Massage Therapy Journal Spring 2025

54 • Massage Therapy Journal

AMTA Continuing Education

Peripheral nerves consist of bundles of neuronal fibers called dendrites and axons. Dendrites are responsible for bringing sensory information from the body to the CNS, while axons take motor information from the CNS to the body. These nerves are also surrounded by layers of connective tissue that serve as protection from compression and other forces. Injuries to peripheral nerves can result from trauma, compression, disease and other potential factors. Damage to these nerves may lead to pain, numbness, tingling, muscle weakness and loss of sensory function. Interestingly, peripheral nerves may be able to repair themselves after an injury. In instances where the nerve does sustain damage, the axons and dendrites will attempt to regrow, directed by the connective tissue structures surrounding the nerve. Cervical Plexus The cervical plexus is a network of nerves that originates from the anterior rami or branches of the first four cervical spinal nerves (C1-C4). It forms within the neck and provides sensory and motor innervation to various structures in the head, neck and upper shoulders. 46,47 1. The lesser occipital nerve arises from C2-C3 and provides sensory innervation to the skin of the scalp posterior to the ear. 48 2. The greater auricular nerve arises from 3. The transverse cervical nerve , sometimes called the cutaneous colli nerve, arises from C2-C3. It provides sensory innervation to the anterior cervical region. 4. The supraclavicular nerve arises from C3-C4 and provides sensory innervation to the skin of the upper chest and shoulder region. 50 5. The phrenic nerve arises from C3-C5 and is the most noteworthy nerve of the cervical plexus. It provides motor innervation to the respiratory diaphragm, the primary muscle C2-C3 to provide sensory innervation to the skin over the external ear, the angle of the mandible and the skin over the parotid gland. 49

involved in breathing. Sensory fibers from the phrenic nerve also deliver sensory input from the central diaphragmatic pleura and peritoneum. 51 6. The ansa cervicalis arises from C1-C3 and is a loop of nerves created by branches from the first three cervical nerves. It innervates muscles of the anterior neck, including the sternohyoid, sternothyroid and omohyoid muscles. 52 Brachial Plexus The brachial plexus is a network of nerves that begins at the spinal cord in the neck and extends through the axillary region. This nerve plexus is responsible for innervating the muscles and providing sensation to the shoulder, arm, forearm and hand. The brachial plexus is formed by the spinal nerves of C5 to T1. These nerves combine, divide and come back together to form the major nerves that control the muscles and transmit sensory information of the upper extremities. 53 The ulnar nerve is a major nerve in the arm, and is a part of the brachial plexus. It arises from the nerve roots of C8 and T1. This nerve travels through the axilla medial to the axillary artery, then medial to the brachial artery and biceps brachii. It then pierces the medial intermuscular septum and courses anterior to the medial head of the triceps. This nerve then passes through a groove created by the medial epicondyle of the humerus and the olecranon process of the ulna and continues on through the cubital tunnel, which is bordered by the medial epicondyle of the humerus, arcuate ligament and the olecranon process of the ulna. Finally, the ulnar nerve continues down the medial aspect of the forearm and over the flexor retinaculum of the wrist and into the hand. The ulnar nerve provides motor innervation to certain muscles of the forearm and most of the muscles in the hand. It controls various movements, including those of the fingers and hand grip. Additionally, the ulnar nerve carries sensory information from the fifth finger and the medial half of the fourth finger. 54

Interestingly, peripheral nerves may be able to repair themselves after an injury

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