SciELO - Scientific Electronic Library Online

 
vol.29 issue1The Cytogenetic Examination as a Tool for the Diagnosis of Chromosomal DisordersHealing of Burns Type AB-B in Guinea Pig (Cavia Porcellus) Using Ulmo Honey Associated with Oral Vitamin C author indexsubject indexarticles search
Home Pagealphabetic serial listing  

Services on Demand

Journal

Article

Indicators

Related links

Share


International Journal of Morphology

On-line version ISSN 0717-9502

Int. J. Morphol. vol.29 no.1 Temuco Mar. 2011

http://dx.doi.org/10.4067/S0717-95022011000100010 

Int. J. Morphol., 29(1):65-69, 2010.

 

Position and Blood Supply of the Carotid Body in a Kenyan Population

 


Posición y Suministro Sanguíneo del Cuerpo Carotídeo en una Población de Kenia

 

Johnstone M. Muthoka; Jameela Hassanali; Pamella Mandela; Julius A. Ogeng'o & Adel A. Malek

Department of Human Anatomy, University of Nairobi, Kenya.

Correspondence to:


SUMMARY: Position and source of blood supply to the human carotid body displays population variations. These data are important during surgical procedures and diagnostic imaging in the neck but are only scarcely reported and altogether missing for the Kenyan population. The aim of this study was to describe the position and blood supply of the carotid body in a Kenyan population. A descriptive cross-sectional study at the Department of Human Anatomy, University of Nairobi, was designed. 136 common carotid arteries and their bifurcations were exposed by gross dissection. The carotid body was identified as a small oval structure embedded in the blood vessel adventitia. Position and source of blood supply were photographed. Data are presented by tables and macrographs. 138 carotid bodies were identified. Commonest position was carotid bifurcation (75.4%) followed by external carotid artery (10.2%), internal carotid artery (7.2%) and ascending pharyngeal artery (7.2%). Sources of arterial blood supply included the carotid bifurcation (51.4%), ascending pharyngeal (21.0%), external carotid (17.4%) and internal carotid (10.2%) arteries. Position and blood supply of the carotid body in the Kenyan population displays a different profile of variations from those described in other populations. Neck surgeons should be aware of these to avoid inadvertent injury.

Key words: Carotid body; Position; Variations; Kenyan.


RESUMEN: La posición y la fuente de suministro sanguíneo del cuerpo carotídeo humano muestra variaciones en la población. Estos datos son importantes durante los procedimientos quirúrgicos y de diagnóstico por imagen en el cuello, pero son poco informados e inclusive faltan por completo en la población de Kenia. El objetivo de este estudio fue describir la posición y el aporte sanguíneo del cuerpo carotídeo en una población de Kenia. Se diseñó un estudio descriptivo de corte transversal en el Departamento de Anatomía Humana de la Universidad de Nairobi. 136 arterias carótidas comunes y sus bifurcaciones fueron expuestas mediante disección simple. El cuerpo carotídeo fue identificado como una pequeña estructura oval ubicada en la adventicia del vaso sanguíneo. La posición y la fuente de suministro sanguíneo fueron fotografiados. Los datos obtenidos fueron presentados en las tablas y fotomacrografías. 138 cuerpos carotídeos fueron identificados. La posición más frecuente fue la bifurcación carotídea (75,4%), seguida de la arteria carótida externa (10,2%), arteria carótida interna (7,2%) y la arteria faríngea ascendente (7,2%). Las fuentes de suministro sanguíneo arterial incluyeron la bifurcación carotídea (51,4%), arteria faríngea ascendente (21,0%), arteria carótida externa (17,4%) y arterias carótidas internas (10,2%). La posición y el suministro sanguíneo del cuerpo carotídeo en la población de Kenia muestra un perfil de variaciones diferente a las descritos en otras poblaciones. Los cirujanos de cuello deben conocer estas variaciones para así evitar lesiones accidentales.

PALABRAS CLAVE: Cuerpo carotídeo; Posición; Variaciones; Kenia.


INTRODUCTION

The human carotid body (HCB) is usually located at the common carotid artery bifurcation (Sarrat-Torres et al., 2006). Variant positions include the external carotid (Ec), ascending pharyngeal (Ap) or internal carotid (Ic) arteries (Khan et al., 1988; Dymecka et al., 2006). These variations are important during the assessment of neck swellings (Lam et al., 1996) or in harvesting of carotid body cell aggregates for auto transplants as in treatment of Parkinsonism (Mínguez-Castellanos et al., 2007).

Arterial blood supply to the organ derives from glomic arteries which usually arise from the carotid bifurcation (Heath, 1989). Other sources include the thyrocervical trunk, vertebral, Ic, Ec or Ap arteries (Sarrat-Torres et al.; Ozay et al., 2008). Failure to recognize these abnormal sources may lead to inadequate haemostasis during carotid tumor resection (Ozay et al.). The incidence of variations in position and blood supply varies between populations (Khan et al.) and despite their clinical significance, data from African populations is scarce and altogether absent for the Kenyan population.

This study therefore investigated the position and blood supply of the carotid body in a Kenyan population

MATERIAL AND METHOD

One hundred and thirty-six (136) carotid blocks were studied by gross dissection at the Department of Human Anatomy, University of Nairobi. Ethical approval was granted by the Kenyatta National Hospital/University of Nairobi Ethics and Research Committee.

Carotid arteries were exposed by placing the head of the cadaver in hyperextension and making an incision along medial border of sternocleidomastoid muscle (SCM) from base of mastoid process to medial end of the clavicle. Skin was reflected and SCM retracted laterally to reveal the carotid sheath. The carotid bifurcation was exposed by blunt dissection. The carotid body was identified as a small oval structure embedded in the blood vessel adventitia. When the HCB was not located at the bifurcation its position was defined as variant.

Position and source of blood supply to the carotid body were recorded on data sheets and representative macrographs taken using a digital camera (Sony Cybershot R, W200, 7.2 Megapixels). Data were presented using macrographs and tables.

RESULTS

One hundred and thirty-eight (138) carotid bodies were identified. Of these, 104 (75.4%) were located on the posterior surface of the carotid bifurcation. Other positions observed were on the External carotid (10.2%), Internal carotid (7.2%) and Ascending pharyngeal (7.2%) arteries (Fig. 1 A-E). There was bilateral asymmetry in 12 individuals (17.7%). In one specimen there were three carotid bodies, two at the bifurcation and one on the internal carotid artery (Fig. 1E).

Fig 1. Macrographs of bifurcation area of common carotid and its branches showing different
positions of the carotid body and origin of corresponding glomic arteries. A) Carotid body
(black asterix) located at the bifurcation of the common carotid artery (CC). Glomic artery
(GA) arising from the bifurcation. B) Carotid body (black asterix) located at the base of the
ascending pharyngeal artery (AP). Blood supply was from the same vessel. C) Carotid body
(black asterix) located at the bifurcation of the CC. Glomic artery (GA) arising from the ascending
pharyngeal artery (AP). D) Carotid body (white asterix) located at the base of the external carotid artery
(EC). Supplied by two glomic arteries (GA) from the same vessel. E) Specimen with three carotid bodies
(black asterixes) located at different positions. Glomic arteries (GA) from internal and external carotid arteries.

 

Arterial blood supply was sourced from the carotid bifurcation in 71 (51.4%) of the specimens. Variations from this pattern are shown in Table I.

 

Further, the variant positions pose a challenge to the clinician trying to identify the nature of any neck swelling since chemodectoma may be mistaken for many other lesions in the cervical region (Arslan et al., 2000). Clinicians in the Kenyan population therefore need to be aware of the variations in position of the HCB.

Blood supply to the carotid body. The HCB usually derives arterial blood from carotid bifurcation, internal carotid, external carotid or ascending pharyngeal arteries (Heath; Sarrat-Torres et al., 2006). Observations of the current study support literature reports that common carotid and external carotid arteries are the commonest sources of blood supply to the carotid body (Heath & Edwards, 1971; Jago et al., 1982). However, here are population differences in supply as derived from these arteries (Table III).



DISCUSSION

Position of the carotid body varies (Khan et al.) with the commonest position being at the carotid bifurcation (Heath; Sarrat-Torres et al.). Observations of the current study are therefore concordant though proportions of variant positions vary between populations (Table II). These variations are important in diagnostic imaging during the assessment of neck swellings (Lam et al.; Sarrat-Torres et al.). In clinical practice, early identification of space occupying lesions in the carotid body is required for successful intervention. Surgical procedures are also safer as there is minimal invasion of surrounding neurovascular structures (Lam et al.).

Source of blood supply to the carotid body is highly variable in the Kenyan population. Whereas in the British population blood supply was mostly sourced from the carotid bifurcation (88%), in the Kenyan population, the ascending pharyngeal, external carotid and internal carotid arteries are major sources together accounting for 49.6% whereas they account for 12% in the British population.

Other studies have focused on animals and observations reveal a highly variable pattern of arterial blood supply to the carotid body in different species. This lack of uniformity of the vascular pattern seems to be related to the degree of variation in the arrangements of the common carotid bifurcation (Chungcharoen et al., 1952).


Information on the sources of blood supply to the HCB helps in exposure and haemostasis during carotid tumor resection (Ozay et al.). Due to the higher variability found in this population surgeons may find it prudent in the preoperative work up to indicate the likely variations in the sources of blood supply to the carotid body so as to avoid unnecessary hemorrhage during surgery.

In conclusion position and blood supply of the carotid body in the Kenyan population displays a different profile of variations from those described in other populations. Neck surgeons should be aware of these to avoid inadvertent injury.

ACKNOWLEDGEMENT

We are grateful to the first year medical students and staff at the department of Human Anatomy for helping in dissection and collection of data.

REFERENCES

Arslan, H.; Unal, O.; Kutluhan, A. & Sakarya, M. E. Power Doppler scanning in the diagnosis of carotid body tumors. J. Ultrasound Med., 19:367-70, 2000.        [ Links ]

Chungcharoen, D.; De Burgh Daly, M. & Schweitzer, A. The blood supply of the carotid body in Cats, Dogs and Rabbits. J. Physiol., 117:347-58, 1952.        [ Links ]

Dymecka, A.; Walski, M. & Pokorski, M. Ultrastructural degradation of the carotid body in the aged rat: is there a role for atherosclerosis in the main carotid arteries? J. Physiol. Pharmacol., 57:85-90, 2006.        [ Links ]

Heath, D. View from beneathPathology in Focus. A new look at the carotid bodies. J. Laryngol. Otol., 103:803-5, 1989.        [ Links ]

Heath, D. & Edwards, C. The glomic arteries. Cardiovasc. Res., 5:303-12, 1971.        [ Links ]

Jago, R.; Heath, D. & Smith, P. Structure of the glomic arteries. J. Pathol., 138:205-18, 1982.        [ Links ]

Khan, Q.; Heath, D. & Smith, P. Anatomical variations in human carotid bodies. J. Clin. Pathol., 41:1196-9, 1988.        [ Links ]

Lam, P. W.; Peh, W. C. & Wei, W. I. Clinics in diagnostic imaging (15). Carotid body tumour. Singapore Med. J., 37:430-2, 1996.        [ Links ]

Lowe, P.; Heath, D. & Smith P. Relation between histological age-changes in the carotid body and atherosclerosis in the carotid arteries. J. Laryngol. Otol., 101:1271-5, 1987.        [ Links ]

Mínguez-Castellanos, A.; Escamilla-Sevilla, F.; Hotton, G. R.; Toledo-Aral, J. J.; Ortega-Moreno, A.; Méndez-Ferrer, S., et al. Carotid body autotransplantation in Parkinson disease: a clinical and positron emission tomography study. J. Neurol. Neurosurg. Psychiatry, 78:825-31, 2007.        [ Links ]

Ozay, B.; Kurc, E.; Orhan, G.; Yucel, O.; Senay, S.; Tasdemir, M.; Gorur, A. & Aka, S. A. Surgery of carotid body tumour: 14 cases in 7 years. Acta Chir. Belg., 108:107-11, 2008.        [ Links ]

Sarrat-Torres, M. A.; Torres, A.; Whyte, J.; Baena, S.; Cisneros, A. & Sarrat, R. Structure, location, function and pathological features of the human carotid body. Eur. J. Anat., 10:1-5, 2006.        [ Links ]

Johnstone M. Muthoka
P. O. Box 30197-00100
Nairobi
Kenya

Email: muthokajm@gmail.com

Received: 14-09-2010
Accepted: 23-12-2010

Creative Commons License All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License