Spine Flashcards
What are the extrinsic muscles of the back? How are they innervated?
Superficial: movements of the upper limb
- trapezius
- levator scapulae
- rhomboid major and minor
- latissimus dorsi
Intermediate: movements of thoracic wall
- serratus posterior superior
- serratus posterior inferior
Innervated by ant. rami of spinal nerves
What are the intrinsic muscles of the back? How are they innervated?
Suboccipital
Splenius
Erector spinae
Inntervated by pos. rami of spinal nerves
- support head and move vertebral column
- move head
- move ribs relative to vertebral column
What are the different types of spina bifida?
Occulta = defect in posterior arch of vertebra of L5 or S1; asymptomatic; overlying skin intact
Cystica = defect in posterior arch of vertebra of L5 or S1; open defect; visible mass
- meningocoele: swelling of dura mater and arachnoid mater
- myelomeningocoele: swelling of dura mater, arachnoid mater, and spinal neural tissue
- rachischisis: spine lies open and neural plate splayed
Ouline a vertebroplasty. When is it indicated?
Body of vertebra filled with bone cement to increase the strength of the vertebral body (prevent further loss of height) and disrupt the pain nerve endings (via heat generated by cement)
Indicated for:
- vertebral body collapse and pain from vertebral body
- osteoporotic wedge fractures
What is kyphosis? Give some causes.
Abnormal curvature of thoracic vertebrae
Can be secondary to TB of thoracic vertebrae —> gibbus deformity
What is scoliosis? Give some causes.
Abnormal lateral curvature + rotational element of one vertebra upon another (true scoliosis)
Congenital: associated with abnormalities of chest wall, genitourinary tract, and heart
May be manifestation of central or peripheral nerve abnormalities e.g. cerebral palsy, polio
Muscular dystrophy: abnormal muscle does not retain normal spine alignment
Bone tumours, spinal cord tumours, localised disc tumours also cause scoliosis.
What is lordosis?
Abnormal curvature of lumbar vertebrae (“swayback deformity”)
What are the components of a vertebral disc?
Nucleus pulposus = gelatinous centre (absorbs compression forces between vertebrae)
Anulus fibrosis = outer ring of collagen and wider zone of fibrocartilage in lamellar configuration (limits rotation of vertebrae)
What are the ligaments of the vertebral column?
Anterior longitudinal ligament = base of skull to ant. surface of sacrum; attached to vertebral bodies and intervertebral discs
Posterior longitudinal ligament = C2 to base of skull (tectorial membrane) to sacrum
Ligamenta flava = pass between laminae of adjacent vertebrae to form posterior surface of vertebral canal (resists separation of laminae in flexion and assists in extension back to anatomical position)
Supraspinous ligament = vertebral spinous processes from C7 to sacrum
Interspinous ligament = between adjacent vertebral spinous process
Ligamentum nuchae = external occipital protruberance to foramen magnum to tip of spinous process of C7 (supports head, attachment for adjacent muscles)
What are the components of spinal stenosis?
Zygapophyseal joint hypertrophy + ligamenta flava hypertrophy + mild disc protrusion = reduced dimensions of vertebral canal
Caused by degeneration of vertebral column
What are the components of vertebral stability?
Anterior column:
- vertebral bodies
- ant. longitudinal ligament
Middle column:
- vertebral bodies
- pos. longitudinal ligament
Posterior column:
- ligamenta flava
- interspinous ligaments
- supraspinous ligaments
- ligamentum nuchae
What are the results of destruction of the components of vertebral stability?
Destruction of one column —> stable injury (rest and analgesia)
Destruction of two columns —> unstable (req. fixation and immobilisation)
Destruction of three columns —> significant neurological defect (fixation to prevent further extension of neurological defect and stabilise vertebral column)
What are the consequences of injury to the craniocervical junction?
High chance of significant spinal cord injury.
- quadriplegia
- phrenic nerve paralysis —> resp. depression
- disruption of central part of symp. nerves —> severe hypotension
What is spondylolisthesis?
Vertebra slips anteriorly due to abnormal anatomy of facet joints or degenerative changes
What is spondylolysis?
Degenerative osteoarthritis of pars interarticularis (region between superior and inferior facets) due to incomplete developlment.
Predisposes to spondylolisthesis.