Flashcards in The Spinal Cord Deck (38):
Where do the C1 and C2 nerve roots exit the vertebral column?
- C1 exits above the atlas
- C2 exits below the atlas
Where do the spinal nerves below C2 exit the vertebral column?
Below the named vertebra
Why is the spinal cord enlarged at the level of the plexuses?
There are more neuron bodies.
Which plexus causes the greatest enlargement in the spinal cord?
- The cervical plexus
At what levels does the thoracolumbar enlargment occur?
From T11 until its greatest circumference at L1.
What is the termination of the spinal cord named?
What is the continuation of axons pass the conus medaliaris termed?
The cauda equina.
What are the 3 protective layers about the spinal cord from outer to inner?
- Dura mater
- Arachnoid mater
- Pia mater
Where is the subdural space found?
Between the dura and arachnoid mater. (This is a potential space that can fill with fluid)
Where is the subarachnoid space found?
- Between the arachnoid mater and pia mater.
What is found with in the aubarachnoid space?
What are the 2 mechanical stabilizations of the spinal cord?
- Filum Terminal/ Terminal Ligament
- Denticulate Ligaments
What is the filum terminal?
- An extension of pia mater that attaches from the caudal portion of the spinal cord to the sacrum, anchoring the cord.
What are the denticulate ligaments?
- An extension of the pia mater that extends laterally from the spinal cord and attaches to the arachnoid, and dura matter, which is attached to bone.
What is the major non-mechanical stabilizer of the spinal cord?
- Cerebrospinal fluid within the subarachnoid that cannot be compressed
What protective coverings of the spinal cord extend with the cauda equina from L1 to the coccyx?
- The arachnoid and dura mater
How is the ventral horn organized in terms of distal/ proximal innervations?
- Lateral portions innervate more distal body parts
- Medial portions innervate more proximal muscles
How is the ventral horn organized in terms of flexors/ extensors?
- Dorsal portion innervates flexors
- Ventral portion innervates extensors
What is the organizing of neurons in the ventral horn according to function called?
- Somatotopic arrangement
What are 2 methods of organization of the neurons within the gray matter of the spinal cord?
- Nuclei arrangements
- Rex laminae arrangements
Which horn works well with a nuclei arrangement? Which horn works well with Rex laminae arrangments?
Dorsal: Rex laminae
Which rex lamina make up the dorsal horn?
1 - 6
Which rex lamina make up the venral horn?
7 - 12
Which rex lamina are the cell pools of the ventral horn?
Which rex lamina is intermediate gray?
Which rex lamina is interneurons of the ventral horns?
Which rex lamina is the commisure of the spinal cord gray matter?
Which rex lamina is the substantia gelatinosa?
Which rex lamina is the marginal zone?
Which rex lamina is the nucleus proprius?
Laminae III and IV
What is another name for the marginal zone/ lamina I?
- Posteromarginal nucleus
What are the 2 functions of the 1st rex lamina?
- Sensory relay for: Pain and Temperature
- Contributes some fibers to LSTT (??? what is this ???)
What are the 3 functions of the 2nd rex lamina?
- Receives afferent information from unmyelinated & thinly myelinated fibers
- Receives information from higher centers (brain stem)
- Modulation of function (especially pain)
What are the 3 functions of the 3rd and 4th rex laminae?
- Sensory processing
- Penetrated by dendrites of large neurons in lamina V
- The same functions as lamina II, but also receives information from touch afferents
What are the 2 functions of 5th rex lamina?
- Receives afferent fibers and interneurons from II, III & IV
- Receives fibers from corticospinal & rubrospinal tracts
What is the function of the 6th rex lamina?
- Receives 1st degree proprioceptive input from muscles and tendons
What is the function of the 9th rex lamina?
- The motor nuclei that innervate skeletal muscles