We seldom think about it when we move any of our body parts. Whether it’s to walk, run, or even raise a hand to wave, we simply perform actions and expect things to happen.
Consider if nerves, muscles, ligaments, bones . . . any of the many things that make up our bodies, decided to stop working properly. In fact, many of you must have experienced this before.
Often it’s an injury after trying an unfortunate move in the gym, or because you’re not resting enough and giving the body time to recuperate.
Whatever the reason for your mild or major injury, we’ve all experienced the pain and suffering of not being able to perform as we would like. Sometimes, at the most basic of tasks.
The thoracodorsal nerve, is one of those that you never want to quit on you. It’s working hard each time you do a push-up, stir a pot, or swipe right on a potential match. It’s ever-present; always going.
So what exactly is the thoracodorsal nerve, and why should you care one iota if it exists or not? Let’s see.
Nerve Supply For The Upper Limbs
Getting down to some medical brasstacks now, all the not-usually-in-everyday-conversation terms included, to really give you the full picture of the importance of the thoracodorsal nerve.
First off, let’s take a look at where its journey begins.
The brachial plexus “is the network of nerves that sends signals from your spinal cord to your shoulder, arm and hand.”
It’s from the posterior cord of this nerves network that the thoracodorsal nerve springs. Though it can receive its fibers from the sixth cervical nerve (C6), the TDN is usually found starting from the seventh and eighth cervical nerves (C7-C8). (2)
In such a complex nerve network, one would think that the role of the thoracodorsal nerve might be diminished, but this is not the case. It serves to help with the steady and continuous functioning of the upper body, as it makes its noble journey through the axilla.
Already wondering what the axilla is? Got you covered. It’s the space below the shoulder where vessels and nerves traverse the upper arm, or the armpit for easy reference.
The thoracodorsal nerve travels tirelessly along it, ensuring that the latissimus dorsi, gets the “battery power” it needs.
Innervates The Latissimus Dorsi
The major function of the thoracodorsal nerve is to make sure the latissimus dorsi has its much needed motor supply, so the shoulder can perform at optimum level.
Without it, our shoulders would hang limp, we’d not be able to do any of the tasks or activities we don’t even think twice about, and this writer would not be able to type so you could read this. In fact, you probably couldn’t even hold your phone or tablet to read about the TDN.
As it makes its way along this path, the thoracodorsal nerve is around 2 – 3 mm, a tiny little stream that does quite a lot. Now before going on, here’s a way to make this process even an even clearer image.
Imagine the trek the thoracodorsal nerve takes as something akin to a train ride. First it dips under the posterior onto the axillary vein and as it clears that leg, appears in the axilla just close enough to the lateral thoracic vein.
It doesn’t stop there though, but does switch tracks both inferiorly and laterally until finally joining a fleet of subscapular vessels, that become one huge network again, known as the thoracodorsal neurovascular bundle.
As the latissimus dorsi is an internal rotator, extensor, and adductor for the shoulder, the importance of it being in top shape cannot be ignored.
The shoulder is the most unstable and moveable joint in the body and any number of problems can occur with it if the thoracodorsal nerve can’t do its job correctly.
Some of the problems you may face with thoracodorsal nerve damage include:
- Loss of flexibility.
- Loss of strength.
- Shoulder joint unable to handle stress.
- Unwanted injuries.
Helps Keep You Strong And Fit
As the latissimus dorsi, greatly aided by the thoracodorsal nerve, allows the shoulder to straighten, extend, and contract in a way that it can be moved toward the body’s midline, and rotate the arm medially, there are a number of activities that this allows us to perform.
Without these actions, not only would everyday tasks become near impossible or at least, highly difficult, but many upper body exercises and activities would be simply out of the question.
- Some of these you wouldn’t want to give up include:
- Mountain biking
- Rock climbing
- Body-weight based upper body exercises (push-ups, burpees, pull-ups, etc)
Who would have thought that a tiny little vein like the thoracodorsal nerve, could contribute so much to the upper body’s functions? It doesn’t even stop there.
As its sworn duty is to work to help the latissimus dorsi, and as that muscle has a scapular (refers to the shoulder/shoulder blade) attachment, it indirectly aids in ensuring that the shoulder’s inferior angle is kept firmly against the chest wall.
It’s further attachment to the ribs, means that the latissimus dorsi can act as a muscle of respiration, and as we trace it back to one of the source veins that allows it to work properly.
Yes, it’s all coming up thoracodorsal nerve.
Must Be Closely Monitored During Surgery
Often an axillary clearance procedure is required during breast cancer surgery for nodal metastases. That’s a major surgery in itself, and can become more complicated if the thoracodorsal nerve is not properly observed.
Injury to the thoracodorsal nerve is one of the complications related to the axillary dissection. Messing with a vein as important as this one is no joke, and surgeons have to keep their eye on the ball during procedures.
Luckily with the right knowledge and technique, this procedure becomes a walk in the park. So there’s no need to worry, the docs have it handled.
Here’s a brief overview of how skilled medical practitioners get it right:
- Remove fatty tissue from the apex of the axilla around the axillary vein with the first dissection.
- Dissect downward and laterally along the course to the arm.
- The thoracodorsal nerve is just under the lateral thoracic vein, which appears at the close to the chest wall.
- On further dissection the nerve is fully-visible.
- After this it can’t be missed for the rest of the procedure.
In the same vein – no pun intended – the thoracodorsal nerve can be used as a nerve graft during lengthy thoracic nerve injury surgery or trauma.
Preventing Injury To Peripheral Nerves
Nerve injury is common yes, but it’s one of those things that no one ever wants. With tell-tale signs like sharp acute or shooting pains, “electric shock” or “pins and needles” sensations, or just persistent tingling sensations and numbness, it can affect a multitude of nerves.
Peripheral nerve injuries are largely preventable injuries and as such, require vigilance in order to avoid.
Unfortunately some patients are more at risk than others for this occurrence. Tobaccos users, diabetics, those who are obese or very thin, or have gone through a surgery that lasted over four hours, are among these.
Something as seemingly simple as if a patient is positioned incorrectly for even a short length of time, can lead to these types of injuries. The thing is, it doesn’t even take long for the patient to notice, as signs of injury are evident within forty-eight hours.
This can then result in further surgery required, burning sensations, difficulty performing regular tasks (raising arms, walking, or getting out of bed) and, also slow down recovery.
So how do patients and medical practitioners prevent this?
In order to prevent injury to peripheral nerves including the thoracodorsal nerve:
- Carefully assess at-risk patients before surgery.
- Position patients for surgery paying close attention to body alignment.
- Use neurophysiological monitoring where possible.
- Staff members and physical therapy professionals collab to determine the best positioning based on the patient’s history and assessment.
The thoracodorsal nerve is a versatile component in our bodies that benefits us in a multitude of ways. As it works hard to help with our upper body functions, it’s important that we do our part to make its job a little easier.