STUDY OF DORSAL SACRAL TRIANGLE IN HUMAN SACRA
Authors: Joshi Manoj Bhavanidatta 
Published: March 2020

Introduction:

Sacrum is a triangular bone shaped by combination of five sacral vertebrae. It is embedded as a wedge between the two innominate bones at the upper and back portion of pelvic bone. The opening show at the caudal conclusion of sacral canal is known as sacral rest. It is shaped due to the disappointment of combination of laminae of the fifth (every so often 4th) sacral vertebra. It is situated inferior to the 4th (or 3rd) fused sacral spines or lower end of median sacral crest. Sacrum is a vital bone for recognizable proof of sex in human skeletal framework. Since it may be a component of hub skeleton and and pelvic support, it has an applied significance in deciding sexual orientation with the assistance of estimation carried upon it. The well- known strategy for assurance of male and female sacra has been the Sacral file (SI). The varieties within the structure of dorsal divider of sacral canal are various. It may be open all through its whole length or there may be moo lying lamina of to begin with sacral vertebra. Other varieties incorporate lacks between its predominant and second rate limits, pulverization of lumen of sacral canal and hard abundance annihilating the break. The nearness of any gaps may allow the needle to elude the canal coming about in subcutaneous statement of anesthetic operator. The sacral hiatus has been used for administration of caudal epidural anesthesia in obstetrics as well as orthopedic practice for treatment and diagnosis. The foremost visit issue experienced in caudal epidural square is needle situation as in some cases it is troublesome to decide the anatomical area of sacral rest particularly in grown-ups. Clinical assessment of needle arrangement can be done with ultrasonography or fluoroscopy. In any case, it isn't continuously doable to do so since of time and cost limitations. Varieties have been found within the shape and level of sacral break. Anatomical points of interest and the information of real shape and size of sacral rest and its varieties play a major part within the victory of needle situation. 

Aim: The main of this study is to find out the anatomical variations of sacral hiatus of the cadaver in human.

Material and Methods: This is a Cross-sectional study carried out on dry human sacra to study the anatomical variations of sacral hiatus. Total 80 human sacra were collected from Department of Anatomy. Only dry sacra with complete sacral hiatus were included in this study. Damaged sacra were excluded in this study. For the study various parameters and measurement were used for the study. With the help of naked eye the shape of the sacral hiatus was noted. The length of sacral hiatus was measured from apex to the midpoint of base; the antero-posterior depth of sacral hiatus at the apex was measured with the help of vernier calipers and recorded as data. With the help of vernier caliper the transverse width of sacral hiatus at the base was also measured between the inner aspects of inferior limit of the sacral cornu with the help of divider and then adjusted and calculated.

Result: In this all the sacrum studied was composed of five segments in 80 cases. There were many variations in the shape of sacral hiatus. In 38 (47.5%) sacra the shape was Inverted-U whereas sacra Inverted V was seen in 21(26.3%).  Both the over sorts were considered as ordinary and the sacral break was show against 4th and 5th sacral sections. The irregular shaped of sacral hiatus was observed in 12(15%) cases. A “Dumbbell” shaped sacral hiatus was observed in 5(6.3%) cases with a nodular bony growth projecting medially from both margins. The dorsal wall of sacral canal was entirely absence in 3(3.8%) cases. a rare phenomenon, absence of sacral hiatus was observed in 1(1.3%) only.

Conclusion: There was variability in the anatomical structure of the sacral hiatus. The inverted U shape of sacral hiatus was most commonly seen. Apex and base of the hiatus were most commonly seen at the level of S4 and S5 respectively. These estimations will be of colossal esteem in administration of caudal epidural anesthesia and variations in shape and estimate of sacral rest will help in preoperative assessment of patients. There are anatomical varieties within the sacral break, which may relate to the complication to caudal epidural anesthesia. Understanding of these varieties may progress the victory rate of caudal epidural anesthesia.

Keywords: Sacrum, Sacral hiatus, apex, base, caudal epidural anaesthesia