PBL Flashcards
What are the general functions of the vertebral column?
Support, movement and protection.
How many vertebrae does a typical human have?
33
How many cervical vertebrae are there?
7
How many thoracic vertebrae are there?
12
How many lumbar vertebrae are there?
5
How many sacral vertebrae are there?
5 (fused)
How many coccygeal vertebrae are there?
4 (fused)
List the components of a typical vertebra. (9)
- vertebral body (anterior)
- vertebral arch
- vertebral foramen
- pedicle
- lamina
- transverse processes
- spinous process
- superior/inferior articular processes
- superior/inferior vertebral notches
What is the purpose of the superior/inferior vertebral notches?
They form intervertebral foramen which spinal nerves can then pass through.
Why is the vertebral column longer than the spinal cord?
It grows faster than the spinal cord
At what level does the spinal cord typically end?
L1/L2
Why are there 8 cervical spinal nerves but only 7 cervical vertebrae?
C1 nerve exits above the C1 vertebra.
What is the cauda equina?
The spinal nerves that arise from the spinal cord bundled together.
What are the movements of the vertebral column?
- flexion
- extension
- lateral flexion
- rotation
Which section of the vertebral column is the most mobile?
Cervical
Which section of the vertebral column is least mobile for flexion/extension/lateral bending?
Thoracic
Which section of the vertebral column has the least rotation?
Lumbar
List the degrees of movement in the cervical region.
- flexion: 65
- extension: 40
- lateral flexion: 35
- rotation: 50
List the degrees of movement in the thoracic region.
- flexion: 35
- extension: 25
- lateral flexion: 20
- rotation: 35
List the degrees of movement in the lumbar region.
- flexion: 50
- extension: 35
- lateral flexion: 20
- rotation: 5
What are the two types of vertebral joints?
Zygapophyseal (facet) and symphysis (IV discs).
What type of joint are the Zygapophyseal joints and where are they found?
Synovial plane joints found between superior and inferior articular processes.
What type of joint are the symphysis joints of the vertebral column?
Secondary cartilaginous/fibrocartilaginous found as intervertebral discs between vertebral bodies.
How many joints does a typical vertebra have?
6 (4 zygapophyseal and 2 IVDs)
List the functions of the IV discs.
- provide stability and flexibility
- pressure regulation
- shock absorption
Describe the annulus fibrosus.
- high tensile strength
- fibrous sheath on outer surface (collagen layers in rings)
- fibrocartilage inner zone
Describe the nucleus pulposus.
- high resilience
- gelatinous structure
- 80-85% water
Why do humans lose about 1% of their height during the day?
When humans are upright there is more pressure on the IV discs than when lying down. This means that there is a slow release of water from the nucleus pulposus causing the IV disc to become thinner, hence some height is lost.
What is a ‘slipped disc’?
A prolapse or hernia of the IV disc.
- a tear in the annulus fibrosus can cause the nucleus pulposus to protrude and this can impinge on the spinal cord or nerves.
What is the atlanto-occipital joint?
The synovial joint between C1 and occipital bone - allows for nodding the heading
What is the atlanto-axial joint?
Synovial joint between C1 and C2 - allows for shaking the head ‘no’
How is C1 different from a typical vertebra?
No body, facet and ligament to for dens of C2
How is C2 different from a typical vertebra?
It has the den or odontoid process to articulate with C1 and allow for rotation of the head.
List the ligaments of the spine.
- anterior longitudinal ligament
- posterior longitudinal ligament
- Supraspinous ligament
- nuchal ligament
- ligamentum flavum
- interspinous/intertransverse ligaments
Describe the anterior longitudinal ligament of the spine.
- runs from base of skull to anterior surface of the sacrum
- attaches to anterior surface of vertebral bodies and IVDs
- prevents hyperextension
Describe the posterior longitudinal ligament of the spine.
- runs from C2 to posterior surface of sacrum
- attaches to posterior surface of vertebral bodies and IVDs
- lines the anterior surface of the vertebra canal
- weakly resists hyperflexion
Describe the Supraspinous ligament of the spine.
- runs from C7 to sacrum
- connects the tips of the spinous processes
- cord like
Describe the nuchal ligament of the spine.
- runs from base of the skull to C7
- strong fibroelastic tissue
- supports the head on the neck
- provides attachment for muscles e.g. trapezius
Describe the ligamentum flava of the spine.
- pass between laminae of vertebrae
- forms part of vertebral canal
- resists separation of verts during flexion
Describe the interspinous ligaments of the spine.
Attaches between spinous processes
Describe the intertransverse ligaments of the spine.
Attaches between transverse processes.
What are the superficial extrinsic back muscles?
- trapezius
- latissimus dorsi
- levator scapulae
- rhomboid major and minor
Describe the trapezius muscle of the back.
Origin: skull, nuchal ligament, spinous processes of C7-T12
Insertion: clavicle, acromion, scapula spine
Innervation: motor from accessory nerve and proprioception from spinal nerves C3/C4
Actions: upper fibres elevate scapula and rotate it during abduction of the arm; middle fibres retract the scapula and lower fibres pull scapula inferiorly.
Describe latissimus dorsi.
Origin: spinous processes of T6-T12, thoracolumbar fascia, iliac crest and inferior three ribs
Insertion: all fibres converge to a tendon that attaches to intertubercular sulcus of the humerus
Innervation: thoracodorsal nerve
Actions: extends, adducts and medially rotates the upper limb