Joints Flashcards
Classify intervertebral joints
Symphysis (secondary cartilaginous) joint
Describe articulation in intervertebral joints
Between vertebral bodies and intervertebral disc; vertebral end plates consist of hyaline cartilage. Superior surface of vertebral body below covered in a cartilaginous endplate that is attached to the annulus fibrosis layer of the intervertebral disc which then bonds to cartilaginous endplate on inferior surface of vertebral body above.
Describe layers of intervertebral disc
Consists of an outer anulus fibrosus, which surrounds a central nucleus pulposus
The discs are thickest in the lumbar and cervical regions
Annulus fibrosus = outer multiple rings of dense, collagen fibres surrounding a wider zone of fibrocartilage arranged in a lamellar configuration.
□ Adjacent concentric rings fibres run in perpendicular directions to add strength and allowing some mobility
□ Composed of 60-70% of water
□ Layers of collagen fibres arranged in sheets called Lamellae - this arrangement of fibres limits rotation between vertebrae
□ Thicker towards centre of disc and in anterior and lateral portions
□ Thinner posteriorly
□ Stiff structure resist buckling and tearing
Nucleus pulposus = fills the centre of the intervertebral disc, is gelatinous, and absorbs compression forces between vertebrae
□ Semi- fluid mass of mucoid material
□ 88% water
□ Deformed under pressure from any direction
□ Transmit the applied pressure in all directions equally to all aspects of annulus fibrosus
What is the function of the intervertebral disc
Shock absorption - hydrostatic properties from high fluid content of both annulus fibrosus and nucleus pulposus layers; able to deform shape and return back to original shape
Allows movement and load transition
Stability to the spinal column
Limit excessive movements
What are the ligaments supporting IV joints
ALL
PLL
What problems can arise in intervertebral discs
Degenerative changes in the anulus fibrosus can lead to herniation of the nucleus pulposus. Posterolateral herniation can impinge on the roots of a spinal nerve in the intervertebral foramen
Fluid in annulus fibrosus and nucleus pulposus layers dehydrate with age leading to loss of height
Prolapsed intervertebral disc (PID) - Nucleus pulposus protrudes through shearing damage in annulus fibrosus (commonly posteriorly), leading to pressure on part of the spinal cord
NB:
Between C1-C2: a central prolapse will push on the spinal cord itself
Sequestrum = Piece of displaced nucleus pulposus that can affect spinal cord on the same level or on levels superior/inferior.
Classify zygapophyseal (facet) joints
Synovial plane joints
Describe articulation in facet joints
Cervical - horizontal AP sloped oval articular facets on the inferior and superior articular processes. superior convex facet face superiorly, slightly posteriorly and laterally to articulate with Inferior concave facet facing inferiorly, slightly anteriorly and medially. All articular surfaces covered in hyaline cartilage.
Thoracic- vertically AP sloped orientated oval articular facets on the inferior and superior articular processes. superior concave facet face posteriorly, slightly superiority and laterally to articulate with Inferior convex facet facing anteriorly, slightly inferiorly and medially. All articular surfaces covered in hyaline cartilage.
Lumbar - vertically wrapped orientated oval articular facets on the inferior and superior articular processes. superior concave facet face medially, slightly superiorly and posteriorly to articulate with Inferior convex facet facing laterally, slightly inferiorly and anteriorly. All articular surfaces covered in hyaline cartilage.
Orientation of facets will limit/facilitate certain movements
Describe the capsule in facet joints
Thin fibrous joint capsule surrounds joint attached to the margins of the articular facets
What are the ligaments supporting facet joints
Ligamentum Flava (Flavum) Intertranverse ligaments Interspinous ligaments Supraspinous ligaments Ligamentum Nuchae (Cx)
What are the problems that can occur in facet joints
Capable of degenerative diseases
Classify uncovertebral joints (joints of Von Lushka)
Synovial plane joints
Unique to cervical vertebrae
Describe articulation in joints of Von Lushka
lateral margins on superior surface of cervical vertebrae are elevated into lips/crests termed uncinate processes.
Uncinate processes face supero-medially to be received by beveled edges facing infero-laterally on the inferior surface of the vertebra above, enclosing IV disc. All articular surfaces covered in hyaline cartilage
Classify Atlanto-occipital joint
Synovial ellipsoid joint; biaxial
Describe articulations in Atlanto-occipital joint
Between Large, convex, articular facets on occipital condyles face inferiorly to be received by large, concave articular facets facing superiorly on superior surface of the lateral masses of the atlas. All Articular surfaces covered in hyaline cartilage
What are the movements in the Atlanto-occipital joint
Flex-Ext
Protraction/retraction
Lateral side flexion
What are the 3 ligaments or membranes supporting the Atlanto-occipital joints
Anterior atlanto-occipital membrane
Posterior atlanto-occipital membrane
Ligamentum nuchae
Classify Atlanto-axial joint
Atlantoaxial joint complex: Synovial joint; biaxial
composed of three synovial joints; one median atlantoaxial joint and two lateral atlantoaxial joints
Median atlantoaxial joint - synovial pivot joint
Lateral atlantoaxial joints - synovial plane joints
