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Peripheral Nerves of the Upper Limb

Learn about the anatomy and function of the complex network of peripheral nerves that supply the upper limb and the symptoms of nerve injury and dysfunction.
2023-04-07

Review of Peripheral Nerves of the Upper Limb

The human body is made up of an intricate network of nerves, blood vessels, and other tissues that supply the brain and other parts of the body with the necessary information and energy to function. The peripheral nervous system (PNS) is one of the major components of the human nervous system and is responsible for the transmission of sensory information, motor control, and autonomic control signals. This article will focus on the anatomy of the peripheral nerves of the upper limb and their importance in controlling the movement and function of the arm and hand.

Anatomy

The peripheral nerves of the upper limb originate from the brachial plexus, which is a network of nerves that supplies the arm and hand. The brachial plexus is formed by the anterior and posterior divisions of the fourth to eighth cervical spinal nerves, which form four main nerve trunks: the medial, lateral, posterior, and anterior divisions. These divisions are further divided into five main nerves: the median, radial, ulnar, axillary, and musculocutaneous nerves. Each of these nerves is responsible for providing sensory and motor innervation to the muscles and skin of the arm, forearm, and hand.

The median nerve is the largest of the five nerves and runs down the arm from the brachial plexus to the wrist. It provides sensory innervation to the skin of the palm of the hand and motor innervation to the muscles of the thumb, index, and middle fingers. It is also responsible for flexing the wrist and fingers.

The radial nerve runs down the arm from the brachial plexus and provides motor innervation to the muscles of the back of the arm and forearm that are responsible for extending the arm at the elbow and wrist. It also provides sensory innervation to the skin of the back of the arm and hand.

The ulnar nerve runs down the arm from the brachial plexus and provides motor innervation to the muscles of the forearm that are responsible for flexing the wrist and fingers. It also provides sensory innervation to the skin of the little and ring fingers.

The axillary nerve runs down the arm from the brachial plexus and provides motor innervation to the muscles of the shoulder and arm that are responsible for abduction and extension of the arm. It also provides sensory innervation to the skin of the shoulder.

The musculocutaneous nerve runs down the arm from the brachial plexus and provides motor innervation to the muscles of the arm that are responsible for flexing the arm at the elbow. It also provides sensory innervation to the skin of the lateral side of the forearm.

Functions

The peripheral nerves of the upper limb are responsible for providing sensory and motor innervation to the muscles and skin of the arm, forearm, and hand. These nerves enable us to feel sensation in our hands and arms and control the movement of our arms and hands.

The median nerve is responsible for providing sensory innervation to the skin of the palm of the hand and motor innervation to the muscles of the thumb, index, and middle fingers. It is also responsible for flexing the wrist and fingers.

The radial nerve is responsible for providing motor innervation to the muscles of the back of the arm and forearm that are responsible for extending the arm at the elbow and wrist. It also provides sensory innervation to the skin of the back of the arm and hand.

The ulnar nerve is responsible for providing motor innervation to the muscles of the forearm that are responsible for flexing the wrist and fingers. It also provides sensory innervation to the skin of the little and ring fingers.

The axillary nerve is responsible for providing motor innervation to the muscles of the shoulder and arm that are responsible for abduction and extension of the arm. It also provides sensory innervation to the skin of the shoulder.

The musculocutaneous nerve is responsible for providing motor innervation to the muscles of the arm that are responsible for flexing the arm at the elbow. It also provides sensory innervation to the skin of the lateral side of the forearm.

Clinical Significance

Damage to the peripheral nerves of the upper limb can result in a condition known as peripheral neuropathy, which is characterized by a loss of sensation, weakness, and pain in the affected limb. This condition is often caused by traumatic injuries, diabetes, or certain infections. Treatment for this condition usually involves medications, physical therapy, or surgery.

In addition, the peripheral nerves of the upper limb can be affected by a condition known as carpal tunnel syndrome (CTS). CTS is caused by the compression of the median nerve in the carpal tunnel, a narrow passageway in the wrist, and is characterized by numbness and tingling in the hand and fingers. Treatment for this condition usually involves medications, lifestyle modifications, and in some cases, surgery.

Conclusion

The peripheral nerves of the upper limb are an important part of the human body, providing sensory and motor innervation to the muscles and skin of the arm, forearm, and hand. Damage to these nerves can result in conditions such as peripheral neuropathy and carpal tunnel syndrome, which can cause pain, numbness, and weakness in the affected limb. Treatment for these conditions usually involves medications, lifestyle modifications, and in some cases, surgery. It is important to seek medical attention if you experience any symptoms of these conditions in order to prevent further damage and improve quality of life.

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