Posterior fasciculus proprius
Fasciculus proprius posterior
A thin layer of short intersegmental fibres in the deepest part of the posterior white column of the spinal cord, next to the posterior horn.
At a glance
- English
- Posterior fasciculus proprius
- Latin (TA2)
- Fasciculus proprius posterior
- System
- Nerve
- Region
- Whole body
- Side
- Single, on the midline
About the posterior fasciculus proprius
The posterior fasciculus proprius is the posterior member of the proper, or propriospinal, system of the spinal cord. With its anterior and lateral partners it makes up a narrow coat of white matter wrapped closely around the grey matter. All three consist of short fibres that begin and end inside the cord. Some run upwards and others downwards, and some cross while others stay on the same side.
In the posterior funiculus the bundle lies in the most anterior, ventral zone, against the grey commissure and the medial face of the posterior horn. Behind it lie the long ascending fibres of the gracile and cuneate fasciculi. Its axons come from neurons in the posterior horn. Each axon splits into an ascending and a descending branch, and these travel for various distances, a few segments in most cases, before turning back into the grey matter. On the way they send side branches and endings into the grey substance of each segment they pass.
Descending branches of entering posterior root fibres are often counted with this bundle. In parts of the cord they gather into small named groups, such as the comma-shaped septomarginal bundles, which lie within the posterior column.
Like the rest of the propriospinal system, this bundle links neighbouring segments. It allows sensory information arriving at one level to influence processing in the posterior horn at others, and it supports reflexes that need several segments to work together. Because it lies so close to the grey matter it is often involved together with the posterior horn in lesions of the back of the cord.
Course and supply
- Supplies
- Links the posterior horns of nearby spinal segments, spreading sensory input and reflex activity over several levels.
- Blood supply
- Lies in the posterior funiculus, supplied by the posterior spinal arteries.
Anthromica
See the posterior fasciculus proprius 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.
