Musculoskeletal Embryology I Flashcards

1
Q

Intraembryonic mesoderm lateral to notochhord and neural tube thickens to form two longitudinal columns of ___ ____

A

paraxial mesoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

By the end of the third week, the paraxial mesoderm becomes segmented into blocks - the ____ (42-44 pairs)

A

somites

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Each somite differentiates into two parts. What is the ventromedial part that form the vertebrae and ribs called?

A

Sclerotome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Each somite differentiates into two parts. What is the dorsolateral part called?

A

dermomyotome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

The myotome region of the dermomyotome forms ____

A

myoblasts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

The dermatome region of the dermomyotome forms the ____

A

dermis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Mesodermal cells give rise to loosely organized embryonic connective tissue called the ___

A

mesenchyme

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

in this process, mesenchymal cells from membranous sheaths, and the bone is formed by osteoblasts and osteoclasts within the membranous model

A

intramembranous bone formation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

in this process, the model of bone is formed by chondrocytes and osteoblasts within the cartilage form bone

A

endochondral bone formation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Vertebrae develop by ___ bone formation

A

endochondral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

At week ___, the sclerotomes appear as paired condensations of mesenchymal cells, migrate around the notochord and neural tube to merge from the opposing somite

A

4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

The body of each vertebra is formed by ____. The densely packed caudal half of one sclerotome grows and fuses with the loosely arranged cephalic half of the next caudal sclerotome to form the mesenchymal ____, the primordium of vertebral body.

A

resegmentation; centrum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

The _____ surrounds the notochord and serves as bony floor for the spinal cord

A

centrum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

The dorsal mesenchymal cells that surround the neural tube form the ___ ___, which is the primordium of the vertebral arch

A

neural arch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

The notochord degenerates where the developing bodies are formed but persists between adjacent vertebral bodes to become the ___ ___ of intervertebral discs

A

nucleus pulposus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

This outer part of the intervertebral discs is formed by original sclerotomal cells that migrate into that site

A

annulus fibrosus

17
Q

At six weeks, ____ centers appear in each vertebra and ____ begins during the eight week

A

chondrificaiton; ossification

18
Q

In normal circumstances, the developing vertebral bodies are formed from migration sclerotomal cells around the neural tube and appearance of chondrification centers that soon unite. If this migration and differentiation fails on one side, results in the failure of half of vertebra to form. These vertebral defects produce ____ of the vertebral column

A

scoliosis

19
Q

some lateral mesenchymal condensations called ___ processes develop in association with vertebral arches of all the developing neck and trunk vertebrae

A

costal

20
Q

In cervical vertebrae, the costal and transverse process give rise to lateral and medial boundaries of ___ foramen.

A

transverse

21
Q

At birth, each vertebra consists of three bony parts connected by cartilage. The bony halves of the vertebral arches fuse during __ to ___ years of life.

A

3; 5

22
Q

Imperfect fusion of vertebral arches can lead to a condition called ___ __, which leaves the spinal cord, spinal nerves and meninges vulnerable to injury

A

spina bifida

23
Q

This type of spina bifida is the failure of formation of the vertebral arch in lumbar vertebrae, although the spinal cord, spinal nerves, and meninges are normal. The defect is often marked by a tuft of overlying hair.

A

spina bifida occulta

24
Q

This type of spina bifida is more severe. The neural tube fails to close, and involves the protrusion of the spinal cord, the meninges, or both through the defects in vertebral arches. These defects are usually associated with significant neurological deficits.

A

spina bifida cystica

25
Q

True or false? Ribs are cartilaginous during the embryonic period but begin to ossify during fetal development.

A

true

26
Q

The lower 5 ribs have no connection to the ___

A

sternum

27
Q

The sternum develops independenttly from mesenchymal condensations called ___ ___, that are located in the ventrolateral body wall

A

sternal bars

28
Q

Each myotome splits into two structures, the dorsal epimere and ventral hypomere, which forms ___ and ____ muscles respectively

A

epaxial; hypaxial

29
Q

_____ divisions of the myotomes form the segmental muscles of the main body axis, the extensor muscles of neck, and the vertebral column (deep back muscles)

A

epaxial

30
Q

What happens to the embryonic extensor muscles that are derived from sacral and coccygeal myotomes?

A

they degenerate

note: their adult derivatives are the dorsal and sacrococcygeal ligaments

31
Q

____ divisions of cervical myotomes form the scalene, prevertebral geniohyoid, and infra hyoid muscles

A

hypaxial

32
Q

The ____ myotomes form the lateral and ventral flexor muscles of the vertebral column (rectus abdominus, external abdominal oblique, transverse abdominus)

A

throacic

33
Q

The intercostal muscles are derived from the ___ myotome

A

hypaxial

34
Q

At limb forming levels, the hypaxial ___ also invade the developing limb buds and give rise to limb musculature

A

myoblasts

35
Q

The ___ myotomes form the quadratus lumborum muscle

A

lumbar

36
Q

Dermatome will become the dermis of the ___ and ___

A

neck; trunk

37
Q

As the somites develop, each is associated with a corresponding ___ ___ growing out from the neural tube.

A

spinal nerve

38
Q

each circumferential band of skin on the trunk receives sensory innervation from a single pair of ___ ___ spinal nerves

A

segmentally related