I.D.2 Shoulder & Arm: Brachial Plexus: Page 1 of 5

Objectives:

4.2.1 Identify the roots, trunks, divisions and cords of the brachial plexus and the terminal branches arising from the cords.

4.2.2 Given a lesion to any part of the cords or branches, predict the sensory and motor deficits expected in the uppper extremity.

Assigned Readings:

Moore's COA: Pages 189-196. See blue boxes on pages 196-200 for clinical correlations. See yellow boxes on pages 200-201 for "The Bottom Line."

Step 1: Begin with the anterior view of shoulders that will allow us to build and define the brachial plexus.

🔍 Tap on image to enlarge

	Step 2: Next, add the C5 nerves.
	Step 3: Add the C6 nerves.
	Step 4: Add the C7 nerves.
	Step 5: Add the long thoracic nerve.

The long thoracic nerve originates from the roots of C5, C6 and C7 before the formation of the formation of the superior, middle and inferior trunks of the brachial plexus.

	Step 6: Add the middle scalene muscle. The long thoracic goes posterior and is hidden by the middle scalene muscle.
	Step 7: Add the serratus anterior. The long toracic innervates the serratus anterior.

	Why is this muscle named in this way?
Because the edge where it attaches to the ribs looks like a serrated knife. (Use the Rotate tool to visualize this edge.)

This nerve is very superficial on the thoracic wall and can be easily damaged. Look at where the serratus anterior attaches.

If this nerve is damaged, what happens to the movement of the upper arm?