Peripheral Nervous System

Lecture: 1/5 chapters

Gross Anatomy

A. Cervical Part

1. How many cervical nerves are there?

2. What is the cervical enlargement?

1. 8 cervical nerves

2. An enlargement that contains neurons that innervate the upper limbs

B. Thoracic Part

How many thoracic nerves are there?

12 thoracic nerves

C. Lumbar Part

1. How many lumbar nerves are there?

2. Q: What is the lumbosacral enlargement?

1. 5 lumbar nerves

2. An enlargement that contains neurons that innervate the lower limbs

D. Sacral Part

What is the conus medullaris?

The end of the spinal cord

E. Cauda Equina

1. What is the cauda equina?

2. What is the filum terminale?

1. A collection of nerve roots

2. A pia mater anchor for the conus medullaris

Spinal Nerve Distribution

A. Cervical Plexus

1. What forms the cervical plexus?

2. What important nerve is contained in the cervical plexus?

3. What does the phrenic nerve innervate?

1. The anterior rami of C1–C4

2. The phrenic nerve

3. The diaphragm

B. Brachial Plexus

What forms the brachial plexus?

The anterior rami of C5–T1

Posterior Cord

1. What nerves are associated with the posterior cord of the brachial plexus?

2. What does the axillary nerve innervate?

1. The axillary nerve and radial nerve

2. The deltoid and teres minor muscles.

What does the radial nerve innervate?

The posterior arm and forearm muscles

Lateral Cord

1. What nerve is associated with the lateral cord of the brachial plexus?

2. What does the musculocutaneous nerve innervate?

1. The musculocutaneous nerve

2. The biceps brachii and brachioradialis muscles

Medial Cord

1. What nerve is associated with the medial cord of the brachial plexus?

2. What does the ulnar nerve innervate?

1. The ulnar nerve

2. Some of the anterior arm and most of the intrinsic hand muscles

Medial & Lateral Cords

1. Which nerve is associated with both the medial and lateral cords of the brachial plexus?

2. What does the median nerve innervate?

1. The median nerve

2. Most of the anterior forearm

c. Lumbar Plexus

What forms the lumbar plexus?

The anterior rami of L1–L4

Femoral Nerve

What does the femoral nerve innervate?

The anterior thigh muscles and hip flexors

Saphenous Nerve

What does the saphenous nerve innervate?

The medial portion of the lower leg and the foot

Obturator Nerve

What does the obturator nerve innervate?

Adductor muscles

D. Sacral Plexus

What forms the sacral plexus?

The anterior rami of L4–S4

Sciatic Nerve

What does the sciatic nerve do?

It splits into several divisions that innervate various areas of the thigh, leg, and foot

Tibial Nerve

• Where does the tibial nerve branch from?

  • What does the tibial nerve branch into?

    • What does the tibial nerve innervate?

• The sciatic nerve

  • The lateral and medial plantar nerves

    • The lower leg and foot

Common Peroneal Nerve

Where does the common peroneal nerve branch from?

The sciatic nerve

1. What does the common peroneal nerve branch into?

2. What does the common peroneal nerve innervate?

1. The superficial and deep peroneal nerves

2. The posterolateral leg and knee

Pudendal Nerve

1. According to the lecture, where does the pudendal nerve branch from?

2. What does the pudendal nerve innervate?

1. The sciatic nerve

2. The genitalia, anus, and perineum

Plexus → Source

1. Cervical: ?

2. Brachial: ?

3. Lumbar: ?

4. Sacral: ?

1. C1–C4

2. C5–T1

3. L1–L4

4. L4–S4

Nerve → Main Function

1. Phrenic → ?

2. Axillary → ??

3. Radial → ??

4. Musculocutaneous → ??

1. diaphragm

2. deltoid + teres minor

3. posterior arm + forearm muscles

4. biceps brachii + brachioradialis

Nerve → Main Function

5. Ulnar → ??

6. Median → ?

7. Femoral → ??

5. some anterior arm + most intrinsic hand muscles

6. most anterior forearm

7. anterior thigh + hip flexors

Nerve → Main Function

8. Saphenous → ??

9. Obturator → ?

10. Sciatic → ???

8. medial lower leg + foot

9. adductor muscles

10. various areas of thigh, leg + foot

Nerve → Main Function

11. Tibial → ??

12. Common peroneal → ??

13. Pudendal → ???

11. lower leg + foot

12. posterolateral leg + knee

13. genitalia + anus + perineum

1. Cervical enlargement → ?

2. Lumbosacral enlargement → ?

3. Conus medullaris → ?

1. upper limbs

2. lower limbs

3. end of spinal cord

4. Cauda equina → ?

5. Filum terminale → ?

4. collection of nerve roots

5. pia mater anchor for conus medullaris