2.2 Spine Curvature, Ligaments, and Joints Flashcards
What are kyphosis curves? Where are they in the body?
- Kyphosis Curves- Curves retained from embryonic spine development. All posteriorly convex / outward curving / bending forwards.
- The spine’s kyphosis include the thoracic kyphosis (T1-T12) and the sacrum kyphosis (S1-S5)
- K comes before L, ∴ Kyphosis develop before Lordosis
- Embryos curve forwards in the womb, therefore kyphosis curves are posteriorly convex / outward curving / bending forwards
What are lordosis curves? Where are they in the body?
- Lordosis Curves- Curves developed after being born. All inward / anteriorly convex / bending backwards.
- The lordodis curves in the body are cervical lordosis (C1-C7) and the lumbar lordosis (L1-L5)
- K comes before L, ∴ Kyphosis develop before Lordosis
- Embryos curve forwards in the womb, therefore kyphosis curves are posteriorly convex / outward curving / bending forwards
Describe how the spine changes from prenatal to adulthood
As an embryo, the whole spine is C-shaped, made up of one large kyphosis curve (posteriorly convex / outward curving / bending forwards)
From three months post-birth and onwards, when the infant starts looking around and sitting up, the spine develops lordosis curves (anteriorly convex / inward curving / bending backwards) , resulting in an S-shaped spine made up of a cervical lordosis (ant convex), thoracic kyphosis (post convex), lumbar lordosis (ant convex), and sacrum kyphosis (post convex)
- K comes before L, ∴ Kyphosis develop before Lordosis
- Embryos curve forwards in the womb, therefore kyphosis curves are posteriorly convex / outward curving / bending forwards
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Embryos and Babies up to Three Months
- Whole spine is one large C-shaped curve
- Made up of all one kyphosis curve (posteriorly convex / outward curving / bending forwards)
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Three Months Onwards
- Spine starts to change when infant starts to sit up and look at the world around them
- Assists with support, stability, and flexibility
- Develop lordosis curves (anteriorly convex / inward curving / bending backwards) in the cervical and lumbar region, whilst retaining kyphosis curves (posteriorly convex / outward curving / bending forwards) in the thoracic and sacral region
- Leading to the spine developing an S-shape
- Made up of the…
- Cervical lordosis- Anteriorly convex / inward curving / bending backwards
- Thoracic kyphosis- Posteriorly convex / outward curving / bending forwards
- Lumbar lordosis- Anteriorly convex / inward curving / bending backwards
- Sacrum kyphosis- Posteriorly convex / outward curving / bending forwards
Label the ligaments
Where is the intervertebral disc, what type of joint is it, what is its function, and describe its structure
- Symphyses/secondary cartilaginous (solid cartilaginous)
- Between adjacent vertebral bodies
- Made up of hyaline cartilage covering the bones, and a layer of fibrocartilage between the two bones.
- Function: Improve stability, support, weight bearing, and shock absorption
- Movement: Enable a small amount of movement
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Structure of Fibrocartilage Disc: Two major components
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Centre: Nucleus Pulposus
- A semi-fluid structure which helps with shock absorption and weight bearing
- Nucleus pulposus is in the centre, like a nucleus is in the centre of a cell
Fruit pulp is semi-liquid, and so is nucleus _pulp_osis
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Outside Rings: Annulus Fibrosus
- Collagen fibres arranged in layers like an onion
- Surrounds and contains nucleus pulposus to maintain it throughout life
- Allows some movement between vertebral bodies when muscles act on the zygapophyseal/facet joints
- _An_nulus fibrosus is like an onion
Annulus _fibr_osis has collagen fibres
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Centre: Nucleus Pulposus
Where is the zygapophyseal joint, what type of joint is it, what is its function, and describe its structure
- Plane/gliding (synovial)
- Between superior and inferior articular processes/facets of adjacent vertebrae
- Multiaxial: Movement along any plane
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Enable:
- Sagittal: Flexion/Extension
- Transverse: Side-Bending (Abduction/Adduction)
- Coronal: Rotation
- Other: Circumduction
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Structure:
- Synovial membrane. Hyaline articular cartilage coating bones, synovial fluid made by a synovial membrane, collagenic fibrous tissue surrounding synovial membrane forming a fibrous capsule.
- Anteriorly (just posterior to the spinal cord), the collagen fibrous capsule is replaced by ligament flavum, a ligament composed of elastin fibres rather than collagen.
- Has a yellow colour
- When not stretched, collagen buckles, which would interfere with the spinal cord. Elastin is more elastic, and therefore does not buckle into the spinal cord when relaxed
- Limits flexion
Where is the costovertebral joint, what type of joint is it, what is its function, and describe its structure
- Plane/gliding (synovial)
- Between superior and inferior demifacets of adjacent thoracic vertebrae and a rib head
- Costo = Rib
Vertebral = Vertebrae - Multiaxial: Movement along any plane
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Enable:
- Sagittal: Flexion/Extension
- Transverse: Side-Bending (Abduction/Adduction)
- Coronal: Rotation
- Other: Circumduction
Where is the costotransverse joint, what type of joint is it, what is its function, and describe its structure
- Plane/gliding (synovial)
- Between costal facet of thoracic vertebrae’s transverse process and rib tubercle
- Costo = Rib
Transverse = Transverse process - Multiaxial: Movement along any plane
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Enable
- Sagittal: Flexion/Extension
- Transverse: Side-Bending (Abduction/Adduction)
- Coronal: Rotation
- Other: Circumduction
Where is the Anterior Longitudinal Ligament and what movement does it limit?
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Anterior Longitudinal Ligament
- Longitudinally along anterior of vertebral bodies
- Limits extension (bending backwards)
Where is the Posterior Longitudinal Ligament and what movement does it limit?
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Posterior Longitudinal Ligament
- Longitudinally along posterior of vertebral bodies
- Limits flexion (bending forwards)
Where is the Ligamentum Flavum, what is its structure, and what movement does it limit?
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Ligamentum Flavum
- Replaces fibrous capsule at anterior side of zygapophyseal/facet joint
- Between superior and inferior articulating processes of adjacent vertebrae on the anterior side
- Rather than collagen, is made up of elastin which is more elastic so that when it is relaxed it does not buckle into the spinal cord
- Limits flexion (bending forwards)
- Replaces fibrous capsule at anterior side of zygapophyseal/facet joint
Where is the Intertransverse Ligament, and what movement does it limit?
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Intertransverse Ligament
- Between transverse processes
- Limits side-bending
Where is the Interspinous Ligament, and what movement does it limit?
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Interspinous Ligament
- Between spinous processes
- Limits flexion (bending forwards)
Where is the Supraspinous Ligament, and what movement does it limit?
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Supraspinous Ligament
- Along tips of spinous processes
- Limits flexion (bending forwards)
Label the Joints
Label the Ligaments
Label the Joints
The dens is held against the anterior arch of the axis by the…
Transverse ligament
Which structure is most likely to be compromised if there is disruption or laxity of the transverse ligament resulting in atlanto-axial instability?
The spinal cord.
Disruption or laxity of the transverse ligament may cause the dens of C2 or the posterior arch of C1 to impinge on the spinal cord within the vertebral column
