Vertebral Column

Question 1

Give 5 main functions of the vertebral column

Answer 1

1. Carries and protects spinal cord and nerves
2. Provides support to thoracic cage
3. Transfers wright from upper body to lower limbs
4. Shock absorbing
5. Muscle attachement point

Question 2

What regions are there in the vertebral column?

How many vertebrae in each?

Answer 2

1. Cervical region (C1-C7)
2. Thoracic region (T1-T12)
3. Lumbar region (L1-L5)
4. Sacral region (S1-S5)
5. Coccyx

Question 3

Label the image

Answer 3

Top to bottom (Right):

1) vertebral body
2) pedicle
3) transverse process
4) Lamina
5) Spinous process

Left:

Vertebral canal

Question 4

What forms the neural arch?

Answer 4

Pedicle, transverse process, lamina, spinous process

Question 5

Label the image

Answer 5

Arrows point to the articular facets

Question 6

Describe the structure of a typical vertebra

Answer 6

• Largest most anterior portion is the vertebral body. Weight bearing portion, gets larger from C2-L5.
• Off the Body comes the neural arch
• Directly off the body are the paired pedicles either side
• These pedicles join the lamina which fuses in the midline
• Off the posterior of the arch is the spinous process
• Where the lamina and pedicle meet on either side is a transverse process (This articulates with ribs in thoracic region).
• In a similar region is a superior and inferior articular process that articulates with adjacent vertebrae.
• The neural arch encloses the vertebral canal which houses the spinal cord/ proximal spinal nerves/ meninges/ blood vessels/ connective tissue/ fat

Question 7

What is C1 called?

Why is its structure special?

What does it articulate with and what joint exists?

What movement does this allow?

Answer 7

C1 is also known as the atlas.

Its structure is special as C1 has no vertebral body or spinous process but is formed of only an arch and transverse processes,

On its arches it has two articulation points for the occipital condyles on the base of the skull.

The joint between the occipital condyles and atlas facets forms a compound synovial joint.

Permits movement- flexion and extension of the neck at the vertebral column.

Question 8

What is a fracture of the atlas called?

What can cause this?

Answer 8

A fracture of the atlas (C1) is called a Jefferson Fracture.

This can be caused by excess compression of C1 e.g. diving into shallow water or force transferred up the spine to C1 during a fall

(always check vertebral column in patients with lower limb/ calcaneal fracture).

Question 9

What is the name of C2?

Describe its structure

Answer 9

• C2 is also known as the Axis
• It is formed by a body with an attached dens/ odontoid process
• off the body come two lateral masses, transverse processes with foramina transversarium.
• It has a posterior neural arch formed by pedicles and a thick lamina
• And a large posterior spinous process
• Has superior and inferior articular processes.

Question 10

What is a hangman’s fracture?

Answer 10

Fracture of the pedicles of C2 often caused by hyperextension of the neck during RTA/sports injury/ hanging.

Can cause compression of the spinal cord, respiratory failure and death.

Question 11

What is whiplash?

Answer 11

Whiplash describes neck injury caused when there is sudden deceleration of the body that results in flexion and hyperextension of the neck

Question 12

Describe the defining structural features of cervical vertebrae

Answer 12

• Smaller vertebral bodies that get larger from C1-C7
• Transverse processes with foramina called foramina transversarium
• Short, bifid spinous processes that get longer from C1-C7
• Triangle shaped verterbral foramen/canal

Question 13

What runs through the foramen transversarium?

What can happen if the foramen transversarium is compressed?

Answer 13

The vertebral arteries running uptowards the brain to form the circle of willis which supplies the neural tissue.

Compression of the foramen transversarium can lead to compression of the vertebral arteries leading to defecit of blood supply to the brain producing stroke like symptoms.

Question 14

What are the defining features of thoracic vertebrae?

Answer 14

• Larger, heart shaped vertebral bodies that increase in size to accomodate more weight/ force applied
• Circular vertebral foramen/canal
• Articulation facets for the ribs: Demifacets on the vertebral bodies:
  
  • Superior facet articulates with head of its own rib
  • Inferior facet articulates with head of rib below
• Transverse process with articulation facet for tubercle of own rib.

Question 15

What are the defining features of lumbar vertebrae?

Answer 15

• Large cylindrical vertebral bodies to cope with large forces applied
• Triangular vertebral foramen/canal
• Articulations aligned to prevent rotational movements which increases the stability of the lumbar region

Question 16

What are the defining features of sacral vertebrae?

What structures pass in this region?

What is the sacral hiatus and what can it be used for?

Answer 16

• Sacral vertebrae are 5 fused vertebrae
• Transmits weight to pelvic girdle
• Triangular in shape with apex pointing inferiorly
• Has a concave anterior surface with anterior sacral foramen for ventral rami of sacral nerves
• Has a convex posterior surface with posterior sacral foramen for dorsal rami of sacral nerves
• The sacral hiatus is a foramina at the distal tip of the sacrum and can be used for a sacral epidural.

Question 17

What is the clinical use of spinous processes?

Answer 17

Spinous processes can be palpated and used to count vertebrae to find key structures:

E.g. Transpyloric plane L1

E.g. Lung apex C7

Question 18

How is the vertebral column inherently stable with little muscle activity?

Answer 18

• Vertebral column has a collection of ligaments and joints that interact with each other to keep vertebral column upright and stable.

Question 19

What structure exists inbetween vertebrae?

Answer 19

• Intervertebral discs exist inbetween the vertebrae
• Formed of outer annulus fibrosus = lamellar arrangement of fibrocartilage, limits rotation
• And an inner nucleus pulposus = rubbery central core made up of hydrated GAG’s that resists compressive forces.

Question 20

What is the name of the joints between superior and inferior articular facets on the neural arches of adjacent vertebrae?

Answer 20

Zygapophyseal joints

Question 21

What happens to the intervertebral discs as you descend the vertebral column?

Answer 21

They increase in thickness to accomodate the greater weight/ force applied as you descend the vertebral column.

Question 22

What happens to the zygaphyseal joints in different regions of the spine?

Answer 22

• The zygaphyseal joints change their orientation as you desend down the spine
• Cervical: close to horizontal, slope inferiorly from anterior to posterior. Allows wide range of movement, flexion, extension, rotation.
• Thoracic: Close to vertical, limits the amount of flexion and extension but rotation still possible.
• Lumbar: Pretty much vertical, joint surfaces are curved and interlocked which limits range of movement. Little rotation in lumbar region but some flexion and extension still.

Question 23

what can happen to the zygapophyseal joints pathologically?

Answer 23

They can dislocate, discs displace away from each other.

Question 24

What happens when force is applied to the vertebral column?

Answer 24

This increases pressure in the nucleus pulposus.

The increase in pressure in the NP increases tension in the AF.

Increased tension in the AF pulls vertebral bodies together increasing stability and limiting further movement between vertebral bodies.

Question 25

Label the image Where can this structure be palpated? What is this structure useful for clinically?

Answer 25

Ligamentum nuchae It can be palpated in the midline of the neck Useful surgically as provides an avascular structure that can be cut down to access the base of the skull.

Question 26

Label the image

Answer 26

Top to bottom: Interspinous ligament Supraspinous ligament Ligamentum flavum

Question 27

What are the ligaments shown? Which ligament is weaker and therefore has implications for disc herniation?

Answer 27

* The anterior longitudinal ligament that forms a broad sheet over the anterior aspect of the vertebral column * The posterior longitudinal ligament that forms a relatively narrow and incomplete ligament on the posterior of each vertebral body, lies within vertebral canal. * As the posterior ligament is narrower and incomplete, disc herniations occur more on the posterior aspect of the vertebral column. (Most common postero lateral where no ligament covers).

Question 28

What is the normal pattern of curvature of the spine?

Answer 28

Lordosis in cervical region Kyphosis in thoracic region Lordosis in lumbar region Kyphosis in sacral region. (Lordosis- anterior curvature) (Kyphosis - posterior curvature)

Question 29

What is the pattern of spinal curvature during development to adulthood? What can happen with ageing? What can happen during pregnancy? What is a pathological deformation of the spinal column curvature?

Answer 29

* When in utero and at birth the spine is in consistent kyphosis * At 6 months cervical lordosis develops as babies hold their heads up * Lumbar lordosis develops as toddlers learn to walk * With ageing, disc degeneration can occur that leads to loss of adult pattern and age related kyphosis. * With pregnancy, the extra weight added in lumbar region can lead to hyperlordosis in lumbar region. Returns to normal pattern after birth. * A pathological condition is scoliosis where there is S-shaped lateral displacement of the spinal column.

Question 30

What pathology is shown in the image?

Answer 30

Wedge or compression fracture to the vertebral column. Caused by excessive force applied to vertebral body that exceeds its loading capacity.

Question 31

What is the name of a fracture of the neural arch of a vertebra without displacement of the vertebral body?

Answer 31

Spondylolysis

Question 32

What pathology is shown? What sign is this?

Answer 32

Spondyloysis is shown on the right hand image. It is known as the scotty dog sign- break of neural arch appears like a scotty dog with a collar on.

Question 33

What is the name of a neural arch fracture with anterior displacement of the vertebral body?

Answer 33

Spondylolisthesis is a neural arch fracture in a vertebra that leads to anterior displacement of the vertebral body.

Question 34

What do superficial back muscles act on? What are they innervated by?

Answer 34

Superficial muscles act on the limbs. Superficial muscles are innervated by the brachial plexus and by cranial nerve XI - accessory nerve.

Question 35

What do deep back muscles act on? What are they innervated by?

Answer 35

Deep back muscles act on the vertebral column and the head. Innervated by dorsal rami of the spinal nerves at each level.

Question 36

Name the muscles What do they do? What are they innervated by?

Answer 36

Splenius capitus- acts on the head and keeps it upright. Innervated by posterior ramus of spinal nerves C3/C4. Erector spinae- acts on the vertebral column to keep it erect. Innervated by dorsal ramus of spinal nerves at each level.

Question 37

What is the occipital triangle? What does it contain? What can occur if nerve entrapment happens in this region?

Answer 37

The occipital triangle is a paired region on either side of the neck, enclosed by three suboccipital muscles and houses the vertebral arteries, suboccipital nerve and venous plexus. If C2 and C3 nerves that supply the back of the neck and top of the head get trapped here it can cause posteior headache or occipital neuralgia.

Question 38

What is occipital neuralgia?

Answer 38

Sharp throbbing pain in the back of the upper neck, back of the head and behind the ears. Due to nerve entrapment of C2/C3 nerves that supply the back of the neck and top of the head.

Question 39

What muscles are highlighted?

Answer 39

Red- erector spinae Green- Quadratus Lumborum Yellow- psoas major

Question 40

What other muscle group acts to support/ move the vertebral column? Name the muscles involved and what actions they can have.

Answer 40

The abdominal muscles also help to support the vertebral column and can help move it. The muscles involved anteriorly are the external oblique- contralateral rotation of torso. Internal oblique- ipsilateral rotation and flexion when bilaterally contracted. Rectus abdominus- flexion of vertebral column.

Question 41

What manouvre can help support the vertebral column? what problems can occur if this manouvre is used too much?

Answer 41

The valsalva manouvre can help provide pneumatic support to the vertebral column. If used too much at increased risk of herniation, defectation/ micturition and rectal prolapse.