Jpn. J. Oral Biol., 31: 83-88, 1989.

ORIGINAL

On the external carotid and its branches in hens

Toshiaki Nakajima, Junzo Okugawa and Hideomi Ikuta

2nd Department of Oral Anatomy , Meikai University, School of Dentistry 1-1 Keyakidai, Sakado, Saitama 350-02, Japan (Chief: Prof. Masayoshi Kumegawa)

〔Accepted for publication : June 17, 1988•l

Key words: Hen/external crotid artery/plastic injection method/comparative anatomy

Abstract: The and its branches were investigated in hens by an acrylic plas- tic injection method. The of hens bifurcated into the internal and external carotid at the level of the second cervical vertebra. The external carotid artery advanced antero-superiorly within the platysma, stylohyoid, and occipitomandibular muscles at the postero-lateral side of the pharynx. Thereafter, it bifurcated into the anterior palatine and facial arteries between the pharynx and capitis rectus muscle at the posterior side of the medial mandibular process of the articular bone. The exter- nal carotid artery sent out the following branches: the occipital, hyomandibular, anterior temporal, sublingual, anterior palatine, and facial arteries.

artery in birds. Introduction The external carotid artery in birds is de- The appearance of the jaw is the most scribed by Bhaduri et al.5) for the pigeon, important event which occurred in the proc- and Gobeil6) and Midtgard7) for the herring ess of evolution of the vertebrates. The jaw gull. But, there is no paper which addresses is transformed from the gill arches, and these the relationship of the skull, jaw formation, traces remain in the jaws of animals lower and their arterial distribution. Thus, in the than birds1). The jaw began to excute an present study, we examined the external carot- important function as an apparatus for prey- id artery of hens, and discussed the relation- ing in fishes and an apparatus for mastication ships of the skull, jaw formation, and arte- in mammals. The jaw is supplied with the rial distribution. external carotid artery which arose with the Materials and Methods development of the jaw. The external carotid arteries of mammals Forty adult White Leghorn hens were developed from the anastomosis of branches used in this study. They were injected with from the internal carotid and stapedial arteri- acrylic plastic from the common carotid artery es2,3). In the ontogeny of man, the external into the arterial system of the head using carotid artery is thought to have developed the acrylic plastic injection method described from the branches of the stapedial artery4). by Taniguchi et al.8,9). Thirty-five heads On phylogetic grounds Romer1) agrees with were macerated in 20% NaOH solution Padget4) that the external carotid artery orig- to obtain corrosion casts. The remaining 5 inates from the stapedial artery. But he heads were embalmed in 10% formalin does not explain about the external carotid solution for dissection. The specimens were 84 Jpn. J. Oral Biol., 31: 83-88, 1989.

Fig.1 Schematic illustration of the external carotid artery and its branches.

ro-superiorly meandering slightly in the medi- al side of the platysma, stylohyoid, and occip- itomandibular muscles at the postero-lateral side of the pharynx. Thereafter, it bifurcated into the anterior palatine and facial arteries between the pharynx and the capitis rectus muscle at the infero-medial side of the exter- nal auditory pore and on the posterior side at the medial mandibular process of the artic- ular bone. Branches of the external carotid artery 1. (Figs. 1, 2, 3) The occipital artery arose from the exter- Fig.2 Lateral aspect of the external carotid nal carotid artery at the medial side of the artery and its branches of which are platysma, with which the ventral capitis rec- the occipital artery, hyomandibular, and tus, trachlomastoideus, complexus, and lateral anterior temporal arteries. capitis rectus muscles, and the skin and mus- cles of the occipital part are supplied. In 4 dissected and observed with an stereoscopic of the 70 cases, the occipital artery arose microscope. from the . In one case, this artery arose from the common caro- Observations tid artery. After its divergence, the artery The common carotid artery ascended in advanced postero-supero-laterally, entered the middle groove of the precervical area to between the stylohyoid and ventral capitis form the longus colli, and it bifurcated into rectus muscles, and bent supero-medially to- the internal and external carotid arteries at ward the lateral side of the internal carotid the level of the second cervical vertebra. artery. After that, it entered between the External carotid artery (Figs. 1, 2, 3, 4, 5) ventral capitis rectus and lateral capitis recuts The external carotid artery advanced ante- muscles, and then passed between the trachlo- T. Nakajima, et al: On the external carotid artery and its branches in hens 85

Fig.3 Lateral aspect of the external carotid artery and its branches of which are the occipital, hyomandibular, anterior temporal, and sublingual arteries. Fig.4 Ventral aspect of the external carotid artery and its branches of which are the anterior tem- poral, sublingual, anterior palatine, and facial arteries. Fig.5 Ventral aspect of the external carotid artery and its branches of which are the anterior pala- tine and facial arteries. Fig.6 Lateral aspect of the . mastoideus and lateral capitis rectus muscles divergence, the hyomandibular artery im- to bend superiorly. Finally, the occipital mediately sent out the posterior temporal artery communicated with the vertebral ar- artery. After that, this artery reached the tery which ascended to the level of the first inferior edge of the stylohyoid muscle to cervical vertebra. descend, and split into the laryngeal and 2. Hyomandibular artery (Figs. 1, 2, 3) lingual arteries. The hyomandibular artery branched off a. Posterior temporal artery (Figs. 1, 2, 3) from the external carotid artery on the medi- The skin of the temporal part, and the al side of the stylohyoid muscle. After its occipitomandibular and mylohyoid muscles 86 Jpn. . Oral Biol., 31: 83-88, 1989.

were supplied by the posterior temporal artery in one case. After its divergence, this artery. After its divergence, this artery pro- artery reached the antero-inferior edge of ceeded postero-superiorly between the stylohy- the external auditory port to advance supero- oid and ventral capitis rectus muscles to reach laterally between the external auditory the posterior edge of the posterior mandi- pore and the occipitomandibular muscle. bular muscle. Thereafter, it reached the tem- Thereafter, it arrived at the temporal part poral and parietal part, and then ascended to ascend under the skin at the anterior side along the lateral side of the occipitomandibu- of the external auditory pore. lar muscle and the posterior side of the ex- 4. Sublingual artery (1, 3, 4) ternal auditory pore. The sublingual artery arose from the exter- b. Laryngeal artery (Figs. 1, 2, 3) nal carotid artery on the posterior side at The mylohyoid and stylohyoid muscles, the medial mandibular process of the articu- the larynx, superior part of the esophagus, lar bone, with which the stylohyoid muscle, and the skin of the laryngeal part were sup- the anterior mandibular gland and the dentary plied by the laryngeal artery. In the begin- bone were supplied. In 26 of the 70 cases, this ning this artery advanced postero-inferiorly, artery arose from the anterior palatine artery. and then curved antero-inferiorly after the In one case, it arose from the facial artery. ramification of the superior esophageal ar- After its emergence, the artery advanced an- tery. After that, it branched off fan-like and tero-infero-laterally along the infero-medial advanced under the skin. side at the medial mandibular process of the c. (Figs. 1, 2, 3) articular bone, and bent antero-inferiorly on The lingual artery entered the medial side the lateral side of the lingual artery. There- of the stylohyoid muscle to advance antero- after, it reached the separation between the medially, and proceeded along the stylohyoid superficial and deep parts of the stylohyoid muscle while sending branches into the mus- muscle, and bifurcated into superficial and cle. After that, it advanced antero-medially deep branches. The superficial branch anas- on to be situated supero- tomosed with the submental artery, and the laterally at the angle of the hyoid, and deep branch distributed itself to the anterior reached the central part at the manubrium of mandibular gland. the hyoid and the posterior end of the ante- 5. Anterior palatine artery (Figs. 1, 4, 5) rior mandibular muscle. At this point, the The anterior palatine artery distributed it- artery sent out the deep lingual artery, with self to the palate, the pharynx, and the nasal which the lingual apex and the anterior man- cavity. This artery was derived from the dibular gland were supplied. The main facial artery, proceeded antero-supero-medi- stem became the submental artery which dis- ally between the ventral capitis rectus muscle tributed its branches into the dentary bone, and the postero-superior wall of the phar- the anterior mandibular gland, and the skin ynx, went round a pointed end at the medial of the mental part. mandibular process of the articular bone, and 3. Anterior temporal artery (Figs. 1, 2, advanced antero-infero-laterally between the 3, 4) dorsal pterygoid muscle and the pharyngeal The occipitomandibular and mylohyoid wall. After that, it proceeded antero-medial- muscles, the external auditory port, and tem- ly to arrive at the inferior end of the pala- poral part of the skin were supplied by the tine bone. These arteries of the right and anterior temporal artery. This artery arose left side anastomosed with each other at a from the external carotid artery on the poste- point below the external naris. After the rior side at the medial mandibular process anastomosis, the artery went along between and the medial side of the ventral capitis the incisive foramen of the right and left rectus muscle. It arose from the facial artery side, divided again into two arteries to arrive in 9 of the 70 cases, from the sublingual at the anterior end of the incisive foramen . artery in 7 cases, from the anterior palatine These arteries then entered into the nasal artery in 4 cases, and from the hyomandibular cavity from each incisive foramen.

J T. Nakaiima, et al: On the external carotid artery and its branches in hens 87

6. Facial artery (Figs. 1, 4, 6) mandibule and masticatory muscles changed The facial artery distributed itself to the according to their different masticatory pat- crest, the ventral capitis rectus, masseteric terns. The arterial distribution system of this and dorsal pterygoid muscles, the supraangular area also changed according to the changes bone, the eyelid, and the frontal part. in bone and muscle, (The arterial system of In 4 of 70 cases, the facial artery arose from each mammals is completed by the anastomo- the internal carotid system. This artery ad- sis branch between the internal carotid, sta- vanced antero-supero-laterally between the pedial, and external carotid arteries. Animals basal sphenoid bone and the medial mandib- with a loose skull have a larger stapedial ular process of the articular bone as it went artery than those with compact skull2,3)). round the quadrate bone to send out the Birds originated from the archosaurian anterior palatine artery, and then appeared branch of reptiles. They have a smaller num- on the posterior edge of the masseter. After ber of neurocranial bones compared with rep- that, it bent antero-superiorly below the tiles. The brain of the birds is covered with medial ocular angle to advance under the bones. And the has lost the coro- skin along the superior edge of the zygomat- noid and prearticular bone1,11). The joint ic bone, bent postero-supero-medially to between the upper and lower jaws of the arrive at the lacrimal bone, and reached the birds is composed of the quadrate and articular crest. bones and both jaws can move11). The exter- nal carotid artery of birds is distributed Discussion here, and has a wider distribution compared The mandible of bony fishes is formed with reptiles. The external carotid artery from the dentary, splenial, angular, supraan- of hens sent out branches to the occipital, gular, prearticular, articular, and coronoid hyomandibular (It corresponds to the exter- bones. The external carotid artery (or lin- nal carotid artery of reptiles, from which gual artery) extends into the mandible by fine branch off the posterior temporal, laryngeal, arteries developed from the trunk of the fore- and lingual arteries.), anterior temporal, sub- most efferent branchial artery1). lingual, anterior palatine, and facial arteries. Reptiles complete the lungs, and miss the The external carotid artery of pigenos5) have gills and the branchal arch. They lost some many difference from hens. This artery small bones in the temporal region, and have sends out the pharyngeus artery, receives the a single splenial and coronoid bone forming comes nervi vagi artery, and lacks the oc- the mandible compared with the bony cipital, temporal and sublingual arteries. The fishes1). In typical reptiles and amphibia, the external carotid artery of the herring gull6,7) fine external carotid artery arises from near lacks the temporal and sublingual arteries. the trunk of the internal carotid artery which This artery in the goose10) is reported to be is situated at the ventral side. This artery the inferior alveolar and infraorbital arteries. has a wider distribution than that in fishes, These distributions cover nearly the same with which the throat and lingua are sup- area as in mammals. But, mammals have plied1,10). The external carotid artery of the drastic changes of the skull compared with reptiles originates from the ventral carotid birds: they have a smaller number of bones artery10). in their neurocranium and can not move the Mammals originated from the synapsida upper jaw. They have only the dentary bone branch of reptiles. Mammals lost much of in the mandible, and have the ability to mas- their neurocranium and developed a solid ticate. Therefore, in mammals recomposi- skull compared with reptiles. Their teeth tion of the arterial system of the head occurs decrease and their mandible had only the during ontogeny. Like wise the external dentary bone, and mammals developed masti- carotid artery of birds undergoes a change in catory ability. The masticatory pattern the phylogeny and the ontogeny of the skull changed in relation to functional requirement and the jaw formation. But, birds have kept over the whole range of mammals, and the many characteristics of the reptiles. The 88 Jpn. J. Oral Biol., 31: 83-88, 1989. external carotid artery of hens changes from the development of the cerebrum in order the ventral carotid artery in ontogeny as to take food. In mammals, the jaws devel- it does in reptiles, and develops to take oped as a mastication organ and the pattern branches from the internal carotid arterial of the arterial distribution differs in compli- system12,13). ance with the spacies and the masticatory The development of the external carotid pattern3,15). Therefore, we suspect that the artery is elucidated by the development of development of the external carotid artery in the cerebrum14). The jaws of the vertebrate vertebrates has been affected by the develop- occurred for predation, and it developed with ment of jaws. development of the cerebrum, and supported

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