Cervical Spine Anatomy and Movement Quiz

Vertebral Artery

• Right and left vertebral arteries arise from the subclavian arteries
• They ascend through the foramen transversarium
• They enter the cranial cavity via the foramen magnum
• They give off branches: meningeal, spinal, and cerebellar arteries
• They combine to form the basilar artery, which supplies the cerebellum, pons, and contributes to the circle of Willis

C1 - Atlas

• No body, pedicle, lamina, or spinous process
• Large transverse process for muscle attachment
• Ring formed by anterior and posterior arch and 2 lateral masses
• Superior articular facets articulate with occipital condyles, forming the atlanto-occipital joint
• Inferior articular facets articulate with C2 articular processes
• Dens (C2) articulates with the anterior arch, forming the atlanto-axial joint (C1/2)
• Transverse ligament between lateral masses

C2 - Axis

• The odontoid process (dens) projects superiorly to articulate with the atlas
• This articulation forms a vertical axis for rotation of the head (and atlas) on the axis, approximately 90 degrees
• Short transverse process
• Bifid spinous process
• No disc between atlas and axis

C7 - Vertebra Prominens

• Largest cervical vertebra
• Similar in shape to thoracic vertebrae
• Large non-bifid spinous process
• Clinical significance: Spinal Stenosis

Spinal Stenosis

• Narrowing of the spinal canal, reducing space for the spinal cord and associated nerves
• Causes: degenerative changes, spinal tumors, congenital conditions (Achondroplasia)
• Symptoms: extension-related radiculopathy, myelopathy

Joints of the Vertebral Column

• Intervertebral Facet or Zygapophyseal Joints
• Uncovertebral Joints (Cx)
• Atlanto-occipital/Craniovertebral Joints (Cx)
• Atlanto-axial Joints (Cx)
• Costovertebral Joints (Tx)
• Costotransverse Joints (Tx)
• Lumbosacral Joints
• Sacroiliac Joints

Intervertebral Disc (IVD)

• Endplate: Hyaline and fibrocartilage
• Diffusion of nutrients through endplate arteries
• Outer annulus fibrosus: rings of fibrocartilage (20), attaches to rims of vertebral bodies
• Inner nucleus pulposus: gelatinous (toothpaste) centre, cartilage cells, collagen fibers (Type II), semifluid ground substance – proteoglycan gel
• 60-70% water in the outer annulus, 70-90% water in the inner nucleus

Clinical - Disc Herniation

• Disc Protrusion, Prolapse, Extrusion, Sequestration

Spinal Coupling

• In the typical cervical spine, lateral flexion is coupled with ipsilateral rotation
• Due to the 45-degree inclination of articular facets
• Movement occurs in the coronal (LF) and transverse (Rot) planes simultaneously
• Note: at the craniovertebral level, a contralateral spinal coupling pattern exists

Neck Muscles

• Superficial: Anterior, Intermediate, Posterior, Lateral, Trapezius, Sternocleidomastoid, Levator Scapulae, Anterior Scalene, Splenius Cervicis/Capitis, Middle Scalene, Iliocostalis Cervicis, Posterior Scalene, Longissimus Cervicis/Capitis, Spinalis Cervicis/Capitis
• Deep: Anterior, Posterior, Longus Colli, Semispinalis, Multifidus, Longus Capitis, Rectus Capitis Posterior Major, Rectus Capitis Posterior Minor, Rectus Capitis Anterior, Rectus Capitis Lateralis, Obliquus Capitis Superior, Obliquus Capitis Inferior

Role of Muscles in the Cervical Spine

• 80% of cervical stability provided by the muscle system in mid-range and functional posture
• Deep sleeve of muscle envelops the cervical spine, providing segmental control
• High density of muscle spindles in deep muscles – sensorimotor control
• Superficial muscles have a greater role in torque production

Posterior Neck Muscles

• Superficial: Splenius Capitis and Cervicis, Iliocostalis Cervicis, Longissimus Cervicis and Capitis, Spinalis Cervicis and Capitis
• Deep: Semispinalis, Multifidus

Lateral Muscles of the Neck

• Sternocleidomastoid, Scalenes (Anterior, Middle, Posterior)

Suboccipital Muscles

• Rectus Capitis Major and Minor, Obliquus Capitis Superior and Inferior

The Triangles of the Neck

• Anterior Triangle: Borders - Superior: Mandible, Lateral: Sternocleidomastoid, Medial: Midline of neck
• Posterior Triangle: Borders - Anterior: Sternocleidomastoid, Posterior: Trapezius, Inferior: Clavicle

Clinical Conditions

• Facet Strain/Arthritis
• Spinal Stenosis
• Disc Herniation
• Myogenic Strain
• Cervical Radiculopathy
• Spinal Cord Compression
• Cervicogenic Headaches
• Cervicogenic Dizziness
• Vertebrobasilar Insufficiency (VBI)
• Craniocervical Instability
• TMJ Dysfunction
• Whiplash Associated Disorder (WAD)