MSK 07-1 - Spinal Nerves and Somatic Plexuses Flashcards
What types of nerves travel through the dorsal, ventral, and lateral horns? At what levels are these horns found? What is another name for these horns?
The dorsal horn (aka posterior grey column) carries the sensory nerve fibers and is found throughout the spinal column
The ventral horn (aka anterior grey column) carries the skeletal motor neurons and is found throughout the spinal column
The lateral horn (aka lateral grey column) carries the sympathetic motor neurons from T1-L2 as well as the parasympathetic motor neurons from S2-S4
Where does the spinal nerve begin and end and what types of nerve fibers does it carry?
The spinal nerve begins where the dorsal and ventral roots merge and ends where the dorsal & ventral ramus, and grey & white rami communicantes begin. The spinal nerves carry a mixture of afferent and efferent neurons.
Where does each spinal nerve exit the vertebral column?
C1 exits between the skull and C1
C2 to C7 exit through the intervertebral foramen above the same number vertebra
C8 exits through the intervertebral foramen above T1
T1 to end of cord exit through the intervetebral foramen below the same number vertebra
What is a dermatome?
An area of skin innervated by a single spinal nerve
Will sensory loss develop is one spinal nerve lesion? Why or why not?
Draw out where the neuronal cell bodies of the somatic efferents are located and how those fibers enter and exit the spinal nerves.
Draw out where the neuronal cell bodies are for the sympathetic efferents and how those fibers enter and exit the spinal nerves.
Draw out where the neuronal cell bodies for the sensory afferents are and how those fiber enter and exit the spinal nerve.
What are myotomes?
Regions of skeletal muscle innervated by a single nerve or spinal cord level.
How is myotome testing done?
By testing movements of joints or muscle groups
What is a somatic plexus? What types of nerve fibers do they contain? What are the somatic plexuses?
A network of nerves derived totally from ventral rami of spinal nerves. They contain muscular motor fibers and skin & joint sensory fibers.
Cervical plexus
Brachial plexus
Lumbar plexus
Sacral Plexus
What is Hilton’s Law?
The nerve supplying the muscles extending directly across and acting at a given joint also innervate the joint
What types of fibers does a visceral plexus carry?
