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Lecture - Human Structure & Function > The Spine > Flashcards

The Spine Flashcards

1
Q

Back pain

A
  • 10% of population get back pain each year
  • Earlier treatment has been shown definitively to produce better outcomes

80% of population will experience backacke in their lifetime

• LBP occurs between 30-70 y/o

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2
Q

Spine – Structure & Function

A
  • Protecs spinal cord
  • Supports BW
  • Axis for body, pivot for head
  • prox. Stability for posture and locomation
  • Axial skelton - as opposed to the appendiculat skeleton
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3
Q

Vertebral column

A

Typically 33 vertebrae • 7 cervical • 13 thoracic • 5 lumbar • 5 fused sacral • 4 fused coccyx

**4 Curves ** • Thoracic kyphosis - primary • Sacral kyphosis - primary • Cervical lordosis - secondary • Lumbar lordosis - secondary

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4
Q

Common Abnormalities

A
  • Scoliosis
  • Hyperlordosis
  • Hypolordosis
  • Hyperkyphosis
  • Hypokyphosis
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5
Q

Facet Joints

A
  • aka zygapophyseal joints
  • Plane synovial joints
  • Between superior and inferior articular process
  • Joint capsule
  • Intra-articular meniscus-joint - Protection and lubrication
  • Guide movement
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6
Q

Facet Jopints – Function

A

It is the primary mechanism by which movement of the spine occurs. The facet joint provides the principle guiding and restraining mechanism of a movement / motion segment.

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7
Q

Intervertebral Discs

A

Function: • Load isbursement • movement

Characteristics: • sustain weight • strong • deformable

Structure: • annulus fibrosis • nucleus pulposis • endplates

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8
Q

IV Discs: Annulus Fibrosis

A
  • 10-20 rings
  • Fibers in rings run at 70 degrees from vertival alternating b/w each
  • Attach to cartilaginous endplates
  • Outer 1/3rd has blood supply and innervations
  • 60-70% water
  • Dry weight 50-60% collagen + proteoglycans
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9
Q

IV Disc: Nucleus Pulposus

A
  • Central location
  • Toothpaste like
  • Transmits forces
  • 70-90% water
  • Dry weight 60% proteoglycans + collagen
  • No blood supply
  • No innervation
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10
Q

Endplates

A
  • Cartilage plates – 0.6-1.0 mm thick
  • Separate discs from vertebral body
  • Bound to the disc – anatomically part of disc
  • Completely covers nucleus and part of annulus
  • Bone marrow – diffusion of nutrients into disc
  • Capillary plexus of endlates also supplies diffused nutrietns to disc
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11
Q

Vertebrae

A
  • Vertebral body
  • Pedicles
  • Lamina
  • Vertebral arch
  • Vertebral foramen
  • Vertebral canal
  • Lateral foramen
  • Spinous process
  • Transverse process
  • Articular process
  • Articular facets
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12
Q

General Characteristics

A
  • Vertebral body
  • Vertebral Arch - Lamina - Pedicle
  • Process - SP - TP (2) - Facets (2)
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13
Q

Movement

A

Controlled by:

  • IV discs
  • Facets
  • Ligaments
  • Back musculature
  • Thoracic most stable due to ribs/sternum
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14
Q

Arthrokinematics

A

Motion Segment • Adjacent halves of 2 vertebrae • Bilateral facet joints • Intervertebral joint with disc • Ligaments • Muscles • Fascia • Spinal Cord

Coupling: Motion around one axis is accompanied by motion around another axis

Example: Right (R) cervical side bending (SB) is coupled with R cervical rotation. The two motions must accompany each other b/c of the orentation of the facet joints

**Flexion: ** Bilateral upglide of superior segment

Extension: Bilateral downglide

Lateral Felxion: Ipsilateral downglide

Rotation: Ipsilateral downglide + contralateral upglide

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15
Q

Cervical Vertebrae

A
  • C1 - C7
  • C1 – Atlas
  • C2 – Axis
  • Typical cervical vertebrae C3 - C6
  • Spinous process of C7 called vertebral prominens
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16
Q

Regional Characteristics:

Typical Cercial Vertebrae

A
  • Body – wider side to side, with uncinate process
  • Verteral foramen
  • Bifid spinous process
  • Transverse foramen C1 - C6
  • Anterior / posterior tubercle of TP
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17
Q

Regional Charasteristics:

Cervical Certebrae

A
  • Unicate processes
  • Guide flexion and extension
  • Limit lateral flexion
  • Site for degenerative changes
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18
Q

C1 – Atlas

A

No body • The atlas has no vertebral body and no SP, just ant / post arches with ant / post tubercles

TP • very wide and long

L and R latral masses

Atlanto-occipital joint • Condyloid/synvial • ROM → Flex 10-15 degrees → Ext 15-25 degrees → Sidebending 5 degrees

Transverse ligament • 7-8 mm attaches to the medial surfaces of each lateral mass and runs posteriorly to the dens

Dens of C2 • Articulates with the posterior surface of the anterior arch, held by transverse ligament

Anterior Tubercle • Attachment for ALL

Posterior tubercle • Ligamentum nuchae

No SP

Groocve for vertebral artery / C1 (nerve)

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19
Q

C2 – Axis

A

• Strongest cervical vertevrae

Dens • blunt projection form superior surface of body of C2

Alar ligament • tip of dens to medial occipital condyles bilaterally

• Forms atlanto-axial joint with Atlas

**3 synovial articulations for atlantoaxial joint ** • Dens / post surface of the anterior arch of C1 • Articular facets of C1 / C2

Odontoid process • Part of C2 “body” • Rotation C1 on C2

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20
Q

Atlanto-Axial Joint

AROM

A
  • Rotates 38-15 degrees
  • Flexion 8 degrees
  • Extension 10 degrees
  • No right and left sidebending
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21
Q

Craniovertebral Joints

optical righting

A

Atlanto-occipital joint • condyloid / synovial • Flex / Ext / SB • Transverse Ligament • act as 1 joint on C2 with rotation. Ex: C1 and the cranium rotate on C2 as a unit

Atlanto-axial joint • 3 articulations - 1 pivot and 2 plane synovial • Rotation • Alar ligaments - connect dens of C2 to margin of foramen magnum

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22
Q

Arthrokinematics of the Cervical Spine

A
  • Facet orientaton 45 degrees to the transverse, 0 degrees to the frontal
  • Superior factes face posteriorly + cranially
  • Inferior facets face anteriorly + caudally
  • Articular Pillars - Formed by the articulations of the superior and inferior articular facets
  • Coupling - Sidebending coupled with rotation to same side except in upper where it is opposite
  • ROM - Flexion 40 degrees - Extension 70-80 degrees - Sidebending 45 degrees - Rotation 80-90 degrees with about 40-45 degrees coming from C1-C2
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23
Q

Thoracic Vertebrae

A
  • Heart shaped body
  • Costal facets on transverse processes and body
  • Transverse process is long, strong and posterolateral
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24
Q

Regional Characteristics:

Thoracic Vertebrae

A
  • Articular facets on: → Vertebral bodies: head of rib → TPs: tubercle of rib
  • Long SP
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25
Q

Arthrokinematics of the Thoracic Spine

A
  • Superior facets face posteriorly + laterally + superiorly
  • Inferior facets face anteriorly + medially + inferiorly
  • Facet oriontation: - 60 degrees to the transverse - 20 degrees to the frontal → Upper thoracic: facets are more in the frontal plane ⇒ Designed for lateral flexion and rotation → Lower thoracic: facet joints are more in sagittal plane ⇒ Designed for flexion and extension
  • Sidebending coupled with rotation to the opposite side
  • ROM is different than that of the cervical spine b/c the facet joints are oriented differently
  • ROM → Flexion 40 → Extension 35 → Sidebending 20 → Rotation 35
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26
Q

Lumbar Vertebrae

A
  • Kidney shpaed body
  • Transverse process → long, slender, directed laterally
  • Accessory proccess → Base of TP = Attachment for intertransversarii
  • Mammillary process → On post surface of superior art. process = Attachment for multifidus
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27
Q

Regional Charasteristics:

Lumbar Vertebrae

A

• Large bodies

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28
Q

Typical Lumbar Vertebrae Lateral

A

• SP project horiyontally (compare to thoracic)

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29
Q

Arthorkinematics of the Lumbar Spine

A
  • Superior facet faces medially and posteriorly
  • Inferior facet faces anteriorly and laterally
  • Desgined for Flex / Ext
  • Coupling: SB w/ contra rotation
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30
Q

Aktive Range of Motion

– Lumbar Spine

A
  • Flexion 60-78 degrees
  • Extension 35-40 degrees
  • Sidebending 20 degrees
  • Rotation 5-10 degrees
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31
Q

Pars Interarticularis

A

The region of the lamina located between the superior and inferior processes

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32
Q

Scotty Dog

– Interpretation

A
  • Ear - Superior articular process
  • Nose - Transverse process
  • Eye - Pedicle
  • Neck - Pars interarticularis (isthmus)
  • Foreleg - Inferior articular process
  • Tail - Superior articular process of opposite side
  • Body - Lamina and Spinous process
  • Hindleg - Inferior articular process of opposite side
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33
Q

Scotty Dog

– labelled

A
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34
Q

“Scotty Dog Fracture”

A
  • Fracture of Pars Interarticularis
  • Appears black on the oblique L-Spine x-ray
  • Giving “Scotty Dog” a black collar
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35
Q

“Scotty Dog Fracture”

– x-ray

A
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36
Q

“Scotty Dog Fracture”

– picture

A
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37
Q

Sacrum

A
  • 5 fused vertebrae
  • Strength and stability → Support the vertebral column → Load Transver to pelvic girdle → Functions in load transfer and stress relief
  • Sacral canal → Nerve root for cauda equina
  • Lumbosacral angle 130-160 degrees
  • Sacral hiatus
  • Auricular surface
  • Cauda equina → all spinal nerve roots caudal to L1
  • Movement → Rotation < 2 degrees → Translation < 7 mm
  • Nutation vs. Counternutation → now: Sacral Felxion vs. Sacral Extension
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38
Q

Coccyx

A
  • Tailbone
  • 4 rudimentary vertebral bones
  • Provides attachment for pubococcygeus and Gluteus Maximus
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39
Q

Ligaments

A

• Vertebral bodies → ALL (Anterior Longitudinal Ligament → PLL (Posterior Longitudinal Ligament)

⇒ PLL injury: swells against Spinal Cord

• Vertebral Arches → Ligamentm flavum (underneath arch) → Supraspinosous → Interspinosous → Intertransversous → Ligamentum nuchae (only on cervical spine - Base-C7; prevents hyperflexion)

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40
Q

Ligaments

– ALL & PLL

A

ALL
• connect vertebral bodies with discs
• prevent hyperextension

PLL • weaker / thinner • inside canal • prevent hyperflexion and disc protrusion

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41
Q

Ligaments

– Lig. flafum

– Lig. Interspinous

– Lig. supraspinous

– Lig. nuchae

A

Ligamenta flava • Join laminae of vertebral arches • Elastic • Prevent Flexion

Interspinous ligament • between Spinous Processes

Supraspinous Ligament • C7 to sacrum • Merges with nuchal ligament

Nuchal Ligament • External occipital protuberance and posterior border of foramen magnum to spinous process of C3 - C5 (C3 - C7) • Becoming increasingly recogniyed for its role in prorioception

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42
Q

Common Pathologies

– Stenosis

p. 460

A

Central Stenosis • Narrowing of vertebral canal • usually caused by disc or bone spur

**Lareal stenosis ** • Narrowing of lateral foramen • Caused by disc or bone spur

Lumbar Spinal Stenosis:

  • one ore more vertebrae
  • hereditary anomaly, making a person more vulnerable to age-related degnerative changes such as IV disc bulging
  • Lumbar spinal nerves increase in size as the vertebral collumn decends, but the IV foramina decrease in size
  • Narrowing is usually maximal at the level of IC discs
  • Stenosis of a lumbar vertebral foramen alone may cause compression of 1+ spinal nerve roots
  • Surgica treatment: decopressive laminectomy

Possible causes: • IV disc protrusion • Spinal stenosis possible • Arthritic proliferation • Ligamentous degeneration

43
Q

Spondylolisthesis

A
  • Fracture of laminae with anterior migration
  • Verteral body moves anterior in relation to vertebral below
  • Can also fracture articular facets and rupture interspinous ligament resulting in psinal cord injury
  • Extension in head butting, weight lifting
  • Flexion in diving injury, head on collision
  • Seat belt across low abdomen in MVA

Inferior articular processes of L5 normally interlock with the articular processes of the sacru. When the defect is bilateral, the body of the L5 vertebrae may slide anteriorly on the sacrum so that it overlaps the sacral promontory. The intrusion of the L5 body into the pelvic inlet reduces the AP diameter of the pelvic inlet. This may compress spinal nerves → low back or lower limb pain

44
Q

Spina Bifida

p. 463

A

⇒ Laminae fail to develop normally → Don’t fuse together to form covering over SC

  • Spina Bifida Occulta → one level without lamina formation, usually at L5 and/or S1 → Location is concealed by skin, often indicated by tuft of hair → most have no back problems
  • Spina Bifida Cystica → multiple levels (more severe) → Meningocele: Meninges herniate thorugh opening → Meningomyelocele: Menginges + neural tissue herniate through opening → usually neurological symptons → e.g.: paralysis of the limbs and disturbance in bladder and bowel control
  • Severe forms result from neural tube defects (devective closure of the neural tube during the 4th week of embryonic development)
  • Congeital
45
Q

Compression Fracture

p. 477

A
  • Usually seen in thoracic spine
  • Usually anterior aspect of body
  • R/O burst fracture (CT scan)

**Causes: ** • Exessive or sudden violent movement • Movement of a type not permitted in a specific region • Sudden forceful flexion (car accidents) • Violent blow to the back of the head

46
Q

Herniated Nucleus Pulposes

p. 474

A
  • Nucleus distends past annular ring → Protrusion of the gelatinous nucleus pulposus into or through the anulus fibrosus
  • Symptons differ depending on severity of distension and location of bulge
  • Caused by loss of lumbar extension, lumbar flexion with sitting posture and frequency of flexion in older population
  • Can also occur traumatically by forceful load esp. in flexion in adolescents

**Causes: ** → Violent hyperflexion my rupture and IV disc → Flexion of the vertebral column produces compression anteriorly and stretching/tension posteriorly, squeezing the nucleus pulposus further post. toward the thinnest part of the anulus fibrosus → n.p. may herniate into the vertebral canal and compress the SC / nerve roots of cauda equina

• Usually extends posterolaterally, where a.f. is relatively thin and does not receive support form post. / ant. longitudinal ligs.

47
Q

Spine Musculature

A

Extrinsic: • Superficial • Produce / control movement • Connect UE to trunk • Respiratory movements

Intrinsic: • True back muscles • Superficial and deep layer • Maintain posture + control movements of vertebral column • Innercated by dorsal rami

48
Q

Extrinsic Musculature

Superficial / Intermediate

A
  • Connect the vertebral column witht he pectoral girdle
  • Trapezius (upper, middle, lower)
  • Latissimus dorsi
  • Rhomboids
  • Levator scapulae
  • Serratus posterior sup / inf are intermediate
49
Q

Upper Trapezius

Middle Trapezius

Lower Trapezius

A

Upper: • Elevate • Adduct • Upward rotation • Point of reference of scapula: Glenohumeral joint

Middle: • Adduct

Lower: • Depress • Adduct • Upward Rotation

50
Q

Latissimus dorsi

A
  • Thoracodorsal nerver
  • What other muscle has the exact same actions? → Lower Trap?
51
Q

Rhomboids

A
  • Adduct
  • Donward Rotation
  • Elevate
  • Dorsal scapula nerve (C5)(disc C5 would be pushing on it)
52
Q

Levator scapulae

A
  • Adduct
  • Downward Rotation
  • Elevate
  • Dorsal scapula nerve (C5)
53
Q

Dorsal Scapula

A
54
Q

Serratus Anterior

A
  • Abduct
  • UR
  • Stailize medial border against thoracic wall
  • Long thoracic nerve palsy
55
Q

Intrinsic Musculature

– Superficial

A
  • Splenius - cervicis - capitus
  • Erector spinae - Illiocostalis thoracis, cervicis - Longissimus thoracis, cervicis, capitus - Spinalis thoracis, cervicis, capitus
56
Q

Splenius Capitis

A
  • Origin: SP C7 - T4
  • Insertion: Mastoid process + lateral 3rd of superior nuchal line
  • Nerve: Dorsal Rami
  • Action: - Bilaterally: Extend head - Unilaterally: Ipsilateral lateral flexion + ipsilateral rotation
57
Q

Splenius Cervicis

A
  • Origin: SP T3 - T6
  • Insertion: TP C1 - C3
  • Nerve: Dorsal Rami
  • Action: - Bilaterally: Extend cervical spine - Unilaterally: Ipsilateral lateral flexion + ipsilateral rotation
58
Q

SLI

A
  • Spinalis
  • Longissimus
  • Iliocostalis
59
Q

Intrinsic Musculature

– Deep

A
  • Semispinalis - thoracis, cervicis, capitus
  • Multifidus
  • Rotatores
60
Q

Semispinalis Cervicis & Thoracis

A
  • Origin: TP T1-T12
  • Insertion: SP C2-T4
  • Nerve: Dorsal Rami
  • Action: Extends cervical spine
61
Q

Semispinalis Capitus

A
  • Origin: TP C7 - T7
  • Insertion: Occipital bone
  • Nerve: Dorsal Rami
  • Action: Extend head
62
Q

Multifidi

A
  • Origin: Sacrum + TP C4 - L5
  • Insertion: SP C, T, L vertebrae (spanning 2-4 segments) + meniscus
  • Nerve: Dorsal Rami
  • Action: - Bilaterally: Extension of vertebrae - Unilaterally: Contralateral rotation

⇒ May play a role in proprioception of the lumbar spine

63
Q

Suboccipital Musculature

A
  • Rectus capitus posterior - major - minor
  • Obliquus capitus - inferior - superior
64
Q

Suboccipital Triangle

A
  • Vertebral artery
  • Suboccipital nerve (dorsal rami of Cervical nerve 1)
  • Vertigo
  • Headaches
65
Q

Rectus Capitus Posterior Major

A
  • Origin: SP C2
  • Insertion: Lateral aspect of the inferior nuchal line
  • Nerve: Dorsal Rami C1 (Suboccipital nerve)
  • Action: Extends head + ipsilateral rotation
66
Q

Rectus Capitus Posterior Minor

A
  • Origin: C1
  • Insertion: Medial aspect of inferior nucha line
  • Nerve: Dorsal Rami C1 (Suboccipital nerve)
  • Action: Extends head
67
Q

Inferior Oblique

A
  • Origin: SP C2
  • Insertion: TP C1
  • Nerve: Dorsal Rami C1 (Suboccipital nerve)
  • Action: Rotates atlas + turning head ipsilaterally
68
Q

Superiror Oblique

A
  • Origin: TP C1
  • Insertion: Between superior and inferior nucha lines
  • Nerve: Dorsal Rami C1 (Suboccipital nerve)
  • Action: Extension + lateral flexion of head
69
Q

Vertebral Artery Course

A

• Suboccipital Triangle

70
Q

Suboccipital Triangle

A
  • RCP Major
  • Superior Oblique
  • Inferior Oblique
  • Contents: - Dorsal Rami C1 (Suboccipital nerve) - Vertebral artery
71
Q

Other muscles which affect the spine

A
  • Iliopsoas
  • Ext. / Int. Obliques
  • Transverse Abdominus
  • Rectus Abdominus
72
Q

Spinal Cord

A
  • Foramen magnum to L2
  • Cervical enalrgement (C4 - T1) - brachial plexus
  • Lumbosacral enlargement (T11 - L1) - cauda equina (collection of the dorsal and ventral roots which make up the lower lumbar and sacral spinal nerves)
73
Q

Branches off the Spinal Cord

A
  • Ventral / dorsal roots
  • Spinal nerve
  • Ventral / dorsal rami
74
Q

Roots

A

Dorsal root • Afferent sensory • Cell bodies outside of spinal cord • Dorsal root ganglia - found at the dorsal root and contains the cell odies of the neurons which make up the sensory components of the spinal nerves.

Ventral root • Effernet motor • Cell bodies in anterior horn gray matter

⇒ Unit to form Spinal Nerve

75
Q

Nerves

A

Horns • found within the SC • Dorsal + ventral

Roots • Dorsal + ventral

Rami • Dorsal + ventral

76
Q

Spinal Neves

A

31 pairs

8 Cervical (but only 7 vervical bodies) • First 7 exit above the vertebral level • C8 exits below C7 body

12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal • exit below level • longer in length at lower level • cauda equina with filum terminale

77
Q

Rami

A

Ventral • Innervate limbs + trunk • Divide into medial + lateral branches

Dorsal • Innervate skin over back + true intrinsic back muscles • Sensory + proprioceptive to facet joints • Divide into medial + lateral branches

78
Q

Innervation

A

Dermatomes = Sensory area that a particular spinal nerve supplies

Myotomes = all muscles receiving innervation from one spinal nerve

79
Q

Spinal Meninges

A

Protect and support spinal cord + spinal nerve roots

  • Dura mater
  • Arachnoid mater
  • Pia mater
80
Q

Dura Mater

A
  • Tough
  • Separated from vertebrae by epidural space
  • Contious with cranial dura
  • Terminal filum → anchors dura to coccyx
  • Dural root sleeves → Extend distal to the dorsal root ganglia
81
Q

Arachnoid mater

A
  • Fibrous / elastic
  • Subarachnoid space
  • Supported by pressure of CSF
82
Q

Pia Mater

A
  • Innermost covering
  • Covers blood vessels
  • Denticulate ligaments - 2 pair - Attach pia to arachnoid and dura
83
Q

Lumbar Cistern

A
  • Subarachnoid space from L2 to second segment of sacrum
  • Area around cauda equina
  • Spinal tap / sponal block / nerve block - Meningitis - Electrolyte balance - Pressure
84
Q

Vasculature of Proximal Spinal Cord

A

By themselves the ASA and the PSAs can supply the short superior portion of SC entirely

Anterior Spinal Artery (medulla to medullary cone) • Derived from multiple branche dunions form vertebral arteries • Located in anteromedian fissure • Gives rise to sulcal arteries - supply 2/3rd of x-section cord

Posterior Spinal Artery (paired as 2) • Vertebral artery or posteroinferior cerebellar artery • Anastomosing channels with ASA in pia mater

85
Q

Vasculature of Descending Spinal Cord

A

Anterior / posterior segmental medullary + dorsal / ventral radicular arteries

Originate from: • Ascending cervical • Deep cervical • Vertebral • Posterior intercostal • Lumbar arteries

Enters vertebral canal via lateral foramen

86
Q

Spinal Arteries

A
  • Anterior Spinal Artery
  • Posterior Spinal Arteries
87
Q

Ischemia of the Spinal Cord

A

Ischemia = deficient blood supply

  • Fractures, dislocations may intefere with the blood supply to the spinal cord from the spinal arteries + medullary arteries
  • Affects function - Muscle weakness - Paralysis
  • Circulatory impairment if segmental medullary arteries are narrowed by Obsturctive Arterial Disease
  • Arterial disease - Death of Neuron
  • Secondary to death ot neurons: Paraplegia (loss of voluntary movement inferior to the the level of impaired blood supply to the spinal cord)
  • Surgery w/ Aorta cross clamped
88
Q

Reflexes

A

Involuntary response to a sensory input

Requirements:

  • Receptor structure
  • Afferent neuron with cell body in ganglion
  • Efferent neuron with cell body in CNS
  • Interneuron (except stretch reflex)
  • Effector organ
89
Q

Stretch Reflex

A

Knee jerk:

  • Stimulus = tap on tendon
  • Tests for patency of LMN and its sensory input
  • Muscle Spindle (MS) is stetched + it sends and afferent signal to spinal cord
  • in SC the axons form the MS synapse onto the efferent motor neurons in the ventral horn (VH)
  • the axons from the VH exit as te ventral root and synapse onto the skeletal muscle of the quadriceps to initiate contraction
  • This reflex helps to keep our postural nad limb musculature at the correct tension in upright positions
  • It is unconscious and occurs at the SC level
90
Q

Withdrawal Reflex

A
  • Stimulus: hean on finger, noxious stimuli
  • Afferent pathway to internuerons - Reciprocal innervation - Efferent motor to stimulate biceps - Efferent motor to inhibit tricepts (antagonist)
  • Brain can override reflex
91
Q

Tract Function

A

Sensory processing • Synapse on neurons in gray matter on same side of spinal cord or medulla

**Motor outflow ** • Cell bodies in anterior horn of SC • Innervate skeletal muscles • Reflex circuit and pathways that descend in white matter

**Reflexes ** • All control in spinal cord, but can be moderated by high brain centers

92
Q

Spinal Gray Matter

A

Posterior Horn • Cell bodies for the sensory information of the spinothalamic tract reside • Also many cell bodie of interneurons

Ventral / Anterior Horn • Cell bodies of large motor neurons • Lower motor neurons • If damaged by themselves patient will have flaccid pralysis, no reflexes (a reflexive) • Lateral enlargement in Cervical + Lumbar

93
Q

Spinal Cord Tracts

A
  • Dorsal Column (medial lemniscus)
  • Spinthalamic (Anterolateral)
  • Lateral Corticospinal
94
Q

Spinal Cord Tracts

– Picture

A
95
Q

Voluntary Motor Pathway

A
  • Corticospinal tract
  • Descending pathway
  • Starts at motor cortex (pre-central gyrus)
  • Upper motor neurons carry information thorugh spinal cord in tracts
  • White matter
96
Q

Corticospinal Tract

A
  • Start at motor Cortex
  • Cell bodies located in the pre-central gyrus
  • Axons from these cells decend - thorugh cerebal hemispheres - thorugh mid brain - through pons - into the medulla
  • In medulla they are know as the pyramids - ca. 85% of these fibers cross over - decussate - in the ducusssation of the pyramids
  • The lateral corticospinal tracts are now on the contralateral side of the SC - end by synapsing with the motor cells of anterior horn
  • Lateral and anterior tracts
97
Q

Spinothalamic Tract

A
  • Ascending
  • Pain / temperature + light touch
  • Originate from neuro receptors in the skin + sub Q. tissue - sensitive to pain, temp + light touch
  • The information travels to the Dorsal Root Ganglion - from there to the SCs posterior horn
  • They synapse in the posterior horn - then immediatley cross the midline - form the contralateral spinothalamic tract (STT)
  • The STT terminates int he thalamus
  • Thalamic cells project to somatosensory cortex in the post-central gyrus
98
Q

Dorsal Colums

A
  • Carry information from receptors - on cutaneous proprioception - descriminative touch - two-point discrimination
  • Information travels on the axons of the cell bodies within the DRG + from there ot the DCs
  • Information acends within the DCs - synapses int he caudal Medulla - then corsses within the SENSORY decussation
  • Information ascends ot the contralateral thalamus - then synapses and travels formt he thalamus ot the primary somatosensory cortex within the post-central gyrus
99
Q

Motor Neuron Lesions

A

**Upper Motor Neuron ** • Spastic paralysis • Hyper reflexia • No sig atrophy • No fasiculations / fibrillations

Lower Motor Neuron • Flaccid paralysis • Hypo reflexia • Atrophy • Fasiculations / fibrillations

100
Q

Autonomic portion of PNS

A

► Involuntary branch of effernet nervous system (vs. voluntary / somatic division)

► CNS to innervated organ

► 2 neuron chain - synapse in ganglion outside CNS

• Preganglionic fiber - Cell bodies in CNS

• Postganglionic fiber - Innervates effector organ - These cell bodies are located in the autonomic ganglia

► Has 2 division

► Sympathetic

► Parasympathetic

► Effect same organ and usually botha re active

► Control visceral activities normally outside conscious control ie. circulation + digestion

101
Q

Autonomic Systems:

2 divisions

A

**Sympathetic ** • Originate in Tx/Lx • Short preganglionic fibers • Long posterior fibers • Synapse in sympathetic chaing (= sympathetic trunk = paravertebral ganglia) • Or synapse in the prevertebral ganglia • FIGHT or FLIGHT

**Parasympathetic ** • Originate in cranial / sacral • Long preganglionic fibers • Short posterior fibers • Synapse in terminal ganglia that lie near effector organ • HOMEOSTASIS

102
Q

Nerve Blocks

A

Spinal Block • Anesthetic into CSF thorug ligamentum flavum into subarachnoid space

Epidural Block • Soinal nerve after exit dural sac itno extradural space

103
Q

Blue Boxes

p 460 - 461

Lumbar Spinal Stenosis, Epidural Anesthesia

A

Lecture - Human Structure & Function (4 decks)

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