V.C - G - Facet Joint Structure & Function - Blood supply/drainage, Innervation, Movement, Pathology (Whiplash & Facet OA)

Question 1

What type joint is a facet joint? What movements does it permit? What is it also known as? What is the facet joint lined by? What forms the joint? How many facets are at every spinal level?

Answer 1

Facet joint aka zygapophyseal joint is a synovial plane joint between the superior articular facet and inferior articular facet of neighbouring vertebrae The joint allows for sliding/gliding movements There are 2 facets at every spinal level, both lined by hyaline cartilage

Question 2

The facet joint contributes to the motion segment of the spine What is the motion segment of the spine?

Answer 2

The motion segment is a functional unit of the spine made up between the 2 vertebral bodies, intervertebral disc and adjoining ligaments It is a tri joint complex - made up between the IV disc and 2 facet joints

Question 3

What does the facet joints help with in the spine? (will go into depth about the movements later)

Answer 3

The facet joint helps with spinal stability, protection of the spinal cord and to limit movement of the vertebral column

Question 4

Each facet joint is enclosed within a thin fibrous capsule What is this thin fibrous capulse lined with? What allows the stretching of the capsule with injury?

Answer 4

The thin fibrous capsule is lined with a synovial membrane which prevents friction during movement The crimp in the capsule (the waveform structure of the fibrils) allows for the stretching of the capsule without injury

Question 5

The facet joint capsule decreases movement at the facet joint What helps to determine the movement at each of the facet joints?

Answer 5

The shape of the articular processes will help to determine the movement at each of the facet joints

Question 6

What helps to reinforce the joint capsule and helps to limit motion of the facet joint? What is this structure composed off and what ligament does it connect to?

Answer 6

The capsular ligaments helps to reinforce the facet joint capsule and helps to limit the movements of the joint

The capsular ligament is composed of collagen which which extends between the vertebrae and connects to the ligamentum flavum

Question 7

Sometimes it is debated whether this structure is just an extension of the synovial membrane into the facet joint cavity or a different structure altogether What would this structure be?

Answer 7

This structure would be the meniscoids Pic on right is showing a cervical meniscoid entrapment

Question 8

Cervical meniscoids are invaginations of the synovial membrane that can vary in shape What is the attachment of the cervical meniscoids?

Answer 8

The meniscoid attaches to the joint capsule peripherally at dorsal and ventral poles and extends towards the centre of the joint

Question 9

What is the composition of the meniscoids? What is its hypothesised function?

Answer 9

It has a composition of adipose tissue, loose and regular connective tissue and collagen fibres that extend throughout the meniscoid The meniscoids hypothesized function is to distribute heavy loads over a large surface area allowing for a smooth sliding/gliding motion

Question 10

What is the innervation of the facet joint?

Answer 10

Facet joints are innervated by the medial branches of the dorsal rami from the spinal nerve

Question 11

What is the arterial supply to the facet joint? Different supply for the cervical, thoracic, lumbar and sacral regions

Answer 11

Cervical region arterial supply - vertebral and ascending cervical arteries Thoracic region arterial supply - costocervical and posterior intercostal arteries Lumbar region arterial supply - lumbar, iliolumbar and middle sacral arteries Sacral region arterial supply - lateral sacral arteries

Question 12

What is the venous drainage of the facet joint?

Answer 12

The facet joint drains to the intervertebral veins which form internal and external venous plexuses around the vertebral column

Question 13

State the innervation, arterial supply and venous drainage of the facet joint

Answer 13

Facet joint innervation - from the medial branches of the dorsal rami of the spinal nerve Facet joint arterial supply - * Cervical- vertebral and ascending cervical arteries * Thoracic - costocervical & posterior interocstal arteries * Lumbar - lumbar, iliolumbar & middle sacral arteries * Sacral - lateral sacral arteries Facet joint venous drainage - drains to intervertebral veins which drain into internal &external vertebral venous plexuses

Question 14

Time to look at the specific structure and function off the facet joints at each vertebral level Lets talk about the atlas C1 What shape are the superior articular facets? Does the anterior end travel towards or away from the midline? What shape are the inferior articular facets?

Answer 14

Superior articular facets of C1 - these are concave in shape, the anterior end is towards the midline Inferior articular facets of C1 - these are flat and round in shape

Question 15

What does the concavity of the superior articular facets of the atlas permit?

Answer 15

The concavity of the superior articular facets of the atlas permits movement

Question 16

Time to look at the specific structure and function off the facet joints at each vertebral level Lets talk about the axis C2 * What shape is the superior and inferior articular facets of C2 and C3? * What direction do C2 articular facets face? * What movement is permitted at the facets of the atlanto axial joint?

Answer 16

Superior articular facet of C2 is oval and is inclined oblique downwards posteriorly Due to the flat facets at the atlanto-axial joint, no movement at the facet joints is permitted here Inferior articular facets of C2 are also oval and face more anteriorly to articulate with C3

Question 17

Lets now discuss C3-C7 vertebrae facet joints What direction do the superior articular facet and inferior articular facets face? (same as the lumbar facets for this answer)

Answer 17

The superior articular facets face posteromedially and the inferior articular facets face anterolaterally

Question 18

The facets in the lower cervical vertebrae (C3-C7) allows for a greater range of movement – flexion, extension, rotation, lateral bending What angle would a line drawn through the facet joints of C3-C7 to the horizontal be? Why is the capsule particularly lax in the cervical region?

Answer 18

The facet joint of C3-C7 vertebrae is oblique at a 45 degree angle to the horizontal The capsule is particularly lax in the cervical region to allow gliding of the vertebrae

Question 19

The range of movement possible at the facet joints in the cervical region (C3-C7) Firstly describe how the facets move during flexion and extension of the cervical facet joint and what the range of motion is

Answer 19

Flexion - the superior articular facet slides upwards and tilts forwards - widening the capsule posteriorly - 25 degrees of flexion is possible Extension - the superior facet tilts and slides posteriorly, the IV space closes and the capsule widens anteriorly - 85 degrees of extension is possible

Question 20

The range of movement possible at the facet joints in the cervical region (C3-C7) Describe how the facets move during lateral flexion and rotation of the cervical facet joint and what the range of motion is What is lateral rotation of the cervical facets always accompanied by? What direction does the capsule open in rotation?

Answer 20

Lateral flexion- the facets slide up and down but also backwards and forwards which is why lateral flexion is always accompanied by rotation - 40 degrees of lateral flexion is possible Rotation - occurs with lateral flexion and is preventing by the gliding of facets against one another, opens capsule int he direction of the head rotation - 50 degrees of rotation is possible

Question 21

Describe flexion, extension, lateral flexion and rotation of cervical vertebrae C3-C7 facet joints

Answer 21

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Question 22

LETS now talk about the thoracic facet joints What direction do the articular facets of the thoracic vertebrae face? What angle is formed from the axial and from the hoiztonal through the thoracic facet joints?

Answer 22

• The thoracic facets are almost vertical facing and therefore almost face posteriorly and anteriorly
• The superior articular facets are slightly posterolaterally facing
• The inferior articular facets are slightly anteromedially facing 20 degrees from the axial and 60 degrees from the horizontal

Question 23

What is the combined range of flexion and extension in the thoracic region? Where is the flexion of the thoracic spine slightly freer and why? What restricts both movements?

Answer 23

The combined range of flexion and extension in the thoracic region is between 50-70 degrees * Flexion of the thoracic spine is limited by the ribs and ligaments * It is slightly freer in the lower thoracic spine due to the attachment of the longer cartilage & floating ribs * Extension of the thoracic spine is restricted by the impact of articular processes

Question 24

Describe how the facets move during lateral flexion and rotation of the thoracic facet joint and what the range of motion is

Answer 24

Lateral flexion has a range of 20-25 degrees of movement being freer in the lower half The contralateral facet joint moves like flexion and the ipsilateral facet joint moves like extension Roughly 35 degrees of rotation is possible - the ainferior articular process of the vertebrae above slides away from the superior articular process of the vertebrae below

Question 25

Describe flexion, extension, lateral flexion and rotation of thoracic vertebrae facet joints

Answer 25

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Question 26

LETS now discuss the lumbar articular facets What direction do the articular facets of the lumbar vertebrae face? What movements does the lumbar facet joints permit? What angle is formed from the axial and from the horizontal through the lumbar facet joints? (state the values for thoracic)

Answer 26

• Superior articular facet - faces posteromedially
• Inferior articular facet - faces anterolaterally
• Lumbar facet joints - 45 degrees from the axial and 90 degrees from the horizontal
• Thoracic facet joints - 20 degrees from the axial and 60 degrees from the horizontal

Question 27

Describe how the facets move during flexion and extension of the lumbar facet joint and what the range of motion is

Answer 27

Flexion - 55 degrees of movement - inferior articular facet glides upwards and forwards on superior articular facet Extension - 30 degrees of movement - inferior articular facets glide down into the superior articular facet and tilt backwards

Question 28

Describe how the facets move during lateral flexion and rotation of the lumbar facet joint and what the range of motion is What is the difference in lateral flexion angle between children and in adults?

Answer 28

Thee is little lateral bending in the lumbar spine - the articular processes on the ipsilateral side become close packed and on the contalateral side they separate and a gap forms - 20-30 degrees adults&60 degrees children Rotation - almost no rotation possible due to the shape and orientation of the lumbar articular facets

Question 29

Describe flexion, extension, lateral flexion and rotation of lumbar vertebrae facet joints

Answer 29

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Question 30

There are no facets between sacral bones as they are fused together What does the fusion of the articular facets form on the sacrum?

Answer 30

The fusion of the articular facets of the sacrum forms the intermediate crest of the sacrum

Question 31

Where do the lumbosacral facets joints exist? What direction do the articular facets of the lumbosacral joint face?

Answer 31

Exists between inferior facets of L5 vertebrae and sacrum

Inferior facets joint of L5 - faces posteromedially

Sacrum superioer facet - faces anterolaterally

Question 32

What are the ligaments stabilising the lumbosacral joint? (dont include, ALL, PLL and ligamentum flavum)

Answer 32

The iliolubar ligament - attaches from L5 transverse processes to ilium Lateral lumbosacral ligaments - attaches from lateral aspect of sacrum to the transverse processes of L5

Question 33

Main movements at the lumbosacral facet joint is flexion and extension Lateral flexion is also possible but decreases from childhood to adulthood What is the range of these movements possible?

Answer 33

Total range of movement of flexion and extension possible at the lumbosacral joint is 18% Lateral flexion decreases from 7% in children to 1 degrees in adults

Question 34

What type of joint is the sacrococcygeal joint? Is there any movement?

Answer 34

Secondary cartilaginous joint No movement

Question 35

State the range of movements at each of the facet joints: * Cervical (C3-C7) * Thoracic * Lumbar * Sacral * Lumbosacral * Coccygeal

Answer 35

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Question 36

The facet joint aids the IV disc in stabilising the spine and supporting spinal motion Weight can bear down and transfer to the facet joints, especially when the spine is in motion to produce movements such as rotation What can happen to the facet joint with repeated weight-bearing loads?

Answer 36

With repeated weight-bearing loads, the facet joint can deteriorate over time leading to facet degeneration which can cause disorders such as facet joint syndrome and facet joint OA

Question 37

BY THE END OF THIS LECTURE, STUDENTS SHOULD BE ABLE TO: * Describe the detailed anatomy of the facet joints * Relate the structure of the facet joint to the function and range of motion * Describe the pathology of whiplash injury We will now describe the pathology of whiplash injury What is whiplash?

Answer 37

Whiplash associated disorders (WAD) are the most common injury associated with road traffic incident (RTA) Whiplash is an acceleration-deceleration mechanism of energy transfer to the neck.

Question 38

Define whiplash again? What may whiplash result from?

Answer 38

Whiplash is an acceleration-deceleration mechanism of energy transfer to the neck It may result from rear end or side on collisions but can also occur during diving and other mishaps

Question 39

What are some of the symptoms of Whiplash?

Answer 39

* Neck stiffness * Pain * Headache * Point tenderness * Upper limb pain * Paraesthesia

Question 40

Whiplash-associated disorder (WAD) is the term given for the collection of symptoms affecting the neck that are triggered by an accident with an acceleration–deceleration mechanism such as a motor vehicle accident What is the classification of whiplash and how many grades are there?

Answer 40

The Quebeck Task Force classifies whiplash on a severity grading of Grade 0 to Grade IV

Question 41

What are the different clinical presentation for Grade 0 to IV Whiplash Associated Disorder?

Answer 41

• Grade 0 - No associated symptoms or physical signs
• Grade 1 - Neck complaints of pain, stiffness or tenderness only. No physical symptoms.
• Grade 2 - Neck complaint and MSK signs
• Grade 3 - Neck complaint and Neurological deficit
• Grade IV - Neck complaint AND fracture or dislocation

Question 42

What is the difference between acute and chronic whiplash?

Answer 42

Acute has lasted 3months

Chronic is whiplash > 3months

Question 43

What are the 4 stages of whiplash?

Answer 43

Stage 1 - Cervical lordosis is lost so there is a flexion deformity of upper and lower C spine

Stage 2 - S-shaped deformity as lower vertebrae extend whilst upper are flexed

Stage 3 - extension of full cervical spine Stage 4 - hyperflexion of C spine

Question 44

What are the forces occurring at each of the stages of whiplash? State what happens at each stage again Al the motion of the neck occurs roughly by 100ms (milliseconds) State at what milliseconds each stage occurs at

Answer 44

* Stage 1 - cervical lordosis is lost so there is a fixed flexion deformity of C-spine - tensile forces * Stage 2 - S-shape forms as lower vertebrae extend and upper vertebrae are flexed - tensile, shearing and compressive forces 50-75ms * Stage 3 - Extension of full cervical spine - tensile and shear forces 75-100ms * Stage IV - Hyperflexion of cervical spine - tensile and shear forces >100ms

Question 45

Which stage is most damage to the facet joints caused by whiplash and where does the damage occur?

Answer 45

Most of the damage to the facet joints caused by whip lash occurs at stage 2 - when the S shape of the cervical spine is formed due to lower vertebrae being extended and upper being flexed Most of the damage will occur at stage 2 between C5/6 vertebrae posteriorly

Question 46

The ligaments and muscles are relaxed as it is an unexpected event allowing for increased sliding of the vertebrae. Where does most stretch occur at the facet joint of C5/6 and therefore where is most compression?

Answer 46

Most stretch will occur anteriorly in the C5/6 facet joint at stage 2 and therefore most of the compression will be posteriorly - the articular surfaces will collide

Question 47

After whiplash, the damage to the facet joint can cause symptoms due to: * Synovitis * Capsule ligament stretch * Nerve and meniscoid impingement * Degenerative changes How do each of these cause symptoms?

Answer 47

Synovitis - inflammation & damage to facet capsule Capsule ligament stretch - poor healing ability leaves patient with chronic pain, increased instability of facet joint can lead to problems eg subluxation Nerve and meniscoid impingement - impingement during collision, or spinal nerves trapped in IV foramen

Question 48

What percentage off over 70s have facet joint degeneration?

Answer 48

75% of over 70s have facet joint degeneration Injury to a joint increases the likelihood of degenerative disease

Question 49

What are the symptoms of facet joint degeneration?

Answer 49

Symptoms usually include stiffness and pain No correlation between symptom severity and x-ray findings

Question 50

Degenerative changes - Articular facets wear away due to poor congruency leading to facet OA What will OA off the facet joint look like?

Answer 50

Due to the damage articular surfaces, to try and maintain the joint congruency we may see the * Loss/Thinning of the joint space * Osteophyte formation * Subchondral sclerosis * Subchondral cyst formation

Question 51

How are whiplash associated disorders diagnosed? When are xrays carried out and why?

Answer 51

Whiplash associated disorders are diagnosed by the accident + symptoms shown Xrays are carried out only if neurological signs as there can be a lot of false positives in the acute phase

Question 52

How are whiplash associated disorders managed?

Answer 52

Early mobilisations and NSAIDs for pain are mainstay Steroid and anaesthetic facet joint injections - not given on the NHS however

Question 53

QUIZ TIME What is another name for facet joints? What is the classification of the facet joint? What type of cartilage is covering the articular surfaces? What innervates the facet joints?

Answer 53

* A facet joint is aka a zygaopophyseal joint * It is a synovial plane type joint * It’s articular surfaces are covered by hyaline cartilage * The joint is innervated by the medial branches of the dorsal rami

Question 54

What joint allows a ‘no’ movement? What spinal region has facet joints angled at 45 o to the horizontal? What movement does the lumbar spine restrict?

Answer 54

The atlanto-axial facet joint allow a ‘no’ movement because there articular surfaces are relatively flat and tilted

The C3-C7 vertebrae has facet joints angled at 45 degrees to the horizontal

The lumbar spine restricts rotation at the facet joint due to the shape and orientation of its articular surfaces

Question 55

What stage of whiplash causes most damage? What is a sign of facet joint degeneration?

Answer 55

Stage 2 of whiplash causes the most damage usually at C5/6 facet joint posteriorly Facet joint degeneration * Symptoms - stiffness & pain Signs on xray - * Loss of joint space * Osteophyte formation * Subchondral sclerosis * Subchondral cysts