Human Anatomy: Vertebral Column Quiz

Cervical Spine, Cord and Nerves and Skull Osteology

• Learning Outcomes:
  • Describe the structure of cervical vertebrae, specifically atlas and axis.
  • Describe the joints between the vertebrae.
  • Describe the vertebral arteries and their course.
  • Discuss the cervical spinal nerves.
  • Describe the spinal meninges and relate the anatomy to a lumbar puncture.
  • Describe the osteology of the skull from frontal, posterior, superior and inferior views.
  • Describe the cranial fossae.

Vertebral Column

• Structure:
  • The vertebral column has 7 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 4 coccygeal vertebrae.
  • Intervertebral discs are crucial for weight bearing. Their size increases from cervical to lumbar vertebrae.
  • Vertebral arches protect contents of the vertebral canal.
  • The vertebral canal houses the spinal cord, its meninges, blood vessels, and spinal nerves.

Functions of the Vertebral Column

• Protection: Spinal cord, nerve roots, and internal organs.
• Base for Attachment: Ligaments, tendons, muscles.
• Structural Support: Connects upper and lower body, maintaining balance.
• Flexibility and Mobility:
  • Flexion (forward bending).
  • Extension (backward bending).
  • Lateral flexion (bending to the sides).
  • Rotation (turning).
  • Any combination of these movements.

Curvatures of the Vertebral Column

• KYPHOSIS: The primary, first formed curve of the vertebral column.
• LORDOSIS: Secondary curves develop as the child sits upright (lumbar) and holds its head erect (cervical).

General Structure of Vertebrae

• Vertebral bodies: Weight bearing components; increasing in size from superior (cervical) to inferior (lumbar).
• Vertebral arches: Protect the structures contained within the vertebral canal.
• Vertebral canal: Houses the spinal cord, the meninges, and the blood vessels.

The Vertebral Arch

• The vertebral arch is formed by the pedicles and laminae.
• It includes spinous processes, which project posteriorly in the midline, and transverse processes on each side.
• Superior and inferior articular processes articulate with adjacent vertebrae.

Joints in the Vertebral Column

• Zygapophysial joints (facet joints): Plane type joints formed between articular processes.
• Secondary cartilaginous joints/symphyses: Intervertebral discs connecting vertebral bodies.

Intervertebral Disc

• A fibrocartilaginous joint connecting the vertebral bodies.
• Annulus fibrosus: Outer layer, high tensile strength, connects adjacent annular epiphyses of vertebral bodies and attaches to cartilaginous endplate.
• Nucleus pulposus: Inner gel-like structure providing resilience and high water content (80-85%).

Ligaments of the Vertebral Column

• Longitudinal ligaments: Anterior - along anterior vertebral bodies, Posterior - along posterior vertebral bodies.
• Ligamentum flavum: Yellow due to elastin, between laminae.
• Interspinous ligament: Connects adjacent spinous processes.
• Supraspinous ligament: Connects spinous processes; ligamentum nuchae in the neck.

Intervertebral Foramina

• Spinal nerves and blood vessels emerge from the intervertebral foramina.

Cervical Vertebrae

• Atlas (C1): Atypical vertebra lacking a body and spinous process. Key features include anterior and posterior tubercles. lateral masses, facilitating nodding; important for articulation with occipital condyles of skull.
• Axis (C2): Atypical vertebra featuring a dens (odontoid process). This structure allows for rotation of the head and articulation with the axis.
• Typical Cervical Vertebrae (C3-C7): These vertebrae typically exhibit a bifid spinous process.

Atlanto-occipital Joint

• Synovial condyloid joints between the superior articular facets of the atlas and the occipital condyles of the skull. Allow nodding movements.

Atlantoaxial Joint

• Synovial pivot joint; allows rotation of the head. Key elements include the atlas and dens/odontoid process of the axis.

Vertebral Arteries

• These arteries supply blood to the spinal cord and brain. They ascend in transverse foramina, enter the foramen magnum, and branch into various spinal arteries and the posterior inferior cerebellar artery (PICA). The two vertebral arteries then merge into the basilar artery.

Clinical Correlate - Cervical Spine Injury

• In trauma patients, clearing the airway should avoid extending the cervical spine.
• Contraindicated for cases with raised intracranial pressure (ICP).

Spinal Cord

• Continuation of the brainstem.
• Extends from the foramen magnum of the skull to the first lumbar vertebrae.
• Important for connecting the brain to the body.

Spinal Cord Segments and Spinal Nerves

• Cervical (8)
• Thoracic (12)
• Lumbar (5)
• Sacral (5)
• Coccygeal (1)

Spinal Cord and Spinal Nerves: Vertebral Level Differences

• Spinal cord segments don't always match corresponding vertebral level.

Spinal Nerves

• Important for communication between the spinal cord and the body; branching out from the spinal cord.
• They emerge from the intervertebral foramina. C1-C7 emerge above their vertebrae, C8 below C7, and Thoracic/Lumbar Below their respective vertebrae.
• There are eight cervical spinal nerves.

Cervical Sympathetic Trunk

• Continuous with thoracic trunk.
• Travels posteriorly to the carotid sheath on the prevertebral fascia.
• Consists of three ganglia (superior, middle, inferior).

Cervical Plexus

• Formed by the anterior rami of C1-C4 spinal nerves.
• Innervates muscles and skin of the neck and part of the head.
• Nerves of note include the lesser occipital, great auricular, transverse cervical, supraclavicular nerves.

Brachial Plexus

• Formed by the anterior rami of C5-T1 spinal nerves.
• Important for controlling muscular and sensory functions throughout the upper limb.

Posterior Rami of Cervical Nerves

• Smaller branches than the anterior rami; the medial branches are sometimes named (the great occipital nerve, the third occipital nerve) to indicate innervation region.
• Each posterior ramus innervates muscles of the back and the skin of the back.

Arterial Supply

• Longitudinal vessels: Anterior and posterior spinal arteries.
• Segmental spinal arteries: Branching of the posterior spinal arteries from PICA, and the ascending cervical arteries, enter and branch off from intervertebral foramina.
• Anterior and posterior radicular arteries: Travel through intervertebral foramina to supply the spinal cord and its nerve roots.
• Artery of Adamkiewicz: A significant branch, arises in the lower thoracic or upper lumbar region

Venous Drainage

• Longitudinal channels and midline channels parallel to the anterior median fissure and posterior median sulcus.
• Veins drain into the internal vertebral plexus in the extradural space.

Lumbar Puncture (Tap)

• A procedure that uses a needle to obtain cerebrospinal fluid.
• Used for various clinical assessments, such as assessing for infection, to measure pressure, and for diagnostic reasons.
• Contraindicated for cases of increased intracranial pressure (ICP).

Practical Questions

• Provided after the references in a separate section. (No detail available from the image provided).

Test your knowledge on the structure and function of the vertebral column, including vertebral bodies, intervertebral discs, and ligaments. This quiz covers key concepts that are essential for understanding the anatomy and biomechanics of the spine.