Vertebrae Characteristics Quiz

Cervical Vertebrae

• Cervical spine consists of seven vertebrae: C1-C7; subdivided into upper (C1, C2) and lower (C3-C7) cervical.
• C7 has unique features, differing from other cervical vertebrae.
• Cervical vertebrae bodies are small, the smallest compared to thoracic and lumbar.
• Short, bifid spinous processes; triangular-shaped and large vertebral foramen accommodates a large spinal cord.
• Transverse processes have anterior and posterior tubercles, with a small transverse foramen for vertebral artery passage from C6-C1.
• Superior articular processes face posterosuperiorly; inferior processes face anteriorly. Presence of uncinate processes on lateral edges of bodies may become more prominent with age.

Atypical Cervical Vertebrae

• C1 (Atlas) resembles a ring, lacks a body, has large superior articular facets for skull articulation allowing nodding motion.
• C2 (Axis) features the dens (odontoid process) enabling rotation, characterized by a small transverse process.
• C7 has a long, non-bifid spinous process resembling thoracic vertebrae; small transverse foramina as the vertebral artery does not pass through.

Thoracic Vertebrae

• Composed of 12 vertebrae (T1-T12), each with a rib associated.
• Thoracic bodies grow larger from T1 to T12; long spinous processes point posterior-inferiorly.
• Round vertebral foramen, distinct from the triangular shape in cervical and lumbar regions.
• Transverse processes are longer and posterior to articular facets; T1-T10 have facets for rib articulation (demifacets).
• Articular processes extend superiorly and inferiorly with surfaces directed anteriorly and posteriorly.

Lumbar Vertebrae

• Comprising five lumbar vertebrae (L1-L5), characterized by large bodies to support body weight.
• Short spinous processes directed almost directly posteriorly and triangular vertebral foramina.
• Transverse processes are short and directed laterally, located anterior to the articular processes.
• Superior articular processes face medially, while inferior ones face laterally, limiting rotation in the lumbar region.
• Mammillary processes on lumbar vertebrae are attachment sites for multifidus muscles.

Sacrum

• Formed from five fused vertebrae, exhibiting a kyphotic curve, functioning as a single bone.
• Contains ventral sacral foramina for nerve root emergence, replacing intervertebral foramina.
• Superior articular processes articulate with L5's inferior processes, with the sacral promontory marking the anterior ridge of the sacral body.
• Lacks typical transverse processes, characterized by wings or ala on either side of the sacrum.

Overview of the Human Spine

• Composed of 33 vertebrae: 7 cervical (neck), 12 thoracic (upper back), 5 lumbar (lower back), 5 fused as the sacrum, and 4 fused as the coccyx.
• Features 4 spinal curves: 2 kyphotic curves (thoracic and sacral) and 2 lordotic curves (cervical and lumbar).

Spinal Curves

• Kyphotic curves:
  • Considered primary, develop during fetal embryonic development.
  • Found in the thoracic and sacral regions.
• Lordotic curves:
  • Considered secondary, developed through life stages.
  • Cervical curve appears by 6 months when infants start holding their heads up.
  • Lumbar curve develops as children begin to stand.

Vertebral Structure Characteristics

• Vertebral Body:
  • Large anterior component providing spinal support.
  • Composed of vascular trabecular bone covered by cortical bone.
  • Size varies in height and width throughout the spine.
• End Plates:
  • Superior and inferior end plates are covered with hyaline cartilage, connecting to intervertebral discs.

Vertebral Arch and Canals

• Vertebral Arch:
  • Formed by pedicles and lamina, posteriorly closing the arch.
  • Creates the vertebral canal, which houses the spinal cord (vertebral foramen).
• Vertebral Foramen vs. Intervertebral Foramina:
  • Vertebral foramen: Large opening for the spinal cord.
  • Intervertebral foramina: Openings for spinal nerves, found on posterolateral sides of adjacent vertebrae.

Articular Features

• Articular Processes and Facets:
  • Articular processes extend superiorly and inferiorly to connect with adjacent vertebrae.
  • Articular facets feature flat surfaces covered with hyaline cartilage.
• Transverse and Spinous Processes:
  • Transverse process: Lateral bony extension.
  • Spinous process: Posterior bony extension.

Regional Variations in Vertebrae

• Cervical Vertebrae:
  • Smallest bodies with unique transverse foramina.
• Thoracic Vertebrae:
  • Characterized by round vertebral foramina and elongated spinous processes.
• Lumbar Vertebrae:
  • Largest bodies with additional features like mammillary processes, which will be explored in detail later.