Nerve and blood supply to upper limb

Question 1

Subclavian artery origins

Answer 1

Left SCA
- Arch of aorta

Right SCA
- Brachiocephalic trunk

Question 2

Subclavian artery is divided by what muscle?

Answer 2

Scalenus anterior

- It passes through the scalene triangle

Question 3

Scalene triangle

• Borders
• Structures that pass through it

Answer 3

Borders:

• Lateral, scalene medius muscle
• Medial, scalene anterior
• Inferior, first rib

Structures that enter through

• Subclavian artery
• Brachial plexus (trunk)

Question 4

Subclavian artery division

Answer 4

In relation to the scalene anterior

• First part= medial
• Second part= behind
• Third part= Lateral

Question 5

First SCA division

Answer 5

Gives rise to
- Vertebral artery

• Thyrocervical trunk —> thyroid, cervical, supra-scapular (scapular anastomosis)

Question 6

Dorsal scapular artery

Answer 6

Branch of SCA

• 2nd or 3rd division
• Contributes to scapular anastomosis/

Question 7

Termination of the SCA

Answer 7

Terminates as axillary artery after crossing outer border of first rib.

Question 8

Axillary artery division

Answer 8

In relation to the pectoralis minor muscle

• First= medial
• Second= behind
• Third= lateral

First and second part associated with brachial plexus

Question 9

Axillary artery termination

Answer 9

Terminates at the lower border of teres major to become the brachial artery.

Question 10

Third division of axillary artery branches

Answer 10

Subcapular
- Part of scapular anastomosis

Anterior+ Posterior circumflex humeral artery
- To the surgical neck and shaft of the humerus

Question 11

Fracture of humeral surgical neck

Answer 11

Can lead to trauma of the ant/post circumflex humeral artery.

Question 12

Brachial artery

• Supplies
• Branch
• Division

Answer 12

Located superficially
- Supplies flexors of the arm (bicep, brachialis etc)

Branch

• Profunda brachii–> supplies extensors (triceps), anastomosis around elbow.
• Runs along radial groove

Division- at cubital fossa.

• Radial
• Ulnar

Question 13

Fracture to humerus

Answer 13

Can cause trauma to profunda brachii artery

Question 14

Radial artery

• Covered by..
• Enters through…
• Pierces what muscle?
• Terminates at

Answer 14

Lateral in forearm, smaller than ulnar

Covered by brachioradialis muscle.

Enters through anatomical snuff box to the dorsal hand

Pierces through first dorsal interosseous muscle

Forms deep Palmer arch

Question 15

Deep palmer arch

Answer 15

Arterial network that anastomoses with the ulnar artery

• It is formed from the radial artery
• Located below flexor tendons

Surface anatomy
- On an extended thumb, it is located on a line drawn from the distal border of the thumb across the palm.

Question 16

Ulnar artery

• Covered by..
• Deep branch
• Terminates at

Answer 16

Medial of forearm, larger than radial.

Covered by flexor carpi ulnaris muscle.

Branch- common interosseous artery
- Supplies muscle in the forearm

Terminates at superficial palmar arch

Question 17

Superficial palmar arch

Answer 17

Terminal arterial network of the ulnar artery
- Located above flexor tendons

Gives rise to palmar digit arteries

Surface anatomy
- One finger breath distal from deep palmar branch.

Question 18

Deep veins

Answer 18

Vanae comintantes
- Paired veins

Drain into axillary vein ultimately

Question 19

Superficial arm veins

Answer 19

Drains from dorsal venous arch
- Cephalic (lateral). Runs within deltopectoral groove.

• Basilic (medial)
• Joined by median cubital vein (where blood is common taken from)

Ultimately drain to axillary veins

Question 20

Lymph nodes

Answer 20

Axillary nodes
- Into axillary vein

Cubital nodes
- Into basilic vein

Deltopectoral node
- Into cephalic vein

Question 21

Brachial plexus

Answer 21

Mixed nerves to the upper limbs

• Motor, sensory and sympathetic fibres
• Axons from multiple spinal nerves

Divisons

• Roots
• Trunks
• Divisions
• Cords
• Terminals

Question 22

Brachial plexus roots

Answer 22

C5-T1 ventral primary rami

Question 23

Dorsal scapular nerve

Answer 23

Originates from C5 of brachial plexus nerve root.

Supplies

• Rhomboids
• Levator scapulae

Question 24

Long thoracic nerve

Answer 24

Roots C5-7 of brachial plexus

- Supplies serratus anterior

Question 25

Motor innervations of brachial plexus roots | C5-T1

Answer 25

C5- Shoulder C6- Flexors in arm C7- Extensors in arm C7/8- Flexor and extensor of forearm T1- Arm intrinsics

Question 26

Brachial plexus trunks

Answer 26

Passes trough scalene triangle Divided into - Superior (C5-6) - Middle (C7) - Inferior (C8-T1) Superior trunk--> suprascapular nerve

Question 27

Suprascapular nerve

Answer 27

Arises from the superior trunk of the brachial plexus Supplies - Supraspinatus - Infraspinatus

Question 28

Divisons of the brachial plexus

Answer 28

Divide from the trunk- anterior and posterior Anterior division, from middle and superior trunk - Forms Lateral cord Anterior division, from inferior trunk - Forms medial cord Posterior divisions from all trunks - Forms posterior cord Anterior divisions - Supply flexor muscles Posterior divisions - supply extensors

Question 29

Cords of the brachial plexus

Answer 29

Described in relation to the axillary artery - Lateral (anterior divisions of superior and middle trunk) - Posterior (posterior divisions of all trunks) - Medial (anterior division of inferior trunk) Located under pectoralis minor muscle.

Question 30

Lateral cord terminates as...

Answer 30

Musculocutaneous nerve Median nerve (w/ median cord)

Question 31

Musculocutaneous nerve

Answer 31

Terminal branch of the lateral cord. (C5-6) Innervates - Motor supply: Coracobrachialis (which it pierces), biceps brachii, brachialis. - Sensory: lateral forearm, via lateral cutaneous nerve of the forearm (at the elbow)

Question 32

Medial cord

Answer 32

Composed of the anterior division of the inferior trunk. Terminates as - Ulnar nerve - Median nerve (w/ lateral cord)

Question 33

Medial nerve

Answer 33

From medial and lateral cord - C8-T, C5-C7. Innervates - Motor to: Anterior forearm and hand EXCEPT flexor carpi ulnaris. - Sensory to: Lateral palm of hand, digits 1-3, half of 4

Question 34

Ulnar nerve

Answer 34

Terminal branch of the medial cord - C8-T1 - Transverses through cubital tunnel (funny bone) Innervates - Motor to: medial anterior forearm and hand, including flexor carpi ulnaris - Sensory to: Medial hand, digits half 4 and 5.

Question 35

Posterior cord termination

Answer 35

Radial nerve Axillary nerve Posterior cord - Posterior divisions of all trunks

Question 36

Radial nerve

Answer 36

Terminal branch of the posterior cord. (C5-6, C7, C8-T1) - Runs along spiral groove of humerus ``` Innervates - Motor (deep branch) to: Posterior arm, forearm (Extensors) Triceps Supinator Brachioradialis ``` - Sensory (superficial branch) to: Posterior arm, forearm, lateral dorsum hand.

Question 37

Axillary nerve

Answer 37

Terminal branch of posterior cord. - Enters quadrangular space Innervates - Motor to: Deltoid, teres minor - Sensory to: badge area of the arm.