The posterior compartment of the arm - muscles and vessels (dave's notes)

Question 1

List the muscles of the posterior compartment of the arm

Answer 1

Triceps - long, lateral and medial heads

Question 2

What is the origin of the long head of triceps?

Answer 2

The infraglenoid tubercle of the scapula

Question 3

What is the origin of the lateral head of triceps?

Answer 3

The upper half of the posterior humerus

Question 4

What is the origin of the medial head of triceps?

Answer 4

The lower half of the posterior humerus (inferomedial to the spiral groove and both intermuscular septae

Question 5

What is the insertion of triceps?

Answer 5

All three heads coalesce and insert into the posterior part of the upper surface of the olecranon process of ulna, and the posterior capsule

Question 6

What is the action of triceps?

Answer 6

Triceps extends the elbow

Question 7

What is the action of the long head of triceps?

Answer 7

Stabilises the shoulder

Question 8

What is the action of the medial head of triceps?

Answer 8

Retracts the capsule of the elbow joint

Question 9

What is the nerve supply to triceps?

Answer 9

Radial nerve (C6,7,8) from the posterior cord, 4 branches.

Question 10

What is the blood supply to the posterior compartment of the arm?

Answer 10

The profunda brachii artery. Supplies triceps

Question 11

What is the course of profunda brachii?

Answer 11

Passes through the quadrilateral space, then at the lateral intermuscular septum divides in to anterior and posterior branches to cubital anastomoses