155Cnlinical Anatomy of the Maxillary Artery

Introduction

The maxillary artery along with the superficial tem-poral artery is a terminal branch of the external carotid artery. Its branches extended into the deep parts of the face, including the maxilla, mandible, cerebral dura mater, and the nasal cavity. Clinically, the maxillary artery plays an important role in superselective intra-arterial infusion chemotherapy for head and neck cancers1, 2), arterial embolization therapy for vascular lesions such as arte-riovenous malformation and refractory nasal bleeding3–7), and reconstruction after tumor resection8, 9).

Studies of the maxillary artery have a long history, dating back to reports by Thomson10), Lauber11), Adachi12), Fujita13), and Lasker14). Recently, Japanese researchers such as Sashi15) and Tsuda16–18) have evaluated the maxil-lary artery angiographically, whereas Kitsuta et al. (19) have macroscopically studied anatomic characteristics. We macroscopically studied the origins, courses, branch-ing patterns, and the luminal diameters of the maxillary artery and its branches in Japanese cadavers.

Subjects and Methods

SubjectsWe studied 28 sides of symmetrically dissected heads

of 15 Japanese cadavers (21 sides in 11 men and 7 sides in 4 women) in which the maxillary artery could be closely examined and measured. All the cadavers were preserved at Department of Anatomy, the Nippon Dental University School of Life Dentistry at Niigata. The mean age was 69.1 ± 16.9 years (range, 22 to 90).

MethodsThe coronoid process was transected, and the tem-

poral muscle was turned superiorly to expose the infra-temporal fossa. After confirming the relation between the lateral pterygoid muscle and the maxillary artery, the lateral pterygoid muscle was removed, and the maxillary artery, its branches, and the surrounding nerves were photographed and sketched in detail. The region extend-ing from the origin of the maxillary artery to the point of entry into the pterygopalatine fossa was carefully removed. The distances between each of the branches and the luminal diameters of the main branches were

Okajimas Folia Anat. Jpn., 87(4): 155–164, February, 2011

Clinical Anatomy of the Maxillary ArteryBy

Ippei OTAKE1, Ikuo KAGEYAMA2 and Izumi MATAGA3

1 Department of Oral and Maxilofacial Surgery, Osaka General Medical Center (Chief: ISHIHARA Osamu)2 Department of Anatomy I, School of Life Dentistry at Niigata, Nippon Dental University (Chief: Prof. KAGEYAMA Ikuo)

3 Department of Oral and Maxillofacial Surgery, School of Life Dentistry at Niigata, Nippon Dental University(Chief: Prof. MATAGA Izumi)

–Received for Publication, August 26, 2010–

Key Words: Maxillary artery, running pattern of maxillary artery, intraarterial chemotherapy, inner diameter of vessels

Summary: The Maxillary artery is a component of the terminal branch of external carotid artery and distributes the blood flow to upper and lower jawbones and to the deep facial portions. It is thus considered to be a blood vessel which supports both hard and soft tissues in the maxillofacial region. The maxillary artery is important for bleeding control during operation or superselective intra-arterial chemotherapy for head and neck cancers. The diagnosis and treatment for diseases appearing in the maxillary artery-dominating region are routinely performed based on image findings such as CT, MRI and angiography. However, validations of anatomical knowledge regarding the Maxillary artery to be used as a basis of image diagnosis are not yet adequate. In the present study, therefore, the running pattern of maxillary artery as well as the type of each branching pattern was observed by using 28 sides from 15 Japanese cadavers. In addition, we also took measurements of the distance between the bifurcation and the origin of the maxillary artery and the inner diameter of vessels. These findings thus obtained could contribute to knowledge of improved accuracy of image diagnosis as an index for embolization and for knowledge of an adequate super-selective intra-arterial chemotherapy.

Corresponding author: Ippei Otake, Osaka General Medical Center, Sumiyoshi-ku, Osaka, 558-8558 Japan. E-mail: otake@gh.opho.jp

156 I. Otake et al.

measured. The following examinations and measure-ments were performed.

1) Levels of maxillary artery branchesThe distance between the origin of the maxillary artery

and the superior margin of the external auditory canal was measured along a line parallel to the axis of the body (Fig. 1). The height of the origin of the maxillary artery was distinguished from the height of the bifurcation of the common carotid artery was classified into 3 groups as described in the following by Ito et al.20): a higher than average bifurcation, located near the region from the 2nd to 3rd cervical vertebrae; a standard bifurcation, located near the region from the 3rd to 4th cervical vertebrae; and a lower than average bifurcation, located near the region from the 4th to 5th cervical vertebrae.

2) Course of the main trunk of the maxillary arteryThe course of the main trunk of the maxillary artery

was classified as following with respect to the lateral pterygoid muscle: with an external course pattern, if the main trunk ran superficial to the lateral pterygoid muscle; or with an internal course pattern, if the main trunk ran deep to the lateral pterygoid muscle (Fig. 2). The positional relation between the maxillary artery and the mandibular nerve was classified as described by Fujita (Fig. 3).

ECA: external carotid a.ST: superficial temporal a. Mx: maxillary a. MM: middle meningeal a. AM: accessory meningeal a. IA: inferior alveolar a. PT: posterior deep temporal a. B: buccal a.AT: anterior deep temporal a. PSA: posterior superior alveolar a.IO: infraorbital a. SP: sphenopalatal a. TM: temporal m. LP: lateral pterygoid m. MP: mesial pterygoid m. ATN: auriculotemporal n. IAN: inferior alveolar n.LN: lingual n. BN: buccal n. FO: foramen ovale FS: foramen spinosum (a.: artery, m.: muscle, n.: nerve)

Fig. 1. Measuring points.

Fig. 2. Positional relationship between Mx and lateral pterygoid.

157Cnlinical Anatomy of the Maxillary Artery

3) Orders of branches arising from the maxillary arteryThe orders of the branches arising from the maxillary

artery were classified as described by Ikakura21). In Type I, after arising from the external carotid artery the maxil-lary artery gives off branches in the following order: the middle meningeal artery, the inferior alveolar artery, the posterior deep temporal artery, the buccal artery, the ante-rior deep temporal artery, the posterior superior alveolar artery, the infraorbital artery, the descending palatine artery, and the sphenopalatine artery. In Type II, the order of the middle meningeal artery and the inferior alveolar artery is reversed. In Type III, the buccal artery is absent. If the posterior superior alveolar artery and infraorbital artery arise from a common trunk, each type is classified as type Ia, type IIa, and type IIIa, respectively (Fig. 4).

4) Distances of the branches from the main trunk of the maxillary artery The distance from the main trunk of the maxillary

artery to each of its branches was measured as described by Shimada et al.22) A silk thread was placed along the course of the vessel and extended in a straight line to measure the distance from the main trunk to each branch. The proportional distance from the origin of the maxil-lary artery to the point of entry into the pterygopalatine

fossa was regarded as 100%, the relative distances of the origins of each of the branches from the main trunk of the maxillary artery were calculated.

5) Luminal diameters of the main trunk of the maxillary artery and its branches The following 9 arteries were studied: the main trunk

of the maxillary artery, the middle meningeal artery, the inferior alveolar artery, the posterior deep temporal artery, the buccal artery, the anterior deep temporal artery, the posterior superior alveolar artery, the infraorbital artery, and the sphenopalatine artery. A section 1 mm in width was cut 1 cm distal to the origin of each branch. Each specimen was cut open parallel to the course of the vessel and mounted on a slide glass. The length between the two ends was measured with the use of a stereo-microscope (Stereo Photo SMZ-10, Nikon Co., Tokyo Japan) and a digital vernier caliper (Digimatic Caliper 500–110, Sankin Co., Ltd., Tokyo, Japan) to derive the lumen diameter. The same site was measured 3 times, and the mean value was calculated. If branches arose from a common trunk, the site 1 cm distal to the origin of the common trunk was measured. The Wilcoxon rank-sum test was used for statistical analysis.

Fig. 3. Positional relationship between Mx, lateral pterygoid, and mandibular nerve

158 I. Otake et al.

Results

1) Height of the origin of the maxillary artery The vertical height of the origin of the maxillary

artery from the superior margin of the external auditory canal ranged from 15.4 mm to 32.7 mm (mean, 23.4 ± 5.1 mm) on the right side and from 12.5 mm to 28.7 mm (mean, 22.6 ± 4.5 mm) on the left (Table 1). The height of the bifurcation of the common carotid artery was stan-dard in 15 patients (53.5%), high in 9 (32.2%), and low in 1 (3.6%) (Table 2).

2) Course of the main trunk of the maxillary artery In the present study, 27 (96.4%) of the 28 sides stud-

ied had an external course pattern, and only 1 (3.6%) had an internal course pattern. Examples of the external and internal course patterns are shown in Figs. 5 to 8, respectively. The positional relation between the maxil-lary artery and the mandibular nerve was classified as described by Fujita13). Type A was most common, present in 22 sides (78.6%), followed by type B in 5 (17.8%) and type C in 1 (3.6%). No side was type D or type E (Table 3).

3) Order of branches arising from the maxillary artery The order of branches arising from the maxillary

artery according to Ikakura’s classification21) was type I

in 7 (25.0%) of 28 sides, type Ia in 12 (42.9%), type II in 2 (7.1%), type IIa in 0 (0%), type III in 3 (10.7%), and type IIIa in 1 (3.6%). Type Ia was most common. The standard patterns of type I or type Ia were found in 19 subjects (67.9%) (Table 4). Three sides were difficult to

Fig. 4. Classification on the derivative order of branches of Mx.

Table 1. Distance between superior margin of external auricular me-atus and origin of Mx

(n = 28/mm)

Right Left

Male

Female

24.3 ± 5.6(15.4~32.7)21.2 ± 3.2(18.4~28.7)

23.2 ± 3.6(17.4~28.7)20.2 ± 7.3(12.5~26.8)

Average 23.4 ± 5.1(15.4~32.7)

22.6 ± 4.5(12.5~28.7)

Table 2. Pattern of bifurcation level of the common carotid artery

Right Left Total

Higher bifurcationStandard bifurcationLower bifurcationUnknown

4 (14.3%)9 (32.1%)1 ( 3.6%)1 ( 3.6%)

5 (17.9%)6 (21.4%)02 ( 7.1%)

9 (32.2%)15 (53.5%) 1 ( 3.6%) 3 (10.7%)

n = 28

159Cnlinical Anatomy of the Maxillary Artery

classify because of reversed orders of branches or dupli-cate branches.

4) Distances of branches from the main trunk of the max-illary artery The mean bilateral distances from the origin of the

maxillary artery to the following branches were as fol-

lows: the middle meningeal artery, 9.4 ± 5.2 mm; the inferior alveolar artery, 17.3 ± 4.4 mm; the posterior deep temporal artery, 29.0 ± 5.7 mm; the buccal artery, 48.7 ± 10.6 mm; the anterior deep temporal artery, 55.4 ± 6.2 mm; the posterior superior alveolar artery, 64.1 ± 8.0 mm; and the infraorbital artery, 66.8 ± 9.2 mm. The dis-tance between the origin of the maxillary artery and the

Fig. 5. Lateral Type. Fig. 6. Lateral type of the Maxillary Artery.

Fig. 7. Medial Type. Fig. 8. Medial type of the Maxillary Artery.

160 I. Otake et al.

point of entry into the pterygopalatine fossa was 78.5 ± 9.3 mm. When this value was regarded as 100%, the rela-tive mean distances until each branch were as follows: the middle meningeal artery, 12.1 ± 6.8; the inferior alveolar artery, 22.0 ± 5.2; the posterior deep temporal artery, 37.3 ± 6.6; the buccal artery, 62.3 ± 11.3; the anterior deep temporal artery, 70.5 ± 4.7; the posterior superior alveolar artery, 81.3 ± 6.4; and the infraorbital artery, 85.2 ± 6.2 (Table 5).

5) Luminal diameters of the main trunk of the maxillary artery and its branches The mean bilateral luminal diameters of the maxillary

artery and its branches were as follows: the main trunk of the maxillary artery, 2.1 ± 0.7 mm; the middle meningeal artery, 1.2 ± 0.2 mm; the inferior alveolar artery, 0.6 ± 0.1 mm; the posterior deep temporal artery, 0.7 ± 0.1 mm; the buccal artery, 0.6 ± 0.2 mm; the anterior deep tempo-ral artery, 0.7 ± 0.2 mm; the posterior superior alveolar artery, 1.0 ± 0.2 mm; the infraorbital artery, 1.0 ± 0.3 mm; and the sphenopalatine artery, 1.2 ± 0.2 mm. There were no statistical significant differences in the mean luminal diameter between the left and right sides (Table 6).

Discussion

Courses of the maxillary arteryThe maxillary artery and the superficial temporal

artery are both terminal branches of the external carotid

artery. The maxillary artery is distributed to the maxilla and mandible and is the most important artery supplying soft and hard tissue in the maxillofacial region. The max-illary artery arises from the external carotid artery pos-teriorly and inferiorly to the neck of the mandible, runs anteriorly to the inner surface of the mandibular ramus, and enters the pterygopalatine fossa, ending in the ptery-gopalatine artery. The maxillary artery can be divided into the mandible, the pterygoid, and the pterygopalatine portions, each of which gives off branches. The courses of the maxillary artery are subject to considerable indi-vidual variation, such as running externally or internally to the lateral pterygoid muscle.

Takarada23) and Ikakura21) classified the origin of the maxillary artery with respect to the posterior border of the ramus of the mandible. Both found that the maxillary artery arose from two fifths above the posterior border of the ramus of the mandible in about 80% of subjects. In contrast, Ito et al.24) used the point corresponding to the eye-ear plane of the superficial temporal artery for refer-ence. A Teflon tube was inserted into the artery at that point, and the distance until the origin of the maxillary artery was measured. The mean distance to the origin of the maxillary artery was 30.9 ± 19.7 mm on the right side and 31.1 ± 1.3 mm on the left. Shintani et al.25) measured the distances between the auricular point and each of its branches and reported that the mean distance to the origin of the maxillary artery was 32.0 ± 9.0 mm. In the present study, we used the superior margin of the external audi-

Table 3. Positional relationship between Mx, the lateral pterygoid, and the mandibular nerve

Lateral type Medial type

A B C D E

Male

Female

RightLeftRightLeft

9 (32.1%) 9 (32.1%) 3 (10.8%) 1 ( 3.6%)

2 ( 7.1%)2 ( 7.1%)01 ( 3.6%)

01 (3.6%)00

0000

0000

Total 22 (78.6%) 5 (17.8%) 1 (3.6%) 0 0

n = 28

Table 4. Derivative order of branches of the maxillary artery

Type Right Left Total (%)

IIaIIIIaIIIIIIaOthers

4 (14.3%)7 (25.0%)002 ( 7.1%)01 ( 3.6%)

3 (10.7%)5 (17.9%)2 ( 7.1%)01 ( 3.6%)1 ( 3.6%)2 ( 7.1%)

7 (25.0%)12 (42.9%) 2 ( 7.1%) 0 3 (10.7%) 1 ( 3.6%) 3 (10.7%)

n = 28

Table 5. Distance between branches of Mx

Diameter (mm) Frequency

MMAIAPTABAATAPSAIFAPterygoid Fo.

2.7~20 ( 9.4 ± 5.2) 8.9~28.5 (17.3 ± 4.4) 8.9~36.7 (29.0 ± 5.7)21.9~66.9 (48.7 ± 10.6)42.5~68.0 (55.4 ± 6.2)51.2~78.7 (64.1 ± 8.0)48.2~87.9 (66.8 ± 9.2)61.3~99.3 (78.5 ± 9.3)

3.8~24.7 (12.1 ± 6.8)12.4~35.3 (22.0 ± 5.2)12.4~49.5 (37.3 ± 6.6)28.6~76.7 (62.3 ± 11.3)61.7~80.4 (70.5 ± 4.7)72.4~96.9 (81.3 ± 6.4)73.9~96.9 (85.2 ± 6.2)100

Min~Max (average ± SD)

Table 6. Luminal diameter of branches of Mx and maxillary artery

Right Left Total (mm)

MAMMAIAAPTABAATAPSAIFASPA

1.7~2.3 (1.9 ± 0.2)0.8~1.9 (1.3 ± 0.3)0.5~1.0 (0.6 ± 0.1)0.5~1.0 (0.7 ± 0.1)0.3~0.7 (0.5 ± 0.1)0.4~1.5 (0.7 ± 0.3)0.7~1.1 (1.0 ± 0.2)0.7~2.2 (1.0 ± 0.4)0.7~1.7 (1.2 ± 0.3)

1.6~5.6 (2.2 ± 1.0)0.7~1.6 (1.2 ± 0.2)0.5~0.9 (0.6 ± 0.1)0.6~1.1 (0.8 ± 0.2)0.3~0.9 (0.6 ± 0.2)0.5~0.9 (0.7 ± 0.1)0.6~1.3 (1.0 ± 0.2)0.7~1.3 (1.0 ± 0.2)1.0~1.6 (1.3 ± 0.2)

1.6~5.6 (2.1 ± 0.7)0.7~1.9 (1.2 ± 0.2)0.5~1.0 (0.6 ± 0.1)0.5~1.1 (0.7 ± 0.1)0.3~0.9 (0.6 ± 0.2)0.4~1.5 (0.7 ± 0.2)0.7~1.3 (1.0 ± 0.2)0.7~2.2 (1.0 ± 0.3)0.7~1.7 (1.2 ± 0.2)

Min~Max (average ± SD)

161Cnlinical Anatomy of the Maxillary Artery

tory canal as a reference point and measured the distance to the origin of the maxillary artery. The mean distance was 23.4 ± 5.1 mm on the right side and 22.6 ± 4.5 mm on the left. We also examined the positional relation be-tween the bifurcation level of the common carotid artery and that of the maxillary artery for 25 sides in which the bifurcation level of the common carotid artery could be evaluated. We had initially assumed that the bifurca-tion level of the maxillary artery was influenced by the bifurcation level of the common carotid artery. Although we had the impression that a high bifurcation level of the common carotid artery was slightly associated with a higher bifurcation level of the maxillary artery than was a standard bifurcation level of the common carotid artery, there was no distinct relation between the bifurcation level of the common carotid artery and that of the maxil-lary artery.

The courses of the maxillary artery have been reported to be diverse. In previous studies conducted in countries other than Japan, the prevalence of an internal course pattern was reported to be 44.7% by Thomson10) in the United Kingdom, 91.5% by Lauber11) in Australia, and 45.6% by Lasker14), who studied Caucasians in the United States. In Japan, a number of investigators, including Adachi12), Fujita13), Takarada23), and Ikakura21), reported that the main trunk of the maxillary artery usually runs superficially to the lateral pterygoid muscle (the external course pattern). The prevalence of an internal course pat-tern has been reported to be only 6.3% to 10.1%12, 13, 21, 23) (Table 7). In individual subjects, the courses of the left and right maxillary arteries are overwhelmingly sym-metrical. The prevalence of different courses of the left and right of the maxillary arteries was reported to be 6.8% (3/47) by Takarada23) and 6.3% (5/80) by Ikakura21).

In our series, only 1 (3.6%) of 28 sides had an internal course pattern; all others had an external course pattern. In the subject with an internal course pattern, the contra-lateral maxillary artery had an external course pattern; the artery was thus asymmetrical. The prevalence of the maxillary artery passing through the belly of the lateral pterygoid muscle was reported to be 0.6% (2/331) by Adachi12), 1.9% (3/158) by Iwamoto et al.27), and 0.5% (1/200) by Lurje28). In addition, Takemura et al.29), Fujimura et al.30), and Tanaka et al.31) reported cases in which the maxillary artery passed through the mandibu-lar nerve, so-called type D of Fujita’s classification13). In our series, however, no subject had a type D pattern. Although Fujita’s classification has been used previously, the prevalence of type D appears to be very low (Table 8).

Consistent with our results, most Japanese have been reported to have an external course pattern of the maxillary artery. The Gow-Gates technique for conduc-tion of anesthesia in clinical dentistry32) is associated with a higher response rate (≥ 95%) than conventional mandibular foramen conduction anesthesia, with a low risk of directly puncturing blood vessels (about 1%). However, Toki33) reported that the Gow-Gates technique had a response rate of only 75% in Japanese patients, lower than that in Australian subjects, as well as a higher rate of intravenous puncture (17%). These results are attributed to differences in the courses of the maxillary artery between Japanese and Australian. Therefore, techniques for anesthesia should not be selected solely on the basis of the results of studies in Australian patients because inappropriate approaches can lead to a reduced rate of response and a higher risk of complications such as vascular puncture.

Branches of the maxillary arteryThe main trunk of the maxillary artery usually extends

into branches in the following order: the deep auricular artery, the anterior tympanic artery, the middle menin-geal artery, the inferior alveolar artery, the masseteric artery, the posterior deep temporal artery, the pterygoid branch, the buccal artery, the posterior superior alveolar artery, the infraorbital artery, the descending palatine artery, the pterygoid canal artery, and the sphenopalatine artery17, 21, 23). In the present study, we classified the order of 8 arteries arising from the maxillary artery (the middle meningeal artery, the inferior alveolar artery, the poste-

Table 7. Comparison of individual observation on the medial type of Mx

Authors Year n medial type (%)

AdachiFujitaTakaradaIkakuraIwamotoTsudaPresent study

1928193219581961198119912005

331119120160158339 28

21 ( 6.3)12 (10.1)11 ( 9.2)15 ( 9.4)11 ( 7.0)22 ( 6.5) 1 ( 3.6)

Table 8. Positional relationship between Mx, lateral pterygoid, and mandibular nerve

Lateral type Medial type

A B C D E

IkakuraTakaradaFujitaPresent study

122 (76.3%) 78 (75.0%) 67 (85.9%) 22 (78.6%)

23 (14.4%)17 (16.3%) 5 ( 6.4%) 5 (17.8%)

11 (6.4%) 7 (6.7%) 5 (6.4%) 1 (3.6%)

1 (0.6%)1 (1.0%)1 (1.3%)0

3 (1.9%)1 (1.0%)00

162 I. Otake et al.

rior deep temporal artery, the buccal artery, the anterior temporal artery, the posterior superior alveolar artery, the infraorbital artery, and the sphenopalatine artery) into 6 groups according to the Ikakura’s classification21). The combined prevalence of the standard types I and Ia was 67.9%. In previous studies of Japanese subjects, the prevalence of these standard types was reported to be 63.9% by Takarada23), who studied 6 arteries from the middle meningeal artery to the posterior superior alveolar artery, 72.1% by Ikakura21), who studied 8 arteries from the middle meningeal artery to the descending palatine artery, and 66.8% by Tsuda17), who studied 7 arteries from the middle meningeal artery to the infraorbital artery. These results suggest that the prevalence of stan-dard types is about 70% in Japanese.

An accessory middle meningeal artery, (i.e., a branch of the middle meningeal artery) was found in 25 (89.3%) of 28 sides. We defined a branch arising from the main trunk of the maxillary artery as an accessory middle meningeal artery and a branch arising from the middle meningeal artery as an accessory branch of the middle meningeal artery, as reported by Kodama34). In our series of 28 sides, an accessory middle meningeal artery was found in 7 sides (25.0%), and an accessory branch of the middle meningeal artery was found in 18 (64.3%). Baumel et al.35) reported that an accessory branch of the meningeal artery was found in 73 of 76 subjects (96%) and that the branch arose from the main trunk of the maxillary artery and from the middle meningeal artery with similar frequency. Ikakura21) reported that accessory branches of the meningeal artery arose from the main trunk of the maxillary artery in about 5% of subjects, similar to the frequency of accessory branches arising from the middle meningeal artery. Yagishita36) found ac-cessory middle meningeal arteries on angiography in 21 of 30 subjects (70.0%), but did not distinguish whether the accessory arteries originated from the main trunk of the maxillary artery or from the middle meningeal artery. Tsuda17) similarly performed angiographic studies of 339 cadavers at through autopsies. An accessory branch of the middle meningeal artery was present in 316 subjects. Of the 316 subjects, 299 (94.6%) had an external course pattern; in 231 (73.1%) the accessory branch arose from the middle meningeal artery. Among 22 subjects with an internal course pattern, the accessory branch arose from the maxillary artery in 14 cases (4.4%). These findings suggest that accessory branches of the middle meningeal artery usually arise from the middle meningeal artery in persons with an external course pattern and from the main trunk of the maxillary artery in persons with an internal course pattern. In the present study, however, an accessory middle meningeal artery was not found in only one of the side of a symmetrically dissected head.

The inferior alveolar artery usually arises distal to the middle meningeal artery. Takarada23) and Ikakura21) reported that the inferior alveolar artery arose at the same

site as, or proximal to, the middle meningeal artery in about 20% of subjects. In the present study, the inferior alveolar artery arose distal to the middle meningeal artery in 25 of 28 sides (89.3%) and proximal to the middle meningeal artery in the 1 side with an internal course pattern and 2 sides in which the inferior alveolar artery arose from 2 sites.

If reconstruction is performed with a temporalis muscle flap, the bifurcation sites and courses of the posterior and anterior deep temporal arteries should be carefully assessed37). In our series, the posterior deep temporal artery arose from the inferior alveolar artery in 1 side with an internal course pattern, but from the main trunk of the maxillary artery in all others. The origin was distal to the inferior alveolar artery. The posterior deep temporal artery did not arise proximal to the inferior alveolar artery or from a common trunk in any subject. In 4 sides (14.4%) in our study, arteries were distributed to the temporalis muscle peripheral to the deep temporal artery. Miura et al.37) found similar arteries at a similar prevalence (15.8%).

The anterior deep temporal artery was present in 26 of 28 sides (92.9%). The anterior deep temporal artery usually arises distal to the buccal artery, but arises from the same site as, or proximal to, the buccal artery in some subjects. The frequencies of these patterns were respec-tively reported to be 15.2% and 5.4% by Takarada23) and 11.3% and 3.5% by Ikakura21).

The buccal artery was absent in 7 of 28 sides (25.0%), a higher prevalence than that reported by Takarada23) and Ikakura21) (11.6% and 10.8%, respectively).

Takarada23) and Ikakura21) reported that the posterior superior alveolar artery and the infraorbital artery arose from a common trunk in about 50% of subjects. In our series, 13 of 28 sides (46.4%) had a common trunk. In 1 of 15 sides (6.7%) without a common trunk, the positions of the posterior superior alveolar artery and infraorbital artery were reversed. In this subject, the maxillary artery ran anteriorly and inferiorly after extending from the anterior deep temporal artery, turned anteriorly and supe-riorly after giving off the buccal artery from the inferior wall, giving off the infraorbital artery from the inferior wall, and then traveled inferiorly and medially and giving off the posterior superior alveolar artery from the lateral inferior wall.

Most previous studies evaluating the distance from the origin of the maxillary artery to each of its branches reported positional relations relative to the surround-ing muscles and nerves. For example, Takarada23) and Ikakura21) studied the positional relations between the origin of the middle meningeal artery and the inferior border of the lateral pterygoid muscle, and between the inferior alveolar artery and the inferior border of the lateral pterygoid muscle as well as the inferior alveolar nerve. However, when performing cannulation for intra-arterial infusion chemotherapy and arterial embolization,

163Cnlinical Anatomy of the Maxillary Artery

not only the courses of arteries, but also the distances between branches are important factors. We therefore measured the absolute distances from the main trunk of the maxillary artery to the origin of each of its branches and calculated the relative distances of each branch from the origin of the maxillary artery, regarding the length from the origin of the maxillary artery to the point of entry into the pterygopalatine fossa to be 100%. The infe-rior alveolar artery and the anterior deep temporal artery showed the smallest variations, the buccal artery showed the largest. Miura et al.37) measured the distance from the origin of the maxillary artery to each of its branches and reported that the mean distance was 11.4 mm for the middle meningeal artery, 15.6 mm for the inferior alveo-lar artery, 31.0 mm for the posterior deep temporal artery, and 53.7 mm for the anterior deep temporal artery. These results were similar to our findings.

Luminal diameters of branches of the maxillary arteryThe diameters of cervical blood vessels used as feed-

ing arteries during vascularized free-flap grafting after malignant-tumor resection have been reported sporadi-cally38, 39). To our knowledge, however, no previous study has measured the luminal diameters of the main trunk of the maxillary artery and its branches. We therefore measured the luminal diameters of branches of the max-illary artery. Recent technical and physical advances in angiography have allowed the external carotid artery and its branches to be superselectively visualized by means of the Seldinger approach via the femoral artery by a retrograde approach from the superficial temporal artery. Superselective intra-arterial infusion chemotherapy1, 2) has become a standard treatment for malignant tumors. Intra-arterial infusion using the Seldinger approach car-ries the risk of causing embolism in the region of the internal carotid artery. To prevent such complications, re-gurgitation of the injected medium used for embolization should be avoided. Our results may be useful for select-ing catheters for intra-arterial infusion chemotherapy and for determining the optimal type and amount of injected medium and thereby prevent regurgitation at the time of vascular embolization.

Conclusions

We examined the origins, courses, branching patterns, and luminal diameters of the maxillary artery and its branches in 28 sides of 15 Japanese cadavers (21 sides in 11 men and 7 sides in 4 women) by means of macro-scopic anatomic techniques. The following results were obtained: 1. The relation between the maxillary artery and the lat-

eral pterygoid muscle was an external course pattern (type A and B, Fujita’s classification) in 27 (94.6%) of 28 sides. As for the positional relation to the trigemi-

nal nerve, the maxillary artery passed inside of the buccal nerve (type B and C) in 21.4% of the sides if the symmetrically dissected heads. However, the max-illary artery did not pass inside the inferior alveolar nerve in any subjects. Namely we could not observe type D and E.

2. The vertical height of the origin of the maxillary artery from the superior margin of the external audito-ry canal was 23.4 ± 5.1 mm on the right side and 22.6 ± 4.5 mm on the left. There was no relation between the bifurcation level of the common carotid artery and that of the maxillary artery.

3. As for the order that each branch arose from the maxillary artery, 67.9% of all sides showed standard patterns.

4. The inferior alveolar artery and the anterior deep temporal artery showed the smallest variations when the site of the origin of each branch of the maxillary artery was expressed relative to the distance from the origin of the maxillary artery to the site of entry into the pterygopalatine fossa.

5. Among branches of the maxillary artery, the luminal diameter was largest for the middle meningeal artery (1.2 ± 0.3 mm) and smallest for the buccal artery (0.6 ± 0.2 mm).

Acknowledgement

On completion of this manuscript, we are deeply in-debted to the donors and their families. We also thank the physicians of Department of Anatomy for their coopera-tion in performing this study.

References

1) Robbins KT, Fontanesi J, et al. A novel organpreservention protpcol for advanced carcinoma of the larynx and pharynx. Arch otlaryngol Head Neck Surg 1996; 122:853–857.

2) Tohnai I, Hayashi K, et al. Preoperative chemotherapy using superselective intraarterial infusion via superficial temporal artery for stage III, IV oral cancer. Jpn. J of Head and Neck Cancer 2002; 28:253–258.

3) Fuse T, Yoshida S, et al. Persistent Bilateral Hemorrhage Con-trolled by Maxillary artery Ligation on the Left Side and Emboli-zation on the Right. Plact Oto-Rhino-Laryngol 1998; 91:8:793–796.

4) Hama T, Dejima K, et al. A Case of Embolization for Reccurent Episaxis after Maxilarry and Ethmoidal Artery Ligation. Plact Oto-Rhino-Laryngol 2000; 93:207–211.

5) Miyamoto M, Nakamura A, et al. Clinical study of Hospitalized Patient with Reccurent Epistaxis. Plact Oto-Rhino-Laryngol 2002; 95:905–909.

6) Iguchi Y, Yao K, et al. A Clinical Study of Surgical Treatment of Epistaxis. Plact Oto-Rhino-Laryngol 2003; 96:541–547.

7) Takahashi Y, Kato A, et al. Super-Selective Intraarterial Emboli-zation for Severe Nasal Hemorrhege. Plact Oto-Rhino-Laryngol 1992; 85:21–220.

8) Mataga I. General conception of the reconstruction of the maxillo-

164 I. Otake et al.

mandible and application of dental implant. Hosp Dent 2002; 14(2):83–98.

9) Nakayama B, Matsuura H, et al. Functional reconstruction of a bilateral maxillectomy defect using a fibula osteocutaneous flap with osseointegrated implants. Plast Reconstr Surg 1995; 96(5): 1201–1204.

10) Thomson MA. Report of the anatomical society of Great Britain and Ireland for the year 1889~1890. J Anat Physiol 1891; 25:89–101.

11) Lauber H. Ueber einige Variet en im Verlauf der Arteria maxillaris interna. Anat Anz 1901; 19:444–448.

12) Adachi B. Das arterinsystem der Japaner. Band 1. Kyoto Univ, Kyoto, 1928, p.85–91.

13) Fujita T. Uber einen Fall von beiderseitig medial vom N. man-dibularis verlaufender A. maxillaries interna, nebst einer Statistik der Verlaufsvariation der Arterie. J Stomatol Soc, Jpn 1932; 6: 250–252.

14) Lasker GW, Opdyke D, et al. The position of the internal maxil-lary artery and its questionable relation to the cephalic index. Rec 1951; 109:11–126.

15) Sashi R. x-ray Anatomy of the Maxillary Artery. Akita J Med 1989; 16:817–831.

16) Tsuda K. Three Dimentional analysis of Arteriographs of the Maxillary Artery in Man–Part 1: The maxillary artery and its branches–. J Jpn PRS 1991; 11:188–198.

17) Tsuda K. Three Dimentional analysis of Arteriographs of the Maxillary Artery in Man–Part 2: Branching patterns of branches of the maxillary artery–. J Jpn PRS 1991; 11:683–690.

18) Tsuda K. Three Dimentional analysis of Arteriographs of the Maxillary Artery in Man–Part 3: Branching patterns in the deep course type of maxillary artery–. J Jpn PRS 1991; 11:855–862.

19) Kitsuta H, Lin E, et al. The Procession of the N. Mandibularis, A Maxillaris and Vv.Maxillares of Japanese people during the Open –mouth Position. Shikwa gakuho 1985; 85:1523–1532.

20) Ito H, Mataga I, et al. Clinical anatomy in the neck region; The position of external and internal carotid arteries may be reversed. Okajimas Folia Anat Jpn 2006; 82(4):157–168.

21) Ikakura K. On the origin, course and distribution of the maxillary artery in Japanese. Arch Dept of Anat Tokyo Dent Coll. (Kouku Kaibou Kenkyu) 1961; 18:91–122 (in Japanese).

22) Shima H, Ohno K, et al. A Clinicoanatomical Exermination of Vessels of the Neck Region Required for Vascular Anastomosis.Showa Shigakukai Zassi (Dent Med Reserch) 1997; 17:171–175

(in Japanese).23) Takarada T. Anatomical studies on the maxillary artery. Shikwa

gakuho 1958; 58:1–20 (in Japanese).24) Itoh I, Ohya T. Exrminations of Intra Arterial Infusion for Oral

Cancers –Distances of Canuration–. J Jpn Stomatol Soc 1979; 28:9–16 (in Japanese).

25) Shintani S, Terakado N, et al. An anatomical study of the arteries for intraarterial chemotherapy of head and neck cancer. Int J Clin Oncol 1999; 4:327–330.

26) Padget DH. Development of cranial arteries in the human embryo. Contrib Embryol 1948; 32:205–262.

27) Iwamoto S, Konishi M, et al. Several Cases of the Anomaries of the running Pattern of the Maxillary Artery. J Natl Def Med Coll 1981; 6:75–78 (in Japanese).

28) Lurje A. On the topographical anatomy of the internal maxillary artery. Acta Anat 1947; 2:219–231.

29) Takemura A, Suwa F, et al. Three cases of the maxillary artery in an abnormal course –penetrating the mandibular nerve–. Jpn J Oral Biol 1983; 25:1136–1139.

30) Fujimura A, Kuan-Hong C, et al. A Case Report in the Route Anomaly of Maxillary Artery. Dent J Iwate Med Univ 1991; 16:109–113.

31) Tanaka S, Inoue K, et al. Maxillary Artery Passing among the Branches from the Mandibular Nerve in a Japanese Man. Tsurumi Univ Dent J 2003; 29:187–191.

32) Gow-Gates GAE. Mandibular conduction anesthesia: A new tech-nique using extraoral landmarks. Oral Surg 1973; 36: 321–328.

33) Toki S. Gow-Gates mandibular block Technique. Nippon Dental Review 1982; 478:177–185 (in Japanese).

34) Kodama M. Maxilary artery, Nipponjin no Karada. Satoh T, Akita K; Tokyo Daigaku Shuppankai, Tokyo, 2000, 208–211.

35) Baumel JJ, Beard DY. The accessory meningeal artery of man. J. Anat 1961; 95:386–402.

36) Yagishita A, Shiga H, et al. Angiograms of accessory meningeal artery. Jpn J Clin Radiol 1979; 24:439–443 (in Japanese).

37) Miura T, Kishimoto S. An anatomic investigation of the vascular pedicles of a temporalis muscle flap. Jpn J Plast Reconstr Surg 1993; 36:1249–1254.

38) Shima H. Anatomy of microvascular anastomosis in the neck. Plast Reconstr Surg 1998; 101:33–41.

39) Shima H. Clinicoanatomical study of forearm flap-On the forearm vessels-JPN. J Oral Maxillofac Surg 1992; 38:60–76.