Brachial Plexus

Question 1

What is the brachial plexus

Answer 1

It is a complicated network of nerves formed by the anterior rami of spinal nerves C5 to T1

Question 2

Where does the brachial plexus originate from

Answer 2

From the neck called the posterior triangle, passes laterally and inferiorly over the 1st rib and enters the axilla

Question 3

What does the brachial plexus consist of

Answer 3

It consists of (medial to lateral) roots, trunks, division and cords

Question 4

Where does all the major nerves that innervate the upper limb originate from

Answer 4

The brachial plexus

Question 5

Functions of nerves entering the upper limb?

Answer 5

1.Sensory innervation of skin and deep structures
2.Motor innervation to muscles
3. Control of diameter of blood vessels
4. Secretion of sweat glands

Question 6

Transition zones of the brachial plexus

Answer 6

Axilla- pyramid shaped found under the armpit
Cubital fossa-triangle shape, found on the elbow joint
Carpal tunnel - tunnel shape/hollow opening found on the wrist joint

Question 7

Robert Trucker drinks cold beer

Answer 7

Roots, trunks, division, cords, branches

Question 8

Roots

Answer 8

> These are the anterior rami of C5 to T1 nerves
they enter the posterior triangle of neck passing between anterior and middle scalene muscles

Question 9

Trunks

Answer 9

> Originate from root; pass laterally over the 1st rib and enter the axilla; 3 trunks;
Superior - C5 & C6
Middle- C7
Inferior - C8 & T1

Question 10

Divisions

Answer 10

Each trunk divides into anterior and posterior divisions

Question 11

Cords

Answer 11

3 cords originate from the divisions; related to 2nd part of axillary artery; lateral, medial & posterior cords

Question 12

Branches

Answer 12

16 branches that arise from roots, trunks and cords

Question 13

Major branches of the brachial plexus

Answer 13

> Axillary nerve
Radial nerve
Musculocutaneous nerve
Ulnar nerve
Median nerve

Question 14

Axillary nerve

Answer 14

> Arises from posterior chord of brachial plexus
it innervates two muscles of the shoulder region and skin over the lower part of the shoulder region

Question 15

Radial nerve

Answer 15

> Arises from the posterior chord of brachial plexus
it innervates all the muscles in the posterior compartment of the arm and forearm
it supplies skin of the back of arm, forearm and hand

Question 16

Musculocutaneous nerve

Answer 16

> arises from the lateral cord of the brachial plexus
it supplies muscles of the anterior compartment of the arm and skin of the lateral aspect of the forearm

Question 17

Ulnar nerve

Answer 17

> arises from medial cord of the brachial plexus
it innervate 2 muscles in the forearm and most of the small muscles of the hand(medial half) and the medial 1 1/2 fingers

Question 18

Median nerve

Answer 18

> arises from the medial and lateral chords of brachial plexus
it innervates most of the muscles of the anterior compartment of the forearm and small muscles of the thumb in the hand
it supplies skin of the lateral half of the hand and the lateral 3 1/2 fingers