Rung-ruangkijkrai T. et al./TJVM 37(3): 51-58. 51 Short Communication Morphology of the Heart of a White-cheeked Gibbon (Hylobates concolor) Tilladit Rung-ruangkijkrai* Wuthichai Klomkleaw Pakorn Prachammuang Abstract The heart was recovered at post mortem from an adult white-cheeked gibbon, Hylobates concolor, for anatomical and histological studies. Macroscopically, it had oval shape, blunt and spherical apex with 3.5 cm. and 5 cm. in width and length. Smooth edged comma-shaped right auricle was markedly bigger than the jagged- edged left auricle. Pectinate muscles were found both at the internal surface of the right auricle and lateral free wall of the right atrium, while limited only in blind part of the left auricle. The coronary arteries supply was left coronary type. The left coronary artery gave circumflex and paraconal interventricular branches. Subsinuosal interventricular and intermediate branches ramified from the circumflex branch. One septal and two papillary muscles were found in both left and right ventricles. There was only one small trabecula septomarginalis in the left ventricle, but three in the right ventricle. Aortic arch gave off brachiocephalic trunk and left subclavian artery. Ligamentum arteriosum linked between the beginning of descending aorta and the junction between the left pulmonary artery and the pulmonary trunk. Histological results were generally indistinct. However, number of blood vessels observed in the atria was less than in the ventricles. Collagen fibers were the major fiber population of the subendocardium while elastic fibers were confined mainly in the subendothelial layer. Keywords : white-cheeked gibbon, heart, anatomy, histology Department of Anatomy, Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330 *Corresponding author 52 Rung-ruangkijkrai T. et al./TJVM 37(3): 51-58. ∫∑§—¥¬àÕ —≥∞“π«‘∑¬“¢ÕßÀ—«„®™–π’·°â¡¢“« ∑‘≈¥‘ √å √ÿà߇√◊Õß°‘®‰°√* «ÿ≤‘™—¬ °≈¡‡°≈’¬« ª°√≥å ª√–®”‡¡◊Õß „π°“√»÷°…“À—«„®¢Õß™–π’·°â¡¢“« æ∫«à“¡’≈—°…≥–°≈¡√’ √Ÿª‰¢à ª≈“¬¡π °«â“ß 3.5 ´.¡. ¬“« 5 ´.¡. ·∫à߇ªìπ 4 ÀâÕß auricle ¢â“ߴ⓬¡’º‘«πÕ°‰¡à‡√’¬∫ ¢Õ∫À¬—° ¢π“¥„À≠à·≈–°«â“ß°«à“¢â“ߢ«“ ´÷Ëß¡’≈—°…≥–‡ªìπ√Ÿª®ÿ≈¿“§ ¢Õ∫¡π ª≈“¬‡≈Á°·À≈¡ ¿“¬„πÀ—«„®ÀâÕß∫π¢«“ æ∫ pectinate muscles ∑—Èߥâ“π„π¢Õß auricle ·≈–ºπ—ߥâ“π¢â“ߢÕß atrium à«π„πÀâÕߴ⓬æ∫‡©æ“– „π auricle ‡∑à“π—Èπ √–∫∫‡≈◊Õ¥∑’Ë¡“‡≈’ȬßÀ—«„®‡ªìπ·∫∫ left coronary type ‡ âπ‡≈◊Õ¥ left coronary artery ·¬°„Àâ 2 ·¢πß §◊Õ circumflex branch ·≈– paraconal interventricular branch à«π subsinuosal interventricular ·≈– intermediate branches ·¬°ÕÕ°¡“®“° circumflex branch ∑—Èß ventricle ¢â“ߴ⓬·≈–¢«“ æ∫ papillary muscles ¢â“ß≈– 3 Õ—π ‚¥¬æ∫∑’˺π—ß°≈“ß 1 Õ—π·≈–∑’˺π—ßÕ‘ √– 2 Õ—π æ∫ trabecula septomarginalis ¢π“¥‡≈Á° 1 Õ—π∑’ËÀâÕß≈à“ߴ⓬ ·≈–æ∫ 3 Õ—π∑’ËÀâÕß≈à“ߢ«“ aortic arch ·μ°·¢πß„Àâ brachiocephalic trunk ·≈– left subclavian artery æ∫ ligamentum arteriosum ‡™◊ËÕ¡√–À«à“ß à«πμâπ¢Õß descending aorta ·≈–√Õ¬μàÕ√–À«à“ß left pulmonary artery ·≈– pulmonary trunk ≈—°…≥–∑“ß®ÿ≈°“¬«‘¿“§‚¥¬∑—Ë«‰ª ‰¡à¡’§«“¡·μ°μà“ßÕ¬à“߇¥àπ™—¥ ·μàæ∫«à“‡ âπ‡≈◊Õ¥∑’Ëæ∫„πÀ—«„®ÀâÕß∫π¡’®”π«ππâÕ¬°«à“∑’Ëæ∫„πÀâÕß≈à“ß ™—Èπ subendothelial layer æ∫‡ âπ„¬ elastic ‡ªìπ à«π„À≠à à«π™—Èπ subendocardium ´÷Ëß¡’§«“¡Àπ“¡“°°«à“ æ∫‡ âπ„¬ collagen fibers ‡ªìπ®”π«π¡“° §” ”§—≠ : ™–π’·°â¡¢“« À—«„® °“¬«‘¿“§ ®ÿ≈°“¬«‘¿“§ ¿“§«‘™“°“¬«‘¿“§»“ μ√å §≥– —μ«·æ∑¬»“ μ√å ®ÿÓ≈ß°√≥å¡À“«‘∑¬“≈—¬ °√ÿ߇∑æœ 10330 *ºŸâ√—∫º‘¥™Õ∫∫∑§«“¡ Introduction were sent to perform the postmortem autopsy at the White-cheeked gibbon (Hylobates concolor pathology unit, Department of Pathology, Faculty of leucogenys or Hylobates concolor), also called black Veterinary Science, Chulalongkorn University. Heart was gibbon or crested gibbon, is generally classified as the removed from the thorax and kept in 10% formalin, then small tailless man-like ape (anthropoid) like chimpanzee, was carefully dissected. The size, shape, weight, width gorilla and orangutan (Janson and Joyce, 1996; Macdonald, and length were identified, described, sketched and 1999). The animal habituates in the rainforests of South measured at macroscopic level. Tissues from both atria and Southeastern Asia such as Thailand, northern Laos, and ventricles were sampled as small pieces, immersed in northwestern Vietnam, Cambodia and Southeastern the same fixative for 2 days at the room temperature, China (Macdonald, 1999; Geissmann et al., 2000; then were dehydrated and process routinely for paraffin Zoothailand, 2007). However, only little is known about embedding and cut into section at 5-7 μm thick. The the heart of the animals in this family, we hope our report sections were stained with H&E and Masson’s trichrome, could provide the basic anatomical and histological data then observed under light microscope. of the heart of white-cheeked gibbon and be beneficial for further researches. Results and Discussion Macroscopic finding Materials and Methods The heart of the white-cheeked gibbon has oval Adult male white-cheeked gibbon weighing 5.5 kg shape with a blunt, spherical apex like in the dog from Dusit zoo, died with non-cardiovascular cause, (Evans and Christensen, 1979). Its longest cranio-caudal Rung-ruangkijkrai T. et al./TJVM 37(3): 51-58. 53 and basio-apex axis was 3.5 cm and 5 cm, respectively. pectinate muscles. The prominent terminal crest was Apparently, coronary, intermediate, subsinuosal and found at the junction of auricle and atrium. Three paraconal interventricular grooves are similar to those pulmonary veins entered the left atrium. Three compact in ruminant and pig (Ghoshal, 1975c,d). The amount of papillary muscles were found in the left ventricle. One yellowish subepicardial fat in the coronary groove is septal papillary muscle of 0.5 cm in width and 0.8 cm in more abundant than in the interventricular groove. length was identified at the interventricular wall. The Both auricles were apparently seen in auricular other two parietal papillary muscles of 0.2 cm in width, surface (Fig. 1). Right auricle was in the form of comma 0.6 and 0.7 cm in length, respectively, were found at the shape with rather smooth edge, whereas the left auricular ventricular free wall. All muscles gave rise to groups of edge was jagged. The concave border was corresponding chordae tendineae, which radiated to anchor to the free with the ascending aorta, while the convex border lied border and the luminal surface of left atrioventricular closed to the conus arteriosus. Left auricle was rather (tricuspid) valves (Figs. 4, 5). Only one small trabecula larger than the right one and slightly covered the septomarginalis of 0.03 cm in diameter and 0.6 cm in beginning of paraconal interventricular groove like length was found at the bottom of the ventricle. anterior interventricular groove in human (Agur and Lee, Interestingly, pectinate muscles were identified 1999). Left coronary artery emanated from ascending both in the right auricle and also at lateral free wall of the aorta and then bifurcated into circumflex and paraconal right atrium which was unlike in the left side (Figs. 4, 5). interventricular branches. The circumflex branch coursed This finding would reflect to its contractile activity. within the coronary (atrioventricular) groove and Caudal to the intervenous tubercle, fossa ovalis of about terminated as subsinuosal interventricular branch in its 0.3 x 0.5 cm in size could be distinctly noticed as a deep corresponding groove on the right side. The paraconal oval depression. A valve was identified at the opening of interventricular branch descended in the paraconal caudal vena cava in similar manner to that of human interventricular groove without reaching the apex, then (Gray, 1918). Right coronary artery left ascending aorta, anatomosed with subsinuosal interventricular branch which ran in the right coronary groove, and then terminated similar to that in ruminant and pig (Nickel et al., 1981). In without giving subsinuosal interventricular branch. addition, the intermediate branch rose from circumflex The subsinuosal interventricular branches ramified from branch, extended ventrally into the intermediate groove on the left coronary artery as found in majority of long-tailed the left side but terminated before reaching the apex monkey (Teofilovski-Parapid and Kreclovic, 1998). (Figs. 2, 3). Internal diameter of ascending aorta, aortic Therefore the coronary artery supply of the white-cheeked arch and descending aorta was about 0.9 cm. The aortic gibbon heart could be defined as left coronary type, which arch gave rise brachiocephalic trunk and left subclavian was similar to that found in dog and ruminant (Ghoshal, artery which was similar to that found in dog, pig and 1975a,d, Nickel et al., 1981; Dyce et al., 1996). Unlike in guinea pig (Nickel et al., 1981; Kabak and Haziroglu, pig, horse, one-humped camel, ostrich, majority of human 2003) with an internal diameter of 0.4 cm and 0.3 cm, and bonnet monkey, subsinuosal interventricular branch respectively (Figs. 1, 3). While gave 3 branches in the rose from right coronary artery, which called bilateral majority of human (Gupta and Sodhi, 2005) and only 1 coronary type (Ghoshal, 1975b,c; Buss et al., 1982; branch; brachiocephalic trunk, in horse and ruminant Bezuidenhout, 1984; Weaver et al., 1986; Ghazi and (Ghoshal, 1975b,d). Tadjalli, 1993; Dyce et al., 1996; Agur and Lee, 1999). Left interatrial septum had smooth surface while One septal and two parietal papillary muscles of the auricular free wall was rough with the interlacing 0.2 cm in diameter and 0.8, 0.7, and 1.5 cm in length, 54 Rung-ruangkijkrai T. et al./TJVM 37(3): 51-58. AB Figure 1 Auricular