KNOW YOUR NERVES: A DEEP DIVE INTO THE MUSCULOCUTANEOUS NERVE

Knowledge is power, and understanding the intricate workings of our body can equip us with the ability to handle unexpected circumstances better. In this light, let’s delve into one of the fascinating components of our nervous system – the musculocutaneous nerve. We’ll explore its anatomy, its functions, and the potential impacts of its injuries.

Anatomy of the Musculocutaneous Nerve

The musculocutaneous nerve begins near the bottom of the pectoralis minor and begins its journey down the arm. It travels through the coracobrachialis and then between the biceps and brachialis. At this point, it continues down the arm, eventually becoming the lateral antebrachial cutaneous nerve, which provides sensation to the skin of the lateral aspect of the forearm.

It’s worth noting that the musculocutaneous nerve innervates three critical muscles of the arm: the coraco-brachialis, the biceps brachii, and the brachialis. To get a more comprehensive understanding of this nerve, let’s look at the actions of these muscles.

Muscle Actions

Coraco-brachialis

The coraco-brachialis contributes to the flexion and adduction of the shoulder. This muscle is primarily responsible for moving the shoulder forward and towards the midline of the body.

Biceps Brachii

The biceps brachii is a key player in the flexion of the elbow and supination of the forearm. Supination refers to the motion that allows the palm of the hand to face upwards or forwards.

Brachialis

Lastly, the brachialis muscle is integral to the flexion of the forearm. It is one of the primary muscles that allow the elbow to bend.

Clinical Pearls: Musculocutaneous Nerve Injuries

Albeit rare, injuries to the musculocutaneous nerve can have significant effects. They typically occur in the axillary region due to direct trauma, such as a knife wound. In such scenarios, the patient would lose function of their entire anterior compartment, including the brachialis, biceps, and coracobrachialis. This means the patient would develop weak shoulder and elbow flexion, as well as weakness in elbow supination.

However, these motions will not be entirely lost because of other muscles like the deltoid, brachioradialis, and supinator. These muscles can assist these motions and are not innervated by the musculocutaneous nerve. Therefore, while the damage is significant, it does not result in complete loss of function.

Equipped with Knowledge

As we better understand the workings of our nerves, we become more equipped to manage potential injuries and ailments. We encourage you to continue learning and expanding your knowledge about the intricate and fascinating human nervous system. For more nerve education, you can follow us at @integrativedryneedling.

Sources:

clinically oriented anatomy by Keith L. Moore et al. (8th edition)

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