Variation in the formation of the retromandibular and the external jugular veins with embryological overview: A case report

Abstract

Awareness of the formation and termination of the head & neck's superficial vein, such as jugular veins, are imperative for anatomists, surgeons, and radiologists during interventional procedures. We report an uncommon variation in the formation of the retromandibular vein and external jugular vein (EJV) in an embalmed male cadaver's right side. The joining of the facial vein and superficial temporal vein within the parotid gland formed the retromandibular vein (RMV). The anterior division joined with the submental vein forming an anomalous venous trunk. The anomalous vein united with the EJV forming a common trunk in the lower third of the neck and terminated into the subclavian vein. We compared the available literature and justified the embryological development of this rare variation.

Full text

Heliyon 9 (2023) e16013
Available online 4 May 2023
2405-8440/© 2023 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license
(http://creativecommons.org/licenses/by-nc-nd/4.0/).
Case report
Variation in the formation of the retromandibular and the external
jugular veins with embryological overview: A case report
Vrinda Hari Ankolekar, Mamatha Hosapatna, Lydia S. Quadros, Suhani Sumalatha,
Anne D. Souza
*
Associate Professor, Department of Anatomy, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, 576104, India
ARTICLE INFO
Keywords:
External jugular vein
Formation
Maxillary vein
Retromandibular vein
Variation
ABSTRACT
Awareness of the formation and termination of the head & neck’s supercial vein, such as jugular
veins, are imperative for anatomists, surgeons, and radiologists during interventional procedures.
We report an uncommon variation in the formation of the retromandibular vein and external
jugular vein (EJV) in an embalmed male cadaver’s right side. The joining of the facial vein and
supercial temporal vein within the parotid gland formed the retromandibular vein (RMV). The
anterior division joined with the submental vein forming an anomalous venous trunk. The
anomalous vein united with the EJV forming a common trunk in the lower third of the neck and
terminated into the subclavian vein. We compared the available literature and justied the
embryological development of this rare variation.
1. Introduction
The ‘external jugular vein’ (EJV) opens into the subclavian vein (SV) just above the midpoint of the clavicle. It is a major vein
collecting blood from the head and neck region. Additionally, the retromandibular vein (RMV) is formed by the union of the ‘su-
percial temporal vein’ (STV) and the maxillary vein (MV) inside parotid gland. The anterior division of the RMV joins with the facial
vein (FV) to form the common facial vein. The posterior division of RMV joins the posterior auricular vein (PAV) to form EJV. These
veins could vary in their commencement, course, and termination, which is clinically signicant [1].
Awareness of the variations of venous pattern of the head and neck region is important for the surgeons, as these veins are used in
oral reconstruction surgeries and the FV is used for microvascular anastomosis. In parotid surgeries and mandibular condylar fracture
reduction, the RMV and its tributaries are identied and ligated to prevent excessive bleeding [2]. During CT and MRI imaging, healthy
veins may appear to be diseased. In this regard, a detailed understanding of normal as well as variant patterns of venous anatomy is
important [3]. Variations of EJV are considered clinically relevant during the cut down approach as an alternative to cephalic vein [4].
The literature reveals several types of variations of RMV and EJV [5–8]. Variations are often seen in the formation and course of
EJV and RMV that is described the literature [9]. However, the authors here report an unusual right-sided variation in the formation of
RMV, the EJV, and their tributaries that have not been reported in the literature earlier.
* Corresponding author. Associate Professor Department of anatomy Kasturba Medical College, Manipal. India
E-mail addresses: vrinda.hari@manipal.edu (V.H. Ankolekar), mamatha.h@manipal.edu (M. Hosapatna), Lydia.quardos@manipal.edu
(L.S. Quadros), suhani.s@manipal.edu (S. Sumalatha), anne.dsouza@manipal.edu (A.D. Souza).
Contents lists available at ScienceDirect
Heliyon
journal homepage: www.cell.com/heliyon
https://doi.org/10.1016/j.heliyon.2023.e16013
Received 8 July 2022; Received in revised form 28 April 2023; Accepted 28 April 2023

Heliyon 9 (2023) e16013
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1.1. Case presentation
During regular dissection of the neck anatomy of a male cadaver aged 60-years at the medical school in South India, we observed
variations in the formation and tributaries of right RMV and the EJV. The cadaver was procured through the voluntary body donation
program of the institute with written informed consent from the donor with two witnesses. The body was donated after the consent
granted from the donor’s next of kin. A written informed consent was obtained from the next of kin for utilizing the data in the form of
observation and image that were procured form the cadaver. Since it is a single cadaveric case report, the Institutional Ethics com-
mittee (IEC) did not recommend taking a separate clearance.
In the cadaver, we observed that the FV joined with the STV inside the parotid gland to form the RMV. The MV drained into RMV as
a tributary. The anterior division of RMV joined with the ‘submental vein’ (SMV) to form an anomalous venous trunk, and the posterior
division joined with the PAV to form the EJV. This EJV had a narrower caliber than that of the anomalous trunk and passed anterior to
the great auricular nerve on the sternocleidomastoid muscle. The anomalous vein united with the EJV forming a common trunk in the
lower third of the neck. The common trunk then traversed supercial to the ‘sternocleidomastoid muscle’ and terminated into the SV.
(Fig. 1). There was no common facial vein on the right side. Facial nerve and the external carotid artery within the parotid gland had a
normal course. All the veins had a usual course on the left side, and they did not show any variation in their pattern.
2. Discussion
The authors have reported a unilateral unusual variation in the formation of RMV and the EJV.
Hollinshed describes that the neck’s veins vary signicantly in their connections with each other, in their size and course, both
unilaterally or bilaterally [10].
Literature review suggests that undivided RMV is the most typical variation [11]. When undivided, it had continued as EJV or
contributed to form EJV by uniting with the posterior auricular vein. In such a situation, it was reported that the FV drained into the
EJV in the neck [12]. In the present case report, we observed an unusual formation of RMV by the union of supercial temporal. The
facial vein and MV joined it as a tributary inside parotid gland. The formation of RMV presented in the current report is unique and is
rarely reported in the literature. Such variations are of clinical signicance while performing interventional radiologic procedures such
as direct puncture venography for done for evaluation of hemodynamics in case of venous malformations [13].
The studies reporting the undivided RMV have also reported the variations in the EJV [8,11]. When undivided it may join with the
FV [14]. At times, there would be a communicating venous channel between EJV and the IJV. The jugular veins could be duplicated or
fenestrated in their course in the neck region [5,6,15,16]. However, the fenestrated vein is the one, which has a single trunk at its
Fig. 1. Cadaveric specimen and its schematic representation showing the facial vein (FV) joining with the supercial temporal vein (STV) forming
the retromandibular vein (RMV). Maxillary vein (MV) drains into RMV. Anterior division (AD) of RMV joins with the submental vein (SMV) to form
an anomalous trunk (AT), which joins later with the external jugular vein (EJV) and forms a common trunk (CT) that drain into the subclavian vein
(SV). Posterior division (PD) of RMV joins with the posterior auricular vein (PA) to form EJV. SCM: Sternocleidomastoid, PG: Parotid gland, FA:
Facial artery, GAN: Great auricular nerve.
V.H. Ankolekar et al.

Heliyon 9 (2023) e16013
3
formation and termination but split in its course. In contrast, a duplicated vein will have double venous trunks throughout its course [5,
17]. The case, which we have reported, does not t both the above criteria because the EJV and the anomalous venous trunk united in
the lower neck and drained into the SV.
In the current case report, we consider the vein, which accompanied the great auricular nerve as EJV because it had the usual
formation and course. However, we considered the venous channel formed by the union of the anterior division of the RMV and the
submental vein as an anomalous venous trunk because it had an unusual origin, course, and termination.
Right-sided venous variations show a higher prevalence than those on the left [18]. Even the present case report revealed normal
venous pattern on the left with variation only in the right side.
The veins of the head and neck start developing embryo (5 mm stage), wherein the rst and second pharyngeal arch veins drain into
the common cardinal vein through the ‘ventral pharyngeal vein’ (VPV). The termination of VPV shifts cranially due to the neck’s
elongation and gives rise to the IJV. Blood of the head and neck area is drained into the ‘primitive maxillary vein’ (PMV). Later, a
‘linguofacial vein’ (LFV) drains the face and tongue and terminates into VPV. PMV decreases in size, and tributaries of PMV and LFV
anastomose with each other. At the 18 mm, stage of the embryo, the LFV becomes the FV and receives the RMV from the temporal
region. The stem of FV beyond the union of RMV forms the common facial vein (CFV) and drains into IJV [19]. In our case report, the
primitive connection between the FV and the RMV is persistent, and the PMV joined the trunk of RMV as a tributary. In the present case
report, the stem of the FV beyond the drainage of RMV disappeared, and therefore, there was no CFV.
Simultaneously a venous plexus formed by the ‘primitive cephalic vein’ and ‘jugulocephalic vein’ (JCV) will surround the
developing clavicle. At the 22 mm stage of the embryo, the JCV disappears. The craniodorsal part of the venous plexus forms the trunk
of the EJV [19]. In the present case report, the persistent JCV has formed the anomalous venous trunk.
This type of variable pattern of veins in the neck is scarce. The surgeons need to be aware of such variations to avoid intraoperative
vascular injury during surgical procedures.
Variation in the formation of the RMV is scarce. There was an anomalous venous trunk in the neck, which united with the EJV. Such
variations are clinically signicant for surgeons and intervention radiologists during the surgical procedures in this region.
Author contribution statement
All authors listed have signicantly contributed to the investigation, development and writing of this article.
Data availability statement
No data was used for the research described in the article.
Additional information
No additional information is available for this paper.
Declaration of competing interest
The authors declare that they have no known competing nancial interests or personal relationships that could have appeared to
inuence the work reported in this paper.
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