Lecture 17: Spinal Cord Flashcards
Dermatome
Area of skin supplied with afferent nerve fibers by a single posterior spinal root
Myotome
All the muscles that are innervated by a single efferent anterior root
-most muscles are composed of more than one myotome
Pairs of spinal nerves Cervical Thoracic Lumbar Sacral Coccygeal
8 cervical 12 thoracic 5 lumbar 5 sacral 1 coccygeal
Cervical enlargement
C3-T1
Lumbar enlargement
L1-S2
Cervical plexus
C1-C4
Brachial plexus
C5-T1
Lumbosacral plexus
L1-S4
Posterior (dorsal) horns
Receive incoming sensory fibers
Anterior (ventral) horns
Site of cell bodies of alpha motor neurons to skeletal muscle fibers
Lateral horns
Site of cell bodies of autonomic neurons
Located only in thoracic and upper lumbar region
White matter : Columns
Consist of myelinated tracts
Spinal cord proper (Conus medullaris) ends at which level
L2
Filum terminale
Extends from conus medullaris (L2) to coccyx
Dorsal root carries
Afferent fibers
Dorsal root ganglion is location of
Cell bodies of afferent neurons
Ventral roots carry
Efferent fibers, no ganglion
Spinal nerve carries
Afferent/efferent
Visceral/somatic
Proprioceptive
Dorsal rami
To epaxial musculature (deep back muscles) and skin on either side of back
Ventral rami
To hypaxial musculature and rest of skin
White ramus communicans
Carries pre-ganglionic sympathetic fibers from lateral horns (thoracolumbar region)
Gray ramus communicans
Carries post-ganglionic sympathetic fibers from paravertebral ganglia back to spinal nerve
Meningeal coverings and space listed superficial-deep
Epidural space Dura mater (tough outer layer) Subdural space Arachnoid Subarachnoid space (Contains CSF) Pia mater (delicate innermost layer) Denticulate ligaments
