Tectospinal tract
Tractus tectospinalis
A crossed descending pathway from the superior colliculus of the midbrain to the upper cervical cord that turns the head towards sights and sounds.
At a glance
- English
- Tectospinal tract
- Latin (TA2)
- Tractus tectospinalis
- System
- Nerve
- Region
- Whole body
- Side
- Single, on the midline
About the tectospinal tract
Also called the colliculospinal tract, the tectospinal tract is a descending pathway outside the pyramids that links the roof of the midbrain with the upper spinal cord. It belongs to the medial group of motor pathways and is concerned with orienting the head and eyes. In the spinal cord it runs in the anterior funiculus, close to the anterior median fissure, and is found only in the upper cervical segments.
The tract begins in the deep layers of the superior colliculus. Soon after leaving, its fibres sweep around the periaqueductal grey and cross the midline behind the medial longitudinal fasciculus, in the dorsal tegmental decussation. They then descend close to the midline through the pons and medulla, near the medial longitudinal fasciculus, and enter the anterior funiculus of the cord. Most fibres end in the first few cervical segments, on interneurons of Rexed laminae VI to VIII, which in turn reach the motor neurons of the neck muscles. Collaterals also pass to the reticular formation and to the gaze centres that control the oculomotor, trochlear and abducens nuclei.
The superior colliculus receives input from the retina and the visual cortex, from the inferior colliculus and from the body, and arranges it into a map of the space around the head. Through the tectospinal tract it produces reflex turning of the head and neck towards a sudden flash of light or a noise, while its connections to the eye movement centres move the eyes in step. Because the tract crosses, a colliculus on one side controls neck muscles on the opposite side.
In humans the tract is small and its exact extent is uncertain. Its role is best seen in the quick, automatic orienting movements made before a person consciously notices what caught their attention.
Course and supply
- Supplies
- Turns the head and neck reflexly towards visual and sound stimuli, acting on the neck muscles of the opposite side and coordinating with eye movements.
- Blood supply
- Runs in the anterior funiculus of the cervical cord, supplied by the anterior spinal artery.
Anthromica
See the tectospinal tract where it really sits, with every layer of the body around it.
- Every layer, one body. Peel from muscle to bone, nerve, vessel and organ, and turn it any way.
- English and Latin. Every structure named the way your exam names it.
- Quiz until it sticks. Short drills on the structures you keep missing.
Free to start. No card.
