The middle cervical ganglion is the smallest of the cervical ganglia, and is occasionally absent or fused with the superior cervical ganglion.  It probably consists of the fused ganglia of C5 and C6.  It is usually situated at the level of the sixth cervical vertebra, in front of the inferior thyroid artery.  It is connected to the superior cervical ganglion superiorly by the sympathetic trunk.  It gives rise to the ansa subclavia, thyroid and cardiac branches.

The thyroid branches of the middle cervical ganglion accompany the inferior thyroid artery to the thyroid and parathyroid glands.  They communicate with the superior cardiac, external laryngeal and recurrent laryngeal nerves.