The muscle trapezius shows considerable morphological diversity. Variations include an anomalous origin and complete or partial absence of the muscle. The present study reported, a hitherto undocumented complete bilateral absence of the cervical part of trapezius. Based on its peculiar origin and insertion, it was named dorsoscapularis triangularis. The embryological, phylogenetic and molecular basis of the anomaly was elucidated. Failure of cranial migration of the trapezius component of the branchial musculature anlage to gain attachment on the occipital bone, cervical spinous processes, ligamentum nuchae between 11 mm and 16 mm stage of the embryo, resulted in this anomaly. A surgeon operating on the head and neck region or a radiologist analyzing a magnetic resonance imaging of the cervical region would find the knowledge of this morphological variation of trapezius useful in making clinical decisions.
Embryonic Structures ; Head ; Magnetic Resonance Imaging ; Neck ; Occipital Bone ; Superficial Back Muscles*

Percutaneous transvenous mitral annuloplasty (PTMA) has evolved as a latest procedure for the treatment of functional mitral regurgitation. It reduces mitral valve annulus (MVA) size and increases valve leaflet coaptation via compression of coronary sinus (CS). Anatomical considerations for this procedure were elucidated in the present study. In 40 formalin fixed adult cadaveric human hearts, relation of the venous channel formed by CS and great cardiac vein (GCV) to MVA and the adjacent arteries was described, at 6 points by making longitudinal sections perpendicular to the plane of MVA, numbered 1–6 starting from CS ostium. CS/GCV formed a semicircular venous channel on the atrial side of MVA. Based on the distance of CS/GCV from MVA, two patterns were identified. In 37 hearts, the venous channel at point 2 was widely separated from the MVA compared to the two ends and in three hearts a nonconsistent pattern was observed. GCV crossed circumflex artery superficially. GCV or CS crossed the left marginal artery and ventricular branches of circumflex artery superficially in 17 and 23 hearts, respectively. As the venous channel was related more to the left atrial wall, PTMA devices probably exert an indirect traction on MVA. The arteries crossing deep to the venous channel may be compressed by PTMA device leading to myocardial ischemia. Knowledge of the spatial relations of MVA and a preoperative and postoperative angiogram may help to reduce such complications during PTMA.
Adult ; Arteries ; Cadaver ; Coronary Sinus ; Formaldehyde ; Heart ; Humans ; Mitral Valve ; Mitral Valve Annuloplasty* ; Mitral Valve Insufficiency* ; Myocardial Ischemia ; Traction ; Veins

Anatomical variations of the colon are described by various authors, but the occurrence of right sided descending and sigmoid colon is rare and has not been reported. We found that the anomalous right-sided descending and sigmoid colon had four parts. The proximal segment of the first part consisted of the descending colon extending across the midline from the splenic flexure to the portion supplied by the left colic artery. The distal segment was supplied by the superior sigmoid artery. The second and third parts formed a loop in the right lumbar region anterior to the lumbar cecum. The fourth part was in the lesser pelvis, extending from right sacroiliac joint to the third sacral body. Parts two, three, and four were supplied by the inferior sigmoid artery, which arose from the right side of the inferior mesenteric artery. The ascending and transverse colon was normally placed. This is a rare anomaly that has not been reported so far in adults and is of immense importance to interventional radiologists and colorectal surgeons. The embryological basis of such an anomaly is defective fixation occurring as early as the 12th-17th week of intrauterine life.
Adult ; Arteries ; Cecum ; Colic ; Colon ; Colon, Descending ; Colon, Sigmoid* ; Colon, Transverse ; Humans ; Lesser Pelvis ; Lumbosacral Region ; Mesenteric Artery, Inferior ; Sacroiliac Joint