Vertebral Column Flashcards
Describe the gross structure of the vertebral column
33 vertebrae: 7 cervical, 12 thoracic, 5 lumbar, 5 sacral, 4 coccygeal
Discrete Single Vertebrae:
• 24 separable vertebrae
• All capable of individual movement
Fused Vertebrae:
• 9 vertebrae fused to give 2 innominate structures
- – Sacrum (fusion of 5 vertebrae)
- – Coccyx (fusion of 4 vertebrae)
Can you label the vertebral column?
What are the gross functions of the the vertebral column?
Project weight of body to pelvis and lower limbs (centre of gravity)
Attachment for bones (skull, ribs)
Attachment for muscles (trunk, pelvic and pectoral girdle)
Protection & passage of spinal cord
Shock absorption
Segmental innervation of the body
How does gravity affect the vertebral column?
The weight of the body is projected into lower limbs about a line that passes centrally through the natural curvatures of the vertebral column. Passes through vertebral column at:
– C1&C2
– C7&T1
– T12&L1
– L5 & S1
• ‘Weak points’ of vertebral column
Vertebral bodies increase in size inferiorly as compression forces increase
Sacral vertebrae: fused, widened & concave anteriorly to transmit weight of the body through pelvis to legs
Label a cross section of the spinal cord being protected by a vertebrae
Vertebral column acts as a conduit through which spinal cord passes
• Allows spinal (segmental) nerves to leave or join the cord at specified points
Describe movements of the vertebral column
Describe the gross structure of a vertebrae
General characteristics:
- Rounded body anteriorly
- Vertebral arch posteriorly
Vertebral foramen: for spinal cord and meninges
Vertebral arch:
Gives rise to 7 processes
• Spinous
• Transverse
• Articular (zygapophyses)
What are some characteristics of the vertebral body?
- Usually the largest part of the vertebra
- Usually the main weight bearing part of the vertebra
- Major site of contact between adjacent vertebrae
- Articular surface covered with hyaline cartilage
- Linked to adjacent vertebral bodies by intervertebral discs
- Size increases from superior to inferior
Can you label the processes of the vertebra?
- 2 superior articular processes (facets) interlock with the vertebra above
- 2 inferior articular processes (not shown) interlock with the vertebra below.
- Thoracic vertebrae: Facets for head and tubercle of ribs
- Lamina + pedicle = vertebral arch
Describe characteristics of the superior and inferior vertebral processes
- Lined with cartilage
- Synovial joints are formed between vertebral arches of adjacent vertebrae
- Spinal nerves emerge through intervertebral foramina (= superior + inferior intervertebral notch)
- Strengthened by Ligamentum Flavum
Describe movements at facet joints
Articulation of superior and inferior articular processes = facet joint (synovial)
• Interlocking design – Prevents anterior
displacement of vertebrae
– Orientation determines amount of flexion and rotation permitted
What are some characteristics of intervertebral discs
- Account for 25% of the length of the vertebral column
- High water content that keeps them turgid
- Decrease in size with age
- Slightly wedge-shaped → secondary curvature of spine
Consist of two regions:
– nucleus pulposus (central)
– annulus fibrosus (peripheral)
Give characteristics of the annulos fibrosus component of intervertebral discs
- Highly complex design
- Made from lamellae of annular
- bands in varying orientations
- Outer lamellae are collagenous
- Inner lamellae are fibro- cartilaginous
- Avascular and aneural
- Surrounds nucleus pulposus
- is the major ‘shock absorber’
- Highly resilient under compression - stronger than the vertebral body
Give characteristics of the the nucleus pulposus
- Remnant of notochord
- Gelatinous
- High osmotic pressure
- Changes in size throughout day
- Changes in size with age
- Surrounded entirely by annulus fibrosus
- Centrally located in the infant
- Located more posteriorly in the adult
What are the characteristics of a typical cervical vertebrae?
- Smallest of the discrete vertebrae
- Form skeleton of the neck
- Bifid Spinous Process (except C7)
- Transverse foramen in transverse process
– Foramen transversarium
– Conduit for vertebral artery and vein (except C7)
– C7 foramen transmits the accessory vertebral vein
- Large triangular vertebral (neural) foramen
- Body is small and broad from side to side.
- Superior articular facet faces upward and backward while inferior articular facet faces downward and forward.
Describe characteristics of the first cervical vertebra
Articulates with:
– Occiput of skull superiorly (atlanto- occipital joint → flexion and extension – “nodding”)
–Axis (C2) inferiorly (atlanto-axial joint → lateral rotation – shaking the head)
- No vertebral body (Body is fused with axis to form dens or odontoid process)
- No spinous process
- Widest cervical vertebra
- Vertebral arches are thick and strong to form a powerful lateral mass
- ‘Nodding’ between superior articular processes of atlas and occipital condyles
Describe characteristics of the second cervical vertebra
-Strongest cervical vertebra
Characterised by 3 main features:
– The Odontoid Process or Dens
– Rugged lateral mass
– Large spinous process
Dens and transverse ligament prevent horizontal displacement of atlas
Describe characteristics of the seventh cervical vertebra
- Vertebra prominens.
- Longest spinous process
- Spinous process is not bifid.
- The transverse process is large, but the foramen transversarium is small and only transmits the accessory vertebral veins.
Describe characteristics of the thoracic vertebrae
Demi-facets on sides of body for articulation with head of rib (T2-T8); whole facets T9-10
Costal facets on transverse processes for articulation with tubercle of rib (except T11 and T12)
Vertebral foramen is small and circular
Give characteristics of lumbar vertebrae
Largest of the discrete vertebrae (large body, thick blunt spinous process)
No foramina on transverse processes (cf. cervical vertebrae)
No costal facets (cf. thoracic vertebrae)
Vertebral foramina are small and triangular
Articular processes face medially (superior) and laterally (inferior) – permit flexion
Describe the curvature of the vertebral column in a young adult
- 4 distinct curvatures
- Sinusoidal profile - confers great flexibility and resilience
- 2 kyphoses (anterior flexions): thoracic and sacrococcygeal
Kyphoses are continuations of the primary curvature of the foetus
2 lordoses (posterior flexions): cervical and lumbar
Lordoses are secondary curvatures
Describe the anterior and posterior ligaments of the vertebral column
Anterior longitudinal ligament:
- Anterior tubercle of atlas to sacrum
- United with periosteum of vertebral bodies
- Mobile over intervertebral discs
- Prevents hyperextension
Posterior longitudinal ligament:
- Body of axis to sacral canal
- Continues superior to axis as ‘tectorial membrane’
- Relatively weak
- Prevents hyperflexion
What are the superspinous ligaments?
- Tips of adjacent spinous processes
- Strong bands of white fibrous tissue
- Lax in extension
- Tight in flexion (mechanical support for vertebral column)
What is ligamentum nuchae?
Attached to:
– External occipital protruberance
– Spinous processes of all cervical vertebrae
– Spinous process of C7
- Maintains secondary curvature of cervical spine
- Helps the cervical spine support the head
- Major site of attachment of neck and trunk muscles (e.g. Trapezius, Rhomboids)
