Superior cervical ganglion
Encyclopedia
The superior cervical ganglion (SCG), the largest of the cervical ganglia
Cervical ganglia
The cervical ganglia are paravertebral ganglia of the sympathetic nervous system. These emerging postganglionic nerves synapse with preganglionic nerves from the thoracic spinal cord. They consist of three paravertebral ganglia:* superior cervical ganglion...

, is placed opposite the second and third cervical vertebræ. It contains neuron
Neuron
A neuron is an electrically excitable cell that processes and transmits information by electrical and chemical signaling. Chemical signaling occurs via synapses, specialized connections with other cells. Neurons connect to each other to form networks. Neurons are the core components of the nervous...

s that supply sympathetic
Sympathetic nervous system
The sympathetic nervous system is one of the three parts of the autonomic nervous system, along with the enteric and parasympathetic systems. Its general action is to mobilize the body's nervous system fight-or-flight response...

 innervation to the face.

It is of a reddish-gray color, and usually fusiform in shape; sometimes broad and flattened, and occasionally constricted at intervals; it is believed to be formed by the coalescence of four ganglia, corresponding to the upper four cervical nerves
Cervical nerves
The cervical nerves are the spinal nerves from the cervical vertebrae.Although there are seven cervical vertebrae , there are eight cervical nerves . All nerves except C8 emerge above their corresponding vertebrae, while the C8 nerve emerges below the C7 vertebra...

. However, note that these fibers are postganglionic fibers that have already synapsed with preganglionic sympathetic fibers derived from the T1 to T4 levels of the spinal cord. The bodies of these preganglionic sympathetic neurons are specifically located in the lateral horn of the spinal cord.

The superior cervical ganglion lies posterior to the sheath of the
internal carotid artery
Internal carotid artery
In human anatomy, the internal carotid arteries are two major arteries, one on each side of the head and neck. They arise from the common carotid arteries where these bifurcate into the internal and external carotid artery, and they supply the brain....

 and internal jugular vein
Internal jugular vein
The two internal jugular veins collect the blood from the brain, the superficial parts of the face, and the neck.-Path:On both sides and at the base of the brain, the inferior petrosal sinus and the sigmoid sinus join to form the internal jugular vein...

, and anterior to the Longus capitis muscle
Longus capitis muscle
The longus capitis muscle , broad and thick above, narrow below, arises by four tendinous slips, from the anterior tubercles of the transverse processes of the third, fourth, fifth, and sixth cervical vertebræ, and ascends, converging toward its fellow of the opposite side, to be inserted into the...

.

It receives input from the ciliospinal center
Ciliospinal center
The ciliospinal center is a structure which receives input from the pretectum, and has output to the superior cervical ganglion.It is located in the intermediolateral cell columns of the spinal cord between C8 and T2....

.
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