GROSS ANATOMY

Detailed explanation-1: -The most important motor branch of the cervical plexus is the phrenic nerve. The plexus also provides motor fibers to the spinal accessory nerve and to the paravertebral and deep muscles of the neck. Each nerve, with the exception of the first cervical nerve, provides significant cutaneous sensory innervation.

Detailed explanation-2: -Origin. The phrenic nerve originates mainly from the 4th cervical nerve, but also receives contributions from the 3rd and 5th cervical nerves (C3-C5) in humans. Thus, the phrenic nerve receives innervation from parts of both the cervical plexus and the brachial plexus of nerves.

Detailed explanation-3: -The phrenic nerve originates from the anterior rami of the C3 through C5 nerve roots and consists of motor, sensory, and sympathetic nerve fibers. It provides complete motor innervation to the diaphragm and sensation to the central tendon aspect of the diaphragm.

Detailed explanation-4: -Its branches consist of a superficial and deep set. The superficial branches are the great auricular nerve, lesser occipital nerve, transverse cervical, suprasternal, and supraclavicular nerves. The deep branches are the phrenic, communicantes cervicales, communicating, and muscular.

Detailed explanation-5: -The phrenic nerve is a branch of the deep cervical plexus and provides the sole motor supply of the diaphragm.