Exam - lecture 17 SPinal Cord Flashcards
What are the three major subdivisions of a typical somite and and the major derrivatives from eachs subdivision?
Regions of Somite
- Dermatome (dermis)
- myotome (muscle)
- Sclerotome (skeleton)
What is a dermatome?
Dermatome (dermis)
the area of skin supplied with afferent nerve fibers by a single posterior spinal root
What is a myotome ?.
myotome (muscle)
all the muscles that are innervated by a single efferent anterior root most muscles are composed of more than myotome
What is the relationship b/w somites and somatic innvervation ?
- arises segmentally along the developing CNS in association with somites
- Part of each somite (the dermomyotome) gives rise to skeletal muscle and dermis of the skin
- Cells that migrate anteriorly give rise to muscles if the limbs and trunks (hypaxial muscles) and to the associated dermis
- Cells that migrate posteriorly give rise to the intrinsic muscles of the back (epaxial muscles) and the associated dermis.
What is the relationship between plexuses and myotome innervations?
What is the early development fof the spinal cord?
What is the general anatomy of the human spinal cord? (W/o plexuses)
- approx 1/2 meter in length
- veries from 1 to 1.5cm in diameter
- enlargement
- cervical
- C3 - T1
- lumbar
- L1 - S2
- cervical
- Conuw Mdeullaris
- ends at about the level of L2
- causda equina
- filum terminale
- thin filament of meningeal tissue extending from conus medullaris to the coccyx
- spinal nerves
- 8 cervical
- 12 thoracic
- 5 lumbar
- 5 sacral
- 1 coccygeal
What is the gross anatomy of the plexuses?
Cervical C1 - C4
Brachial C5 - T1
Lumbosacral L1 -S4
how does the cauda equina develope?
What is anatomical charactisitcs of the cross sectional spinal cord?
- Central canal
- Gray matter
- “H”-shaped
- White matter
What is the relation between the horns, columns, and commissures?
- gray matter
- horns
- equivalent of CNS nuclei
- posterior (dorsal) horns
- recieve incoming sensory
- Anterior (ventral) horns
- site of cell bodies of alpha motor neurons to skeletal muscle fibers
- Lateral horns
- located only in thoracic and upper lumbar region
- site of cell bodies of autonomic neurons
- horns
- White matter:
- columns (funiculi)
- consists of myelinated tracts
- posterior (dorsal) columns
- ANterior (ventral) columns
- Lateral columns
- COmmissures
- white
- anterior
- posterior
- Gray
- anterior
- posterior
- white
- columns (funiculi)
What is the general structure and function of a typical spinal nerve from rootlets to autonomic rami?
- Dorsal root
- carries afferent fibers
- with dorsal root ganglion
- Ventral rootlets and root
- carries efferent fibers
- no associated ganglion
- spinal nerve carriers
- Mixture of fibers
- both afferent and efferentboth visceral and somatic
- proprioceptive
- both afferent and efferentboth visceral and somatic
- Mixture of fibers
- Primary rami
- dorsal (posterior)
- to expaxial musculature (deep back muscles) and skin on either side of dorsum of back
- ventral (anterior)
- to hypaxial musculature (rest of skelta l musculature including limbs ) ad rest of skin
- dorsal (posterior)
- Autonomic Rami
- white ramus communications
- carries pre-ganglionic sympathetic fibers from lateral horns of central gray of spinal cord (thoracolumbar regions)
- Gray ramus communications
- carries post ganglionic sympathetic fibers from paravertebral gangiia back to spinal nerve
- white ramus communications
What are the menigeal coverings and spaces around the spinal cord?
- epidural space
- dura mater
- tough outer layer
- subdural space
- arachnoid subarhnoid space
- subarachnpod space
- contains CSF
- Pia mater
- delicae innermost layer
- Denticulate ligaments
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