The medial longitudinal fasciculus is a heavily myelinated bundle of fibers located near the midline of the brainstem. It extends from the midbrain to the cervical spinal cord and connects nuclei that control eye movements and neck musculature. The medial longitudinal fasciculus coordinates conjugate eye movements and associated movements of the head.

1. Medial longitudinal bundle
The medial longitudinal fasciculus is a
heavily myelinated composite tract,
lying near the midline, ventral to the
periaqueductal grey matter.
Dr M Idris Siddiqui

2. 1.Nuclei of
oculomotor nerve
2.Trochlear nucleus
3.Pons
4.Fourth ventricle
5.Abducent nucleus
6.Vestibular nucleus
7.Medial longitudinal
fasciculus

4. Medial longitudinal fasciculus
• A longitudinal bundle of fibers extending from
the upper border of the midbrain into the cervical
segments of the spinal cord, located close to the
midline and ventral to the central gray matter; it
is composed largely of fibers from the vestibular
nuclei ascending to the motor neurons
innervating the external eye muscles (abducens,
trochlear, and oculomotor nuclei), and
descending to spinal cord segments innervating
the musculature of the neck.
• Syn: fasciculus longitudinalis medialis [NA], Collier's tract, medial
longitudinal bundle, posterior longitudinal bundle.

6. The medial longitudinal fasciculus
• In midbrain:
• It ascends to the interstitial
nucleus (of Cajal), which lies in
the lateral wall of the third
ventricle, just above the
cerebral aqueduct.

8. Position
• The fasciculus retains its position relative
to the central grey matter through the
midbrain, pons and upper medulla, but is
displaced ventrally by successive
decussations of the medial lemnisci and
lateral corticospinal tracts.
• At spinal levels it is synonymous with the
medial vestibulospinal tract.

11. The medial longitudinal fasciculus
• It ascends to the interstitial nucleus (of Cajal),
which lies in the lateral wall of the third
ventricle, just above the cerebral aqueduct.
• The medial longitudinal fasciculus interconnects
– The oculomotor nuceus,
– Troclear nuceus ,
– Abducens nuceus,
– Edinger-Westphal nuceus,
– Vestibular nuceus,
– Reticular nuceus and
– Spinal accessory nuclei,
• It coordinates conjugate eye movements and
associated movements of the head and neck.