IVD-Functions/Ligaments Flashcards
How does the intervertebral disc attach to the vertebral body?
Sharpey’s fibers from the outer lamellae of the annulus fibrosus are firmly embedded into the epiphyseal rims of the adjacent vertebral bodies
What are the divisions of the embryonic somite?
the sclerotome, myotome, and dermatome
What structure is formed following migration of sclerotomes to surround the notochord?
the intrasclerotomal fissure or fissure of von Ebner
What does the intrasclerotomal fissure or fissure of von Ebner become?
the perichordal disc
What will the dense sclerotomite become?
the upper part of the vertebral segment forming below
What structure forms following migration and subsequent mixing of the sclerotomites?
the vertebral blastema
What part of the interertebral disc will the notochord form?
the nucleus pulposus
What part of the intervertebral disc will the perichordal disc form?
the annulus fibrosus
What is the earliest indicator of the position of the adult intervertebral disc?
the intrasclerotomal fissure or fissure of von Ebner
What vertebral levels will the anterior longitudinal ligament attach to?
those between occiput and S3 inclusive are traditionally indicated
What is the lowest extent of the anterior longitudinal ligament based on recent studies?
L3
What is believed to form the anterior longitudinal ligament in the lumbar spine?
the tendon of the crura of the diaphragm
What innervates the anterior longitudinal ligament?
the anterior neural plexus formed by fibers from the ventral primary ramus and sympathetic postganglionic fibers from the paravertebral ganglia
What is the function of the anterior longitudinal ligament?
it brakes or limits dorsi-flexion or hyperextension of the vertebral column
What was ossification of the anterior longitudinal ligament in the lumbar region identified as?
Forestier’s Disease
What is ossification of the anterior longitudinal ligament ligament in the lumbar region now identified as?
Diffuse Idiopathic Skeletal Hyperostosis or DISH
Newer research suggests what regional variation in the posterior longitudinal ligament?
prominent in the cervicals, occasional in the thoracics, rare in the lumbars
What is the relationship of the posterior longitudinal ligament attachment laterally?
it forms the anterior boundary of the spinal canal
What is the innermost layer of the posterior longitudinal ligament called?
the perivertebral ligament
What is the function of the posterior longitudinal ligament?
it brakes or limits flexion of the vertebral column
Where is ossification of the posterior longitudinal ligament most commonly identified?
the cervical spine with an 80% incidence
What is the clinical sign of posterior longitudinal ligament ossification in the cervical spine?
a loss of hand and finger dexterity
What is the clinical sign of posterior longitudinal ligament ossification in the lumbar spine?
faltering gait
What is the gender, age, and ethnic bias associated with ossification of the posterior longitudinal ligament?
it is greater in males over 50 and has a higher incidence in the Japanese
Based on histology, what is the classification of the intervertebral disc?
a cartilaginous (amphiarthrosis) symphysis
What is the name given to the ligamentum flavum based on appearance and histology?
it is a yellow elastic ligament
What fibers are most ligaments made up of?
collagen type I fibers which are whitish in appearance
Where is ossification of the ligamentum flavum most commonly identified?
the thoracic spine or thoracolumbar transition zone
What is the relationship between the capsular ligament and mobility?
the more lax/loose the capsular ligament is, the greater the motion of the joint
What regions of the vertebral column demonstrate the greatest laxity of capsular ligaments?
the cervical and lumbar regions
What layers are present in the capsular ligament?
a superficial layer of collagen fibers and a deep layer of elastic fibers
If the zygapophyseal capsular ligament is not significantly involved in restricting motion what is its function?
it is probably involved in proprioceptive feedback to the muscles stabilizing the vertebral couple during movement
What is now thought to be a major function of the interspinous ligament?
it is more likely a proprioceptive transducer for the spinal reflex
What is the name given to the superficial layer of the ligamentum nuchae?
the funicular layer or part
What is the name given to the deep layer of the ligamentum nuchae?
the lamellar layer or part
What are the attachment sites for the superficial layer of the ligamentum nuchae?
the external occipital protuberance, external occipital crest, and spinous tubercle of C7
What is the histological make-up of the human ligamentum nuchae?
it is a yellow elastic ligamentum, but has more collagen fibers than in quadrupeds
What is the classic function of the human ligamentum nuchae?
it brakes or limits flexion of the cervical spine
What is the termination level inferiorly for the supraspinous ligament according to current literature?
primarily at L4 (73%); between L4 and L5 (5%)
What is now thought to be a major function of the supraspinous ligament?
it is a proprioceptive transducer for the spinal reflex
