Spinal Cord Flashcards
anterior and caudal extent of spinal cord
foramen magnum
level of the L1-L2 vertebra
Approximate length of SC
Males 45 cm
Females 42 cm
denticulate ligaments
pial folds that stretch from the surface of the cord to the dural sheath midway between the dorsal and ventral roots
serve as landmarks in identifying the anterolateral segments of the cord for cordotomies for relief of intractable pain
31 segments of spinal cord
8 cervical 12 thoracic 5 lumbar 5 sacral 1 coccygeal
position of spinal nerves in relation to the vertebrae
C1 above the atlas
C8 below the C7 vertebrae and above T1
all other spinal nerves exit beneath corresponding vertebrae
Relationship of Spinal Cord Segments and vertebral spines
C1 SC - C1 spine C7 SC - C6 spine T6 SC - T4 spine L1 SC - T10 spine S1 SC - T12 to L1 spine
Cellular Organization of the spinal cord Lamina I Lamina II III, IV V VI VII VIII IX X
Lamina I - posteromarginal nucleus Lamina II - substantia gelatinosa III, IV - nucleus proprius V - neck of posterior horn VI - base of posterior horn VII - intermediate zone, intermediolateral horn VIII - commissural nucleus IX - ventral horn X - grisea centralis
extends from the tip of the conus and attaches to coccygeal ligament made of pia
Filum terminale
cervical enlargment
C5-T1
lumbar enlargement
L2-S3
True or False
Dorsal medial fissure: shallow
Ventral Medial Fissure: deep
True
from PICA, supplies posetrior one-third of spinal cord
Posterior Spinal Arteries
Largest radicular artery
arises from Left side at T10 in approximately 80% of people
Artery of Admakiewicz
Primary watershed areas
Midthoracic region of the SPinal Cord, Levels T1-T4 and T8-T9 prone to ischemic change during thoracic surgery or hypotension
Venous drainage
diffuse -> epidural -> empty into vena cava
ependymomal tumor that presents at the lumbar cistern
Arises from a remnant of ependymal cells from the central canal
Myxopapillary ependymoma
areas of SC where proportion of gray to white is greates
lumbar and cervical
Gray Matter Lamina with
interneurons, respond to noxious stimuli, sensibility to pain, release naturally occurring opiates, thereby limiting release of substance P from pain sensitive dorsal root fiber
Lamina II
Substantia Gelatinosa
Gray Matter Lamina
Neurons that receive inputs from large fiber , which mediate finely locali ed touch,
stereognosis, proprioception, vibration sense.
Secrete γ-aminobutyric acid (GABA).
Laminae III, IV, V, VI
Nucleus Proprius
Gray Matter Lamina
From T1–L2, receives inputs on joint position and sends info to the cerebellum via the
dorsal spinocerebellar tract.
Lamina VII
Clarke’s Column
Gray Matter Lamina
From T1–L2, preganglionic neurons project to sympathetic ganglia.
Lamina VII
Intermediolateral cell column
Gray matter lamina
Involved in reflxes, main target of descending motor commands from motor/
premotor cortex and brain stem.
■ All inhibitory, use glycine > GABA.
■ 1a interneurons: Inhibit motor neurons of antagonist muscle; receive sensory input
from agonist muscle’s spindle afferents.
■ 1b interneurons: Inhibit motor neurons of agonist muscle; receive sensory input
from agonist muscle’s Golgi tendon organs.
■ Renshaw cells: Have direct input agonist muscle, inhibits agonist motor neuron and
the interneurons of antagonist muscles → increases antagonist muscle tone.
Lamina VIII
Ventral horn interneurons
Gray Matter Lamina
Pools of motor neurons that innervate skeletal musculature.
■ α1: Innervate fatigable and fatigue-resistant fast-twitch muscles.
■ α-II: Innervate fatigue-resistant slow-twitch muscles.
■ γ: Innervate intrafusal muscle fibers of muscle spindle .
Lamina IX
Ventral horn motor neurons
