The brainstem, located in the cranium, is part of the central nervous system and plays an essential role in survival functions.

Position. The brainstem originates under the brain within the cranial cavity and passes through the occipital foramen. It then joins the upper part of the vertebral canal where it is extended by the spinal cord (1).

Structure. The brainstem is made up of a gray matter surrounded by a white matter. Within this white matter, we also find gray matter nuclei from which 10 of the 12 cranial nerves will emerge (2), from the XNUMXrd to the XNUMXth cranial nerve.

The brainstem is made up of three structures:

• The midbrain, located below the diencephalon, is extended by the bridge. It consists of two bulges, the cerebral peduncles.
• The bridge is located between the midbrain and the medulla oblongata. On its posterior surface, it is separated from the cerebellum by the fourth ventricle, a cavity where cerebrospinal fluid circulates.
• The bridge is located between the midbrain and the medulla oblongata. On its posterior surface, it is separated from the cerebellum by the fourth ventricle, a cavity where cerebrospinal fluid circulates.

Passage of motor and sensory pathways. The brainstem constitutes the passage zone of many motor and sensory pathways.

Cardiovascular center. The brainstem, and more particularly the medulla oblongata, plays an essential role in cardiac regulation. It modulates the frequency and strength of the heart’s contractions. It also modulates blood pressure by impacting the diameter of blood vessels (2).

Respiratory center. The brainstem, including the medulla oblongata and the bridge, initiates and modulates respiratory rhythm and amplitude (2).

Other brainstem functions. Other roles are associated with the brainstem, and more particularly the medulla oblongata, such as swallowing, salivation, hiccups, vomiting, coughing, or even sneezing (2).

Of degenerative, vascular or tumor origin, certain pathologies can develop in the brainstem and affect the central nervous system.

Stroke. Cerebrovascular accident, or stroke, is manifested by obstruction, such as the formation of blood clots or the rupture of a blood vessel in the brain. (3) This pathology can impact the functions of the brainstem.

Head trauma. It corresponds to a shock to the skull which can cause brain damage. (4)

Parkinson disease. It corresponds to a neurodegenerative disease, the symptoms of which are in particular a tremor at rest, or a slowing down and reduction in the range of motion. (5)

Multiple sclerosis. This pathology is an autoimmune disease of the central nervous system. The immune system attacks the myelin, the sheath surrounding nerve fibers, causing inflammatory reactions. (6)

Tumors of the brainstem. Benign or malignant tumors can develop in the brainstem. (7)

Drug treatments. Depending on the pathology diagnosed, certain treatments may be prescribed such as anti-inflammatory drugs.

Thrombolyse. Used during strokes, this treatment consists of breaking up the thrombi, or blood clots, with the help of drugs. (3)

Surgical treatment. Depending on the type of pathology diagnosed, surgery may be performed.

Chemotherapy, radiotherapy. Depending on the stage of the tumor, these treatments can be implemented.

Physical examination. First, a clinical examination is performed in order to observe and assess the symptoms perceived by the patient.

Medical imaging exam. In order to assess brainstem damage, a cerebral and spinal CT scan or a cerebral MRI can in particular be performed.

biopsy. This examination consists of a sample of cells.

Lumbar puncture. This exam allows the cerebrospinal fluid to be analyzed.

Thomas Willis is an English doctor considered one of the pioneers of neurology. He was one of the first to present a concrete description of the brain, notably through his treatise cerebral anatome. (8)