Revisited Anatomy of Additional Heads of Biceps Brachii Muscle and Coexisting Musculocutaneous Nerve Variants

Abstract

Introduction:To determine the incidence and gross morphology of additional head of biceps brachii in the Indian population, and to note concurrent musculocutaneous nerve variations. Subjects and Methods: One hundred and twenty upper limbs (males-100, females-20) from 60 formalin-embalmed cadavers were utilized for the study. Results: The additional heads were found in 11 cadavers. Third head was present in 16.6% and fourth head in 1.7%. The variation was unilateral in 72.7% and bilateral in 27.3% cadavers. Out of 120 limbs, 14 had additional head, and 71.4% of these were left-sided. In 73.3%, additional head joined with tendon and with the belly of BB in 26.7%. Three types of origin: anterolateral, posteromedial and high humeral were observed in 60%, 26.7% and 13.3%, respectively. The additional muscle was 11.7 ± 3.9 cm in length. The mean length on the right and left sides was 9.8 ± 3.3 cm and 12.4 ± 3.9 cm, respectively. Incidence of concurrent additional head and musculocutaneous variations was 42.8%. The nerve variations were unilateral with 80% on the left, and ipsilateral to additional muscle. Conclusion: The incidence of additional head in biceps brachii is 18.3% in the Indian population. Most common presentation is of a left-sided third head, and musculocutaneous variants occur on the same side as additional muscle. Presence of extra head should be considered during the analysis of the diagnostic scans, and awareness of the associated musculocutaneous nerve variations would be helpful in avoiding complications during surgical interventions.

Accessory heads of the biceps brachii muscle: A systematic review and meta‐analysis

“…A total of 26 studies (2800 upper limbs) reported the occurrence of the accessory heads of biceps brachii muscle in relation to gender (Al‐Kushi, 2013; Asvat et al, 1993; Ballesteros et al, 2014; Cheema & Singla, 2011; Duran & Arquez, 2016; Gindha et al, 2015; Ilayperuma et al, 2011; Kervancioglu & Orhan, 2011; Koizumi, 1934; Kopuz et al, 1999; Kosugi et al, 1992; Kumar & Baidya, 2018; Le Double, 1897; Lee, 2013; Nasr & Hussein, 2013; Nayak et al, 2006; Rodriguez‐Niedenführ et al, 2003; Ruiz et al, 2017; Salve et al, 2013; Sato, 1969; Sawant et al, 2012; Schwerdtfeger et al, 2018; Shalini & Anupama, 2013; Techataweewan et al, 2016; Verma & Sakthivel, 2019; Wahengbam et al, 2015). Meta‐analysis of the relevant studies revealed that the accessory heads are more prevalent in males (10.2%; 95% CI 7–13%) than in females (7.3%; 95% CI 4–10%).…”

“…Proportional analysis was performed with the use of 36 studies (628 upper limbs with the accessory head of the biceps brachii muscle) (Al‐Kushi, 2013; Asvat et al, 1993; Chandrupatla & Sultana, 2016; Cheema & Singla, 2011; Chitra & Kalaiyarasi, 2016; da Silva Leal, 1926; Duran & Arquez, 2016; Gindha et al, 2015; Gupta & D'Souza, 2014; Ilayperuma et al, 2011; Kervancioglu & Orhan, 2011; Koganei et al, 1903; Koizumi, 1934; Kopuz et al, 1999; Kosugi et al, 1992; Kumar et al, 2008; Kumar & Baidya, 2018; Le Double, 1897; Lee, 2013; Nasr & Hussein, 2013; Nayak et al, 2006; Poudel & Bhattarai, 2009; Rai et al, 2007; Rodriguez‐Niedenführ et al, 2003; Salve et al, 2013; Sato, 1969; Sawant et al, 2012; Schwalbe & Pfitzner, 1894; Schwerdtfeger et al, 2018; Shalini & Anupama, 2013; Techataweewan et al, 2016; Ughade et al, 2012; Varlekar et al, 2011; Verma & Sakthivel, 2019; Wahengbam et al, 2015; Wood, 1868). The number of studies is higher than in the overall gender prevalence analysis because several studies had to be excluded from the overall investigation since the gender of the cohort was not mentioned in the material and methods section and the gender was reported only in the results section in relation to the findings so that the overall male to female ratio could not be obtained for the prevalence investigation.…”

“…The side distribution was sufficiently described in 51 studies (5877 upper limbs) (Agarwal & Gopal, 2020; Al‐Kushi, 2013; Asvat et al, 1993; Avadhani & Chakravarthi, 2012; Bagoji et al, 2014; Ballesteros et al, 2014; Bharambe et al, 2015; Chandrupatla & Sultana, 2016; Chauhan, 2010; Cheema & Singla, 2011; Chitra & Kalaiyarasi, 2016; da Silva, 2016; Duran & Arquez, 2016; Gindha et al, 2015; Guerrero et al, 2018; Gupta & D'Souza, 2014; Gupta et al, 2020; Kervancioglu & Orhan, 2011; Khaledpour, 1985; Kopuz et al, 1999; Kosugi et al, 1992; Kudo & Bando, 1965; Kumar et al, 2008; Kumar et al, 2012; Kumar & Baidya, 2018; Lingaswamy et al, 2015; Manoj et al, 2012; Mantraratnam & Bhattam, 2016; Morampuri et al, 2015; Nalluri et al, 2016; Nasr & Hussein, 2013; Nayak et al, 2006; Patel et al, 2016; Pathak et al, 2016; Poudel & Bhattarai, 2009; Radhika et al, 2017; Rai et al, 2007; Ravi et al, 2020; Rodriguez‐Niedenführ et al, 2003; Salve et al, 2013; Sandeep et al, 2012; Sato, 1969; Schwalbe & Pfitzner, 1894; Sthapak et al, 2016; Sugavasi et al, 2015; Suhani et al, 2013; Tenchini, 1879; Ughade et al, 2012; Varlekar et al, 2011; Verma & Sakthivel, 2019; Wahengbam et al, 2015; Zlabek, 1933). The accessory heads occur on the right side with an overall prevalence of 3.4% (95% CI 2–4%), and 3.2% (95% CI 2–4%) on the left side (Table…”

“…A total of 42 studies (271 upper limbs with accessory heads) reported data on the innervation of the accessory heads of the biceps brachii muscle (Agarwal & Gopal, 2020; Al‐Kushi, 2013; Asvat et al, 1993; Ballesteros et al, 2014; Bharambe et al, 2015; Chandrupatla & Sultana, 2016; Chauhan, 2010; Cheema & Singla, 2011; Chitra & Kalaiyarasi, 2016; Duran & Arquez, 2016; Gindha et al, 2015; Gupta et al, 2020; Ilayperuma et al, 2011; Kervancioglu & Orhan, 2011; Kumar et al, 2008; Kumar et al, 2012; Kumar & Baidya, 2018; Lee, 2013; Lingaswamy et al, 2015; Manoj et al, 2012; Mantraratnam & Bhattam, 2016; Morampuri et al, 2015; Nalluri et al, 2016; Nayak et al, 2006; Patel et al, 2016; Pathak et al, 2016; Poudel & Bhattarai, 2009; Ravi et al, 2020; Rincon et al, 2002; Rodriguez‐Niedenführ et al, 2003; Ruiz et al, 2017; Salve et al, 2013; Sawant et al, 2012; Schwerdtfeger et al, 2018; Sthapak et al, 2016; Sugavasi et al, 2015; Suhani et al, 2013; Tenchini, 1879; Ughade et al, 2012; Varlekar et al, 2011; Verma & Sakthivel, 2019; Wahengbam et al, 2015). The accessory head most commonly receives innervation from the musculocutaneous nerve (94.4%; 95% CI 89–99%).…”

“…Multiple classification systems have been previously proposed (Bharambe et al, 2015; Geurrerro et al, 2018; Verma & Sakthivel, 2019). Unfortunately, none of the existing proposed classifications could have been implemented for the purpose of our meta‐analysis since the disparity among them is vast, which makes it unable to pool the heterogeneous data extracted from the included studies together.…”