Dermatomes/Myotomes and spinal nerve plexuses Flashcards Preview

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Flashcards in Dermatomes/Myotomes and spinal nerve plexuses Deck (29)
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1
Q

Name the 3 primary germ layers

A

Endoderm, mesoderm, ectoderm

2
Q

What does the endoderm create?

A

Internal linings of the body, and some internal organs

3
Q

What does the ectoderm create?

A

Outer linings of the body; skin and hair

4
Q

What does the mesoderm create?

A

All other tissues; dermis, heart, muscles, bones, blood, connective tissue, formation of internal body cavity

5
Q

What does the paraxial mesoderm create?

A

The head and somites

6
Q

What do somites create?

A

The sclerotome, myotome, dermotome

7
Q

Sclerotome is

A

Bones and cartilage

8
Q

Mytome is

A

Skeletal muscles

9
Q

Dermotome is

A

Dermis layer of skin

10
Q

What happens to somite cells that migrate anteriorly?

A

They give rise to the muscles/skin of the trunk and upper limbs (hypaxial muscles)

11
Q

What happens to somite cells that migrate posteriorly?

A

They give rise to intrinsic muscles/skin of the back (epaxial muscles)

12
Q

What is the main job of the posterior horn?

A

Sensory

13
Q

What is the main job of the anterior horn?

A

Motor function

14
Q

Posterior ramus innervates?

A

Epaxial muscles of back/skin

15
Q

Anterior ramus innervates?

A

Hypaxial muscles of trunk and upper limbs

16
Q

What will an injury to a posterior root cause?

A

Sensory deficits only

17
Q

What will an injury to an anterior root cause?

A

Motor deficits only

18
Q

What is a dermatome?

A

Single area of skin that is supplied with afferent nerve fibers from a SINGLE posterior spinal root

19
Q

What causes the dermatomes of the lower extremities to have a pulled look?

A

Internal rotation of the leg during development

20
Q

What is a myotome?

A

All of the muscles innervated by a SINGLE efferent anterior root – most muscles are composed of multiple myotomes

21
Q

What happens if there is an injury to 1 segment of anterior rootlets?

A

This may lead to weakness of the muscle but NOT complete loss of function due to the muscle being innervated by multiple myotomes

22
Q

What is a plexus?

A

Multiple spinal nerves combining to form 1 PERIPHERAL nerve

23
Q

Femoral nerve

A

L2-L4 spinal nerves

24
Q

Obturator nerve

A

L2-L4 spinal nerves

25
Q

Sciatic nerve

A

L4-S3 spinal nerves

26
Q

Tibial nerve

A

Branch of sciatic; L4-S3

27
Q

Common fibular nerve

A

Branch of sciatic; L4-S2

28
Q

Lateral femoral cutaneous nerve

A

L2-L3 spinal nerves

29
Q

Posterior femoral cutaneous nerve

A

S1-S3 spinal nerves