Posterior Arm and Radial Nerve

Question 1

What muscle occupies the entire posterior compartment of the arm?

Answer 1

Triceps

Question 2

Where does the triceps arise?

Answer 2

Arises by a long head from the scapula and two shorter heads (lateral and medial) from the humerus

Question 3

Where does the triceps terminate?

Answer 3

Common tendon of triceps is inserted into the olecranon process of the ulna

Question 4

Where is the proximal attachment of the long head of the triceps?

Answer 4

On the infraglenoid tubercle of the scapula

Question 5

What is the main action of the triceps on the elbow joint?

Answer 5

Chief extensor of the elbow

Question 6

What is the action of the anconeus muscle?

Answer 6

Assists triceps in extending elbow

Question 7

What is the nerve supply to the triceps and anconeus?

Answer 7

Radial nerve

Question 8

What is the radial nerve a branch of?

Answer 8

It is the terminal branch of the posterior cord of the brachial plexus

Question 9

What does the radial nerve supply?

Answer 9

All the extensor muscles of the elbow and wrist joints

Question 10

What is the course of the radial nerve in the arm?

Answer 10

It enters the arm anterior to the long head of the triceps and runs with the profunda femoris artery and curves around the midshaft region of the humerus in the radial groove

Question 11

What is the segmental root value of the radial nerve?

Answer 11

C5-T1

Question 12

Which artery accompanies the radial nerve within the radial groove?

Answer 12

Profunda brachii artery

Question 13

Which muscles are most likely to have their innervation affected by a midshaft humeral fracture?

Answer 13

All muscles of the posterior compartments of the arm and forearm