This article is an anatomical, physiological, and terminological discussion for two related cardiac structures: The Vincula Aortæ and the cardiac folds of Rindfleisch.

The topic of this article was triggered by a LinkedIn post by Dr. Guillermo Stöger, an Argentinian cardiac surgeon who works in the Cardiac Department of the Heart Center in Leipzig, Germany.

In his post, Dr. Stöger describes the Vincula Aortæ as “communication or adhesions” between the intrapericardial portion of the ascending aorta and the intrapericardial portion of the pulmonary trunk. In this segment these two vessels share their adventitia layer as well as a rich vascular supply. Dr. Stöger also describes the presence of small vessels in the area, which can cause a hematoma when a dissection or trauma of one of this vessels happens.

So, what is the Vincula Aortæ? It was first described by Georg Eduard Von Rindfleisch (1836-1902), a German pathologist and histologist in an article in German published in 1884 titled “Ligament-like connections between the aorta and pulmonary artery (vincula aortae)” [1]. In this article Rindfleisch describes the movement of the pulmonary trunk and ascending aorta caused by the pressure fluctuations between systole and diastole, forcing these two structures to twist and separate in opposite directions. While the ascending aorta tends to move towards the right sternoclavicular joint, the pulmonary trunk tends to move towards the left third intercostal space. Rindfleisch states that the presence of the intervascular “ligaments” reduces the mobility of these structures.  

Click for a larger image

Being a histologist, Rindfleisch describes the structure of this intervascular structure (the Vincula Aortæ) as containing connective and fibrofatty tissue with vascular structures, encased in adventitia, and all of them covered by the visceral pericardium (epicardium). The accompanying image, modified from the original by WC Roberts [12], shows how the ascending aorta and pulmonary trunk share their adventitia; the arrows point to the area where there is connective tissue. Rindfleisch posits that the constant movement of the vessels and pericardium slowly causes the pericardium to wrinkle and fill with fat causing a semilunar elevation 2 -3 cm superior to the root of the aorta. He says that these fatty pads are more evident in people over 40 years of age.

It should be pointed out that Rindfleisch described the intervascular communication between the ascending aorta and pulmonary trunk, as a “clamp”, and also as “adhesions” or “ligaments”, and he named them “Vincula Aortæ”; but although he described the pericardial fatty fold caused by the movement of these structures, he did not name it. Later they were eponymically referred to as the “folds of Rindfleisch”. According to Netter [2] when more than one is present only the larger and usually most superior of these folds is so called.

The following mage is from Rindfleisch’s 1884 article and shows a tear in the ascending aorta with an aortic dissection. Interestingly, he says that the tears in the aorta (or pulmonary trunk) happen higher in these vessels, distal to the Vincula Aortae, which gives the lower segments additional strength.

In 2003 Morrison et al [3] published a description of the Fold of Rindfleisch stating that they were “unaware of a formal description of this structure”, naming it “crista aortæ ascendentis”. They described neurovascular bundles, fat and connective tissue in this structure, ending with a recommendation to do careful hemostasis to avoid hemorrhage intra and postoperatively, just as Dr. Stöger suggested recently.

Modified from Parke (1966)

In a “Letter to the Editor” following Morrison’s publication, Dr. Wesley Parke refuted it stating that the structure in question had already been described 40 years earlier in 1966 by himself [4], followed by a detailed study of the vessels in the region in 1970 [5]. Parke references brief statements on these folds by Davis in 1927 [6] and Hans Smetana in 1930 [7]. Parke calls this fold the “aortic ridge” and ascribes to it a cushioning function between the aorta and the right atrial appendage. No mention of Rindfleisch.

The image (modified from Parke's 1966 original) shows two specimens of the ascending aorta. The arrows point to the folds of Rindfleisch. Note that specimen 3 has a double semilunar fold. 

The importance of the work of Dr. Wesley Parke is the detailed description of the “vasa vasorum” that provide blood supply to the aorta and pulmonary trunk creating a plexus of vessels. Careful hemostasis is needed to prevent bleeding when working at the root of the pulmonary trunk and aorta. 

Parke mentions Hans Smetana (1894 - 1977). His paper "Vasa Nutritia der Aorta" describes the many vasa vasorum of the aorta and his work was followed by W. Parke who described the complex blood supply to the ascending aorta and pulmonary trunk. Following are two images modified from the original works by these authors. Again, it is critical to point out the importance of these vessels found in the area of the Vincula Aortae when performing surgery.

There are research articles on the fatty ridges found in the proximal ascending aorta, but many have forgotten the contributions of Rindfleisch. In 1999 F. Unger named it the “plica transversa aortæ” [8]. This letter was criticized, by Falkowski et al [8] reminding that the structure was first named “Plica semilunaris nach Rindfleisch” by Julius Tanders (1869 – 1936) in his book “Anatomie des Herzens” [10]. Falkowski says “it is not the first time we have encountered self-given names to structures that have been previously studied and named a century, and sometimes centuries ago”.

Rindfleisch was the first to describe and name the common connective tissue and adventitia between the intrapericardial ascending aorta and pulmonary trunks (vincula aortae) and the fold of pericardial tissue that should bear his name: the aortic semilunar fold (plica semilunaris aortæ) of Rindfleisch.

 Sources:
1. “Uber Klammeratigae Verbindungen zwischen Aorta und Pulmonal arterie (Vincula aortae)”. Rindfleisch E Von. 1884. Virch Arch Pathol Anat Physiol Klin Med 96: 302–306.
2. “CIBA collection of medical illustrations” Netter F. 1971; vol 5, The Heart. section 1, plate 5.
3. “Surgically Relevant Structure on the Ascending Aorta” Morrison, JJ; Codispoti, M; Campanella, C. 2003 J Clin Anat 16:253-255
4. “The human aortic ridge and cushion” Parke, WW; Michels, NA 1966 Anat Rec, 154: 185-193. 
5. “The vasa vasorum of the ascending aorta and pulmonary trunk and their coronary and extracardiac relationships” Parke WW. 1970 Am Heart J 80:802– 810 
6. “The periaortic fat bodies” Davis DJ. Arch Path and Lab Med 1927 4:937-942
7. “Vasa Nutritia der Aorta: Smetana, H. 1929 Virchows Archiv für pathologische Anatomie und Physiologie und für klinische Medizin. 274: 170-187
8. “The Plica Transversa Aortae: An Addendum to the Anatomic Nomenclature of the Heart” Unger, F. 1999 Ann Thorac Surg 68:2383-91
9. “Plica transversae aortae—fold of Rindfleisch” Falkowski, G; Dzigivker, I; Bitran, D. 2001 Ann Thorac Surg 7:1-761-762
10. “Anatomie Des Herznes” Tandler, J et al. 1913. Publisher Gustav Fischer
11. “"Tratado De Anatomía Humana” Testut, L.; Latarjet, A. Barcelona, Spain: Salvat Editores, 1943.
12. “Aortic dissections: Anatomy, consequences, and causes” Roberts WC (1981). Am Heart J 101:195-214.
13 “The Fatty Ridge and Fatty Cushion of the Human Pulmonary Trunk” Nadkarni, SD, et al. Anatomical Record 1976 187: 107-112
14."Stedmans Medical Eponyms" Forbis, P.; Bartolucci, SL; 1998 Williams and Wilkins