Vertebral column

Question 1

Name the 5 functions of the vertebral column

Answer 1

• Carries and protects the spinal cord and nerves
• Provides support to the thoracic cage
• Transfers weight from the upper body to the lower limbs
• Shock absorbing
• Muscle attachment point

Question 2

Label the parts of the vertebrae

Answer 2

Question 3

What is the odontoid process?

Answer 3

Part of the C2 vertebrae (axis) that forms a pivot joint with the atlas. Enables rotation of the head

Question 4

Curvatures of the vertebrae

Answer 4

Cervical - lordosis Thoracic - kyphosis Lumbar - lordosis Sacral - kyphosis Thoracic and sacral curvatures develop during the foetal period and are retained throughout life, cervical and lumbar curvatures do not fully develop until after birth

Question 5

Features of cervical vertebrae

Answer 5

Small wide body Large triangular vertebral foramen Transverse processes have foramina transversaria (vertebral arteries and sympathetic plexus pass through) Short and bifid spinous processes (C3-C5), C6 and C7 longer

Question 6

Features of thoracic vertebrae

Answer 6

Heart shaped body with costal facets for articulation with the ribs

Smaller circular vertebral foramen

Long strong transverse processes. Length decreases from T1-T12

Long spinous processes that slope posteroinferiorly. Tip extends to the level of the vertebral body below.

Question 7

Features of lumbar vertebrae

Answer 7

Large kidney shaped body, larger and heavier than bodies of other vertebrae

Triangular vertebral foramen

Long slender transverse processes.Accessory processes on the posterior surface

Superior articular facets directed medially and inferior articular facets directed anterolaterally. Aligned to resist rotational movements

Short hatchet shaped spinous processes.

Question 8

Scoliosis

Answer 8

Curved back characterised by lateral curvature and rotation of the vertebrae. Caused by asymmetric weakness of intrinsic muscles of the back, failure of half of the vertebra to develop or a difference in the length of lower limbs.

Question 9

Features of atlas (C1)

Answer 9

Consists of two lateral masses connected by anterior and posterior arches. No spinous process or body Flat inferior facets articulate with axis

Question 10

Features of axis (C2)

Answer 10

Strongest cervical vertebra Odontoid process projects superiorly and forms a pivot joint with C1 to allow rotation of the head

Question 11

Describe the structure of intervertebral joints

Answer 11

Secondary cartilagenous joints (symphyses)

Present from below C2 - above S1 with increasing thickness

Provide strong attachments between vertebral bodies

Articulating surfaces connected by IV discs

Stabilised by supraspinous, interspinous ligaments and ligamenum flavum

Question 12

Describe the structure of IV discs

Answer 12

Each disc consists of an outer annulus fibrosus and inner nucleus polyposus

Annulus fibrosus: concentric lamellae of fibrocartilage.

Nucleus polyposus: gelatinous central core of IV disc rich in glycosaminoglycans which draws in water (85% water at birth).

Turgid nucleus acts as a semifluid support for vertebrae during movement.

Question 13

How does the structure of IV discs change with age?

Answer 13

With age, the nucleus polposus dehydrates, elastin and proteoglycans are replaced by collagen. Eventually they become dry andn granular.

The annulus fibrosus then assumes a greater share of the vertical load

Lamellae of annulus fibrosus thickens with age and develops deep fissures and cavities. Degeneration can allow herniation of the NP and IV disc prolapse

Question 14

Name the ligaments that support the vertebral column (3)

Answer 14

Anterior longitudinal ligament

Posterior longitudinal ligament

Ligamentum flavum

Question 15

Describe the structure of the 3 ligaments that support the vertebral column

Answer 15

Anterior longitudinal ligament: strong, broad fibrous band that covers and connects the anterolateral aspects of the vertebral bodies and IV discs. Extends from sacrum to C1 and occipital bone. Maintains stability of intervertebral joints and limits extension of the column

Posterior longitudinal ligament: narrower fibrous band that runs within the vertebral canal along the posterior aspect of the vertebral bodies. Mainly attached to the IV discs. Runs from C2 to the sacrum. Helps prevent hyperflexion of the vertebral column and posterior herniation of IV discs.

Ligamentum flavum: Fibrous elastic tissue that extends vertically between lamina of the vertebrae, binding adjoining vertebrae together. Resist separation of the vertebral laminae by stopping abrupt flexion of the vertebral column, thus preventing injury to the IV discs.

Question 16

What are the three ligaments that lie between vertebrae?

Answer 16

supraspinous ligament (stong)

interspinous ligament (weak)

ligamentum flavum: Help preserve the mornal curvatures of the vertebral column and assist with straightening the column after flexing

Question 17

Nuchal ligament

Answer 17

Strong medial ligament of the neck. Composed of thickened fibroelastic tissue extending from occipital bone to the spinous processes of C3-C5.

Acts as a site of muscle attachment

Question 18

What layers do you penetrate in a midvertebral needle insertion?

Answer 18

the skin

supraspinous ligament

interspinous ligament

ligamentum flavum

Question 19

How do IV discs respond to pressure placed on the vertebral column?

Answer 19

Forces applied to the vertebral column increase pressure in the nucleus polposus which becomes compressed. This tenses the annulus fibrosis. Tension limits movement between vertebral bodies

Question 20

Role of spinal curvatures

Answer 20

Helps keep centre of gravity in a evenly distibuted in a central position over S1/S2

Question 21

What can cause changes to spinal curvature?

Answer 21

Age-related kyphosis

Osteoarthritis - IV disc degeneration

Pregnancy - hyper lumbar lordosis

Scoliosis - lateral curvature

Muscular dystophy - weakened spinal muscles. causes hyperlordosis required to stand upright

Question 22

Muscles of the back (function)

Answer 22

Extrinsic muscles:
Superficial - produce and control limb movements (trapezius, latisimus dorsi, rhomboids). Innervated by anterior rami of spinal nerves (trapz CN XI)
intermediate - produce and control respiratory movements (serratus posterior superior, serratus posterior inferior)

Intrinsic muscles: innervated by posterior rami of spinal nerves and act to maintain posture and control movements of the vertebral column.
Superficial - splenius muscles (keeps head upright)
Intermediate - erector spinae (extend head and vertebrak column)

Question 23

Suboccipital triangle

Answer 23

Located at the superior part of the back of the neck, inferior to the occipital region of the head.

Triangle lies deep to trapezius. Contains vertebral artery and suboccipital nerve (C1)

Significance:
Winding course of vertebral arteries through foramen transversaria and suboccipital triangle becomes clinically significant when blood flow is reduced. Prolonged turning of the head causes light-headedness, dizziness and blackouts.

Question 24

How do abdominal muscles support the vertebral column?

Answer 24

External oblique, internal blique and transversus abdominus laterally rotate the trunk (and vertebral column)

Contracting abdominal muscles against a closed glottis provide a pneumatic cushion to support the vertebral column. This helps keep it upright

Rectus abdominus helps maintain stability of the lumbar spine