Cervical Plexuses

The cervical plexuses lie deep in the neck on either side. They are formed by the anterior branches of the first four cervical nerves. Fibers from these plexuses supply the muscles and skin of the neck. In addition, fibers from the third, fourth, and fifth cervical nerves pass into the right and left phrenic (fren'ik) nerves, which conduct motor impulses to the muscle fibers of the diaphragm.

Cauda equina

Cauda equina

Sacral nerves

Coccygeal nerve

Figure 11.30

The thirty-one pairs of spinal nerves are grouped according to the level from which they arise and are numbered in sequence.

Sacral nerves

Coccygeal nerve

Figure 11.30

The thirty-one pairs of spinal nerves are grouped according to the level from which they arise and are numbered in sequence.

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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