MSK 14 - The Cervical + Thoracic Spine Flashcards
How many vertebrae do the typical cervical and thoracic spine how?
Are they mobile or immobile?
- 7 cervical + 12 thoracic vertebrae
- Cervical = mobile
- Thoracic = Immobile (movement restricted by ribs)
Describe the characteristics/anatomy of a typical (C3-C6) cervical vertebrae
What runs through the transverse foramen within the cervical spine?
- C3 to C6 have all anatomical features of lumbar spine vertebrae + 1) Bifid spinous process + 2) Transverse foramen
- C1-C6 transmits vertebral artery, vein + sympathetic nerve plexus through foramen. C7 transmits accessory vertebral vein only.
Describe the different features on an atypical C1 (atlas) vertebrae
1) No vertebral body + No spinous process
2) Large transverse process
3) Anterior arch provides attachment for anterior longitudinal ligament, posterior for ligamentum nuchae.
4) Large lateral mass superiorly to support the neck and head.
What is the characteristic features of the atypical C2 (axis) vertebrae?
- The odontoid process, the broadest spinous process of the cervical vertebrae.
What features allow the C1 + C2 vertebrae articulate?
What happens if these features are affected?
- Dens (odontoid process) + transverse ligament prevent horizontal displacement of atlas. A pivot that allows rotation.
- Transverse ligament can be fractured or eroded in RA, leads to atlantoaxial instability. When patient flexes, compression of spinal cord leading to neurological symptoms in arms + legs
Describe the structure of the atypical C7 vertebrae
- Longest spinous process (vertebrae prominens)
- Spinous process is not bifid
- The transverse process is larger, but foramen is small and only transmits accessory vertebral veins
Where do the 8 cervical nerve roots exit the 7 cervical vertebrae?
- Nerve roots exit horizontally, above their vertebrae body (e.g.: C2 in between C1/C2)
- Apart from C8 nerve root, exits at C7/T1 junction
What are the ligaments of the cervical and thoracic spine?
What is ligamentum nuchae and what is its function?
- Same arrangement as lumbar spine - ligamentum flavum, intraspinous ligament, supraspinous ligament, anterior longitudinal ligament + posterior longitudinal.
- Nuchae is thickening of supraspinous ligament, maintains secondary curvature of cervical spine + helps cervical spine support head. Major site of attachment of neck and trunk muscles (trapezius + rhomboid)
What are the movements of the cervical spine?
What joints provide flexion/extension + rotation?
- Very flexible segment of spine
- Flexion (head forward), Extension (head back), rotation + lateral flexion.
- Atlanto-axial joint provides 50% of rotation (shaking head)
- Atlanto-occipital joint provides 50% of flexion/extension (nodding). Other 50% for both by rest of cervical spine
What features should you be able to identify on a PA view + lateral view of a cervical spine X-ray?
- PA = transverse process of C4, spinous processes, lamina
- Lateral = anterior + posterior arches of atlas, intervertebral joint, intervertebral foramen, spinous processes, transverse processes
Describe the differences of the anatomy of a thoracic vertebrae
What are the two places the rib articulates with the vertebrae?
- Demi-facets on sides of vertebrae for articulation with head of rib
- Vertebral foramen is small and circular
- 1) The head of rib with the body of the vertebrae
- 2) The neck of the rib with the transverse process
What features should be present on a sagittal view MRI of the thoracic spine?
- Vertebral body, intervertebral discs, all ligaments, spinal cord, meninges/dura
What are the triad of changes seen in cervical spondylosis (OA)?
What can spondylosis lead to + what are the symptoms of this?
- 1) Loss of disc height 2) Osteophytes 3) Facet joint OA
- Can lead to radiculopathy (via osteophyte in foramen + irritation of nerve root) or myelopathy (via osteophyte in vertebral canal + compression of spinal cord)
- Radiculopathy (compression of nerve roots) leads to sensory symptoms (dermatomal paraesthesia/pain) and motor symptoms (muscle weakness) - depends on which nerve root is affected.
What can cause cervical radiculopathy in 30 to 50 year olds?
What is the mechanism that compresses nerve root?
- Prolapsed cervical intervertebral disc
- Tear of annulus fibrosis, nucleus pulposus migrates through into spinal canal + compresses nerve root.
How does cervical myelopathy occur?
What are the anatomical changes + symptoms associated?
- A result of spondylosis and cervical spinal cord compression (in 50-80 Y.O’s)
- Thickened ligamentum flavum, osteophytes + changes in SC signalling.
- Progressive worsening, clumsiness, loss of fine movements + balance
