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Page 2 of 11 Tirelli et al. J Cancer Metastasis Treat 2023;9:20 https://dx.doi.org/10.20517/2394-4722.2022.98

INTRODUCTION
Cervical lymph node status is the most important prognostic factor in head and neck cancer. Neck
[1,2]
dissection (ND) is one of the key steps in the treatment of these cancers . The history of ND begins in the
19th century when surgeons attempted to remove cervical lymph node disease en bloc at the same time as
the primary cancer. The first systematic description offered by Jawdynski in 1888 and later popularized by
[3,4]
Crile in the early 20th century formed the basis of the current techniques . The technique has evolved over
time, moving on to conservative ND (proposed by Suarez), selective ND, where only the nodal groups
considered at greatest risk for metastasis from a given primary site are dissected, and superselective ND,
defined as complete removal of all nodes and all fibrofatty tissue contents along the defined boundaries of
[1,5]
one or two contiguous neck levels . Over the years, the focus on preserving function and minimizing
morbidity has made ND the far less invasive surgery that is widely employed today . In 1998, in order to
[1]
provide a standard nomenclature to guide ND, Robbins proposed a classification that divided the lymph
nodes of the neck into levels and sublevels, a classification now adopted by all head and neck surgeons
worldwide . The submandibular triangle (or submaxillary or digastric triangle) corresponds to that region
[6]
of the neck that is immediately below the body of the mandible. Classical anatomical descriptions indicate
the upper limit of this area as the lower border of the body of the mandible and a line drawn from its angle
to the mastoid process, while the lower limit is given by the anterior and posterior belly of the digastric
muscle. The mylohyoid muscle and hyoglossal muscle form the floor of this triangle. The stylomandibular
ligament divides the submandibular triangle into two parts . In the Robbins classification, the
[7]
submandibular triangle corresponds to level IB, even though the limits of the posterior part differ slightly;
following the Robbins classification, level IB is bounded by the body of the mandible, the posterior belly of
the digastric muscle, the stylohyoid muscle, and the anterior belly of the digastric muscle .
[6]
Within this triangle lies a group of lymph nodes whose anatomy and oncological role has only been clarified
[8,9]
in recent years, the so-called “perimarginal nodes (PMN)” . The aim of this paper is to review the
anatomical description and oncological role of these lymph nodes. To this end, we carried out a PubMed
search using the keywords “perimarginal nodes/lymph nodes” (2 results), “perifacial nodes/lymph nodes”
(8 results), “preglandular nodes/lymph nodes” (8 results) and “retroglandular nodes/lymph nodes”
(1 result). All of the articles retrieved were included in the review. A search for “Rouvière nodes/lymph
nodes” yielded 126 papers, only one of which was included, since the others concerned anatomical areas
that were not relevant to our study (retropharyngeal, abdominal, etc.). The reference lists of the papers
retrieved were analyzed and relevant articles were included in our review.

ANATOMY OF LYMPHATICS OF THE SUBMANDIBULAR AREA
The first description of a constant node in the area where the facial artery crosses the horizontal branch of
the mandible was made by the German anatomist and pathologist Hermann Stahr, and that description was
later also reported in Henry Gray’s Anatomy [9,10] . In 1932, Henri Rouvière published his “Anatomie des
lymphatiques de l’homme”, in which he precisely described the submandibular lymph nodes, dividing them
into five groups (preglandular, prevascular, retrovascular, retroglandular, intraglandular) . In his
[11]
description, three to six lymph nodes were identified, with a number that was inversely proportional to their
size. He described the preglandular group, delimited by the submandibular gland, the mandible and the
anterior belly of the digastric muscle, and the retroglandular group that lies posterior to the submandibular
gland, medial to and below the angle of the mandible. The group of prevascular and retrovascular lymph
nodes consisted of lymph nodes defined in relation to the anterior facial vein (AFV), the former
corresponding to the Stahr gland. Finally, he described the group of intracapsular submandibular lymph
nodes consisting of lymph nodes within the submandibular gland [12,13] . In 1998, DiNardo revisited and
refined Rouvière’s classification of the submandibular lymphatics, confirming the anatomist’s description