This section is from the book "Applied Anatomy: The Construction Of The Human Body", by Gwilym G. Davis. Also available from Amazon: Applied anatomy: The construction of the human body.
The five sets of nodes just described, viz., the submental, submaxillary, superficial upper cervical, posterior auricular, and superficial occipital, are all regarded as superficial nodes. As a matter of fact this division of the lymphatic nodes into superficial and deep is not of practical value. The communication between the various nodes is quite free. Adjacent nodes communicate and the superficial nodes communicate with the deep ones below.
On account of this an affection is not always limited to a single node but often involves those to each side and those lying still deeper. In the submaxillary region the nodes will almost certainly be found to lie under the fascia along with the submaxillary gland. When the occipital nodes are enlarged they may not only be found in the space already described but also on the adjacent trapezius and sternomastoid muscle and even beneath the outer edge of the trapezius below the deep fascia.
The anterior cervical lymphatics is the name given to those which tend to show in the anterior cervical triangle either beneath or in front of the sternomastoid muscle, between it and the median line. There are some nodes in the median line but they are almost all deep down in the neck above the sternum. The other nodes may be either superficial or deep, mostly deep, along the edge of the sternomastoid muscle. They follow the sheath of the vessels. This is a very extensive chain of nodes. They may extend in all directions. As regards depth they may be on the deep fascia along the edge of the sternomastoid or following the external jugular vein. If deeper they follow the internal jugular vein and carotid artery directly up to the base of the skull, also behind and below the mastoid process and alongside of the transverse process of the atlas (first cervical vertebra). They extend under the sternomastoid posteriorly, deep in the suboccipital region. Should they be enlarged downward they will protrude behind the posterior edge of the sternomastoid into the posterior cervical triangle; if anteriorly they will follow it down into the space of Burns in front of the trachea and thence into the superior mediastinum.
The posterior cervical nodes show behind the posterior edge of the sternomastoid, along the edge of the trapezius, and also above the clavicle. They not infrequently fill the posterior cervical triangle and extend beneath the muscles on each side.
Below they may be continuous with enlarged nodes in the axilla and extend anteriorly under the sternomastoid into the pretracheal region and mediastinum. They are frequently excised for both tuberculosis and carcinoma. In so doing particular care is to be taken on account of the transversalis colli and suprascapular arteries and veins, with which they may lie in contact, as well as the terminal portion of the external jugular.