Normal and Abnormal Development of Left Vertebral Artery and Its Implications in Cervical Region Surgery

Aortic arch (AA) anomalies occur in approximately 3-5% of cadavers, but these atypical branches remain a point of discussion in cervical region surgery. This case report describes a 73-year-old Caucasian female who died of renal failure following a complicated urinary tract infection whose left vertebral artery (LVA) originated from the AA between the left common carotid and subclavian arteries. The preforaminal part of the LVA was 5 mm in diameter and entered the C6 transverse foramen while the right vertebral artery (RVA) arose from the right subclavian was 6.5 mm in diameter and entered the C5. Embryologically, VAs are formed during weeks four through eight by development of longitudinal anastomoses linking the cervical intersegmental arteries (ISA). The ISA regress except the seventh, which becomes the proximal subclavian artery, the point of origin of the adult VA. Persons with LVA that arises from the AA may be asymptomatic; however, secondary dilatation of the RVA may be implicated in the development of cerebrovascular disorders and atherosclerotic changes due to increased blood flow. Additionally, the anatomical positioning of a left vertebral artery is important when considering an anterior approach for cervical spine surgery and other head-neck procedures when soft structures arteries, veins and muscles are retracted to reach the cervical spine.

Clustered Origin of the Left Coronary Artery from the Left Sinus of Valsalva: Uncharacteristic Developmental Event in the Temporally Regulated Process

Coronary artery development is a sequential and progressively regulated process. However, there are a number of reports available on the disturbance to this temporal process resulting in variations of the artery. In these instances, the function of the coronary arteries was normal in providing blood supply to the heart. The normal and abnormal coronary artery development has been studied using a variety of approaches and the knowledge continues to evolve. The cadaveric specimen was obtained from the “willed body program” for the purpose of student dissection. During the cadaveric dissection of a 94-year old male Caucasian we observed that the left coronary artery arose from the coronary ostium in a cluster of multiple branches. A detailed study of the origin of the left coronary artery showed that there is one ostium from which multiple branches arose. The right coronary artery arose normally from the right coronary ostium. The coronary veins were normal and returned the blood through the coronary sinus to the right atrium. The anomalous finding is discussed in the light of what is already known about the normal coronary artery development and rationalize a possible explanation. We conclude that the abnormal development of the coronary artery is rarely detrimental and provides adequate blood circulation to the heart. However, knowledge of such malformation is important in clinical practice.

Clustered Origin Of Left Coronary Artery From The Left Sinus Of Valsalva: Uncharacteristic Developmental Event In The Temporally Regulated Process

Background: The coronary artery development is a sequential and progressively regulated process. However,there are number of reports available on the disturbance to this temporal process resulting in variations of theartery. In these instances, the function of the coronary arteries was normal in providing blood supply to theheart. The normal and abnormal coronary artery development has been studied using variety of approaches andthe knowledge continues to evolve.Materials and Methods: The cadaveric specimen was obtained from the “willed body program” for the purpose ofstudent dissection. We report here an anomaly found in a 94-year old Caucasian male died of cerebral arteryinfarction.Results and Observations: We observed that the left coronary artery arose from the coronary ostium in a clusterof multiple branches. The right coronary artery arose normally from the right coronary ostium. Further dissectionshowed the co-dominant nature of the left and right coronary arteries in providing blood supply to the posterioraspect of the heart and the interventricular septum.Conclusions: Knowledge of coronary artery and its disposition is important in clinical practice especially incoronary artery stent placement, coronary artery bypass surgery and coronary sinus catheterization.

A Study Of Test Construct And Gender Differences In Medical Student Anatomy Examination Performance

Background: A number of studies compare cognitive abilities of male and female students from elementaryschool through high school employing various test constructs and reported presence of gender-related differenceshaving to do with the mode of assessment. The purpose of the present study was to examine whether there is adifference in the performances of male and female medical students. We employed two types of test constructsviz., constructed response (CR) and selected response (SR) examinations that use the same question stem.Materials and Methods: Two types of test questions, CR and SR, were studied. Each CR and SR question used thesame question stem to assure all questions were matched. Study participants were incoming first year medicalstudents enrolled in a six-week summer enrichment anatomy course prior to the start of the school year. Group1 included 16 students (8 male and 8 female) and Group 2 19 students (7 male and 12 female). The coursefocused on study of the thorax and abdomen and the student performances were analyzed.Results and Discussions: Mean scores and statistical analysis showed comparable performance between maleand female students. The independent sample t-test showed that, statistically, there were no significant differencesin performances of male and female students in the CR or SR examinations, except in the Group 1 male and femaleabdomen SR examination [t (14) = 1.934, p< 05 1 tailed]. Collectively, these results show that male and femalestudents in both the groups performed better in the SR test than the CR test.Conclusions: Gender poses no limitation to medical student performance, irrespective of the type of examinationformat. It is possible to adopt CR examination as a formative evaluation tool for students to identify theirdeficits and strategize effective learning.