spinal anatomy Flashcards
how many vertebra are in the spine
33
portion of the spinal cord that allows for passage of the spinal cord
- vertebral foramen
what are lateral notches
- know as intervertebral foramina
- allows for passage of the nerves
- if discs become damaged pressure is exerted on them
what is the sacral cornu
- the bony process used to identify the sacral hiatus
- good for caudal block
scoliosis
- lateral curvature
kyphosis
- posterior curvature
lordosis
- anterior curvature
what are the 3 ligaments of the spine
- supraspinous
- intraspinous
- ligamentum flavum
where is the epidural space
- between the ligamentum flavum and dura mater
- runs from base of cranium to sacral sulcus
- average depth is 5 cm (2.5 - 8cm)
where does the spinal cord stop in adults and peds
- starts at medulla oblongata
- L2 in adults
- L3 in peds
what are the 3 layers of the meninges
- dura mater
- arachnoid mater
- pia mater
which meninge layer holds CSF
- arachnoid mater
how many spinal nerves are there
- 31 pairs
- 8 cervical
- 12 thoracic
- 5 lumbar
- 5 sacral
- 1 coccygeal
where in the spine are the nerves located
- 1st is between base of skull and atlas
- cervical correlate with vertebra below
- after T1 they correlate with vertebra above
where is the cord enlarged
C5 - C7 and L2 - S3
where is the brachial plexus located
C4 - T1
where is the lumbar and sacral plexus
L2 - S3
where is the cauda equina
L1 - S5
what is the dorsal root
- sensory neurons, incoming
- laminae 1-6
what is the ventral root
- motor neurons, outgoing
- laminae 7-9
what regions make up the spinal cord
- dorsal
- lateral
- ventral
what is the grey matter subdivided into
10 laminae of Rexed
what is laminae 2 called
- substancia gelatinosa
what is the substancia gelatinosa
- is where first order neurons of the spinothalamic tract synapse
- mu and k opioid receptors, presynaptic and post synaptic are found of these nerve cells
- are targets to manage pain
what does the dorsal white matter consist of
- ascending sensory fibers tracts
what do the lateral and ventral white matter consist of
- descending motor tracts
- can ascend to the brain or
- association tracts originate and terminate entirely within the spinal cord (reflexes)
what do sensory/ afferent fibers do
- ascend
- transmit pain, temp, pressure, touch, vibration, and proprioception
where are sensory/ afferent fibers located
- in the epidermis and dermis
what are the 2 classifications of sensory fibers and where are they
- exteroceptors (near surface of skin and oral mucosa)
- proprioceptors (deep in skin, joints, ligaments, tendons, muscles, periostium)
what are the two main sensory tracts
- dorsal column - medial lemniscus
- anterolateral pathway
dorsal column - medial lemniscus pathway
- sensory signal enters dorsal root
- ascends through dorsal column on same side
- arrives at medulla and crosses over (1st order to 2nd order synapse)
- ascends via medial lemniscus tract through brainstem (2nd order neuron)
- arrives at thalamus (2nd to 3rd order neuron)
anterolateral pathway
- sensory enters through dorsal horn (1st order)
- immediately crosses, synapses in the dorsal horn of grey matter (rexed laminae)(1st to 2nd order)
- ascends to thalamus (2nd order)
- synapses in brainstem or thalamus (2nd to 3rd)
- interpreted in brain (3rd order)
fiber and details of dorsal column medial lemniscus
- large myelinated fibers
- discrete types of mechanoreceptive sensations
- very specific
- vibration, movement against skin, position of joints, fine touch
fibers, sensations and details of anterolateral system
- small myelinated
- slower speeds
- broad spectrum of sensory modalities (pain, touch, warm, cold)
- non-specific
- sexual sensations
SNS preganglionic fibers
- b fibers
- originate in the intermediolateral gray horn between T1-L2
- exit the spinal cord via ventral nerve root (white rami)
- paired segmental paravertebral ganglia form sympathetic trunk
what are the cervical ganglia divided into
- superior ganglia
- medial ganglia
- inferior ganglia
stimulation of the SNS superior ganglia causes
- mydriasis (dilation, contraction of radial muscle)
- constriction of ciliary muscles of the head
damage to the cervical paravertebral ganglia causes what
- horner syndrome
what are the signs of horner syndrome
- miosis (pupil constriction)
- ptosis (drooping eyelid)
- anhydrosis (lack of sweating)
inferior ganglia forms what
- fuses with first thoracic to form the stellate ganglia
- located C5-C6
what are the 4 stages of pain
- transduction
- transmission
- modulation
- perception
T-4 correlates with what
- nipple line
T6/7 correlates with what
- xiphoid process
T- 10 correlates with what
- umbilicus
corticospinal tract
- supplies voluntary muscles of the trunk and extremities
- originates in the large, upper motor neurons in the precentral gyrus
- most neuromuscular disorders originate here (cerebral palsy and ALS)
