Inner longitudinal nerve fiber bundle of the brainstem

Fasciculus longitudinalis medialis

FLM, MLF(Medial Longitudinal Fascicle)

Well collected bundle of nerve fibers running, one on the right and one on the left side of the brainstem, dorsally near the mean line from the upper border of the mesencephalonthrough the entire brainstem and continuing some distance down into the cervical spinal cord.
The inner vestibulo-spinal conduction pathway is part of FLM.

FLM connects the vestibulocerebellum, the balance nuclei, the nuclei of the eye muscle nerves, some "auditory nuclei", the gaze direction centers of the brainstem, and motor neuronal nuclei of the cervical spinal cord with each other. The latter have to do with the movements of the head; e.g. n. accessorius nucleus in the spinal cord.

FLM makes it possible, among other things, to keep your gaze firmly fixed on something in the environment - i.e. that the image that falls on the retina remains firmly in place - despite moving the head and/or the body's balance position changing. This is the vestibulo-occular reflex

FLM also contains the path system parts that enable saccades.

The inner tractus tegmentalis medialis runs together with FLM from the upper part of the mesencephalon down to the olivainferior complex.