STATISTICAL STUDIES ON THE ANOMALOUS MUSCLES KYUSHU-JAPANESE. The First Department of Anatomy, Kurume University School of Medicine, Kurume, Japan

Transcription

1 THE KURUME MEDICAL JOURNAL Vol. 16, No. 2, 1969 STATISTICAL STUDIES ON THE ANOMALOUS MUSCLES OF THE KYUSHU-JAPANESE PART 4 : THE MUSCLES OF THE UPPER LIMB SADATO SATO The First Department of Anatomy, Kurume University School of Medicine, Kurume, Japan (Received for publication July 19, 1969) INTRODUCTION There are plenty of investigation on the muscular system of the upper limb especially it is virtually impossible to exhaust the list of the anomalouss muscles observed in this region of the body at autopsy. The fact that numerous cases of anomaly have been found in the muscles of the arm seems to bring out an interesting question not only ontogenetically, but also comparative anatomically, and the statistical reports about them seem to give an important subject for discussion about this problem. Regarding the literature on the anomalous muscles in the upper limb there are lots of reports by Wood (1865), Frohse and Frankel (1875), Gruber (1879), Schwalbe and Pfitzner (1889), Le Double (1897), Steffens (1910), Loth (1912), Eckstein (1912), and others in Europe and America. Also in Japan, a large number of autopsy cases showing these anomalies have been described for the first time by Adachi (1901, 1909), and then by Koganei and Shikinami (1907), Sano (1931), Iwami (1950, 1951), Ko, Abe, and Sekizawa (1958), Ko (1958), Suzuki (1955), Takeda, Ishikawa, Yoshihara, Kawahara (1955), Takeuchi, Noda (1961), and others. However, as far as we know, a general description of these anomalous muscles has not been attempted in literature yet. Upon this, observations were made at our institute on the frequency of appearance of the surplus head, accessory head, attachment anomaly, and anomaly of the attaching tendon in the muscles of the upper limb (the Biceps brachii, Palmaris longus, Flexor pollicis longus, Extensor digiti minimi and Extensor digitorum) and on their frequency of lack be here reported asking for the criticism of the wise public. MATERIAL AND METHOD The material, the method of observation, and its statistical procedure are exactly the same as described in Part 1. 69

2 70 SATO, S. 1) Biceps brachii OBSERVATIONS The Biceps brachii begins with 2 heads, the long head arising from the supraglenoid tubercle and glenoidal labrum and the short one arising from the apex of the coracoid process. The former runs out side the capsula articularis along the superior surface of the Caput humeri and goes downward in the intertubercular sulcus enveloped in the intertubercular synovial sheath. When it comes out of the joint cavity it forms the spindle-shaped venter musculi together with the latter which turning gradually into the tendon and penetrating deeply into the space between the brachio-radialis muscle and a group of flexor muscles of the forearm is inserted to the tuberosity of the radius. In addition, a part of the tendon becomes a thin bicipital apponeurosis and radiates to the superomedial side of the fascia antebrachii. However, the muscle with a surplus head was sometimes observed. As shown in Table 1, the present muscle with a surplus head appeared in 35 of 386 limbs in the male Kyushu-Japanese (9.07 }1.46%) and in 17 of 250 limbs in the female (6. 80 }1. 59 %), that is, it showed a rate of appearance of about 8 per cent. TABLE 1 Frequency appearance of the surphus head in the Biceps Individually, it was more frequent of the right side in male and on the left in females, but no significant difference was noted between them. On sex distinction, as given in Table 2, the male presented a higher frequency of it on both sides than the female, but there was no statistically definite difference between both sexes. TABLE 2 Sexual difference of the surphus head in the Biceps

3 STATISTICAL STUDIES ON THE ANOMALOUS MUSCLES 71 On the other hand, the ethnoanatomical comparison with the neighboring populations given in Table 3 revealed that the frequency of its appearance in the Kyushu-Japanese estimated by us is higher than that of the Japanese twins of Hayashi, the Japanese of Miyazawa, Koizumi and Adachi, the northern Chinese of Bando, the black race of Loth, the Englishmen of Wood, the Alsatian of Schwalbe and Pfitzner, and the Russian of Nassedkine, and similar in its numerical value to that of the Chinese of Nakano, and the Portuguese of Silva. TABLE 3 Comparison with other races of the surphus head in the Biceps 2) Triceps brachii The Triceps brachii arises with 3 heads; the medial, lateral, and long one The medial head arises extensively from the posterior surface of the humerus and the muscular septa of both sides, and, forming a broad tendon plate by gathering like a feather, is attached to the olecranon of the ulna in adhesion with the Capsula articularis, while the lateral one arises adjacent to

4 72 SATO, S. the superior edge of the radial neural groove and, presenting a flat plate in shape, is attached to the upper end and the lateral edge of the tendon plate. The long head arises from the inf raglenoid tubercle of the scapula and, running downward through the space between the Teres major and minor muscles, reaches the medial edge of the tendon plate. This muscle, too, like the Biceps, was found having a surplus head, and at the same time the existence of the capitulum was also observed. Concering the frequency of this surplus head it was observed that as shown in Table 4, it was found in 9 out of 364 limbs in the male Kyushu-Japanese (2.47 }0.81%) and in 9 out of 438 limbs in the female (3.63 }1.19 %), in a frequency of average 3 per cent. TABLE 4 Frequency appearance of the surphus head in the Triceps On side distinction, though the male showed a higher frequency of it on the left side, and the female on the right, no significant difference was noted. On sex distinction, as seen in Table 5, the female presented a higher frequency of appearance on both sides than the male, but there was no definite difference between both sexes. TABLE 5 Sexual difference of the surphus head in the Triceps The comparison with the nieghboring populations given in Table 6 revealed that the Kyushu-Japanese of us are higher in frequency than the Japanese embryos of Ko, the Japanese twins of Hayashi, and the Japanese of Miyazawa and Adachi, lower than the Japanese of Koizumi, and similar in values to the northern Chinese (l) of Bando.

5 STATISTICAL STUDIES ON THE ANOMALOUS MUSCLES 73 TABLE 6 Comparison with other races of the surphus head in the Triceps 3) Palmaris longus The Palmaris longus arises from the medial epicondyle of the humerus and the medial aspect of the antebrachial fascia, running soon downward as an elongated tendon. After reaching the palm over the flexor retinaculum, it passes into a fanned palmar aponeurosis. Observations on the frequency of lack of this muscle seen in Table 7 disclosed that it lacks in 33 of 406 limbs in the male Kyushu-Japanese (8.13 }1.36 %) and in 6 of 262 limbs in the female (2.29 }0. 92 %), that is, its frequency of lack amounts to 8 per cent in males and 2 per cent in females. Individually, it lacks more frequently on the right side in the male, but no definite difference was present. TABLE 7 Frequency of lack in appearance of the Palmaris longus TABLE 8 Sexual difference of the Palmaris longus

6 74 SATO, S. On sex distinction as shown in Table 8, it lacks more frequently both sides in the female, which indicates an evident difference in disposition. The comparison with the neighboring populations, as seen in Table 9, revealed that the Kyushu-Japanese of us are higher in its frequency of lack than the Japanese embryos of Ko, the Japanese twins of Tamaru, the Japanese of Adachi, the northern Chinese of Ki, and the Negro of Loth, and lower than the Russian of Gruber, the American of George, the Englishmen of Thompson, the French of Le Double, and the Alsatian of Schwalbe and Pfitzner. TABLE 9 Comparison with other races of the Palmaris longus 4) Flexor pollicis ion gus The Flexor pollicis longus arises under the radial head of the Flexor digitorum superficialis from the anterior aspect of the radius and the region of the interosseous membrane of the forearm adjacent to it. Its venter musculi represents a half feather in shape, the tendon running downward along the lateral side of the tendinous bundle of the Flexor digitorum prof undus. After reaching, the palm through the flexor canal, it is inserted into the fundus of the distal phalanx of the thumb passing through between

7 STATISTICAL STUDIES ON THE ANOMALOUS MUSCLES 75 both the superficial and prof and heads of the Flexor pollicis brevis. In this case an accessory head was often observable. As to the frequency of appearance of the accessory head in this muscle, Table 10 showed that it appeared in 83 of 356 limbs in the male Kyushu-Japanese (23.31 }2.24 %), and in 68 of 248 limbs in the female (27.42 }2.83 %), averaging about 25 per cent in frequency. TABLE 10 Frequency appearance of the accessory head in the Flexor pollicis longus On side distinction, though the male showed a higher rate of appearance on the right side than on the left, no definite difference could be confirmed. On the other hand, regarding the sex distinction Table 11 showed that the female presented a higher rate of appearance on both sides than the male, but there was no definite difference between both sexes. TABLE 11 Sexual difference of the accessory head in the Flexor pollicis longus The comparison with the neighboring populations desclosed that it less frequent in the Kyushu-Japanese of, us than the Aino of Sano (70%), the Japanese of Adachi (62.7%), the European of Le Double (33.3%), and the Negroes of Loth (89.3%). 5) Extensor digiti minimi The Extensor digiti minimi represents a feeble muscle bundle separating from the Extensor digitorum whose tendon runs downward along the lateral side of the 4 th tendons of it and, reaching the back of the hand through the 5 th. Canal under the extensor retinaculum, passes into the aponeurosis of the

8 76 SATO, S. back of the finger after dividing into 2 parts on the dorsal aspect of the 5 th finger. Therefore, the attachment anomaly of this muscle and the frequency of appearance of the accessory head were observed statistically as follows a) Attachment anomaly With regard to the frequency of appearance of this muscle attached else where without passing into the aponeurosis of the finger back Table 12 showed that it appeared in 3 of 344 limbs in the male Kyushu-Japanese (0.87 }0.50%) and in 2 of 236 limbs in the female (0.85 }0.59%), in frequency of average 0.9 per cent. TABLE 12 Frequency appearance of the attachment anomaly in the Extensor digiti minimi On side distinction, it was slightly more frequent on the left side than on the right, but no definite difference was noted. On sex distinction, according to Table 13, it was found that the female is higher in frequency on the right side, and the male on the left, without showing any significant difference between both sexes. TABLE 13 Sexual difference of the attachment anomaly in the Extensor digiti minimi b) The frequency of the accessory head As shown in Table 14, the accessory head appeared in 19 of 312 limbs in the male Kyushu-Japanese (6.09 }1.35%) and in 13 of 220 limbs in the female ( %), in frequency of average 6 per cent. On side distinction, though it was more frequent on the right side in the male and on the left side in the female, but no definite difference was noted.

9 STATISTICAL STUDIES ON THE ANOMALOUS MUSCLES 77 TABLE 14 Frequency appearance of the accessory head in the Extensor digiti minimi On sex distinction, Table 15 showed that the male presented a higher frequency of appearance on the right side, and the female on the left, but there was no significant difference between two sexes. TABLE 15 Sexual difference of the accessory head in the Extensor digiti minimi 6) Extensor digitorum The Extensor digitorum arises from the lateral epicondyle of the humerus, the medial surface of the antebrachial fascia near it, and the elbow joint, and gradually becomming 4 tendons, reaches the back of the hand through the 4 th canal under the extensor retinaculum. Then it passes into the aponeurosis of the finger back on the dorsal aspect of the 2nd, 3rd, 4th and 5th fingers. Besides its insertion in the basis of the proximal phalanx, the tip of the tendon divides into three, of which the middle one is attached to the basis of the middle phalanx and the other two to the basis of the distal phalanx. Therefore, the frequency of lack of the tendon of the 5th finger in this muscle and that of appearance of the tendon inserted in the first finger were observed statistically. a) The frequency of lack of the tendon of the 5th finger. As to the frequency of lack of the tendon of the 5th finger, Table 16 showed that it lacks in 69 of 366 limbs in the male Kyushu-Japanese (18.85 }2.04%o) and in 38 of 242 limbs in the female (15.70 }2.34 %), that is, in frequency of about 17 per cent. On side distinction, it lacks more frequently on the right side than on the left in both sexes, without showing any definite difference.

10 78 SATO, S. TABLE 16 Frequency of lack in appearance of the tendon in the 5th finger On sex distinction, Table 17 showed that the male presented a higher frequency of lack on both sides than the female, but no signigicant difference was noted between both sexes. TABLE 17 Sexual difference of the tendon in the 5th finger As seen in Table 18, the comparison with the neighboring populations disclosed that the present Kyushu-Japanese are higher in the frequency of lack TABLE 18 Comparison with other races of the tendon in the 5 th finger

11 STATISTICAL STUDIES ON THE ANOMALOUS MUSCLES 79 than the Japanese embryos of Ko and Hayashi, and the Japanese of Koganei and Inoue. b) The frequency of appearance of the tendon attached to the first finger. As seen in Table 19, the tendon attached to the 1 st finger appeared in 99 of 354 limbs in the male Kyushu-Japanese (27.97 }2.39%) and in 63 of 232 limbs in the female (27.16 }2.92 %), in frequency of average 27 per cent. TABLE 19 Frequency appearance of the tendon attached to the let Finger On side distinction, the male showed a higher rate of appearance of the right side and the female on the left, but there was no definite difference between both sides. On sex distinction, Table 20 revealed that the male showed a higher percentage of appearance on both sides than the female, but no significant difference was noted between both sexes. TABLE 20 Sexual difference of the tendon attached to the 1 st finger CONCLUSION On adult subjects for dissection of the Kyushu-Japanese (domiciled at Fukuoka Prefectuce) the frequency of the surplus head, the presence of the accessory head, attachment anomaly of the tendon, and its existence were investigated and the following results were obtained: 1) The surplus head of the Biceps (brachii) showed a frequency of % in the male and that of 6.80 }1.59% in the female. 2) The surplus head of the Triceps (brachii) showed a frequency of % in the male and that of 3.63 }1.19% in the female.

12 80 SATO, S. 3) The Palmaris longus showed a frequency of lack of 8.13 }1.36% in the male and that of 2.29 }0. 92% in the female so that it seems to lack more frequently with some difference in disposition in the male than in the female. 4) The accessory head of the Flexor pollicis longus showed a frequency of }2.24% in the male and that of }2.83% in the female. 5) Attachment anomaly of the Extensor digiti minimi appeared in % in the male and in 0.85 }0.59% in the female. In addition the accessory head of this muscle appeared in 6.09 }1.35% in the male and in 5.91 }1.59% in the female. 6) The tendon of the 5th finger of the Extensor digitorum lacked in % in the male and in }2.34% in the female. Moreover, the tendon attached to the 1st finger in this muscle appeared in }2.39% in the male and in }2.92% in the female. 7) The above-mentioned muscles except the Palmaris longus didn't show any side and sex differences, and were generally higher in frequency as compared with those of the neighboring populations. ACKNOWLEDGMENT The auther wishes to express his cordial thanks to Prof. Yoshio TAKESHIGE for his invaluable suggestions and criticism and his gratitude to Assist. Prof. Michio MIYAZAKI for his many valuable discussions. REFERENCES 1) ADACHI, B. and FUJISAWA, U.: Research of the exceptional muscles of the Japanese. (Part 1) J. anthrop. Soc. Nippon, 15, 166, ) ADACHI, B. : Beitrage zur Anatomie der Japaner. XII. Statistik der Muskel-varietaten. Zschr. f. Morph. u. Anthrop., 12, 261, ) ECKSTEIN, A.: Bemerkungen uber des Muskelsystem eines Neger-Fetus. Anat. Anz., 41, 334, ) FROHSE, T. and FRANKEL. M.: Die Muskeln des menschlichen Armes. Jena, Bardeleben, Handbuch der Anatomie des Menschen. 5) GRUBER, W.: Beobachtungen aus der menschlichen and vergleichenden Anatomie. Berlin, ) IWAMI, SH. : Studies on the musculature of the upper extremities of the Japanese fetus. I Report, On the muscles of the brachum. Acta med., (Fukuoka) 20, 766, ) IWAMI, SH. : Studies on the musculature of the upper extremities of the Japanese fetus. II Report, On the musculature of the forearm and the hand of the fetuses. Acta med., (Fukuoka) 21, 1073, ) KOGANEI, R., ARAI, S. and SHIKINAMI, J.: Statiscs on the muscular anomalies. Tokyo J. med. Scis., 17, 127, ) LOTH, E. : Beitrage zur Anthropologie der Negerweichteile. Stuttgart, ) LE DOUBLE.: Traite des variations du systeme musculaire de l'homme. Paris, 1897.

13 STATISTICAL STUDIES ON THE ANOMALOUS MUSCLES 81 11) Ko, K., ABE, Y. and SEKIZAWA, G.: The surplus head of the Biceps brachii. Bull. anat. Depat. Iwate med. Coll., 5, 93, ) Ko,K.: Anatomical studies on the musculature of the upper extremities of the Japanese fetus, Bull. anat. Dept. Iwate med. Coll., 5, 107, ) SANO, Y.: Studies on the constitution of the "Aino". Part II : On the musculature of the upper extremities of the "Aino". Fukuoka Acta med., 24, 31, ) SUZUKI, M.: Studies on the Palmaris longus of the Japanese. J. anthrop, Soc. Nippon, 63, 29, ) STEFFENS, F. and KOERNER, O.: Bemerkungen uber des Muskelsystem eines Papua- Neugeborenen. Anat. Anz., 36, 1, ) SCHWALBE, G. and PFITZNER, W. : Varietatenstatistik and Anthropologie. Erste Mitteilung, Anat. Anz., 4, 705, ) TAKEUCHI, T. and NODA, Y.: On the lack of the Palmaris longus and the Palmar aponeurosis. Nihon Univ. J. Med., 20, 953, ) TAKEDA, R., ISHIKAWA, H., YOSHIHARA, M. and KAWAHARA, K.: On the Palmaris longus in Kyushu-Japanese. Jour. Kurume Med. Ass., 18, 1051, ) WOOD, J. : Varieties in human myology. Proceedings of the Royal Society of London. 14, 386, 1865.