Anat Sci Int DOI 10.1007/s12565-015-0288-8
CASE REPORT
Five-headed biceps brachii muscle with a rare origin from the tendon of pectoralis major muscle Sung-Suk Je1 • Bori Park1 • Jinu Kim2 • Sang-Pil Yoon2
Received: 11 March 2015 / Accepted: 14 May 2015 Ó Japanese Association of Anatomists 2015
Abstract We found a five-headed biceps brachii (BB) muscle associated with the pectoralis major muscle in a 43-year-old Korean male cadaver during a routine dissection course. A supernumerary head originated from the anterior surface of the distal tendinous part of the pectoralis major muscle, lay in the sulcus between the short and long heads of BB muscle, and terminated at their point of union. The additional two accessory heads originated from the body of the humerus between the insertion site of the coracobrachialis muscle and the origin site of the brachialis muscle and inserted into the distal part of the united muscle belly of the BB muscle. The additional accessory heads were supplied by branches of the musculocutaneous nerve. Although a supernumerary head of BB muscle originated from the pectoralis major is a peculiar finding, morphological details on the presence of another combined variation might be essential for clinicians as well as anatomists. Keywords Biceps brachii muscle Supernumerary head Pectoralis major muscle
Introduction Historically, the biceps brachii (BB) muscle is described as a two-headed muscle and is also known to be one of the most variable muscles of the human body (Macalister 1875; Bergman et al. 2014). Supernumerary heads of the BB occur in about 10 % of individuals (148 reports in 1453 individuals) based on meta-analysis of reports until 1926 (da Silva Leal 1926), also appearing in about 12 % in a recent report (Bergman et al. 2014). Occurrence of the third supernumerary head is a common variant, but the presence of three supernumerary heads is still rare. The prevalence of three supernumerary heads is about 0.17 % (Adachi 1910), in which the extra heads commonly originate from the humerus. The similar fiveheaded BB was recently reported, 100 years thereafter (Lee et al. 2014), although a BB with seven heads was once reported without morphological details (Pires de Lima 1923). We report herein a five-headed BB associated with a rare origin from the pectoralis major muscle, although the additional two supernumerary heads were documented with the most common form originating from the humerus.
Case report & Sang-Pil Yoon [email protected] 1
Medical Course, Medical School, Jeju National University, Jeju-Do 690-756, Republic of Korea
2
Department of Anatomy, School of Medicine, Jeju National University, 102 Jejudaehak-ro, Jeju-Si, Jeju-Do 690-756, Republic of Korea
During a routine dissection at Jeju National University Medical School in 2014, a case of supernumerary heads of the BB was observed on the left arm of a 43-year-old Korean male cadaver, whose cause of death was ‘‘hepatic failure’’. During the superficial dissection of the anterior region of the arm, we observed an abnormal BB on the left side of the cadaver. This muscle had five heads. Whereas the short
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and long heads had their normal origin, the 3rd head originated from the anterior surface of the distal tendinous part of the pectoralis major muscle. The 3rd head lay in the sulcus between the short and long heads and terminated at their point of union (Fig. 1a). The 4th and 5th accessory heads of the BB originated from the body of the humerus at the insertion site of the coracobrachialis muscle and inserted into the distal part of the united muscle belly of the BB (Fig. 1b). The musculocutaneous nerve pierced the coracobrachialis muscle, ran under the BB and the 3rd head, then coursed between the 4th and 5th accessory heads of the BB and the brachialis muscle, and finally continued to the lateral cutaneous nerve of forearm. The accessory heads of the BB were innervated by branches of the musculocutaneous nerve during the course: the 3rd head was innervated by a branch from the nerve to BB, and the 4th and 5th heads were supplied by a branch from the musculocutaneous nerve
Fig. 1 Photographs of the supernumerary heads of biceps brachii muscle before (a) and after (b) reflecting the pectoralis major muscle (Pm) and cutting the belly of the biceps brachii muscle. A supernumerary (3rd) head originated from the tendon of Pm and inserted into the muscle belly of the traditional short head (SH) and long head (LH) of the biceps brachii muscle. The additional two (4th and 5th) heads were found between the insertion of coracobrachialis muscle and the origin of brachialis muscle under the biceps brachii muscle, and inserted into the muscle belly inferiorly of the biceps brachii muscle. The musculocutaneous nerve (arrowheads) ran between the biceps brachii muscle including the supernumerary heads and the brachialis muscle, and continued to the lateral cutaneous nerve of forearm (arrow). CB coracobrachialis muscle, Deltoid deltoid muscle
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before the musculocutaneous nerve gave off the nerve to brachialis muscle (Fig. 2).
Discussion The supernumerary head of the BB might originate from the shaft of humerus, the coracoid process, medial intermuscular septum, capsule of shoulder joint, tendon of the pectoralis major muscle, and terminal part of the deltoid or the coracobrachialis muscle and insert into the common belly of the BB (Testut 1884; Mori 1964; Kosugi et al. 1992; Rodrı´guez-Niedenfu¨hr et al. 2003; Nasr and Hussein 2013). The commonest site of origin of the extra head of the BB is the medial aspect of the humerus in common with the insertion of the coracobrachialis muscle, with the least one being a tendinous origin from the pectoralis major muscle.
Supernumerary head from the pectoralis major muscle Fig. 2 Schematic diagram of the branching pattern of the musculocutaneous nerve to the supernumerary heads of the biceps brachii muscle. LC lateral cord, MC medial cord, UN ulnar nerve, MN median nerve, CB nerve to coracobrachialis, BB nerve to biceps brachii, B nerve to brachialis, LCNF lateral cutaneous nerve of forearm, 3rd nerve to the 3rd supernumerary head of the biceps brachii, 4th and 5th nerve to the 4th and 5th supernumerary heads of the biceps brachii
Among various origins of the supernumerary head, the terminal tendon of pectoralis major had a suspected prevalence of about 4 % (Greig et al. 1952; Mori 1964), being the rarest anomaly of supernumerary head observed. Macalister (1875) reported the 48 variations of BB, among which only 2 cases were related to the pectoralis major: a slip to the short head from the tendon insertion of pectoralis major and an instance of the origin of the long tendon of the BB from the tendon of pectoralis major. This variant has recently been reported in two cases, unilaterally (Sargon et al. 1996) or bilaterally (Fraser et al. 2014). Previous works showed the presence of a supernumerary head originated from the pectoralis major, but we report herein three supernumerary heads associated with a rare origin from the pectoralis major muscle with the other two supernumerary heads documented with the most common form originating from the humerus. Embryologically, the third head of the BB was considered as a part of the brachialis muscle that was separated by the musculocutaneous nerve, being classified by Kosugi et al. (1992); a similar case was also reported by our laboratory (Lee et al. 2014). Phylogenetically, variations of the BB were explained as a remnant of a ‘‘tuberculo-septale’’ head that, together with short and long heads, is present in hylobates but is a product of regression in humans and anthropoids (de Burlet and Correlje´ 1919). Other small supernumerary heads, just like the 4th and 5th supernumerary heads in this case, seem to be related to division of origin as suggested by Kosugi et al. (1992). Even though the embryological explanation of the accessory heads of BB was well described, the supernumerary head originating from the pectoralis major described herein has rarely been described to the best of our knowledge. The supernumerary head in this cadaver is likely the result of some minor failure of some of the complex regulation system that acts in concert to ensure proper placement of
myogenic cell groups during limb development, as previously suggested (Fraser et al. 2014). Taken together, such dysgenesis including the division of origin and the anomalous insertion into the pectoralis major could explain the development of this case. No significant clinical manifestations have been recorded in most cases of supernumerary head of the BB (Nasr and Hussein 2013). The presence of a supernumerary head of the BB, however, is known to affect the course and branching of the musculocutaneous nerve (Kosugi et al. 1992), which could cause compression of surrounding neurovascular structures. Moreover, the significant bulk of the supernumerary head associated with the pectoralis major muscle may lead to variation of normal mechanical actions including flexion and supination of the forearm, as previously suggested (Fraser et al. 2014). There was no additional variation of the musculocutaneous nerve, but there was significant bulk of the 3rd head associated with the pectoralis major muscle in this case, which might lead to variation of normal action without clinical manifestations. Knowledge of these variations may be important for clinicians preparing a certain procedure on the arm with or without nerve impairment.
Conclusions Our finding of a five-headed BB with a rare origin from the pectoralis major muscle is unique/very rare to the best of our knowledge, and the significant bulk of the supernumerary head associated with the pectoralis major muscle might change its functional aspects relative to other accessory heads. Therefore, knowing the presence of another combined neuromuscular variation with supernumerary head of the BB is essential for clinicians as well as anatomists, although there was no additional variation of the musculocutaneous nerve in this case. Conflict of interest interest to declare.
The authors of this study have no conflicts of
References Adachi B (1910) Beitra¨ge zur Anatomie der Japaner. XII. Die Statistik der Muskelvarieta¨ten. Zeitschrift fu¨r Morphologie und Anthropologie 12:261–312 Bergman RA, Afifi AK, Miyauchi R (2014) Illustrated encyclopedia of human anatomic variation: opus I: muscular system: alphabetical listing of muscles: B. http://www.anatomyatlases.org/ AnatomicVariants/MuscularSystem/Text/B/02Biceps.shtml. Accessed Apr 2014 da Silva Leal M (1926) Les chefs surnume´raires du biceps brachial chez les monstres te´ratence´phaliens. Socie´te de Biologie (et de ses filiales) Comptes Rendus (Hebdomadaires des Se´ances et Memories) Tome II:1285–1286
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S. Je et al. ¨ ber variationen des menschlichen de Burlet HM, Correlje´ J (1919) U musculus biceps brachii. Gegenbaurs Morphol Jahrb 50:403–416 Fraser PR, Howard LW, Rosales AA, Guttmann GD (2014) Bilateral symmetrical supernumerary heads of biceps brachii with rare pectoralis major insertion. Surg Radiol Anat. doi:10.1007/ s00276-014-1307-5 Greig HW, Anson BJ, Budinger JM (1952) Variations in the form and attachments of the biceps brachii muscle. Q Bull Northwest Univ Med Sch 26:241–244 Kosugi K, Shibata S, Yamashita H (1992) Supernumerary head of biceps brachii and branching pattern of the musculocutaneous nerve in Japanese. Surg Radiol Aant 14:175–185 Lee SH, Jeon JY, Yoon SP (2014) A combined variation of the musculocutaneous nerve associated with a supernumerary head of the biceps brachii muscle. Folia Morphol (Warsz) 73:366–369 Macalister A (1875) Additional observations on muscular anomalies in human anatomy (third series), with a catalogue of the principal muscular variations hitherto published. Trans R Ir Acad Sci 25:1–134
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Mori M (1964) Statistics on the musculature of the Japanese. Okajimas Folia Anat Jpn 40:195–300 Nasr AY, Hussein AM (2013) Morphology and clinical implication of the extra-head of biceps brachii muscle. Folia Morphol 72:349–356 Pires de Lima JA (1923) Sur la fre´quence de quelques anomalies musculaires chez les Portugais. C R Hebdomadaires Seanc Mem Soc Biol 88:1329–1330 Rodrı´guez-Niedenfu¨hr M, Va´zquez T, Choi D, Parkin I, San˜udo JR (2003) Supernumerary humeral heads of the biceps brachii muscle revisited. Clin Anat 16:197–203 Sargon MF, Tuncali D, Celik HH (1996) An unusual origin for the accessory head of biceps brachii muscle. Clin Anat 9:160–162 Testut L (1884) Les Anomalies Musculaires Chez l’Homme Expliquees par l’Anatomie Comparee Leur Importance en Anthropologie. In: Masson G (ed) Libraire de l’Academe de Medecine, Paris, pp 370–397
CASE REPORT
Five-headed biceps brachii muscle with a rare origin from the tendon of pectoralis major muscle Sung-Suk Je1 • Bori Park1 • Jinu Kim2 • Sang-Pil Yoon2
Received: 11 March 2015 / Accepted: 14 May 2015 Ó Japanese Association of Anatomists 2015
Abstract We found a five-headed biceps brachii (BB) muscle associated with the pectoralis major muscle in a 43-year-old Korean male cadaver during a routine dissection course. A supernumerary head originated from the anterior surface of the distal tendinous part of the pectoralis major muscle, lay in the sulcus between the short and long heads of BB muscle, and terminated at their point of union. The additional two accessory heads originated from the body of the humerus between the insertion site of the coracobrachialis muscle and the origin site of the brachialis muscle and inserted into the distal part of the united muscle belly of the BB muscle. The additional accessory heads were supplied by branches of the musculocutaneous nerve. Although a supernumerary head of BB muscle originated from the pectoralis major is a peculiar finding, morphological details on the presence of another combined variation might be essential for clinicians as well as anatomists. Keywords Biceps brachii muscle Supernumerary head Pectoralis major muscle
Introduction Historically, the biceps brachii (BB) muscle is described as a two-headed muscle and is also known to be one of the most variable muscles of the human body (Macalister 1875; Bergman et al. 2014). Supernumerary heads of the BB occur in about 10 % of individuals (148 reports in 1453 individuals) based on meta-analysis of reports until 1926 (da Silva Leal 1926), also appearing in about 12 % in a recent report (Bergman et al. 2014). Occurrence of the third supernumerary head is a common variant, but the presence of three supernumerary heads is still rare. The prevalence of three supernumerary heads is about 0.17 % (Adachi 1910), in which the extra heads commonly originate from the humerus. The similar fiveheaded BB was recently reported, 100 years thereafter (Lee et al. 2014), although a BB with seven heads was once reported without morphological details (Pires de Lima 1923). We report herein a five-headed BB associated with a rare origin from the pectoralis major muscle, although the additional two supernumerary heads were documented with the most common form originating from the humerus.
Case report & Sang-Pil Yoon [email protected] 1
Medical Course, Medical School, Jeju National University, Jeju-Do 690-756, Republic of Korea
2
Department of Anatomy, School of Medicine, Jeju National University, 102 Jejudaehak-ro, Jeju-Si, Jeju-Do 690-756, Republic of Korea
During a routine dissection at Jeju National University Medical School in 2014, a case of supernumerary heads of the BB was observed on the left arm of a 43-year-old Korean male cadaver, whose cause of death was ‘‘hepatic failure’’. During the superficial dissection of the anterior region of the arm, we observed an abnormal BB on the left side of the cadaver. This muscle had five heads. Whereas the short
123
S. Je et al.
and long heads had their normal origin, the 3rd head originated from the anterior surface of the distal tendinous part of the pectoralis major muscle. The 3rd head lay in the sulcus between the short and long heads and terminated at their point of union (Fig. 1a). The 4th and 5th accessory heads of the BB originated from the body of the humerus at the insertion site of the coracobrachialis muscle and inserted into the distal part of the united muscle belly of the BB (Fig. 1b). The musculocutaneous nerve pierced the coracobrachialis muscle, ran under the BB and the 3rd head, then coursed between the 4th and 5th accessory heads of the BB and the brachialis muscle, and finally continued to the lateral cutaneous nerve of forearm. The accessory heads of the BB were innervated by branches of the musculocutaneous nerve during the course: the 3rd head was innervated by a branch from the nerve to BB, and the 4th and 5th heads were supplied by a branch from the musculocutaneous nerve
Fig. 1 Photographs of the supernumerary heads of biceps brachii muscle before (a) and after (b) reflecting the pectoralis major muscle (Pm) and cutting the belly of the biceps brachii muscle. A supernumerary (3rd) head originated from the tendon of Pm and inserted into the muscle belly of the traditional short head (SH) and long head (LH) of the biceps brachii muscle. The additional two (4th and 5th) heads were found between the insertion of coracobrachialis muscle and the origin of brachialis muscle under the biceps brachii muscle, and inserted into the muscle belly inferiorly of the biceps brachii muscle. The musculocutaneous nerve (arrowheads) ran between the biceps brachii muscle including the supernumerary heads and the brachialis muscle, and continued to the lateral cutaneous nerve of forearm (arrow). CB coracobrachialis muscle, Deltoid deltoid muscle
123
before the musculocutaneous nerve gave off the nerve to brachialis muscle (Fig. 2).
Discussion The supernumerary head of the BB might originate from the shaft of humerus, the coracoid process, medial intermuscular septum, capsule of shoulder joint, tendon of the pectoralis major muscle, and terminal part of the deltoid or the coracobrachialis muscle and insert into the common belly of the BB (Testut 1884; Mori 1964; Kosugi et al. 1992; Rodrı´guez-Niedenfu¨hr et al. 2003; Nasr and Hussein 2013). The commonest site of origin of the extra head of the BB is the medial aspect of the humerus in common with the insertion of the coracobrachialis muscle, with the least one being a tendinous origin from the pectoralis major muscle.
Supernumerary head from the pectoralis major muscle Fig. 2 Schematic diagram of the branching pattern of the musculocutaneous nerve to the supernumerary heads of the biceps brachii muscle. LC lateral cord, MC medial cord, UN ulnar nerve, MN median nerve, CB nerve to coracobrachialis, BB nerve to biceps brachii, B nerve to brachialis, LCNF lateral cutaneous nerve of forearm, 3rd nerve to the 3rd supernumerary head of the biceps brachii, 4th and 5th nerve to the 4th and 5th supernumerary heads of the biceps brachii
Among various origins of the supernumerary head, the terminal tendon of pectoralis major had a suspected prevalence of about 4 % (Greig et al. 1952; Mori 1964), being the rarest anomaly of supernumerary head observed. Macalister (1875) reported the 48 variations of BB, among which only 2 cases were related to the pectoralis major: a slip to the short head from the tendon insertion of pectoralis major and an instance of the origin of the long tendon of the BB from the tendon of pectoralis major. This variant has recently been reported in two cases, unilaterally (Sargon et al. 1996) or bilaterally (Fraser et al. 2014). Previous works showed the presence of a supernumerary head originated from the pectoralis major, but we report herein three supernumerary heads associated with a rare origin from the pectoralis major muscle with the other two supernumerary heads documented with the most common form originating from the humerus. Embryologically, the third head of the BB was considered as a part of the brachialis muscle that was separated by the musculocutaneous nerve, being classified by Kosugi et al. (1992); a similar case was also reported by our laboratory (Lee et al. 2014). Phylogenetically, variations of the BB were explained as a remnant of a ‘‘tuberculo-septale’’ head that, together with short and long heads, is present in hylobates but is a product of regression in humans and anthropoids (de Burlet and Correlje´ 1919). Other small supernumerary heads, just like the 4th and 5th supernumerary heads in this case, seem to be related to division of origin as suggested by Kosugi et al. (1992). Even though the embryological explanation of the accessory heads of BB was well described, the supernumerary head originating from the pectoralis major described herein has rarely been described to the best of our knowledge. The supernumerary head in this cadaver is likely the result of some minor failure of some of the complex regulation system that acts in concert to ensure proper placement of
myogenic cell groups during limb development, as previously suggested (Fraser et al. 2014). Taken together, such dysgenesis including the division of origin and the anomalous insertion into the pectoralis major could explain the development of this case. No significant clinical manifestations have been recorded in most cases of supernumerary head of the BB (Nasr and Hussein 2013). The presence of a supernumerary head of the BB, however, is known to affect the course and branching of the musculocutaneous nerve (Kosugi et al. 1992), which could cause compression of surrounding neurovascular structures. Moreover, the significant bulk of the supernumerary head associated with the pectoralis major muscle may lead to variation of normal mechanical actions including flexion and supination of the forearm, as previously suggested (Fraser et al. 2014). There was no additional variation of the musculocutaneous nerve, but there was significant bulk of the 3rd head associated with the pectoralis major muscle in this case, which might lead to variation of normal action without clinical manifestations. Knowledge of these variations may be important for clinicians preparing a certain procedure on the arm with or without nerve impairment.
Conclusions Our finding of a five-headed BB with a rare origin from the pectoralis major muscle is unique/very rare to the best of our knowledge, and the significant bulk of the supernumerary head associated with the pectoralis major muscle might change its functional aspects relative to other accessory heads. Therefore, knowing the presence of another combined neuromuscular variation with supernumerary head of the BB is essential for clinicians as well as anatomists, although there was no additional variation of the musculocutaneous nerve in this case. Conflict of interest interest to declare.
The authors of this study have no conflicts of
References Adachi B (1910) Beitra¨ge zur Anatomie der Japaner. XII. Die Statistik der Muskelvarieta¨ten. Zeitschrift fu¨r Morphologie und Anthropologie 12:261–312 Bergman RA, Afifi AK, Miyauchi R (2014) Illustrated encyclopedia of human anatomic variation: opus I: muscular system: alphabetical listing of muscles: B. http://www.anatomyatlases.org/ AnatomicVariants/MuscularSystem/Text/B/02Biceps.shtml. Accessed Apr 2014 da Silva Leal M (1926) Les chefs surnume´raires du biceps brachial chez les monstres te´ratence´phaliens. Socie´te de Biologie (et de ses filiales) Comptes Rendus (Hebdomadaires des Se´ances et Memories) Tome II:1285–1286
123
S. Je et al. ¨ ber variationen des menschlichen de Burlet HM, Correlje´ J (1919) U musculus biceps brachii. Gegenbaurs Morphol Jahrb 50:403–416 Fraser PR, Howard LW, Rosales AA, Guttmann GD (2014) Bilateral symmetrical supernumerary heads of biceps brachii with rare pectoralis major insertion. Surg Radiol Anat. doi:10.1007/ s00276-014-1307-5 Greig HW, Anson BJ, Budinger JM (1952) Variations in the form and attachments of the biceps brachii muscle. Q Bull Northwest Univ Med Sch 26:241–244 Kosugi K, Shibata S, Yamashita H (1992) Supernumerary head of biceps brachii and branching pattern of the musculocutaneous nerve in Japanese. Surg Radiol Aant 14:175–185 Lee SH, Jeon JY, Yoon SP (2014) A combined variation of the musculocutaneous nerve associated with a supernumerary head of the biceps brachii muscle. Folia Morphol (Warsz) 73:366–369 Macalister A (1875) Additional observations on muscular anomalies in human anatomy (third series), with a catalogue of the principal muscular variations hitherto published. Trans R Ir Acad Sci 25:1–134
123
Mori M (1964) Statistics on the musculature of the Japanese. Okajimas Folia Anat Jpn 40:195–300 Nasr AY, Hussein AM (2013) Morphology and clinical implication of the extra-head of biceps brachii muscle. Folia Morphol 72:349–356 Pires de Lima JA (1923) Sur la fre´quence de quelques anomalies musculaires chez les Portugais. C R Hebdomadaires Seanc Mem Soc Biol 88:1329–1330 Rodrı´guez-Niedenfu¨hr M, Va´zquez T, Choi D, Parkin I, San˜udo JR (2003) Supernumerary humeral heads of the biceps brachii muscle revisited. Clin Anat 16:197–203 Sargon MF, Tuncali D, Celik HH (1996) An unusual origin for the accessory head of biceps brachii muscle. Clin Anat 9:160–162 Testut L (1884) Les Anomalies Musculaires Chez l’Homme Expliquees par l’Anatomie Comparee Leur Importance en Anthropologie. In: Masson G (ed) Libraire de l’Academe de Medecine, Paris, pp 370–397
