Blood vessels and nerves travel through the shoulder, providing a blood supply and sensation to the shoulder and arm.
Blood vessels of the shoulder
There are 4 main arteries that supply blood to the shoulder:
- The subclavian artery is located beneath the collarbone. This is where blood enters the shoulder region.
- The axillary artery is located in the armpit region. The axillary artery is a continuation of the subclavian artery and supplies the upper arm with blood.
- The thoracoacromial artery is a branch of the axillary artery and is located at the top of the shoulder. It divides into 4 branches that serve the shoulder and upper chest.
- The brachial artery travels down the upper arm. It is a continuation of the axillary artery. Branches of the brachial artery provide blood supply to the muscle and bones of the shoulder.
The blood supplied by these arteries travels back to the lungs for oxygenation via veins in the shoulder and arm.
Nerves of the shoulder
Nerves are responsible for providing signals to the brain to move the arms and can sense temperature, pain, and touch. Some of the nerves that run through the shoulder are part of a network called the brachial plexus. The brachial plexus has many nerves that contribute to it, such as:
- The ulnar nerve
- The median nerve
- The radial nerve
- The musculocutaneous nerve
In some people, shoulder pain may be a symptom of a nerve being pinched where it originates in the upper spine. In these cases, the shoulder may feel numb, weak, or have a “pins and needles” feeling.
Nerve blocks—numbing medication that is injected into a group of nerves—may be used to prevent or treat certain types of shoulder pain. In some cases, nerve blocks will be used as a form of regional anesthesia during surgery.