A plea for extension of the anatomical nomenclature: Vessels

This article is the fourth and last part of a series aimed at extending and correcting the anatomical nomenclature. Because of the rapid development of internet and the use of electronic formats in communication in anatomy, embryology, histology, medical education, and clinical medicine, an appropriate, precise, and concise anatomical nomenclature is required. Such tool enables to avoid any potential confusion and possible scientific/medical mistakes. The up-to-date official anatomical terminology, Terminologia Anatomica, is available longer than 20 years and needs to be refined and extended. The authors have collected and listed 210 terms and completed them with definitions and/or explanations. We aimed to start a discussion about their potential incorporation into the new revised version of the Terminologia Anatomica. This article is primarily focused on the vessels of the human body (arteries, veins, and lymphatic system).


INTRODUCTION
This article is the fourth and last part of a series aimed at extending and correcting the anatomical nomenclature. It closes a set of contributions to extent and revise the technical norm for naming morphological structures of the human body in relation to the anatomical nomenclature of the nervous system and senses [1], locomotor system [2], and organs [3]. All the general statements and discussions concerning the history, grammar, and clinical relevance of the anatomical nomenclature and terminology are parts of our previous set of articles. We have also repetitively stressed the importance of anatomical nomenclature in enabling clear, unanimous, and unambiguous communication among specialists. All revised or newly proposed terms to be potentially incorporated into the only official valid version of the anatomical nomenclature called Terminologia Anatomica (TA) are summarized in these articles [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15].
International Federation of Associations of Anatomists (IFAA) is the only organ responsible for worldwide valid official terminology in human anatomy, histology, and embryology. Concerning the anatomical nomenclature, its last version is quite old-fashioned as it was issued already 22 years ago, in 1998 [16], by not anymore existing Federative Committee on Anatomical Terminology (FCAT), which was in 2005 renamed to Federative International Committee on Anatomical Terminology (FICAT) and in 2009 replaced by Federative International Programme on Anatomical Terminology (FIPAT). Now, FIPAT prepares a new edition called Terminologia Anatomica 2, which is already available online as a draft not yet approved by IFAA and thus not official [17]. The anatomical terminology of vessels is also part of the Terminologia Histologica, published in 2008 [18], Terminologia Embryologica in 2013 [19] and its revision Terminologia Embryologica 2, issued in 2017 [20], and concerning the brain and sensory organs as a part of the Terminologia Neuroanatomica, published in 2017 [21].
The authors have gathered anatomical terms of vascular system absent in the Terminologia Anatomica that they have encountered during their scientific and educational work. Some terms listed here are mentioned and explained in classical textbooks and familiar to all anatomist and thus they are not completed with references. Other terms have been reviewed, refined, or proposed de novo for anatomical structures which were previously not well described and/or defined.
Terms presented in bold italics are newly created terms proposed for incorporation into the Terminologia Anatomica, terms presented in plain italics are already listed in the Terminologia Anatomica, terms within quotation marks are non-recommended or obsolete, terms in parentheses are eponyms, synonyms, or explanations, and terms marked with 209 www.bjbms.org

ANATOMIA GENERALIS
• Fasciculus vasonervosus* (neurovascular bundle) is a bundle of a nerve and one or more vessels. The peripheral or cranial nerve is accompanied by an artery and one or two veins, or, if located in a superficial compartment, a asterisks have been already stated in some of our previous works. In total, 210 terms are suggested for incorporation into the TA: 22    www.bjbms.org liber is deflected from the wall toward the opposite valvule, and the lumen is closed. A space formed then by the facies parietalis valvulae is termed the sinus valvulae. A junction between the margo affixus and the margo liber is denominated the cornu valvulae and the slightly elevated parts between adjacent ends of the margines affixi are termed the commissurae valvae as they connect the two valvules. The body of the valvule is called the cuspis valvulae and it is thickened at the margo affixus in the double-horseshoe-shaped agger valvulae (clinically frequently called "tuberculum" or "limbus") [28]. • Vasa gonadalia is a general term which can be used either during the early development when the gender of the embryo is still indifferent or if referred to the vasa testicularia in male or to the vasa ovarica in female unspecificly, i.e. when general features of these vessels are discussed, not related to the gender. • Vasa cruralia is a general term for the principal trunks of the leg (vasa tibialia anteriora, vasa tibialia posteriora, and vasa fibularia) and can be used when they are considered as general vessels coursing within the leg and supplying the leg and foot.

COR
• Crux cordis is an area on the facies posterior cordis where the sulcus coronarius and the sulcus interventricularis posterior meet. • In pathology, the division of the heart atrium into the corpus atrii and the vestibulum atrii is used. Both parts of the atrium are smooth due to the absence of the musculi pectinati. On the right side, musculi pectinati are overlapping from the auricle onto the free atrial wall and they divide the atrium dextrum into the vestibulum atrii and the corpus atrii. On the left side, the musculi pectinati are reduced to the auricle only and thus, the vestibulum atrii and the corpus atrii are in direct continuation. The corpus atrii sinistri receives the venae pulmonales (comprises the ostia venarum pulmonalium) and the vestibulum atrii sinistri is a smooth part of the atrium below this level. • Cuspis valvae mitralis/tricuspidalis features three parts: The apex, the margo, and the basis.  Each indentation in the hierarchies is the expression of a "part_of" relation: When an anatomical entity A is indented below B, it means "A part_of B." Terms stated in parentheses are variable.  [11]. • Angiosoma* is an anatomical unit of tissue composed of skin, subcutaneous tissue, fascia, muscle, and bone which is nourished by a specific artery and drained by specific veins [22]. The whole human body consists of 40 angiosomes [23]. Arteriosoma is such anatomical unit supplied by a specific artery [24] and venosoma* is the same unit drained by a specific vein. In case the extent of the venous drainage is different from arterial supply of the angiosoma, the anatomical unit is termed phlebosoma* [25]. The anatomical unit drained by superficial lymphatic vessels is then termed lymphosoma [13,26]. • Some organs (lungs, liver) feature two types of circulation -nutritive and functional. It is necessary to denominate them also in Latin and there exist terms: The vasa privata for the nutritive circulation and the vasa publica for the functional one [27].  • Arteria subclavia dextra aberrans (ASDA)* is a clinically relevant but rather rare variant (approximately 1% of cases) of the arteria subclavia, ramifying as the very last branch from the arcus aortae, left (distally) to the origin of the arteria subclavia sinistra, and crossing the midline to the right side. It may run in front of the trachea as the ASDA pretrachealis (5% of all ASDA), between the trachea and the esophagus as the ASDA retrotrachealis (15%) and between the esophagus and the vertebral column as the ASDA retrooesophgea (retroesophageal right subclavian artery/RRESA/), found in about 80% of all ASDA). In the two latter cases, it could compress the esophagus and may cause problems with swallowing termed dysphagia lusoria that is why in the case of present clinical symptoms, the variant artery used to be called the "arteria lusoria" [11,31]. • Arteria pyramidalis is a variant branch from the distal part of the arteria thyroidea superior, just before its bifurcation into its ramus anterior et posterior, supplying the lobus pyramidalis glandulae thyroideae, when present (40% of cases) [32]. • Arteria supraclavicularis is a smaller branch either from the arteria transversa cervicis directly [10] or from its ramus superficialis, coursing within the regio cervicalis lateralis and supplying the fascia and the skin above and below the clavicle. Based on the statistics, the current terminology using the term arteria princeps pollicis is not specific enough as the word princeps describes the principal (largest) source artery which rather varies for the thumb -the largest caliber features the arteria metacarpalis palmaris prima -that is why the term "arteria princeps pollicis" should be abandoned and removed from the TA [46]. • An inconstant artery branches from the arteria radialis at the dorsum of the hand just before it enters the space between the heads of the musculus interosseus dorsalis primus. This artery then runs distally on the dorsal surface of the muscle and at the distal margin of the first web space, it turns back into the palm and forms an anastomosis with the arcus palmaris superficialis. Miletin et al. reported its incidence (12%) and proposed the term ramus superficialis dorsalis arteriae radialis [47]. • Arteria spinalis anterior is an unpaired vessel originating as a confluence of a short paired innominate artery branching from the arteria vertebralis. These short transverse vessels can be denominated as the ramus vertebrospinalis dexter et sinister. • Arteria medullaris segmentalis is a term of the TA replacing the clinically used arteria radiculospinalis; another vessel, arteria radiculopialis, is important in clinical medicine and gives off the pial vasocoronae, encompassing the spinal cord horizontally and emanating the rami perforantes to supply the white matter; finally, the arteria spinalis anterior branches off the arteriae sulcocommissurales into the fissura mediana anterior to supply the grey matter [48,49]. • Arteria radicularis magna (listed in TNA [21]) or the "artery of Adamkiewicz" is the largest and clinically the most important ramus spinalis arteriae intercostalis posterioris and thus it should be termed the ramus spinalis magnus (arteriae intercostalis posterioris  [4][5][6]13,54], which can be agreed to. • Three branches of the arteria profunda femoris, supplying the posterior and medial groups of the thigh muscles are called the arteriae perforantes and classified using numbers according to the level of their origin as the arteria perforans prima*, arteria perforans secunda*, and arteria perforans tertia*. Their accompanying veins are denominated in a bit different way as the venae comitantes arteriarum perforantium* due to the fact that the term venae perforantes is reserved for the veins interconnecting the superficial and deep venous systems [9,13,15,54]. • Truncus tibiofibularis* is the short proximal segment of the arteria tibialis posterior, between its origin from the arteria poplitea to the branching point of the arteria fibularis [13]. • Arteriae tarsales mediales should be specified as the arteria tarsalis medialis proximalis* and the arteria tarsalis medialis distalis*; arteriae tarsales laterales as the arteria tarsalis lateralis proximalis* and the arteria tarsalis lateralis* [13]. • Arteria sinus tarsi medialis ("arteria canalis tarsi; arteria of Salvi") and arteria sinus tarsi lateralis ("arteria anastomotica tarsi; ramus anastomicus tarsi; perforating vessel of sinus tarsi") are important feeding arteries of the talus with variable origin from the arteria tibialis posterior (or less often from the arteria plantaris medialis), and from the arteria dorsalis pedis (or less often from the arteria tarsalis lateralis proximalis or arteria malleolaris lateralis anterior), respectively [13,55].  [56], also called "retroarticular/retrodiscal plastic pad/cushion (of Zenker)" [57] or "trilaminar zone (of Smeele)" [58], is the posterior continuation of the discus articularis articulationis temporomandibularis, consisting of the stratum superius (fibroelastic loose network of elastic and collagen fibers, adipose tissue and fine vessels, attached to the posterior margin of the fossa mandibularis ossis temporalis), stratum inferius (stiff/non-elastic network of collagen fibers, attached to the caput mandibulae), and in between interposed genu vasculosum (adipose tissue, connective tissue and mainly a venous plexus, a dorsal extension of the plexus pterygoideus), which serves as shock-absorber during the joint movements. • Arcus venosus xiphoideus is a transverse venous arch (present in approximately 80%) connecting the venae thoracicae internae dextrae et sinistrae across the midline, located ventral to the symphysis xiphosternalis [59]. • Vena incisurae scapulae is a variable vein (58%), originating on the facies costalis scapulae, below the incisura scapulae, either from a vein accompanying the nutrient artery of the scapula and/or veins located beneath the fascia of the musculus subscapularis. It passes through the incisura scapulae and drains into the vena suprascapularis immediately after passing the notch [60,61].

SYSTEMA LYMPHATICUM
Generally, the term "lymphoid" meaning from the linguistic point of view precisely "similar to lymph" ("eidos" is a Greek term for the form) should be abandoned and instead the term "lymphatic" should be preferred in all terms related to the lymph, i.e. also in the denomination of the whole chapter: Systema lymphaticum. , and finally nodi lymphatici mesenterici inferiores centrales situated along the trunk of the arteria mesenterica inferior. • The lymphatic trunks of the limb (also known as "collectors") can be divided into the superficial and deep, the former running independently on the superficial veins, and the latter extending in intimate relation to the deep vascular bundles. The term "lymphaticus" should www.bjbms.org be preferred to its grammatically incorrect synonym "lymphoideus" -see above [4,10]. o Three main superficial lymphatic trunks of the upper limb constitute from the plexus lymphaticus palmaris* on the palmar aspect of the digits and hand: Truncus lymphaticus lateralis membri superioris* travels on the lateral side of the forearm and arm and empties into the nodi lymphatici axillares or directly into the plexus lymphaticus axillaris and nodi lymphatici cervicales lateralis profundi; truncus lymphaticus medialis membri superioris* courses on the medial side of the forearm and arm and empties into the nodi lymphatici axillares; and truncus lymphaticus anterior membri superioris* runs on the ventral side of the forearm and empties into one of the former trunks [12]. o Three main superficial lymphatic trunks of the upper limb constitute from the plexus lymphaticus plantaris* on the inferior aspect of the toes and sole: Truncus lymphaticus medialis membri inferioris* ascends in front of the malleolus medialis on the ventromedial aspect of the leg dividing into the fasciculus medialis* (traveling medially to the condylus medialis femoris) and the fasciculus lateralis* and drains into the nodi lymphatici inguinales superficiales; truncus lymphaticus lateralis membri inferioris* courses on the lateral aspect of the leg and usually drains into the nodi lymphatici inguinales superficiales; and truncus lymphaticus posterior membri inferioris* runs on the posterior aspect of the leg and drains into the nodi lymphatici poplitei profundi [13]. o The deep lymphatic trunks are termed according to the blood vessel they accompany: Truncus ulnaris*, truncus radialis*, truncus interosseus anterior et posterior*, and truncus brachialis*; truncus tibialis posterior et anterior*, truncus fibularis*, truncus popliteus*, and truncus femoralis*. In the pelvis, the situation is more complicated, see [13].

DISCUSSION
Some anatomically and/clinically very important terms have been already mentioned in our previous articles, but we felt inevitable to remind readers of them [6,8,9,[11][12][13]15]. If we check the anatomical terminology in current journals, monographs, and textbook, there are still many terms found to be obsolete, incorrect, or even eponymic although the last revision of the anatomical nomenclature -Terminologia Anatomica (TA) -has been issued more than 20 years ago and eponyms have been banned from the anatomical nomenclature already in the Parisiensia Nomina Anatomica (PNA) in 1955 [16,[72][73][74][75][76].
If we check the new proposal of Terminologia Anatomica 2 (TA 2), posted online [17] as a not yet approved version (the approval is planned at the next IFAA meeting in Istanbul in 2022), there are not many changes concerning the vessels, but there are some substantial changes concerning the heart which should be thoroughly reviewed and considered if they are appropriate and if they have a chance to be accepted by clinicians [e.g., change of the sulcus interventricularis posterior (including the ramus interventricularis posterior) to "sulcus interventricularis inferior" (and "ramus interventricularis inferior")].
The main task of every anatomist and all anatomical societies, which continues and never stops, is to cultivate, clean, and revise the anatomical nomenclature not only in the anatomical field, education, journals, and textbooks but above all among clinicians, physicians, secondary school teachers, as well as lay public not only in English and Latin but also in individual languages.