الفهرس 
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Abstract
Thirty six heads of clinically normal adult sheep and dogs of both sexes (eighteen of each species) were used in this study. The heads of adult sheep (3-5 years old) were collected from Al-Amria slaughter house while the adult dogs (5-7 years old) were collected from different sources in Elbehira governorate. Adult dogs were anesthetized by IM injection of a mixture of xylazine hydrochloride and IV injection of thiopental sodium. Then, the dogs were bled, and their heads were collected.
Ten head used for gross morphology, six for scanning electron microscope and twenty head for arterial supply of tongue) the twenty head of arterial supply were divided into ten head for latex , six for radiography and four for microvasculature. We study the morphology of the tongue, arterial supply of the tongue and made anatomical references for the tongue by making computed tomography on injected tongue of sheep and dog.
These studies demonstrated that the tongue is an identical example for the accommodation with the feeding behavior of the animal. The aim of the study to investigate more details about the gross morphology of the tongue by using gross and scanning electron microscope, to investigate more detail about the arterial supply of the tongue by using latex, radiograph and Indian ink for visualization of microvasculature and to provide an anatomical references for the computed tomography and cross sectional anatomy of the tongue in sheep and dog which not available in any previous literature.
For gross anatomical study of the tongue, the tongue of fresh sheep and dog were dissected carefully in some specimens, we left the tongue in the lower jaw to investigate the extrinsic muscles, while in others it was separated to examine the external morphology. and varies gross morphological features and parameters were recorded for each animal separately and the different measurements of the tongue were carried.
For examination of papillae of the tongue, the scanning electron microscopical examination was carried out by taking tissue blocks from the dorsal and lateral surfaces of of six adult sheep and dogs (3 from each species).
The apex and root of tongue of dog is longer than that of sheep while body of tongue of sheep is longer than that of dog. In sheep the length of tongue is 13 cm, the apex lengh is 3.5 cm, body is 8.5 cm and root is 1.5 cm in length while in dog the length of tongue is 12.5 cm apex length is 3.5 cm, body is 6 cm and root is 2.5 cm.
The apex of tongue of sheep was wholly pigmented represent 27% of total length of tongue and body represent 62% and the long body in sheep is due to presence of torus linguae which play role in mastication and swallowing of food. The width of body of tongue is variable where it was narrow about 2 cm at the level of second lower premolar tooth, then increased gradually caudalwards reached about 3 cm at torus linguae and then it decreased in width again to become 2.5cm infront of palatoglossal fold.
In dog the apex of tongue represent 40% of total length of tongue so apex of tongue is long and this due to feeding and drinking behavior of the animals while the body in dog represents 48% of total length of the tongue. Its width was nearly fixed along its length that was 3.5 cm.
In sheep, the filiform papillae decreased in height caudal ward and the filiform papillae of lingual body had no secondary papillae, the lenticular papillae were found on the torus linguae between the two rows of the vallate papillae. The origin of the lenticular papillae was surrounded by prominent papillary groove, the conical papillae were located on the torus linguae, but were condensed on its two lateral portions. The shafts of conical papillae were curved along their lenghths characterized by wide base and blunt tip and presence of papillary groove. The fungiform papillae were located on free edges of the tip and body of the tongue and few in the rostral part of the torus linguae. The fungiform papillae were oval and its surface were smooth and presence of taste pores. The vallate papillae were eighteen to twenty four in number and arranged into two rows on each side of the caudal part of the torus linguae in front of the palatoglossal arch. They were surrounded by gustatory grooves separate the papillae from the surroundings and presence of prominent annular pad.
In addition to the presence of the conical, lenticular and vallate papillae in the torus linguae of tongue of sheep, few filiform and fungiform papillae could be observed in this area. This is attributed to the role which is played by the torus linguae during mastication and swallowing of food.
While in dog, the filiform papillae increased in height caudal word and the filiform papillae of lingual body consist of main primary papillae and some secondary papillae. Conical papillae found on root of tongue characterized by narrow base and pointed tip and its surface were rough. The fungiform papillae were numerous at the tip and along the lateral surfaces of the tongue, and few may be located caudal to vallate papillae and surface of this papillae was rough due to presence of ridges and grooves .The vallate papillae were two or three papillae arranged on either side along the median groove on the root of the tongue, and three papillae were most frequently found in the left side and surrounded by annular goove and lack annular pad.
The extrinsic muscle in sheep (geniglossus, hyoglossus and styloglossus) not divided while in dog genioglossus divided into three bundle (vertical bundle, oblique bundle and straight bundle) and styloglossus divided into three head (anterior head, long head and short head. The division of extrinsic muscle in dog allows wholly movement of tongue and shaping of tongue during drinking.
To Study the intra-lingual distribution of lingual artery, several procedures were used after animal preparation, using tranquilizers and sedatives before exsanguination. Once the heads were removed and the arterial tree was flushed, several methods were used as latex injection, radiograph, Visualization of microvasculature of lingual mucosa.
The tongue of sheep received its arterial supply mainly through the lingual artery and its terminal branches. The root was supplied by the muscular and perihyoid branches from the lingual artery. The lingual body was supplied by branches originating from the sublingual and deep lingual arteries. The apex of tongue received blood from the deep lingual artery. While in dog, the root was supplied directly from the lingual artery and the lingual body and apex were supplied by branches originating from deep lingual arteries. The sublingual artery was not major arterial supply for the tongue, but it partially supplied the extrinsic muscle of the tongue.
The lingual artery in sheep gave several branches (perihyoid branch, glandular branches, muscular branches, sublingual artery and deep lingual artery while in dog the lingual artery gave (ascending palatine branch, muscular branch, hyoid ramus and gave deep lingual artery). The sublingual artery in dog not arose from lingual artery but arose from facial artery.
The deep lingual artery in sheep gave dorsal lingual branch its number were 15 in number in left deep lingual and 10 in right deep lingual and ventral lingual branch its number were 10 branches in left side and 6-7 branches in the right side. The deep lingual artery passed in tortuous manner and the left deep lingual reach to the tip while the right deep lingual end before the tip by 3-4 cm.
In dog the deep lingual artery gave dorsal lingual branch its number ranged from 12-14 branches and the last rostral four branches were the largest and ventral lingual branch were ranged from 8-10 in number and were distributed mainly into geniogloassal and styloglossal muscles as well as the ventral free part of the tongue. The deep lingual arteries passed parallel to the tip of tongue and both deep lingual artery reach to tip of tongue.
We made anatomical reference for the injected tongue of sheep and dog and we explain lingual artery and lingual structure in every section. The computed tomography examination was applied on the whole tongues of two adult sheep and dog which were injected by lead oxide. The tongue was serially sectioned using the computed tomography scanner. The scanned images were taken caudally from the root rostral wards till the level of the tip of tongue with 1 cm intervals. Then cross sections of two frozen tongues which were serially cut using a table of band saw, and the cross sections were 1cm a part beginning from the level of the root until the tip of the tongue. The slices were numbered and gently cleaned from debris with water and light brushing, and were photographed immediately with the rostral surface of each slice facing the camera.
The results obtained in the present study were discussed and compared with those of several authors having performed earlier studies in sheep, dogs, small ruminants and other domestic animals.