The human hand is a very specialised anatomy that plays a big role in both large and fine motor tasks.  A complicated network of nerves, muscles, bones, and blood vessels is needed for the hand to move in a coordinated way.

 The nerve supply to the hand from the brachial plexus is one of the most important things that allows us to move and feel things. This subject is especially important for medical students who are getting ready for tough medical exams like NEET PG. Keep reading to learn more about how the nerves supply the hand.

Anatomy of Nerve Supply to the Hand

The knowledge of the nerve supply to the hand is important for both anatomical understanding and clinical application. The hand is motor and sensory innervated by 3 prominent nerves—median, ulnar, and radial nerves, all of which are branches of the brachial plexus. 

Here is a detailed outline of the anatomy of hand nerves: 

1. Median Nerve 

It arises from the medial and lateral cords of the brachial plexus. It passes through the carpal tunnel and provides recurrent branch (motor to thenar muscles) and common/proper palmar digital nerves (sensory to palmar surface of lateral 3½ digits and nail beds).

It innervates 5 hand muscles—lumbricals 1 & 2, abductor pollicis brevis, opponens pollicis, and flexor pollicis brevis (in part, being a hybrid muscle with double innervation). In the front forearm, it provides innervation to all the muscles except for flexor carpi ulnaris and the medial half of flexor digitorum profundus, which are innervated by the ulnar nerve.

2. Ulnar Nerve

The ulnar nerve, which originates from the medial cord of the brachial plexus, penetrates the hand through Guyon’s canal, above the flexor retinaculum. It branches off into deep (motor) and superficial (sensory) branches.

The deep branch supplies 15 intrinsic muscles of the hand, all hypothenar muscles, lumbricals 3 & 4, palmar and dorsal interossei, and adductor pollicis. The sensory supply is for the medial 1½ fingers, both on the palmar and dorsal sides. In the forearm, it innervates flexor carpi ulnaris and the medial half of flexor digitorum profundus.

3. Radial Nerve

The radial nerve originates from the brachial plexus’ posterior cord and supplies no intrinsic muscles of the hand. In the hand, the superficial branch gives sensory supply to the dorsal lateral hand, covering the proximal dorsal surface of the lateral 3½ digits.

The function of the radial nerve is essential in wrist and finger extension by its motor branches to the forearm extensors.

What is the Clinical Significance of Nerve Supply to the Hand?

The nerve supply to the hand is crucial for maintaining both motor function and sensory perception, enabling precise finger movements and touch. 

Injuries to the ulnar, median, or radial nerves are responsible for conditions such as carpal tunnel syndrome, cubital tunnel syndrome, or radial nerve palsy, each compromising activities of daily living and fine motor skills.

Ulnar nerve damage, based on location (brachial plexus, elbow, or wrist), can produce claw hand, sensory impairment, or wasting of intrinsic muscles. Remarkably, Klumpke palsy resulting from injury to the lower trunk of the brachial plexus can be accompanied by Horner syndrome. 

Diagnostic precision depends on clinical evaluation and often nerve conduction testing to localise lesions and devise effective treatment.

FAQs About Nerve Supply to the Hand

1. How is the nerve supply in the hand tested?

The Phalen test is a simple means of determining median nerve involvement. Flexing wrists for 60 seconds, the test can detect tingling or numbness — indications of impaired hand nerve supply. A positive test assists in the detection of conditions such as carpal tunnel syndrome.

2. How many nerves are involved in the hand’s function?

The Phalen test is a simple means of determining median nerve involvement. Flexing wrists for 60 seconds, the test can detect tingling or numbness — indications of impaired hand nerve supply. A positive test assists in the detection of conditions such as carpal tunnel syndrome.

3. What is the name of the test used to check hand nerve function?

Electromyography (EMG) and nerve conduction studies are assessments that evaluate the performance of the muscles and nerves in the hand. These tests are employed to identify anomalies in the supply of the hand nerves that could be impairing movement or sensation.

4. What is the function of the median nerve?

The median nerve supply to the hand arises from the brachial plexus. It plays a crucial role in both motor function and sensation in the forearm and hand. As part of the nerve’s supply, it provides movement in certain muscles and provides feeling from the palm and a few fingers.

5. What can happen in case a nerve in the hand is damaged?

Damage to the nerves can lead to loss of movement, tingling, numbness, weakness, or even loss of function. Depending on the area of the hand nerve supply and the degree of damage, the degree of impairment varies. 

A complete understanding of the nerve supply to the hand is essential for medical students who wish to excel in the subjects of clinical anatomy and neurology. From the diagnosis of injuries to surgical accuracy, such an understanding is the cornerstone of good patient care.

The interaction of the median, ulnar, and radial nerves illustrates the intricacy and clinical importance of upper limb anatomy. To simplify your NEET PG preparation and delve beyond intricate ideas, visit DocTutorials. The study materials created by DocTutorials simplify such complex concepts related to anatomy and neurology for better learning.

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