Spine Anatomy/Physiology Flashcards

1
Q

Vertebral Column

A

33 total vertebrae

  • 7 cervical
  • 12 thoracic
  • 5 lumbar
  • 5 sacral
  • 3-4 coccyx

Function: support trunk & protect spinal cord

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2
Q

Spinal Nerves

A
  • C1 above C1 vertebra
  • C8 between C7/T1
  • Thoracic & lumbar nerves below their respective vertebra (L5 nerve exits at L5/S1 interface)
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3
Q

Spinal Curves

A

Function: Allow greater load bearing
4 Curves:
- Cervical Lordosis: convex anteriorly b/t C1 & T2
- Thoracic Kyphosis: concave anteriorly b/t T2 & T12
- Lumbar Lordosis: convex anteriorly b/t T12 & sacral joints
- Sacral Kyphosis: concave anteriorly b/t lumbosacral joint & tip of the coccyx

  • Kyphoses = primary curves; present at birth
  • Lordosis = secondary curves; develop w/ development of erect posture
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4
Q

Vertebral Columns

A

Anterior: Vertebral body

  • Sustains compressive loads
  • Increases in mass & area from cervical to lumbar regions

Middle: Pedicles
- Transfers forces b/t anterior & posterior columns

Posterior:

  • Laminae, articular processes, & spinous/transverse processes
  • Provide area for muscle attachment & help regulate movement
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5
Q

Articular Processes of Vertebrae

A

Cervical: point inferiorly & anteriorly (up & down) – flexion & extension

Thoracic: point posteriorly & superiorly (front & back) – rotation

Lumbar: point laterally (side to side) – flexion & extension

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6
Q

Vertebral Components

A
  1. Vertebral body–anterior; supports body weight
  2. Vertebral arch–posterior; encloses the vertebral foramen to protect the spinal cord; consists of 2 rounded pedicles & 2 flat laminae that unite posteriorly in midline
  3. 3 processes (2 transverse, 1 spinous); provide muscle attachments
  4. 4 articular processes (2 superior, 2 inferior); junction = articular facet (zygapophyseal joint) w/ a capsule & articular cartilage
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7
Q

Cervical Vertebrae

A
  • Transverse processes contain a foramen transversarium (except C7), which vertebral arteries pass through*
  • Small & wide vertebral body
  • Large & triangular vertebral foramen
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8
Q

Atlas

A

C1 vertebra:

  • body replaced by an anterior arch
  • function: support head w/ 2 prominent articular facets to balance occipital condyles (allows for free flexion)
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9
Q

Axis

A

C2 vertebra: dens, odontoid process

  • articulates w/ anterior arch of C1
  • held in place by ligaments, allowing it to be a pivot that the atlas rotates around
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10
Q

Odontoid Fractures

A

-Type 1 (left)–mechanically stable; avulsion fracture of the alar ligaments

Type 2 (center)–MC & worst prognosis; instability & non-union are possible; located at base of odontoid

Type 3 (right)–favorable prognosis if reduced; fracture through the cancellous bone of the vertebral body

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11
Q

Thoracic Vertebrae

A
  • 2 hemifacets (superior & inferior costal facets) on each body, which attach to rib heads
  • 1 facet (transverse costal facet) on each transverse process for attachment of rib tubercle
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12
Q

Thoracic Vertebrae: “Rule of 3’s”

A

Describes the relationship b/t the spinous processes & thoracic vertebral bodies

  • T1-3: spinous processes project at the same level as the attached vertebral body
  • T4-6: spinous process project 1/2 vertebra below the attached vertebra
  • T7-9: spinous process located 1 full vertebra below the attached vertebra
  • T10-12: spinous processes return to the same level as the attached vertebral body
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13
Q

Sacrum

A

5 fused sacral vertebrae –> single bone

Sacral Hiatus:

  • caudal end of the sacrum
  • laminae of 5th sacral vertebrae are not fused, leaving an inferior opening (epidural space NOT near the dura mater)
  • used in anesthesia & analgesia
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14
Q

Spinal Surface Anatomy

A
C0 = external occipital protuberance
C1 = atlas transverse process below mastoid process
C2 = 1st bony prominence below occiput
C3 = level of the hyoid bone
C4-5 = level of the thyroid cartilage
C6 = level of cricoid ring
C7 = spinous process does not move w/ extension
T2 = superior angle of the scapula
T3 = scapular spine
T7 = inferior angle of the scapula
T12 = inferior rib margin
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15
Q

Superficial Back Muscles

A
Trapezius
Latissimus dorsi
Levator scapulae
Rhomboid major
Rhomboid minor
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16
Q

Trapezius

A

Origin: (1) external occipital protuberance (2) ligament nuchae (3) spinous process of C7-T12

Insertion: (1) lateral 1/3 of clavicle (2) acromion (3) spine of scapula

Innervation: spinal accessory nerve (CN 11)

Action: scapular movement

  • Superior fibers–elevation & upward rotation
  • Middle fibers–retraction
  • Inferior fibers–depression & upward rotation
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17
Q

Latissimus Dorsi

A

Origin: (1) spinous processes of T7-T12 (2) thoracolumbar fascia (3) iliac crest

Insertion: bicipital groove of humerus

Innervation: thoracodorsal nerve

Action:

  1. adduct, extend, & internally rotate the humerus
  2. scapular depression & protraction
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18
Q

Levator Scapulae

A

Origin: transverse processes of C1-C4

Insertion: superior part of the medial border of the scapula

Innervation: dorsal scapular nerve

Action: elevation & downward rotation of the scapula

19
Q

Rhomboid Major/Minor

A

Origin:

  • Major: spinous process of T2-T5
  • Minor: (1) ligamentum nuchae (2) spinous processes of C7-T11

Insertion: vertebral border of the scapula

Innervation: dorsal scapular nerve

Action: retraction & downward rotation of the scapula

20
Q

Suboccipital Muscles

A

Rectus capitus posterior major
Rectus capitus posterior minor
Obliquus capitus inferior
Obliquus capitus superior

21
Q

Rectus Capitus Posterior Major Muscle

A

Attach:
- spinous process of C2 –> occipital bone

Action:
- extension of the head and neck

Innervation:
- C1 dorsal rami (suboccipital nerve)

22
Q

Rectus Capitus Posterior Minor Muscle

A

Attach:
- posterior tubercle of C1 –> occipital bone

Action:
- extension of the head & neck

Innervation:
- C1 dorsal rami (suboccipital nerve)

23
Q

Obliquus Capitus Inferior Muscle

A

Attach:
- spinous process of C2 –> transverse process of C1

Action:
- ipsilateral extension & rotation of the head

Innervation:
- C1 dorsal rami (suboccipital nerve)

24
Q

Obliquus Capitus Superior Muscle

A

Attach:
- transverse process of C1 –> occipital bone

Action:
- ipsilateral extension & lateral flexion of the head

Innervation:
- C1 dorsal rami (suboccipital nerve)

25
Q

Intermediate Back Muscles

A

Serratus posterior superior

Serratus posterior inferior

26
Q

Serratus Posterior Superior

A

Origin: (1) ligament nuchae (2) spinous process of C7-T2/3

Insertion: superior border of ribs 2-5

Innervation: ventral rami (T1-5)

Action: forced inspiration (by elevation of the ribs)

27
Q

Serratus Posterior Inferior

A

Origin: (1) spinous process of T11-L2/3 (2) thoracolumbar fascia

Insertion: inferior borders of ribs T9-T12

Innervation: ventral rami (T9-T12)

Action: forced expiration (by depression of the ribs)

28
Q

Deep Lateral Back Muscles

A

Splenius capitus
Splenius Cervicis

Action:

  1. Extension of the head & cervical spine w/ bilateral contraction
  2. Ipsilateral flexion of the head & cervical spine w/ unilateral contraction
29
Q

Splenius Capitis Muscle

A

Origin:

  1. Ligamen nuchae
  2. Spinous processes of C7-T3

Insertion: Lateral occipital bone

Innervation: Dorsal primary rami (C3-C5)

30
Q

Splenius Cervicis

A

Origin: Spinous processes of T3-T6

Insertion: Transverse processes of C1-C3

Innervation: Dorsal primary rami (C5-C7)

31
Q

Erector Spinae Muscle

Deep Parallel Group

A
  1. Spinalis (thoracis, cervicis, capitus)
    - -attaches spinous processes from the semispinalis capitis superiorly to L1-2
  2. Longissimus (thoracis, cervicis, capitus)
    - -attaches transverse processes from the mastoid process superiorly to the thoracolumbar fascia inferiorly
  3. Illiocostalis (lumborum, thoracis, cervicis)
    - -attaches ribs from the transverse processes of C4-C6 superiorly to the iliac crest inferiorly

Action: Extension of the spine
Innervation: Dorsal rami

32
Q

Transversospinalis Muslce

Deep Medial Group

A
  1. Semispinalis (thoracis, cervicis, capitus)
    - Attach: posterior occiput/cervical spinous process to distal transverse processes
    - Action: extend & rotate spine to opposite side
  2. Multifidi (lumborum, thoracis, cervicis)
    - Attach: runs in groove b/t transverse & spinous processes from C2 to the sacrum
    - Action: extend, laterally flex, & rotate spine
  3. Rotatores (lumborum, thoracis, cervicis)
    - Attach: laminae superiorly to the transverse process of the inferior vertebra
    - Action: rotation b/t adjacent vertebrae

Innervation: Dorsal rami

33
Q

Deep Intersegmental Muscle Group

A
  1. Interspinalis
    - Attach: spinous processes
    - Action: extension of spine
  2. Intertransversarii
    - Attach: transverse processes
    - Action: lateral bending of spine
  3. Levatores Costarum
    - Attach: ribs to transverse process of C7-C11
    - Action: elevation of ribcage

Innervation: Dorsal Rami

34
Q

Spine Ligaments

A
  • Composed primarily of collagen–allow minimal elongation
  • Highly innervated & pain sensitive

Function:

  • Provide intrinsic stability
  • Transfer tensile loads from one vertebrae to another to facilitate motion & prevent sudden forces
35
Q

Supraspinous Ligament

A

Across tips of spinous processes

  • does not exist below L3
  • Limit flexion (thus, can be injured w/ forced flexion)
36
Q

Interspinous Ligament

A

Runs b/t spinous processes C7-L3

- Limit flexion (thus, can be injured w/ forced flexion)

37
Q

Ligament Flavum

A

Paired ligaments connecting adjacent laminae

  • No afferent pain innervation
  • Limit flexion (thus, can be injured w/ forced flexion)
38
Q

Anterior Longitudinal Ligament

A
  • Runs along the anterior aspect of the vertebral body from the occiput to the sacrum
  • Narrower superiorly & broader inferiorly
  • Limits extension of the spine (thus, can be injured w/ forced extension, spondylolisthesis, or fractures/dislocations of the vertebrae
39
Q

Posterior Longitudeinal Ligament

A
  • Runs along the posterior aspect of the vertebral body from C2 to the sacrum
  • Broad in the cervical region, hourglass in the thoracic region & tapers in the lumbar region
  • Covers only 50% of the vertebral body
  • Limits flexion of the spine (thus, can be injured w/ forced flexion or w/ fractures/dislocations of the vertebrae
40
Q

Thoracolumbar Fascia

A
  • 3 layers: anterior, middle, posterior
  • Connects muscles (latissimus dorsi, transversus abdominis, internal obliques, gluteus maximus), ligaments, & bones to allow for coordinated movements of the spine
  • Kinetic chain–humerus is connected to the contralateral femur
41
Q

Intervertebral Disc

A

Components:

  • inner nucleus pulposus (water & mucoprotein gel in a network of type II collagen)
  • outer annulus fibrosus (15-20 laminae composed of type I collagen in an oblique layering)–increases tensile strength (posterolaterally-less organized, less strong)
  • end plates (cartilage)

Nucleus pulposus contents retain fluid, which decreases w/ age & becomes replaced by amorphous fibrocartilage, which changes the mechanical behavior

42
Q

Lumbar Disc Herniation

A

MC = Posterolateral herniation

  • Posterolateral protrusion at L4/5 disc affects L5 nerve
  • Posterolateral protrusion at L5/S1 disc affects S1 nerve
43
Q

3-Joint Complex

A

Disc + 2 facet joints

Kirkaldy-Willis Degenerative Cascase

  • pathology of 1 joint affects the others
  • begins w/ years of rotation & flexion –> cumulative compressive strain & microtrauma
  • degeneration of the spine (= spondylosis)