A golden ratio for foramen magnum: an anatomical pilot study.

BACKGROUND: The foramen magnum (FM) is an important landmark because of its close relationship to key structures such as the brainstem and spinal cord, an extension of the medulla oblongata. Because of the similarity in their shape, the existence of a relationship between cranial length and anteroposterior diameter of the FM, and between cranial width and transverse diameter of the FM may reveal the magnificent harmony of the skull and FM. Based on this idea, we investigated the existence of this harmony in skulls that we used in our study. MATERIALS AND METHODS: In this study, 60 adult dry skulls belonging to the Turkish population were examined. The anteroposterior and transverse diameters of the foramen magnum and the length and width of the skull were measured. Measurements were made directly on the skull using a digital sliding calliper. New indices and ratios were applied with those measurements. RESULTS: Our study suggests that FM width and FM length could be estimated by using the cranial length and cranial width measurements in the skull by accepting the mean of these coefficients (4.62) as the golden ratio. The average of the coefficients of cranial width to FM width ratio (4.62 ± 0.35 [95% CI: 4.52-4.70]) and the average of the coefficients of cranial length to the FM length ratio (4.62 ± 0.50 [95% CI: 4.49-4.76]) were found to be equal to each other. In order to check the accuracy of this hypothesis, FM width and FM lengths were estimated with the help of new equations. CONCLUSIONS: In the present study, the ratio between the anteroposterior and transverse diameters of both FM and the cranium was estimated at 4.62, indicating a magnificent harmony between cranial and subcranial structures. With this ratio, it is easy to estimate FM's size based on simple cranial measurements.

Anatomy of parotid gland and its secretory ducts in sheep.

BACKGROUND: The parotid gland in sheep ends freely in front of the masseter muscle, and paracondylary section of occipital bone and extends deep until pterygoid extends of sphenoid bone and hyoid bone. The structure of salivary glands in mammals has been thoroughly studied using histological and sialographic method. This study aimed to reveal the detailed anatomic features and race-specific differences of the canal system of the parotid glands in Akkaraman sheep by using the corrosion cast technique. MATERIALS AND METHODS: Thirteen sheep parotid glands from 7 Akkaraman sheep were used in this study. Parotid glands were removed from their places with ducts. Measurements were made with a calliper from back to front, top to bottom and inside to outside. After dissection of the parotid glands, their volumes were measured according to the 'Archimedes principle'. Also, 13 sheep parotid glands were examined using the polyester resin method. RESULTS: In the present study, our average metric results were: length of parotid duct was 10.92 ± 1.027 cm, length of parotid gland was 5.87 ± 1.04 cm, volume of parotid gland was 12.50 ± 2.48 cm³, thickness of parotid gland was 0.75 ± 0.36 cm and width of parotid gland was 4.07 ± 0.43 cm. The average weight of the parotid gland of Akkaraman sheep was identified as 25.3 g. Accessory parotid gland was not encountered in the current study. CONCLUSIONS: It was observed that polyester entered into the parotid duct and filled up until the acinus and made both acinus and secretory ducts well-examined in this study. It was also observed that the parotid gland consisted of lobes and lobules. The average number of lobes was 12. The number of lobules in a lobe varied between 3 and 16, each lobe consisted of an average of 9 lobules. It was found that each lobe has its own lobar duct.

The morphology of the afferent and efferent domain of the sheep glomerulus.

BACKGROUND: It is important to know the morphology of the glomerulus in order to explain kidney infiltration. The present study aims to research the morphology of afferent and efferent domains of sheep kidney glomeruli. MATERIALS AND METHODS: In this study, 2000 glomeruli from 20 kidneys of Akkaraman sheep were examined using the polyester resin method. RESULTS: It was found that the glomeruli of sheep kidney usually had an afferent arteriole as well as an efferent arteriole. Besides, it was also found that five glomeruli had two efferent arterioles. It is known that the afferent domain constitutes the largest part of the glomerulus. In two of the glomeruli that we examined, the afferent domain formed the 1/2 of the glomeruli wherein the other two glomeruli afferent domain formed the 3/4. CONCLUSIONS: It is known that there are many anastomoses between the afferent and efferent domain of capillaries. However, it is not well-explained how anastomosis is created between the afferent and efferent domains. In our study, it was identified that those anastomoses were not inside the lobes but between the surrounding capillaries.

Arteries of the carotid body in rats.

The arterial blood supply of 40 carotid bodies in 20 Wistar rats of both sexes, aged 10-12 weeks (250-350 g), was examined by light microscopy. The carotid bodies of all rats were supplied by only one carotid body artery. The average diameter of the carotid body arteries was 40 microns. This artery arose either from the external carotid artery (97.5%) or the occipital artery (2.5%). There was an intimal cushion at the origin of the carotid body artery. The carotid body artery, after reaching the caudal pole of the carotid body, divided into the first-order branch. In the carotid body, the paranchyma was divided into the second-order branch. The carotid body artery was of the muscular type.

Measurements of axial length and radius of corneal curvature in the rabbit eye.

The axial length of the eye, the radius of the anterior corneal surface, and the diameter of the cornea were measured on 40 eyes of 20 New Zealand White rabbits. The ultrasonographic measurements of the axial length of the eye showed a mean value of 15.12 +/- 0.51 mm (15.33 +/- 0.50 mm in males, 14.96 +/- 0.46 mm in females). The mean corneal radius was 7.26 +/- 0.26 mm (7.18 +/- 0.9 mm in males, 7.32 +/- 0.33 mm in females); the mean value of the difference in corneal curvature between two principle meridians was 0.21 +/- 0.12 mm; and the mean horizontal and vertical diameters of the cornea were 13.41 +/- 0.34 mm and 13.02 +/- 0.30 mm, respectively. Although the diameter of the cornea of rabbits was bigger than that of humans (average, horizontal 11.75 mm, vertical 10.55 mm), the axial length of the eye was 0.7 times that of humans (23-24 mm), and the radius of corneal curvature was relatively smaller than that in humans (7.7-7.8 mm).

Intradural disc herniations pathogenesis, clinical picture, diagnosis and treatment.

The relatively rare occurrence and uncertainty about pathogenesis of intradurally displaced disc herniations stimulated an anatomico-pathological study into intradural disc herniations. The relation between the ventral dura and posterior longitudinal ligament in the cervical, thoracic, lumbar and sacral regions were examined macroscopically and microscopically, and ventral and dorsal dural thickness was compared in 20 adult autopsies on patients who died from various causes; in addition, 20 late abortions and newborn cadavers were investigated in the same way. In this study, a total of 40 autopsies has shown that the ventral dura is most frequently and firmly attached to the posterior longitudinal ligament at the L4-L5 level and these adhesions may be congenital. In the adult cadavers dorsal dura was found to be thicker than the ventral dura in the lumbar and lower cervical interspaces. Three personal clinical cases of intradurally herniated disc prolapse are shortly described and the diagnosis and management of this pathology discussed.