Vertebral Column Flashcards
Functions of vertebral column
• Protects spinal cord and spinal nerves.
• Supports weight of body above pelvis.
• Provides a partly rigid and flexible axis for body.
• Plays important role in posture and locomotion.
Source of haematopoetic, gives blood to body
Number of vertebral columns
N= 33 Cervical=7 Thoracic= 12 Lumbar= 5 Sacrum= 5 Coccyx= 4
Composition of vertebrae
• Vertebral body consists of vascular, trabecular (spongy, cancellous) bone enclosed by thin compact bone layer.
Curvatures of the spine
Cervical curvature (lordosis): acquired secondarily when infant can support weight of it’s own head. Thoracic curvature (kyphosis): primary curvature present in fetus. Lumbar curvature (lordosis): acquired secondarily when infant can stand upright and support its own weight. Sacral curvature: primary curvature present in feature.
Typical vertebra features
• Seven processes arise from the vertebral arch of a typical vertebra Spinous process (1), transverse process (2), articular processes (4)
Cervical vertebrae
Greatest range of movement because of relatively thick IV discs, nearly horizontal orientation of articular facets and less mass of body surrounding cervical vertebrae.
Atlas (C1)
- No vertebral body or spinous process
- Paired lateral masses (bears weight)
- Widest cervical vertebra (most lateral transverse processes)
- Superior articulation with occipital condyles (atlanto-occipital joints)
- Inferior articulation with “Axis” C2
Axis (C2)
- Strongest
- Odontoid process (“Dens”)
- Small transverse processes
- Large bifid spinous process
- Superior articulation with “Atlas” C1
- Inferior articulation with C3
Function of transverse foramina
Vertebral artery branches from the SUBCLAVIAN ARTERY.
Ascends through C6-C1 to enter foramen magnum.
Instability caused by:
• Ligamentous laxity;
• Shallow and angled facet joints;
• Under-developed spinous processes;
• Incomplete ossification of odontoid process;
• Relatively large head;
• Fulcrum of motion at C2-C3 (adults C5-C6);
• Weak neck muscles.
• Younger children more susceptible to upper cervical spine injury (occiput -> C3).
• 8-10-years-old cervical spine reaches adult proportions.
Pediatric cervical spine
Structure that traverse the vertebral foramen
Spinal cord
Structure that traverse the intervertebral foramen
Spinal nerves
Structure that traverse the transverse foramen (only in cervical vertebra)
Vertebral artery
Intervertebral discs
Function: shock absorbers; give mobility Anulus fibrous = fibrocartilage Nucleus pulposus = gelatinous remnant (collagen, hydrated proteoglycans) of embryonic notochord •IV discs thickest in lumbar region; •Secured by anterior and posterior longitudinal ligaments. Pain insensitive inner 2/3 Pain sensitive outer 1/3
Hunchback
Kyphosis: Accentuated flexion of thoracic spine.
Aetiology: poor posture, osteoporosis.
Swayback
lordosis: Accentuated extension of lumbar spine.
Aetiology: weakened trunk muscles, late pregnancy, obesity.
Scoliosis
Accentuated lateral and rotational curve of the thoracic or lumbar spine.
Aetiology: genetic, trauma, idiopathic; occurs in adolescent girls more than boys
Most unstable lumbar vertebra
L4 - L5
Lumbar vertebrae
•Large kidney-shaped body for weight-bearing;
•Mid-sized triangular vertebral foramen;
•Facets are face medial or lateral direction permitting good flexion
and extension;
•Spinous processes are short.
Atypical lumbar
Extra ribs on L1
Coccyx
no vertebral arches or vertebral canal (dural sac of spinal cord ends at S2)
Anterior longitudinal ligament
Strong and prevents hyperextension of spine (only ligament that limits extension!)
Attached to vertebral bodies AND I.V. discs. Foramen magnum-sacrum