Functional Anatomy of Human Rexed laminae.

                                                         

There are 10 Rexed Laminae identified by Swedish Neuroscientist Bore Rexed in 1950. These are gray matter layers widely distributed in Dorsal , ventral and lateral columns of the Spinal cord at various level.

Lamina I
It is located in the dorsal hone. It consist of scattered large neurons that receive afferent connections from Lissauer's Tract.These neurons are mainly involved in Noceception ( pain Sensation). Pain sensation relayed here can not be modulated.

Laminae II&III
Lamina II with overlap with Lamina III approximately conterminous with the Substantia Gelatinosa of Rolando.These lamina contain inter-neurons that receive pain and temperature afferents from Lissauer's Tract.But make no contributions to the DCML pathway.

Lamina IV
It contains polymodal sensory neurons , That are activated by many different sensory stimuli. Cells in Lamia IV gives rises to the Contralaeral Spinothalamic Tract.

Laminae V & VI
These layers are indistinguishable in humans. Cells in lamina IV and V to VI make up the Nucleus Proprious. It is involved in pain and temperature sensation.

Lamina VII
It is the most extensive Cytoarchetectonic Layer in human spinal cord.Between C8 and L3 the medial portion of the lamina VII contains dorsal Nucleus of Clark.Degeneration of Neurons in Clarks Nucleus is indicated in friedreich's Ataxia.Cells in Nucleus Dorsalis of Clark gives rise to Dorsal spino cerbellar tract.Intermedio- lateral gray column of the lamina VII contains preganglionic sympathetic neurons between T1 and L2 and preganglionic parasympathetic neurons between S2 and S4.

Lamina VIII
It contains interneurons involved in motor control including Renshaw cells that receives collaterals from nearby Lamina IX.

Lamina IX
It contains the Alpha Motor Neurons. There is a Nuclear group at all levels that innervates axial and proximal Muscles and a lateral Nuclear group at cervical and Lumbar enlargements that innervates distal extremity muscles.

Lamina X
It surrounds the central spinal canal.It contains neurons that receives visceral afferent information.


REFERENCES

1) William. W. Cambell, DeJong's the neurological Examination 7th edition (2012)ch:24 pp: 379-381

2) Brent .L.Fogal, Randlop.W.Evans, Clinical Neurogenetics (2013)