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A dermatome is an area of skin that is mainly supplied by afferent nerve fibres from the dorsal root of any given spinal nerve. [ 1 ] [ 2 ] There are 8 cervical nerves (C1 being an exception with no dermatome), 12 thoracic nerves , 5 lumbar nerves and 5 sacral nerves .
A myotome is the group of muscles that a single spinal nerve innervates. [1] Similarly a dermatome is an area of skin that a single nerve innervates with sensory fibers. Myotomes are separated by myosepta (singular: myoseptum). [2] In vertebrate embryonic development, a myotome is the part of a somite that develops into muscle.
The dermatome is the dorsal portion of the paraxial mesoderm somite which gives rise to the skin . In the human embryo, it arises in the third week of embryogenesis. [2] It is formed when a dermomyotome (the remaining part of the somite left when the sclerotome migrates), splits to form the dermatome and the myotome. [2]
The peripheral nervous system (PNS) is divided into the somatic nervous system, the autonomic nervous system, and the enteric nervous system.However, it is the somatic nervous system, responsible for body movement and the reception of external stimuli, which allows one to understand how cutaneous innervation is made possible by the action of specific sensory fibers located on the skin, as well ...
Posterior Dermatomes. The axial line is the line between two adjacent dermatomes that are not represented by immediately adjacent spinal levels. Although dermatomes are shown to be discrete segments on dermatomal maps (like in the image opposite), they are in fact not; adjacent dermatomes overlap with one another.
An area innervated by a single dorsal root is called a dermatome. Neurologists rely on maps of dermatomes and peripheral nerve fields to diagnose areas of nerve damage based on somasthetic or proprioceptive deficits in specific dermatomes and peripheral nerve fields.
In somitogenesis, somites form from the paraxial mesoderm, a particular region of mesoderm in the neurulating embryo.This tissue undergoes convergent extension as the primitive streak regresses, or as the embryo gastrulates.
The notochord and the neural tube activate the protein SHH, which helps the somite to form its sclerotome. The cells of the sclerotome express the protein PAX1 that induces the cartilage and bone formation. The neural tube activates the protein WNT1 that expresses PAX 2 so the somite creates the myotome and dermatome.