Arising from the sympathetic trunk, the cervical ganglia consist of three sets of ganglia. These three sets are referred to as the superior, middle, and inferior cervical ganglia. Cervical ganglion are responsible for transferring signals through the central nervous system via neurons and connections to various organs and regions of the human body.
Signals transmitted by the sympathetic nervous system are involved in actions related to the functioning of the human body. The various branches of the cervical area ganglia effect organs such as the eyes, heart, and lungs. In addition, they also impact reactions related to the skin, such as sweating.
The sympathetic trunk consists of ganglia extending along the length of the spine on both sides of the spinal column. Ganglia run from the coccyx, or tailbone, to the base of the skull. Along the sympathetic trunk, various sets of ganglia arise from both sides of vertebral column and distribute signals to the entire body.
Largest of all of the cervical ganglia, the superior ganglia are located near the second and third cervical vertebra. Other structures near the superior ganglia include the internal carotid artery and the internal jugular vein. The superior ganglia branch off into four branches, called the inferior, lateral, medial, and anterior branches.
Branches of the superior ganglia are responsible for sending signals to various nerves and areas of the body. The inferior branch helps communicate with the middle ganglia, and the medial branches of the superior ganglia extend to the laryngeal nerves. In addition to the four branches, the superior ganglia also give rise to the superior cardiac nerve. Superior ganglia can transmit to the central nervous system signals that can affect pupil dilation, sweat secretion of the skin, and heart rate.
Middle cervical ganglia are located near the sixth cervical vertebra. It gives rise to the middle cardiac nerve. The middle cervical ganglion is the smallest of these ganglia. Heart rate can be affected by signals transferred by the middle ganglia.
Another portion of the cervical ganglia, the inferior ganglia, is positioned near the final cervical vertebra and can also be intermingled with the first thoracic ganglia. The inferior cardiac nerve branches off of the cervical inferior ganglia. Arising from the inferior cardiac nerve are various blood vessels, such as the subclavian artery, thyroid artery, and common carotid artery. Inferior cervical ganglia transmit neurons that can affect bronchial dilation in the lungs.