Session 4 - Dermatomes Flashcards Preview

Semester 2 - MSK > Session 4 - Dermatomes > Flashcards

Flashcards in Session 4 - Dermatomes Deck (23)
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1
Q

What are embryonic precursors of skin and muscle known as?

A

Dermamyotomes

2
Q

From what do dermamyotomes arise?

A

Somites

3
Q

What do dermamyotomes differentiate into?

A

Dermis (dermatome) and muscle (myotome)

4
Q

What does a spinal segmental nerve comprise of?

A
Dorsal roots (sensory or afferent)
Ventral roots - efferent
Efferent can be
- Motor to skeletal muscle
- Autonomic to smooth muscle and glands
5
Q

What happens as the mixed spinal nerve emerges through intervertebral foramen?

A

It divides into dorsal and ventral ramus

6
Q

What is a dermatome?

A

An area of skin supplied by a single spinal nerve

7
Q

What is a myotome?

A

Group of muscles innvervated by a single spinal nerve

8
Q

What is the cutaneous distribution of a peripheral nerve?

A

An area of skin a peripheral nerve innervates - it is NOT a dermatome

9
Q

What is a motor unit?

A

made up of a motor neuron and the skeletal muscle fibers innervated by that axon

10
Q

What is the nerve supply root to the lower limb?

A

Lumbar and Sacral spinal segments
L1 - L4
L4 - S4

11
Q

Describe the lumbar plexus

A

Forms behind the psoas major muscle

Nerves emerge either medial or lateral to the borders of the psoas major muscle

12
Q

What nerves emerge lateral to the psoas major muscle in the lumbar plexus?

A

The femoral (L2-L4)
•Iliohypogastric
•Ilioinguinal
•Lateral cutaneous nerve of the thigh

13
Q

What nerves emerge medial to psoas major muscle?

A
  • The obturator nerve

* The lumbosacral trunk

14
Q

What is the sacral plexus composed of?

A
Lumbosacral trunk (Half of L4 and all L5)
Sacral spinal segmental out flow (S1-S4)
15
Q

Where does the sacral plexus form?

A

Plexus forms within the pelvic cavity

• Plexus lies in relation to piriformis

16
Q

What regions does the sacral plexus supply?

A

Pelvic region Gluteal region Perineal region The lower limb (via the sciatic nerve

17
Q

What does C4 innervate?

A

Skin Over The Shoulder Tip

18
Q

What does C5 innervate?

A

Radial side of Upper Arm

19
Q

What does C6 innervate?

A

Radial Side of Forearm

20
Q

What does C7 innervate?

A

skin of the hand

21
Q

What does C8 innervate?

A

Ulnar side of the Forearm

22
Q

What does T1 innervate?

A

Ulnar side of the Upper Arm

23
Q

What does T2 innervate?

A

Skin of the Axilla