16 Neves and Vasculature of the Upper Extremity
Learning Objectives:
- Describe the brachial plexus and its branches.
- Identify the components of the brachial plexus.
- Describe the vasculature of the upper extremity and identify the regions supplied or drained by each vessel.
- Identify the major arteries and veins of the upper extremity.
Terms to Know
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Arteries of the Upper Extremity
Veins of the Upper Extremity
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Brachial Plexus
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Introduction
In this lab you will learn about the neurovasculature of the upper extremity. You will learn about the brachial plexus, which eventually branches into all nerves that innervate the upper extremity. You will also learn about the subclavian, axillary, and brachial arteries and their branches that eventually provide the whole upper extremity with blood. You are responsible for the information in this lab guide on the muscles or structures innervated or supplied by these nerves and arteries.
Lab Activities
Activity 1: Nerves of the upper extremity
Explore the brachial plexus. In general, your first step should be looking for the “M” formed by the parts of the medial and lateral cords coming together to form the median nerve. This will help you get your orientation of what is medial and what is lateral. Once you know which is the medial or lateral cord, you can narrow down the branches coming from them. The M sits just anterior to the axillary artery. This also makes it easier to identify the posterior cord sitting posterior to the “M” and the axillary artery.
- Notice where the nerves are running to. If you know the muscles they innervate and see them entering that muscle, you will be able to identify which nerve it is.
- Here are a few tips for specific nerves in the axillary region:
- Dorsal scapular nerve: This nerve will emerge very early from the brachial plexus, near the neck, and you will be able to see it running posteriorly to the rhomboids and levator scapulae.
- Suprascapular nerve: This nerve will run posteriorly from the brachial plexus towards the scapula. It runs through the suprascapular notch inferior to a ligament forming a bridge across the notch (called the transverse scapular ligament) to reach the supraspinatus and then through the spine of the scapula to reach the infraspinatus.
- Lateral pectoral nerve: This nerve runs from the brachial plexus to the pectoralis major. You can also know that it is the lateral pectoral nerve rather than the medial because it will branch off the lateral cord.
- Medial pectoral nerve: This nerve is usually the first branch from the medial cord, and it runs through the pectoralis minor, innervating it on its path to the pectoralis major.
- Medial brachial and medial antebrachial cutaneous nerves: These nerves will branch distal to the medial pectoral nerve off of the medial cord. They run to the skin of the medial arm and forearm.
- Long thoracic nerve: This nerve runs tight to the thoracic wall, innervating the serratus anterior muscle. This is also vis