A test yourself image of the posterior view of the upper arm and shoulder showing the bony elements and the deeper muscles. The visible structures are numbered 1-6. The answers in the box below are as follows 1. Teres Minor 2. Teres Major 3. Triceps Brachii: Long Head 4. Triceps Brachii: Lateral Head 5. Latissimus Dorsi 6. Triceps Brachii: Medial Head.