the eye muscles that will move the eye inferiorly and laterally (towards the outside bottom corner). If it is injured you may have double vision and a hard time gazing downward.

Cranial nerve 5 – the trigeminal nerve – controls touch, temperature and pain sensation for the face. It also controls the sensation of the first two thirds of the tongue as well as controls the muscles that allow you to chew your food. If it is injured you may have facial pain, numbness or tingling.

Cranial nerve 6 – the abducens nerve – controls one of the eye muscles that will abduct the eye (move it to the outside). If it is injured your eye will turn inward and you may have double vision.

Cranial nerve 7 – the facial nerve – controls the muscles that move the face. It also is in charge of taste for the first two thirds of the tongue. If it is injured you will have facial weakness – drooping - and potentially a change in taste.

Cranial nerve 8 – the vestibulocochlear nerve – controls hearing and helps with balance. If it is injured you may have hearing loss, ringing in the ears, dizziness and balance issues.

Cranial nerve 9 – the glossopharyngeal nerve – controls touch and taste from the back third of the tongue. It also controls the muscles of the pharynx. If it is injured you may have difficulty swallowing and talking.

Cranial nerve 10 – the vagus nerve – controls visceral sensation from a variety of organs, including the heart, lungs and abdominal organs. It also innervates the smooth muscles of those same organs. If it is injured you may have voice changes and digestive problems.

Cranial nerve 11 – the spinal accessory nerve – innervates the trapezius muscles and the sternocleidomastoid muscles. If it is injured you will have a droopy shoulder, a shoulder blade that protrudes, and difficulty shrugging the arm and turning the head.

Cranial nerve 12 – the hypoglossal nerve – innervates the tongue muscles. If it is injured you will have difficulty moving your tongue, making it difficult to talk, chew and swallow.

Cranial nerve dysfunction can be caused by a variety of conditions, such as trauma, inflammation, tumors and underlying medical conditions.

The symptoms depend on which nerves are impacted. A trained physiotherapist will be able to ask the right questions and complete the proper tests to be able to determine whether you may have cranial nerve dysfunction. Book into Panther Sports Medicine today.