Anatomy-Lexicon

What is the long thoracic nerve

The long thoracic nerve is also known as the long thoracic nerve. This is a nerve that arises from the brachial plexus.
More specifically, the nerve originates from the pars supraclavicularis and contains nerve roots from the spinal cord segments C5, C6 and C7 from the neck area.
Its function is limited to the innervation of a muscle.

This means that it is a purely motor nerve and does not take on any sensitive tasks.

Course of the long thoracic nerve

After the nerve roots have united to form the brachial plexus, purely motor fibers of the spinal cord segments C5, C6 and C7 separate from this above the clavicle and form the thoracic nerve longus.

This then first penetrates the scalenus medius muscle from the center.
This penetration lies a little below the dorsal scapular nerve. The nerve then runs over the first rib and bends caudally towards the abdomen.

From there on, the nerve lies mainly between the latissimus dorsi muscle and the serratus anterior muscle relatively far superficially on the rib cage. For each of the nine muscle bellies of the serratus anterior muscle, the long thoracic nerve gives off several motor branches, so-called rami musculares, for innervation.

The ninth muscle belly of the serratus anterior muscle is located on the ninth rib, which is why the nerve can reach a considerable length for its position near the trunk of the body in tall people.

Function of the long thoracic nerve

The only function of the long thoracic nerve is the motor innervation of the serratus anterior muscle.
For this, signals from the spinal cord are transmitted via the nerve cells of the nerve to the muscle, through which they are processed and executed.

The muscle has an important function for the movement of the shoulder blade and thus also for the movement of the upper arm.
If the nerve is damaged, movement is restricted.

Pain

Pain caused by damage to the long thoracic nerve is not very common. This usually results in persistent, slight pain in the area of the shoulder blade or the side of the chest.

Damage can be caused by various causes. Most often, after long periods of wearing a rucksack or a bag with a belt, a pressure lesion occurs with a subsequent complete or incomplete functional failure.

After the end of the exercise, there is often an improvement.
In rare cases, the functional impairment and the pain persist. Furthermore, pain can occur after direct trauma from a blow or a stab injury, but this does not differ significantly from the pain resulting from a pressure lesion.

Loss, paralysis, and lesion of the long thoracic nerve

Damage to the long thoracic nerve is not very common.
This is noticeable through pain, reduced mobility of the shoulder and arm and a protruding backward shoulder blade.

The most common cause of nerve damage is carrying a heavy rucksack or bag for too long with a strap that presses on the side of the chest above the long thoracic nerve. This is called a pressure lesion.

In addition, traumatic events such as a blow can damage the nerve.
Furthermore, the nerve can be damaged as a result of an operation in the area of the armpit or the chest.

In the course of inflammatory processes, the nerve can also be affected more frequently. Jerky or very extreme movements of the shoulder girdle and arm can also damage the nerve.

Depending on the cause and extent, these lesions can either regress completely, partially or not at all.

Scapula alata

Since the long thoracic nerve provides motor innervation to the serratus anterior muscle, damage to the nerve leads to a malfunction of the muscle.

One of the tasks of the muscle is to fix the shoulder blade to the chest.
To do this, a continuous pull is exerted on the shoulder blade in the direction of the chest. If the nerve is damaged, this means that the shoulder blades or the shoulder blade protrude backwards.

This is often referred to as wing-like protruding dorsally. The symptom is exacerbated when the arms are raised forward against resistance. Furthermore, when the scapula alata occurs, it is no longer possible to raise the arms to the side above the horizontal.

The cause of the symptom of the scapula alata may be a lesion of the long thoracic nerve. However, other diseases can also be the cause.

Read more on the subject under: Scapula alata