MEDICAL BIOLOGY, ANATOMY, HUMAN PHYSIOLOGY AND PATHOLOGY - Ya.I. Fedoniuk 2010

ANATOMY, PHYSIOLOGY, PATHOLOGY

SECTION 3. ANATOMICAL AND PHYSIOLOGICAL ASPECTS OF BODY FUNCTION SELF-REGULATION

FUNCTIONAL ANATOMY OF THE PERIPHERAL NERVOUS SYSTEM

SPINAL NERVES

2. ANTERIOR BRANCHES

2.1. Cervical plexus

The cervical plexus (plexus cervicalis) is formed by the Anterior branches of the four upper cervical Spinal Nerves (Fig. 3.39). It lies lateral to the transverse processes of the upper cervical vertebrae between the Muscles; its branches emerge from beneath the posterior border of the sternocleidomastoid Muscle and are divided into three groups: cutaneous branches (sensory), muscular (motor), and mixed.

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Fig. 3.39. Diagram of the Innervation of the HEAD and Neck by the cervical nerves

The sensory branches include the following nerves: 1) lesser occipital nerve; 2) great auricular nerve; 3) transverse cervical nerve; 4) supraclavicular nerves. All of them innervate the Skin of the occiput, auricle, external acoustic meatus, and neck.

The muscular (motor) branches innervate the Deep Muscles of the Neck and, joining with a branch of the Hypoglossal nerve (XII pair of Cranial Nerves), form the ansa cervicalis, which innervates the Infrahyoid muscles of the neck.

The mixed branch of the cervical plexus is the phrenic nerve, which passes into the thoracic cavity and innervates the Diaphragm, Pleura, and Pericardium, while the right phrenic nerve also supplies the Liver.