Int J. MorphoL, 25(2):407-410,2007.

Osteometric Studies of the Skull of Red Sokoto (Maradi) Goats (Capra hircus): Implications for Regional Anaesthesia of the Head

Estudios Osteométricos del Cráneo de las Cabras Rojas de Sokoto (Capra hircus): Implicaciones para la Anestesia Regional de la Cabeza

Olopade, J. O. & Onwuka, S. K.

Department of Veterinary Anatomy, Faculty of Veterinary Medicine, University of Ibadan, Nigeria.

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SUMMARY: The study involved the measurements of some clinically important landmarks for regional anesthesia in the head of twenty five Red Sokoto goats. The length and maximum height of the mandibles were 12.7cm and 7.7cm respectively. The distance from the mandibular foramen to the base of the mandible was 3.0cm while the distance between the lateral alveolar root and mental foramen and from the facial tuberosity to the infra-orbital foramen was 1.8cm in both instances. The data was discussed with regard to its importance in proper tracking of some nerves in aid of regional anaesthetic procedures in the head of the Red Sokoto goat and was compared with our results reported for the West African Dwarf breed.

KEYWORDS: Osteometry; Red Sokoto goats; Regional Anaesthesia; Skull.

RESUMEN: El estudio abarca las medidas de algunas líneas clínicamente importantes para la anestesia regional en las cabezas de 25 cabras rojas de Sokoto. La longitud y altura máxima de las mandíbulas fue de 12.7cm and 7.7cm, respectivamente. La distancia del foramen mandibular a la base de la mandíbula fue 3.Oran mientras que, la distancia entre la raíz alveolar lateral y el foramen mental y entre la tuberosidad facial y el foramen infraorbital fue 1.8cm, en ambas instancias. Los datos fueron discutidos con respecto a su importancia en el tratamiento apropiado de algunos nervios, en la ayuda de procedimientos anestésicos regionales en la cabeza de la cabra Roja de Sokoto. Estos resultados fueron comparados con los reportados por nosotros para la cabra enana del Oeste africano.

PALABRAS CLAVE: Osteometría; Cabra Roja de Sokoto; Anestesia Regional; Cráneo.

INTRODUCTION

Nigeria has one of the largest populations of goats in Africa (FAO, 1997). The Red Sokoto goats which are considered as delicate animals, with an estimated population of over 17 million forms a formidable resource of the livestock industry in Nigeria and are also found widespread in neighbouring countries (Gall, 1996).

The Red Sokoto breed are mainly found in the northwestern part of the Nigeria where the animal feed on tough dry matter due to scarcity of fresh vegetation (Kene & Uwagie-Ero, 2001). This report coupled with the facts that the goats are prone to tooth pathologies, and exhibited the highest incidence of dental abnormalities amongst three goats breeds in Nigeria (Kene & Agbo, 1998; Olopade, 2006) means that the breed may be prone to oral lacerations and may need dental extraction. It is thus vital that a study of the landmarks of the head that can aid regional anaesthesia be conducted. We had earlier reported clinical applications of the mandibular and maxillofacial osteometry of the West African Dwarf goat (Olopade & Onwuka, 2005, 2006).

The aim of this work is to provide information on clinically important parameters that may aid regional anaesthesia of the head of the Red Sokoto goat.

MATERIAL AND METHOD

Atotal of 25 Red Sokoto goats were used for this study. The animals were obtained from Sokoto town and environs in northwestern Nigeria. The animals were selected at antimortem examination in the abattoir and slaughter slabs and after being adjudged clinically healthy were aged and weighed. After slaughter, the heads were purchased and processed in the laboratory using the hot water maceration technique as described by Simoens et al. (1994) and Terai et al. (1998). Atotal of 9 measurements were done in the upper jaw and mandibles using metric rules and the results were presented as mean ± S.D. in Table 1. The parameters measured are described below and shown in Figs. 1-3.

RESULTS AND DISCUSSION

The mandibular length (12.7cm) and maximum mandibular height (7.7cm) in this study were higher than the values obtained for West African Dwarfs in the southwestern and southeastern parts of Nigeria which were 12.0cm and 7.0cm, and 11.81cm and 7.11cm respectively (Olopade & Onwuka, 2005, 2006), similar observations were seen in the values of the distances between the condyloid fossa and height of mandible, condyloid fossa to mandible base and from the mental foramen to the caudal border of the mandible (Figs. 2,3) (Olopade & Onwuka 2005,2006).

Fig. 1. Schematic diagram of the skull of the goat (Lateral view).

The mandibular nerve block is important for the desensitization of all the teeth in the lower jaw of the side of the block. The distance of the mandibular foramen to the base of the mandible and that from the caudal border of the mandible to the vertical line drawn downwards from the middle of the mandibular foramen (see fig 2) are clinically important landmarks that will aid the regional anaesthesia of this nerve (Hall et al, 2000). The respective values of these landmarks at 3.0 ± 0.4cm and 1.6 ± 0.3cm were similar to the 2.6cm and 1.6cm obtained for the West African Dwarf goat (Olopade & Onwuka, 2005).

Fig. 2. Schematic diagram of the mandible of the goat (Median view).

In the anterior aspect of the mandibular canal, injection can be made through the mental foramen to desensitize the mental aspect of the mandibular nerve. This will ensure the loss of sensation of lower incisors, premolars and lower lip on that side (Hall et al.). The distance between the lateral end of the alveolus of the incisor tooth to the mental foramen as seen in fig 3 is an important landmark in achieving this block. This distance at 2.0 ± 0.3cm was not far apart from the 1.6cm obtained in the West African Dwarf goat (Olopade & Onwuka, 2005).

Fig. 3. Schematic diagram of the mandible of the goat (Lateral view).

Te infraorbital nerve block ensures the desensitization of the skin of the lip, nostril and face on that side of the level of the foramen, and in the horse, incisors and first two premolars of that same side are also desensitized. An important landmark in obtaining this block is the facial tuberosity, and the estimated distance between it and the infraorbital foramen from which the infraorbital nerve emanates. The infraorbital foramen is generally dorsally placed between premolar one and two (May, 1970) and more of premolar two in adult Red Sokoto goats (Olopade, 2006). These facts of the location of the foramen with the knowledge of the distance of 1.8cm from it to the facial tuberosity will aid the exact targeting of this nerve in the live animal. The equivalent distance in the West African Dwarf goat from two different regions in Nigeria ranged from 1.6-1.8cm (Olopade & Onwuka 2005; 2006).

In describing the techniques of regional anaesthesia in the horse and dog, Hall et al., allowed margins of about 1.0-1.5cm for some landmark measurements in which the local anaesthesia can be injected. Going by the results in this study (Table I) and the earlier results obtained for West African Dwarf goats, the differences in most of the parameters measured here were usually below 1.0cm between and within the breeds. We are thus suggesting that these vital landmarks for regional anaesthesia of the head can be standardized amongst the Red Sokoto and West African Dwarf breeds and the knowledge may prove vital in saving prized livestock that may have a poor prognosis in regard of their tolerance of general anaesthesia.

REFERENCES

FAO (Food and Agricultural Organisation). FAO Production Yearbook, 1996 Rome, 50:1997.

Gall,C. Goat breeds of the world. 1^st edition. Margraf. Verlag. Weikershem. Germany, 1996.

Hall, L.W.; Clarke, K.W & Trim, C. M. Wright's Veterinary Anaesthesia and Analgesia. 10^th edition. ELBS& Bailliére Tindall, London, 2000.

Kene, R. O. C. & Agbo, C. N. Dental Abnormalities of Three Breeds of Nigerian Goats. Tropical Veterinarian, 16:15-23, 1998.

Kene, R. O. C. & Uwagie- Ero, E. A. Dental Abnormalities of Nomadic Cattle of Nigeria. Tropical Veterinarian, 19(3):191-9,2001.

Olopade, J. O. Morphometric analysis of the skulls of three breeds of goats in Nigeria. PhD. Thesis. Department of Veterinary Anatomy, University of Ibadan, 2006.

Olopade, J. O. & Onwuka, S. K. Some aspects of the clinical anatomy of the mandibular and maxillofacial Regions of the West African dwarf goat in Nigeria. Int. J. Morphol., 23(1):33-6, 2005.

Olopade, J. O. & Onwuka, S. K. An Osteometric study of the skull of the West African dwarf goat from South Eastern Nigeria. II:Mandibular and maxillofacial features. NVJ 27(2):66-10, 2006.

Simoens, R; Poels, R. & Lauwers, H. Morphometric analysis of the foramen magnum in Pekingese dogs. Am. J. Vet. Res. 55:33-9, 1994.

Terai, S.; Endo, PL; Rerkamnuaychoke, W.; Hondo, E., Agungpriyono, S.; Kitamura, N.; Kurohmadu, M.; Kimura, J.; Hayashi, Y.; Nishida, T. & Yamada, J. An osteometrical study of the cranium and mandible of the lesser mouse Deer (Chevrotain), Tragulus javanicus. J. Vet. Med. Set, 60(10):1097-105, 1998.

Received: 24-01-2007 Accepted: 12-03-2007

Correspondence to:

Dr. Olopade, J. O.
Department of Veterinary Anatomy
Faculty of Veterinary Medicine
University of Ibadan,
NIGERIA

Tel: 234-8023860829

Email: jkayodeolopade@yahoo.com jo.olopade@mail.ui.edu.ng