Robert G. Louis

The relationship of myocardial bridges to coronary artery dominance in the adult human heart

Myocardial bridging is recognized as an anatomical variation of the human coronary circulation in which an epicardial artery lies in the myocardium for part of its course. Thus, the vessel is ‘bridged’ by myocardium. The anterior interventricular branch of the left coronary artery has been reported as the most common site of myocardial bridges but other locations have been reported. The purpose of this study was to provide more definitive information on the vessels with myocardial bridges, the length and depth of the bridged segment, and the relationship between the presence of bridges and coronary dominance. Two hundred formalin‐fixed human hearts were examined. Myocardial bridges were found in 69 (34.5%) of the hearts with a total of 81 bridges. One bridge was found in 59 of these hearts and multiple bridges were observed in ten (eight with double bridges and two with triple bridges). Bridges were most often found over the anterior interventricular artery (35 hearts). Bridges were also found over the diagonal branch of the left coronary artery (14), over the left marginal branch (five) and over the inferior interventricular branch of the left coronary artery (six). Bridges were also found over the right coronary artery (15 hearts), over the right marginal branch (four) and over the inferior interventricular branch of the right coronary artery (two). The presence of bridges appeared to be related to coronary dominance, especially in the left coronary circulation. Forty‐six (66.6%) of the hearts with bridges were left dominant. Forty‐two of these had bridges over the left coronary circulation and four over the right coronary circulation. Seventeen hearts (24.6%) were right dominant. Eleven of these had bridges over the right coronary circulation and six over the left coronary circulation. The remaining six hearts were co‐dominant with four having bridges over the left coronary circulation and two over the right coronary circulation. The mean length of the bridges was 31 mm and the mean depth was 12 mm. The possible clinical implications of myocardial bridging may vary from protection against atherosclerosis to systolic vessel compression and resultant myocardial ischaemia.

Anatomical and surgical considerations of the sacrotuberous ligament and its relevance in pudendal nerve entrapment syndrome

In view of the paucity of literature, this study was undertaken to reappraise the gross anatomy of the sacrotuberous ligament (STL), with the objective of providing an accurate anatomical basis for clinical conditions involving the STL. We studied the gross anatomy of the STL in 50 formalin fixed cadavers (100 sides) during the period of 2004–2005. All specimens exhibited an STL with a ligamentous part and (87%) of specimens exhibited a membranous (falciform) segment, which extended towards the ischioanal fossa. The variations of the falciform extensions were classified into three types. In Type I (69%), the falciform process extended towards and along the ischial ramus to terminate at the obturator fascia. In Type II (108%), the falciform process extended along the ischial ramus, fused with the obturator fascia and continued towards the ischioanal fossa. In addition, the medial border of the falciform process descended to fuse with the anococcygeal ligament, forming a continuous membrane. Lastly, in Type III (13%), the falciform process of the STL was absent. The above mentioned data could have an important implication to the understanding of the relationship between the pudendal nerve and the sacrotuberous ligament and their relevance to pudendal nerve entrapment syndrome.

An anatomical classification of the variations of the inferior phrenic vein

The majority of anatomical textbooks of gross anatomy offer very little information concerning the anatomy and distribution of the inferior phrenic vein (IPV). However, in the last decade, an increasing number of reports have arisen, with reference to the endoscopic embolization of esophageal and paraesophageal varices, as well as venous drainage of hepatocellular carcinomas (HCC). The IPV is one of the major sources of collateral venous drainage in portal hypertension and HCC. The aim of this study was to identify the origin and distribution of the IPVs (right and left), both in normal and (selective) pathological cases. We have examined 300 formalin-fixed adult cadavers, without any visible gastrointestinal disease, and 30 cadavers derived from patients with HCC. The right IPV drained into the following: the inferior vena cava (IVC) inferior to the diaphragm in 90%, the right hepatic vein in 8%, and the IVC superior to the diaphragm in 2%. The left IPV drained into the following: the IVC inferior to the diaphragm in 37%, the left suprarenal vein in 25%, the left renal vein in 15%, the left hepatic vein in 14%, and both the IVC and the left adrenal vein in 1% of the specimens. The IPVs possessed four notable tributaries: anterior, esophageal, lateral and medial. The right IPV served as one of the major extrahepatic draining veins for all 30 cases of HCC. These findings could have potential clinical implications in the transcatheter embolization of esophageal and paraesophageal varices, as well as in mobilizing the supradiaphragmatic segment of IVC.

Chondroepitrochlearis muscle, a case report and a suggested revision of the current nomenclature

We present a rare case of an accessory muscular slip originating from pectoralis major and inserting onto the medial epicondyle of the humerus and the medial brachial intermuscular septum. According to the current nomenclature this muscle is defined as a chondroepitrochlearis; however, we propose a new nomenclature: thoracoepicondylaris. This term more accurately reflects the origin and insertion of this, and the few similar cases that have been reported in the literature. Clinical considerations of such a variation include ulnar nerve entrapment and functionally limited abduction of the humerus.

A case of an anomalous radial artery arising from the thoracoacromial trunk

We present a case of an anomalous radial artery (ARA), which arose as a branch of the thoracoacromial trunk. After giving rise to the lateral thoracic artery, the ARA continued superficially through the brachium and antebrachium, terminating as the deep palmar arterial arch. This anomalous artery was found to completely replace the radial artery which normally arises from the brachial artery. Embryological considerations and possible clinical consequences are discussed.