An Introduction to gross anatomy and somatic tissue innervation

Question 1

Which myotome group is responsible for elbow flexion & wrist extension?

Answer 1

C6

Question 2

What is the myotatic reflex?

Answer 2

This tests the integrity of the connection between afferent and efferent neurons at a specific spinal segmental level.

Question 3

During early mesoderm development, where are undifferentiated cells located?

Answer 3

They are aligned adjacent to the notochord

Question 4

Which myotome group is responsible for lateral head rotation?

Answer 4

C3

Question 5

Define what a dermatome is.

Answer 5

area of skin innervated by a segmented level of the spinal nerve root.

Question 6

Which myotome group is responsible for elbow extension & wrist flexion?

Answer 6

C7

Question 7

Which myotome group is responsible for thumb extension?

Answer 7

C8

Question 8

When does somatic nervous system development occur?

Answer 8

Occurs at Carnegie states 9-11 of embryo development (19-26 days)

Question 9

Which myotome group is responsible for finger abduction?

Answer 9

T1

Question 10

Which myotome group is responsible for head flexion?

Answer 10

C1

Question 11

Which myotome group is responsible for shoulder abduction?

Answer 11

C5

Question 12

Define a nerve plexus.

Answer 12

A network of nerve branches that intersect and connect. In the somatic nervous system, the ventral rami of adjacent spinal nerves mix and mingle together to form the various trunks and divisions, which ultimately convey both afferent and efferent nerve fibers to multiple terminal nerve branches (i.e. peripheral nerves). The nerve plexuses of the somatic nervous system are the following: cervical, brachial, lumbar, and lumbosacral. The autonomic nervous system contains plexuses within the body cavities.

• Combo of efferent and afferent nerve fibers

Question 13

What is a myotome?

Answer 13

This is the muscle that is served by the spinal cord root. It is also the greatest concentration of motor neurons within the anterior gray columns that provide efferent supply to the agonist muscle groups.

Question 14

What is the concept of “Double Coverage” and why is it important?

Answer 14

During development, axons follow the migration of myogenic cells from the anterior gray columns of the spinal ganglion into the limb. this causes a bunch of nerves to invade the developing limb and mix with the myogenic cells.

This occurs in order to ensure that groups of skin and muscles are not supplied by the ventral rami of only a single source.

Without this concept or adaptation the loss of function due to single nerve damage would result in an inability to use entire systems within the body.

Question 15

Illustrate the anatomy of a spinal nerve.

Answer 15

Question 16

Which myotome group is responsible for head rotation?

Answer 16

C2

Question 17

Which myotome group is responsible for scapular elevation?

Answer 17

C4