Embryology Week 4

What is the name of the connection between the notochordal canal and the secondary yolk sac?

Neurenteric canal

What degenerates to make the neurenteric canal?

Hypoblast and endoderm

What mixes when the neurenteric canal opens?

Amniotic fluid and secondary yolk sac fluid

What closes the whole within a few days of the neurenteric canal opening?

Endoderm cells

Most is the most common malformation occurring due to failure of the neurenteric canal to form?

Split cord malformation

What are the AKAs of split cord malformation?

diastematomyelia / diastomyelia

What is the term for 2 spinal cords?

Diastomyelia

What are the neurological sequelae of disastomyelia?

Neurogenic bladder

Lower extremity and sensory problems (radiculopathy)

Low back pain with radicular pain

What % of people with diastomyelia have congenital scoliosis?

70%

What is the major cause of congenital scoliosis?

Hemivertebra

What are common comorbities with diastomyelia?

Congenital scoliosis

Lumbar radicular pain

Progressive weakness of the lower extremities

What causes weakness of the lower extremities in people with diastomyelia?

IVF collapse and cord degeneration

What is the name of the structure that closes the neurenteric canal?

Notochordal plate

What germ layer does curling of the notochordal plate occur in?

Mesoderm

What creates the notochordal tube?

Notochord cells fusing in the dorsal midline

What fills the notochordal tube to make it solid?

Notochordal cells

When is the notochord referred to as the definitive notochord?

When it completely separates from the endoderm and ectoderm

What molecule is produced by notochordal cells in the nucleus pulpsosus?

Proteoglycans

What replaces notochord cells in the nucleus pulpsosus?

Chondrocyte-like cells

What happens if the chondrocyte-like cells are exposed to the blood?

Painful autoimmune inflammation response

What nerves are activated by autoimmune attack of chondrocyte-like cells?

Sinuvertebral nerve nociceptors

How is the inflammatory attack of chondrocyte-like cells perceived?

Low back pain

Where can inflammatory autoimmune low back pain refer to?

SI joint, buttock, or anterolateral thigh

What is the #1 cause of chronic low back pain?

Discogenic pain

What kind of disc damage can expose chondrocyte-like cells to the blood?

Radial annular tear (grade 3)

What is the only way to see an annular tear?

Provocative discography