LP #95 The Brachial Plexus

Question 1

A network of nerves

Answer 1

Plexus

Question 2

4 somatic plexus

Answer 2

• Cervical (C1-C4): neck, scalp & shoulder
• Brachial (C5-T1): upper limb
• Lumbar (L1-L4): lower limb
• Sacral (L4-S4): gluteal region & lower limb

Question 3

2 nerve roots

Answer 3

• Dorsal (sensory) nerve root

* Ventral (motor) nerve root

Question 4

• composed of dorsal & ventral roots
• mixed nerves contain sensory & motor nerve fibers
• very short then branch

Answer 4

Spinal nerves

Question 5

Branches of mixed spinal nerves are dorsal & ventral rami (which are mixed)
*mixed nerves contain sensory & motor nerve fibres

Answer 5

Rami

Question 6

Only _______ rami contribute to somatic plexuses

Answer 6

Ventral

Question 7

Rami communicants:

Answer 7

Part of ANS

Question 8

• Large network of nerves
• From ventral rami C5-T1
• located in neck & axilla:
• ends in axilla where its cords travel along axillary artery & give rise to primary nerves of upper limb

Answer 8

The Brachial Plexus

Question 9

The brachial plexus Innervations

Answer 9

• upper limb
• pectoral girdle
• extrinsic back mms

Question 10

Brachial plexus organization:

* Real Tired? Drink Coffee

Answer 10

• Ventral rami
• Trunk
• Division
• Cords
• (branches: peripheral nn)

Question 11

Produce network of nerves

• arise from nerve roots via spinal nerves
• originate from C5-T1 spinal nerves

Answer 11

Ventral rami

Question 12

Trunks: 5 ventral rami converge into 3 trunks?

Answer 12

• upper (C5,C6)
• middle (C7)
• lower (C8, T1)

Question 13

Trunks diverge to form anterior & posterior divisions?

Answer 13

Divisions

Question 14

• posterior divisions converge to form posterior cord
• anterior divisions of upper & middle trunks converge to form lateral cod
• anterior division of lower trunk forms medial cord

Answer 14

Cords

Question 15

Fascial compartments of upper limb

Arm?

Answer 15

• ant compartment:
• elbow/shoulder flexors
• post. Compartment:
• elbow/shoulder extensors

Question 16

Fasical compart. Of upper limb

*Forearm?

Answer 16

• Ant. Compart.:
• wrist/ finger flexors
• Post. Compart.:
• wrist/ finger extensors

Question 17

4 major nerves Innervate upper limb mm?

Answer 17

• Musculocutaneous
• Radial
• Median
• Ulnar

Question 18

• anterior brachial mm?
• posterior brachial & antebrachial mm?
• all lateral antebrachial mm; some lateral hands mm
• flexor carpi ulnaris; most hand mm

Answer 18

• musculocutaneous nerve
• radial nerve
• medial nerve
• ulnar nerve

Question 19

• originates from Posterior Cord
• spinal segments: C5-C6
• innervates:
• motor: deltoid & teres minor
• sensory: skin & joint capsule of shoulder

Answer 19

Axillary

Question 20

• originates from lateral cord
• spinal segment: C5-C7
• innervates ant. Brachium:
• motor: Biceps brachii, brachialis & coracobrachialis
• sensory: skin on lateral forearm (very variable)

Answer 20

Musculocutaneous

Question 21

• originates from lateral & medial cords
• spinal segment: C5-C8, T1
• innervate:
• motor: most wrist flexor mm; 4 intrinsic hand mm
• sensory: skin on lateral hand (palm) & dorsum of fingers 2-3

Answer 21

Median

Question 22

• originates from medial cord
• spinal segment: C8, T1
• innervates:
• motor: few wrist/finger flexor mm & most intrinsic hand mm
• sensory: skin on ant. & post. Hand, medial third

Answer 22

Ulnar

Question 23

• originates from posterior cord
• largest n of brachial plexus
• spinal segment: C5-C8, T1
• innervates:
• motor: posterior mm of the arm & forearm; supinator
• sensory: skin on posterolateral surface of upper limb except dorsum of fingers 2-3

Answer 23

Radial

Question 24

Brachial plexus: minor peripheral nerves (Motor nerves)

Answer 24

• Dorsal scapular
• Long thoracic
• Thoracodorsal
• Nerve to subclavius
• Suprascapular nerve
• Medial pectoral
• Lateral pectoral
• Upper subscapular
• Lower subscapular

Question 25

Brachial plexus: minor peripheral nerves (Cutaneous nerves)

Answer 25

* Medial brachial cutaneous * Medial antebrachial cutaneous * Superior brachial cutaneous * Inferior brachial cutaneous * posterior brachial cutaneous

Question 26

* originates from ventral ramus of C5 | * innervates rhomboids & levator scapula

Answer 26

Dorsal scapular

Question 27

* originates from ventral rami C5-C7 | * innervates serratus anterior

Answer 27

Long thoracic

Question 28

* originates from ventral rami C6-C8 | * innervates latissimus dorsi

Answer 28

Thoracodorsal

Question 29

* originates from ventral rami C4-C6 | * innervates suclavius

Answer 29

Nerve to subclavius

Question 30

* originates from ventral rami C4-C6 | * innervates supraspinatus, infraspinatus & the shoulder joint

Answer 30

Suprascapular nerve

Question 31

* originates from ventral rami C8-T1 | * innervates pectoralis minor, pectoralis major

Answer 31

Medial pectoral

Question 32

* originates from ventral rami C5-C7 | * innervates pectoralis minor, pectoralis major

Answer 32

Lateral pectoral

Question 33

* originates from ventral rami C8-T1 | * innervates skin on medial brachium to medial epicondyle & olecranon

Answer 33

Medial brachial cutaneous

Question 34

* originates from ventral rami C8-T1 | * innervates skin on medial antebrachium to wrist

Answer 34

Medial antebrachial cutaneous

Question 35

* originates from ventral rami C5-C6 | * innervates skin over lower deltoid mm & lateral side of mid-arm

Answer 35

Superior brachia cutaneous

Question 36

* originates from ventral rami C5-C6 | * innervates skin n inferolateral aspect of arm

Answer 36

Inferior brachial cutaneous

Question 37

* originates from ventral rami C5-C8 | * innervates skin on posterior arm as far as olecranon

Answer 37

Posterior brachial cutaneous