2010, Vol. 5 No. 2, Article 71

A Note on Hyoid Bone of Yak (Bos grunniens)

K. B. Dev Choudhury*¹ and M. Bhattacharya

National Research Centre on Yak
I.C.A.R., Dirang, Arunachal Pradesh 797101

¹Department of Veterinary Anatomy,
College of Veterinary Sciences & A.H., R. K. Nagar, Tripura (W) 799 008.

*Corresponding Author; e-mail address: [email protected]

ABSTRACT

Gross anatomical study of hyoid bone of yak was conducted. The bone consisted of stylohyoid, epihyoid, ceratohyoid, basihyoid and thyrohyoid parts. The corresponding parts of hyoid bone of male yak measured larger than that of the female. Anatomical structure of hyoid bone of yak was comparable to that of ox except that in yaks the thyrohyoid was found fused with the basihyoid in both sexes.

KEY WORDS

Hyoid bone, yak.

INTRODUCTION

The yak is an animal of choice at high altitudes. Paucity of literature on the hyoid bone of yak was noted. Hence, the present study was undertaken.

MATERIALS AND METHODS

The study was conducted on adult male and female (N=2) yaks that were apparently free from any chronic disease. After slaughtering the animals, the hyoid bones were carefully dissected out and cleaned properly. The measurements of different parts of hyoid bones were recorded with the help of vernier calipers.

RESULTS

The hyoid bone was found lying between the two rami of mandible supporting the root of the tongue, pharynx and larynx. Gross examination revealed that the bone consisted of stylohyoid, epihyoid, ceratohyoid, basihyoid and thyrohyoid parts (Fig. 1). Sisson (1975) and Ghosh (2003) observed similar anatomical structure of hyoid bone in ox. Measurements (Table 1) of different parts of the bone showed a considerable variability. The corresponding parts of hyoid bone of male measured larger than that of female yak.
A short tubercle lingual process projecting out from the rostral end of basihyoid to support the tongue (Fig. 1) was observed which corroborated the findings reported by Nickel et al. (1986) in ox. The dorsal end of the stylohyoid bifurcated into tympanohyoid and stylohyoid angle (Fig. 1). The tympanohyoid articulated through a cartilage with the styloid process of the petrous part of the temporal bone. These findings also were in line with those reported earlier by Sisson et al. (1975) in ox.

DISCUSSION

In light of the present observations and previous reports it can be inferred that grossly the hyoid bone of yak is comparable to that of ox except that in yaks the thyrohyoid lies fused with the basihyoid in both sexes.

ACKNOWLEDGEMENTS

Authors are thankful to the staff members of National Research Centre on Yak I.C.A.R., Dirang, Arunachal Pradesh for their help during the research work.

REFERENCES

1. Ghosh RK. Primary Veterinary Anatomy. 3rd Edition. Current Book International, Calcutta, Chennai and Mumbai, 2003.

2. Nickel R, Schummer A, Seiferle E. The Locomotor System of the Domestic Mammals. Verlag Paul Parey, Berlin, Humburg, 1986.

3. Sisson S. Ruminant Osteology. Sisson and Grossman’s The Anatomy of Domestic Animals, Vol. I, 5th Edition. W B Saunders Co., Philadelphia, 1975.

TABLES

Table 1. Average measurements of hyoid bone in yak

FIGURES

Fig. 1: Hyoid bone of yak