M. K. Ocal

The circulus arteriosus cerebri in the guinea pig.

Arteries to the brains of guinea pigs were injected with latex and the circulus arteriosus cerebri was studied. Most of the arterial blood to the guinea pig brain came from the internal ophthalmic and vertebral arteries. The internal carotid arteries were extremely thin. In addition to an anastomosis that was found between the right vertebral and the basilar arteries in one specimen, the right vertebral artery anastomosed with the left vertebral artery in eight specimens and in one animal the basilar artery was double along a major part of its length.

A Quantitative Study on the Trachea of the Dog

This study was carried out to record the detailed morphometric structure of the trachea in dogs using 15 female and four male healthy adult mongrel dogs. The diameter and thickness of each tracheal ring were measured, the number of tracheal rings varying from 36 to 45. All data were subjected to statistical analysis which was carried out on individual sections of the trachea, i.e. the cranial cervical, middle cervical, thoracic inlet and the intrathoracic tracheal regions, which consisted of 12, 12, nine and 12 tracheal rings, respectively. Fusion of the tracheal rings was especially obvious in the cranial cervical and thoracic inlet regions as a result of neck movements. The diameter and thickness of the tracheal rings are smallest at the thoracic inlet level because the direction of the trachea changes at this point where the thoracic inlet is relatively small and surrounded by bone. The ratios of inner transverse to inner vertical and outer transverse to outer vertical diameters were almost the same, between 1.14 and 1.25 in all regions, which indicated that the trachea is near‐circular in shape in the dog. At the thoracic inlet level cross‐sectional lumen areas are 7 and 6% smaller than those in the middle cervical and intrathoracic regions, respectively. The thinnest cartilage was seen at the thoracic inlet level where there is a risk of tracheal collapse.

A quantitative study on the digital bones of cattle.

The bones of 64 digits from eight Holstein male cattle were studied quantitatively to determine whether any differences existed respective on the corresponding bones of the different digits. For this purpose, the greatest and abaxial greatest lengths, the smallest diaphysial breadths, the breadths of proximal and distal ends of the proximal and middle phalanges, the lengths of dorsal surfaces, the heights of extensor processes, the greatest diagonal lengths and the middle breadths of the soles from the distal phalanges were measured. Comparison showed that measurements between the right and left sides did not differ significantly. However, differences were found for almost all measurements between the forelimb and hindlimb. The proximal and middle phalanges were found to be shorter and broader in the forelimb and the broadness was more noticeable than the length. The distal phalanx of the medial forefoot had the greatest value in four measurements while the smallest values were found in the lateral hind foot. The results indicated that the morphometry of the digital bones could be important from both phylogenetic and clinical aspects.

Computed tomographic assessment of the trachea in the German shepherd dog.

Computed tomographic (CT) examination of the trachea was performed in 10 German shepherd dogs to determine the normal value of some tracheal measurements under general anesthesia and in sternal recumbence position. Measurements obtained from nine segments were evaluated in four groups as the cranial cervical, caudal cervical, thoracic inlet and the thoracal tracheas. The inner transverse (T) and vertical (V) diameters were measured with the aid of electronic calipers from the software of the CT scanner. The cross-sectional lumen area (CSA) was calculated by using vertical and transverse diameters. The ratio of the transverse and vertical diameters (T/V) was also calculated. There was not any significant difference between thoracic inlet and thoracic tracheas, however, the mentioned regions were found to be significantly different from both cranial and caudal cervical regions in all measurements except the ratio of T/V. The ratio of T/V between 0.92 and 1.06 gradually changed and there was not any statistical difference between subsequent regions while differences were found among further regions. The largest CSA, seen in cranial cervical trachea was as 364.62 mm2 and decreased gradually to 309.29, 245.69 and 226.50 mm2 in caudal cervical, thoracic inlet and thoracic tracheas, respectively. From the point of view of technique, CT examination of the dog trachea was very easy and it was possible to take sensitive and repeated measurements. It, however, may be accepted as expensive and that it is disadvantageous to require general anesthesia. The data presented in this study represent tracheal values in the healthy German shepherd dog under the conditions of the study.

Morphometry of the Thoracic Spine in German Shepherd Dog: A Computed Tomographic Study

Computed tomographic images of the thoracic spine of 13 German shepherd dogs were examined in order to determine the thoracic spine morphometry. Examinations were carried out in the transverse plane both intervertebral and mid‐vertebral levels of the each thoracic vertebrae. The dorsoventral and interpedicular diameters of the spinal canal, the dorsoventral and transverse diameters of the vertebral body, the dorsoventral and transverse diameters of the spinal cord and also the cross‐section area of the spinal canal were measured. The maximum values were found to be at the level of C7‐T1. The shapes of the spinal canal and cord were circular in middle part, the shape became transverse oval in the cranial and caudal parts of the thoracic spine. The most significant correlation between the diameters was found to be in male dogs, except between dorsoventral diameters of the spinal canal and that of the vertebral body and between dorsoventral diameters of the spinal canal and transverse diameters of the vertebral body.

Computed tomographic measurements of the hip morphology of 10 healthy German shepherd dogs

Linear measurements were made by computed tomography of the diameter of the femoral head, the width and depth of the acetabulum and the dorsal and ventral acetabular rim distances in 10 healthy German shepherd dogs, and angular measurements were made of the axial acetabular index, acetabular anteversion, and the dorsal and ventral centre-edge angles. There were no significant differences between the measurements made on the left and right sides. The width of the acetabulum was about twice its depth, and was a little larger than the diameter of the femoral head. The mean values of the axial acetabular index, acetabular anteversion, and ventral and dorsal centre-edge angles were 100.9°, 25.1°, 48.0° and 12.2°, respectively.

A quantitative study on the retial arteries in one-humped camels

The brain arteries of camels were injected with latex and the rostral epidural rete mirabile, which is situated inside the cavernous sinus at the base of the brain, was studied both grossly and quantitatively. The rostral epidural rete mirabile is formed by the retial branches of the maxillary and external ophthalmic arteries and also the internal carotid artery. When the ratio of the blood supply to the rete was estimated from the diameter of each vessel, it was found that the branches of the maxillary artery carried 76.41%, the branches of the external ophthalmic artery carried 10.26% and the internal carotid artery carried 13.33%.

Geometry of the femoral condyles in dogs

The stifle joint is one of the most important joints in dogs from the orthopaedic point of view. The aim of this study was to document the morphometric values of femoral condyles, given the close relationship between the shape and function of an anatomic structure. The left femora of 16 mid-sized dogs were used, and diameter and nine radii as well as cranial and caudal bow lengths from each condyle were measured. The photographs were taken of the distal femora from both sides. All measurements were obtained from these images by using software. Additionally, the rotation angle was calculated from the intercondylar distance and the difference between lateral and medial bow lengths. In addition to the rotation angle, the difference of diameter and nine radii between the lateral and medial condyles was determined. All radii except getting at 90° were significantly different between the medial and lateral condyles. The greatest values were determined in the caudal part of the medial condyle. This results the smaller contact area and a greater pressure on the underlying surface, and therefore the meniscus and articular cartilage of the caudal part of the medial side suggests the possibility of a risk of injury as the stifle joint flexes. The mean rotational angle of the femur was also calculated to be 2.18° laterally and 1.02° medially in the caudal and cranial parts of condyles, respectively. The result of this study showed that the lateral and medial condyles had different shapes in canine femur.

A Quantitative Study of the Aorta of the Chicken (Gallus domesticus)

The different segments of the aorta were studied quantitatively in five age groups of chicken. It was observed that the widest diameter and the thickest media occur on the 56th day in each segment, except for the thoracic aorta, which had the widest diameter on the 42nd day and the thickest media on the 70th day.

A quantitative study on the retial arteries in the bovine fetus

The rostral epidural rete mirabile was injected with latex and the retial arteries were studied quantitatively in three groups of bovine fetuses. It was seen that the differences between the diameters of the right and left retial arteries were not significant. An interesting observation was that the diameter of the internal carotid artery decreased gradually with an increase in the gestational age, but this reduction was made up for the maxillary artery via the rostral rete branches. The proportion of the blood supply to the rete was also determined in three groups of fetuses.