DR2: Arm and brachial plexus

Question 1

What are the 3 flexor muscles of the arm?

Answer 1

Biceps brachii
Coracobrachialis
Brachialis

Question 2

What is the origin, insertion and function of biceps brachii?

Answer 2

Origin: supraglenoid tubercle of scapula (long head), coracoid process (short head)
Insertion: radial tuberosity
Function: flexion at shoulder and elbow, supinator of forearm

Question 3

What is bicipital aponeurosis?

Answer 3

Extension of biceps tendon

Crosses medially over superficial flexors of forearm to attach to posterior border of ulna via deep fascia

Question 4

What is the origin, insertion and function of coracobrachialis?

Answer 4

Origin: coracoid process
Insertion: medial aspect of humerus, halfway down shaft
Function: flexion at shoulder

Question 5

What is the origin, insertion and function of brachial?

Answer 5

Origin: distal half of anterior of humerus
Insertion: ulna tuberosity
Function: flexion at elbow

Question 6

What muscles are in the posterior compartment of the arm?

Answer 6

Triceps brachii

Question 7

What is the origin, insertion and function of triceps brachii?

Answer 7

Origin: infraglenoid tubercle (long head), posterior aspect of humerus above spiral groove (lateral head), posterior aspect of humerus below spiral groove (medial head)
Insertion: olecranon process of ulna
Function: extension

Question 8

What are the roots of the brachial plexus?

Answer 8

C5
C6
C7
C8
T1

Question 9

What branches come from the lateral cord?

Answer 9

Lateral pectoral nerve
Lateral head median nerve
Musculocutaneous nerve

Question 10

What does the lateral pectoral nerve supply?

Answer 10

Pectoral muscles

Question 11

Describe the path of the musculocutaneous nerve

Answer 11

Pierces coracobrachialis 5cm distal to conjoint tendon

Emerges on lateral aspect just above elbow

Question 12

What is a terminal branch of the musculocutaneous nerve?

Answer 12

Lateral cutaneous nerve of forearm

Question 13

What does the lateral cutaneous nerve of the forearm supply?

Answer 13

Skin of lateral forearm on dorsal and ventral aspects

Question 14

What are the branches of the medial cord?

Answer 14

Medial pectoral nerve
Cutaneous nerves of arm and forearm
Ulnar nerve
Medial head median nerve

Question 15

What does the medial pectoral nerve supply?

Answer 15

Pectoralis muscles

Question 16

What does the ulnar nerve supply?

Answer 16

Flexor muscles of forearm and small muscles in the hand

Question 17

What does the median nerve supply?

Answer 17

Muscles in the anterior compartment of the arm (flexors)

Question 18

What are the branches of the posterior cord?

Answer 18

Upper subscapular
Thoracodorsal
Lower subscapular
Radial nerve
Axillary nerve

Question 19

What does the radial nerve supply?

Answer 19

muscles and skin over posterior aspect of upper limb, triceps and extensor muscles of forearm

Question 20

Describe the path of the radial nerve

Answer 20

Leaves axilla into posterior compartment. spirals laterally around shaft of humerus on medial side of triceps, through spiral groove then into anterior compartment under muscles on lateral side of foreaem

Question 21

What does the axillary nerve supply?

Answer 21

Teres minor
Deltoid
Badge area of skkin

Question 22

What forms the quadrangular space?

Answer 22

Borders of teres minor, teres major, humerus and long head of triceps

Question 23

What is the stem artery to the upper limb?

Answer 23

Subclavian artery

Question 24

What does the right subclavian branch from?

Answer 24

Brachiocephalic trunk

Question 25

What does the left subclavian branch from?

Answer 25

Arch of aorta

Question 26

What happens to the subclavian artery as it passes over the 1st rib?

Answer 26

It becomes the axillary artery

Question 27

When does the axillary become the brachial artery?

Answer 27

When it crosses lower border of teres major

Question 28

What is a major branch of the brachial artery?

Answer 28

Profunda brachii artery which supplies triceps and elbow joint