Facet Joints

Question 1

Describe the zygapophyseal (facet) joint

Answer 1

• Located posteriorly in the vertebral column on articular processes of the vertebrae.
  
  • Between the inferior facet of one vertebra and the superior facet of the one below.
• Synovial plane joints - allows gliding movements
• Function - allows movement between the vertebrae
• Carry 3-25% of spinal loading in axial compression

Question 2

What surrounds the facet joint?

Answer 2

Capsular ligament surrounds the facet joint increasing stability

Question 3

Where does arterial supply of the facet joints come from?

Answer 3

• Vertebral
• Deep cervical
• Ascending pharyngeal
• Superior intercostal artery

Question 4

Where does venous drainage of the facet joints go?

Answer 4

• Intervertebral veins
• Internal vertebral plexus (within the epidural space in the vertebral canal)

Question 5

Which muscles attach on the facet joint capsules?

What are the other features of the facet joint capsule?

Answer 5

• Multifidus
• Semispinalis capitis
• Muscle attachments possibly increase the integrity / strength of the capsule.
• Facet capsules contain nociceptors (pain) and low threshold mechanoreceptors (mechanical pressire).

Question 6

What are the ‘other’ facet joints of the vertebral column?

Answer 6

• Facet for dens - on the anterior arch of the atlas
• Transverse costal facet for tubercle of rib - on transverse process of thoracic vertebrae.
• Inferior and superior costal facets for the head of the rib - on the body of thoracic vertebrae.

Question 7

What is a facet joint?

Answer 7

The area between 2 facets.

A facet is simply a flat surface on a bone which allows for articulation.

Question 8

Describe the anatomy of the superior facet joint of C1 (atlas)

Answer 8

• Concave superior facet (although some are planar due to variation) - articulates with convex occipital condyles of the skull.
  
  • For this reason, the atlanto-occipital joint is not a true facet joint because the articulation is not between two vertebrae.
• Elongated, kidney-shaped
• Occupies most of the lateral mass of the superior aspect of the atlas.
• Direction - superior, medial, posterior
• Permits the YES movement

Question 9

Describe the anatomy of the inferior facet joint of C1 (atlas)

Answer 9

• Relatively flat inferior facet - articulate with the convex superior articular facets of C2.
• Smaller and rounder than the superior facet of C1.
• Direction - faces inferior and medial
• Permits the NO movement

Question 10

Describe the anatomy of the superior articular facets of C2 (axis)

Answer 10

• Articulate with inferior facets of the atlas
• Large surface to transmit the weight of the head to its body.
• Very slightly convex
• Face superiorly and laterally - allows gliding motion
• Permits NO movement

Question 11

List the stabilisers of the atlanto-occipital joint

Answer 11

• Nuchal ligament
• Anterior atlanto-occipital membrane - densely packed fibres
• Posterior atlanto-occipital membrane

Question 12

List the stabilisers of the atlanto-axial joint

Answer 12

• Cruciate ligament formed from the transverse ligament of axis and longitudinal bands superiorly and inferiorly
• Apical ligament
• Alar ligament
• Tectorial ligament continues as the posterior longitudinal ligament

Question 13

Describe the anatomy of the superior facet joints of the typical cervical vertebrae (C3-C7)

Answer 13

• Orientated superiorly
• Convex

Question 14

Describe the anatomy of the inferior facet joints of the typical cervical vertebrae (C3-C7)

Answer 14

• Orientated inferiorly, anteriorly and medially
• Concave

Question 15

Describe the general features of the facet joints of typical cervical vertebrae

Answer 15

• Orientated approximately 45° from the transverse plane
• Thin and flexible joint capsule
• Allows a wide range of motion for the neck
• Facets become more vertical towards the bottom of the cervical spine

Question 16

Which nerves innervate the cervical facet joints?

Answer 16

Medial branches of cervical dorsal rami.

This pattern of innervation is found only in the cervical region due to the presence of an 8th cervical spinal nerve with no corresponding vertebra.

Question 17

Describe the anatomy of the superior facet joints of the thoracic vertebrae

Answer 17

• Directed posterolaterally
• Convex

Question 18

Decribe the anatomy of the inferior facet joints of the thoracic vertebrae

Answer 18

• Directed anteromedially
• Concave

Question 19

Describe the general features of the facet joints of the thoracic vertebrae

Answer 19

• Orientation of the facet joints
  
  • Inclined 60° from the transverse plane
  • Inclined 20° posteriorly from the coronal plane
• Allows rotation and lateral flexion
• Articular processes of thoracic vertebrae are elongated vertically
• Flexion and extension movements are very limited due to the orientation of the facet joints

Question 20

Which nerves innervate the facet joints of the thoracic vertebrae?

Answer 20

Medial branches of the dorsal rami C8-T12, corresponding to the superior facets involved in the joint and the vertebra superior to that.

Example: T7-T8 innervated by medial branches of T6 and T7 dorsal rami.

Question 21

Describe the anatomy of the superior facet joints of the lumbar vertebrae

Answer 21

• Directed medially initially
• Directed posteromedially at the lower lumbar levels because facets move into the coronal plane as they descend.

Question 22

Describe the anatomy of the inferior facet joints of the lumbar vertebrae

Answer 22

• Directed laterally initially
• Directed anterolaterally at the lower lumbar levels because facets move into the coronal plane as they descend.

Question 23

Describe the general features of the facet joints of the lumbar vertebrae

Answer 23

• Facets are originally orientated in the sagittal plane, but move towards the coronal plane at lower levels.
• Primary movements: flexion and extension
• Secondary movements: some rotation of the lower lumbar spine
• Facets are elongated vertically
• Superior facets situated further apart than the inferior processes

Question 24

Which nerves innervate the facet joints of the lumbar vertebrae?

Answer 24

Medial branches of the dorsal rami T12-L5

Question 25

What is the purpose of the sagittaly orientated facet joint of the superior lumbar vertebrae?

Answer 25

To severely limit rotational movements and facilitate only flexion and extension movements

Question 26

What is the purpose of the coronally orientated facet joints in the lower lumbar vertebrae?

Answer 26

To allow a small degree of rotation, but the primary movements are still flexion and extension.

Question 27

Describe the joint capsules between the lumbar vertebrae and relate their structure to function

Answer 27

* Shorter and less slack / pliable than the joint capsules present between the cervical vertebrae. * Therefore, there is a smaller degree of flexion in the lumbar spine compared to cervical.

Question 28

What happens if the facets of the lumbar vertebrae are damaged?

Answer 28

An alternate method of weight-bearing forms - loads are transferred to the annulus fibrosus and the anterior longitudinal ligament for support. Although destruction of facet joints alone will not cause instability of the spine, more force will be transmitted to the intervertebral disc which may accelerate disc degeneration.

Question 29

Describe the anatomy of the facet joints of the sacral vertebrae

Answer 29

* No facets within the sacrum due to fusion, with the exception of S1 which fuses with L5. * The facet joint between L5 and S1 faces medially and posteriorly to prevent anterior gliding of the spine. * It facilitates flexion and extension, but prohibits rotation.

Question 30

Describe the anatomy of the facet joints of the coccyx

Answer 30

* The first coccygeal vertebra articulates with the sacrum (S5) at the sacrococcygeal joint. * The joint is usually a symphysis (secondary cartilaginous), but can sometimes be fused or synovial. * Have 2x coccygeal cornua - processes on Co1 which articulate with S5.

Question 31

Describe the coccygeal cornua

Answer 31

* 2x articular processes on the posterior aspect of the first coccygeal segment. * Each articulate / fuse with the sacral cornu on S5 * The articulation between the cornua and the sacrum isn't a true facet joint but is the equivalent of a facet joint in this region of the vertebral column.

Question 32

Describe the first column of the spine

Answer 32

* **1st column (anterior)** * Anterior longitudinal ligament * Anterior half of the vertebral body and IV discs

Question 33

Describe the second column of the spine

Answer 33

* **2nd column (middle)** * **​**Posterior longitudinal ligament * Posterior half of vertebral body and IV discs

Question 34

Describe the third column of the spine

Answer 34

* **3rd column** * **​**Facet joints * Interspinous ligaments * Pedicles * Spinous processes

Question 35

Describe the method of clinically determining stability of the spine?

Answer 35

* When assessing spinal instability, clinicians classify the spine as a 3 column system. * The spine is considered stable until 2 of the 3 columns are damaged

Question 36

Which ligaments limit extension of the spine?

Answer 36

Anterior longitudinal ligament

Question 37

Which ligaments limit flexion of the spine?

Answer 37

* Posterior longitudinal ligament * Ligamenta flava * Interspinous ligaments * Supraspinous ligaments * Intertransverse ligaments * Nuchal ligament (cervical region only)

Question 38

What are the ligaments of the sacrococcygeal joint?

Answer 38

* Anterior sacrococcygeal ligament * Posterior sacrococcygeal ligament (superficial and deep) * Lateral sacrococcygeal ligament * Ligament connecting sacral cornu and transverse process of 1st coccygeal vertebra

Question 39

Describe the posterior sacrococcygeal ligament

Answer 39

* Divided into superficial and deep parts * Superficial component is called the sacrococcygeal membrane - spans from the sacral hiatus to the posterior surface of the coccyx * Deep component extends within the sacral canal between the posterior aspects of the 5th sacral and 1st coccygeal vertebrae.

Question 40

What injuries are associated with hyperextension / hyperflexion (particularly at high velocity)?

Answer 40

* Increased muscle tonicity, inflammation and possibly impingement of nerves and vessels. * Possible injuries: * Anterior intervertebral disc rupture * Lesions to the articular surfaces and capsules of the zygapophyseal joints * Whiplash associated disorder develops - symptomatic side effects of a motor vehicle crash

Question 41

Describe whiplash which results from child abuse

Answer 41

* Can be seen in a child where vigorous shaking has occurred * Signs include: * Convulsions * Irritability * Bulging fontanelle * Paralysis * Vomitting * At age 5-6 vision loss and hearing loss become apparent

Question 42

Describe step 1 of sustaining a whiplash injury

Answer 42

* **S-shape** * Initial extension of C5-C6 * Flexion at the cranial end of the cervical spine * Causes a sigmoid shape

Question 43

Describe step 2 of sustaining a whiplash injury

Answer 43

* **Hyperextension** * During this, the anterior portion of the vertebral bodies separate * The facet joints are impacted

Question 44

Describe step 3 of sustaining a whiplash injury

Answer 44

* **Hyperflexion** * During this, the posterior portion of the vertebral bodies separate (sometimes causing ligamentous damage) * Facets and surround capsules are stretched to the point of damage

Question 45

What are the symptoms of whiplash?

Answer 45

* Confusion * Difficulty concentrating * Dizziness * Visual issues * Tinnitus

Question 46

What causes most of the pain associated with a whiplash injury?

Answer 46

* The highest compressive forces are on posterior aspect of the lower cervical spine (C5/C6) * This area is responsible for most of the pain associated with whiplash * Zygapophyseal pain accounts for ~50% of the pain associated with whiplash. * Impingement of the meniscoid (synovial fold) is another cause of pain. * Impingement is registered by the nociceptors within the capsule, sending pain signals. * 50% of people who suffer from whiplash will never fully recover.

Question 47

How is whiplash classified?

Answer 47

* Using the QTFC or MQTFC - Quebec task force classification / modified Quebec task force classification 0-4. * 0 = no neck pain * 4 = spinal stenosis, fracture or dislocation

Question 48

Describe facet joint degeneration and include a list of its main causes

Answer 48

* Closely associated with degenerative disc disease and can induce the onset of facet joint degeneration. * Causes instability of a vertebral motion segment (because facet joints are important for weight bearing of the spine) - puts extra stress on the intervertebral disc, resulting in further deterioration. * Main causes of facet joint degeneration: * Ageing * Injury * Infection * Inflammation

Question 49

List the indicators of facet joint degeneration

Answer 49

* Loss, wear and tear or necrosis of articular cartilage * Sclerosis * Subchondral bone exposure * Calcification of the capsule * Formation of osteophytes

Question 50

Describe the stages of facet joint deneration

Answer 50

1. Grade 1 - narrowing space within facet joint 2. Grade 2 - indication of sclerosis or hypertrophy of subchondral bone 3. Grade 3 - formation of osteophytes around the margins of facet joints * This growth can cause narrowing of the IV foramen which can impinge on the spinal nerve causing shooting pains, such as sciatica in the lumbar region. Pathria et al. (1987) created this grading system