As we have already pointed out, this is sometimes double, the two being joined together by a short grayish band. When this condition exists, the portion in front, which is always the smaller, is known as the middle cervical ganglion.

The afferent branches, or those which go to the ganglion, are two in number, one resulting from the union of small filaments from the second, third, fourth, fifth, sixth, and seventh pairs of cervical nerves, and the other derived from the eighth cervical nerve.

The efferent branches of the inferior cervical ganglion are mainly distributed to the heart. Some very fine filaments may also be seen to enter the anterior mediastinum, or proceed to the branches of the brachial trunk.