Abstract
Introduction
The proximal insertion beyond coracoid process of pectoralis minor is considered as hidden culprit of rotator cuff disorders. The ectopic insertion is also associated with thoracic outlet syndrome. The current review was conducted to provide a comprehensive evidence-based assessment of the anatomical characteristics of ectopic insertion of pectoralis minor.
Materials and methods
A through systematic search was conducted on the major electronic database, PubMed, EMBASE, Google Scholar and Journals of Anatomy, orthopedics, plastic surgery, sports medicine. The primary outcome was to measure the prevalence of ectopic insertion of pectoralis minor tendons. The data extraction was conducted for pooled estimation and metanalysis.
Results
A total of 25 studies were included for systematic review. The overall pooled estimate of ectopic insertion of Pectoralis Minor was 19.27% (95% CI 15–24%). The prevalence rate in dissected specimen was 21% (CI 15–28%) and in arthroscopic evaluation was 22% (95% CI 5–59%) which was marginally higher with wide confidence interval due small sample size. The prevalence rate in MRI and USG were 15 and 12%, because MRI and USG have almost similar sensitivity in the detection of anomalous insertion of Pectoralis Minor. The distribution of subtypes of anomalous or ectopic insertion based on Le Double classification was 34% for type I, 42 and 9% for Type III. The incidence of ectopic insertion of pectoralis minor was highest in Japanese population. The female and left side have slightly higher incidence at insignificant level.
Conclusion
The preoperative MRI or at least USG evaluation of shoulder joint must be conducted for appropriate surgical planning, because the prevalence of ectopic insertion is around 20%. The preoperative detection of anomalous insertion of pectoralis minor can be crucial in minimizing the incidences of iatrogenic injuries of tendon or post-operative complications.
Similar content being viewed by others
References
Lambert A (1925) A rare variation in the pectoralis minor muscle. In: Anat Rec https://doi.org/10.1002/ar.1090310303. Accessed 22 Mar 2020
Le Double AF (1897) Traité des variations du système musculaire de l’ homme. Schleicher Frères, Paris, pp 252–255
Henry BM, Tomaszewski KA, Ramakrishnan PK et al (2017) Development of the anatomical quality assessment (AQUA) tool for the quality assessment of anatomical studies included in meta-analyses and systematic reviews. Clin Anat 30(1):6–13
Dumontier C, Sautet A, Gagey O, Apoil A (1999) Rotator interval lesions and their relation to coracoid impingement syndrome. J Shoulder Elbow Surg 8:130–135. https://doi.org/10.1016/S1058-2746(99)90005-8
Fang-Dschau (1937) An insertion variety of the M. pectoralis minor that occurs frequently in the Chinese. Contribution to the racial anatomy of the Chinese. J Morphol Anthropol 119–123
Gruber W (1860) The supernumerary chest muscles of man. Commissioners of the Imperial Academy of Sciences, St Petersburg
Hijioka A, Suzuki K, Kobayashi Y, Hojo T, Nakashima T (1977) The relationship between an abnormal insertion of the pectoralis minor and the coracohumeral ligament. Shoulder Surg 15:9–12
Homsi C, Rodrigues M, Silva J, Stump X, Morvan G (2003) Anomalous insertion of the pectoralis minor muscle: ultrasound findings. J Radiol 84(9):1007–1011
Kolts I, Busch LC, Tomusk H et al (2002) Macroscopical anatomy of the so-called “rotator interval”. A cadaver study on 19 shoulder joints. Ann Anat-Anat Anz 184:9–14
Krause CFT (1880) Manual of human anatomy. Buchhandlung, Hanover
Lee CB, Choi SJ, Ahn JH et al (2014) Ectopic insertion of the pectoralis minor tendon: inter-reader agreement and findings in the rotator interval on MRI. Korean J Radiol 15:764–770. https://doi.org/10.3348/kjr.2014.15.6.764
Lee KW, Choi YJ, Lee HJ et al (2018) Classification of unusual insertion of the pectoralis minor muscle. Surg Radiol Anat 40:1357–1361
Lee SJ, Ha DH, Lee SM (2010) Unusual variation of the rotator interval: insertional abnormality of the pectoralis minor tendon and absence of the coracohumeral ligament. Skeletal Radiol 39:1205–1209
Lim TK, Koh KH, Yoon YC et al (2015) Pectoralis minor tendon in the rotator interval: arthroscopic, magnetic resonance imaging findings, and clinical significance. J Shoulder Elbow Surg 24:848–853
Macalister A (1866) On muscular anomalies in human anatomy, and their bearing upon homotypical myology. Proc R Ir Acad 1836–1869(10):121–164
Sappey C (1867) Sappey Traite d’anatomie descriptive, vol. II, part I Paris. Acta Anat 125:125–131
Schwarz GM, Hirtler L (2019) Ectopic tendons of the pectoralis minor muscle as cause for shoulder pain and motion inhibition—explaining clinically important variabilities through phylogenesis. PLoS ONE. https://doi.org/10.1371/journal.pone.0218715
Seib GA (1938) The m. pectoralis minor in American whites and American negroes. Am J Phys Anthropol 23:389–419
Terra BB, de Figueiredo EA, Monteiro GC et al (2011) Estudo da variação anatômica da inserção do proximal do músculo peitoral menor/study of the anatomical variation of proximal insertion of pectoralis muscle. Rev Ciênc EM SAÚDE 1:67–71. https://doi.org/10.21876/rcsfmit.v1i1.20
Tochihara J (1933) About the proper bands of the scapula, as well as about the omoclavicular connections in the Japanese. Jap J Med Sci 1:1–3
Ueki H, Yoshimura H, Hiyama K, Mochizuki T, Nimura A, Akita K (2014) Clinical study on pectoralis minor extension tendon. Shoulder Joint 38(2):369–371
Vieta RD, Alvarez DPG (2013) Pectoralis minor insertion tendon (Pectoralis Minor). A variant to keep in mind. Arthroscopy (B. Aires) 20:35–41
Wagenseil F (1936) Studies on the muscles of the Chinese. J Morphol Anthropol 1:39–150
Weinstabl R, Hertz H, Firbas W (1986) Connection of the coracoglenoid ligament with the pectoralis minor muscle. Cells Tissues Organs 125(2):126–131
Wood J (1866) Variations in human myology observed during the winter session of 1866–67 at King’s College, London. Proc R Soc Lond 15:518–546
Wood (1868) Variations in human myology observed during the winter session of 1867–1868 at King's College, London. Proc Roy Soc 16:483–525
Yashimura H, Mochizuki T, Muneta T et al (2007) The insertion of the pectoralis minor tendon: an anatomic study in Cadavers. Katakansetsu 31:217–219. https://doi.org/10.11296/katakansetsu.31.217
Ruiz FS, Ruiz AT, Butani P (2020) Anomalous insertion of the pectoralis minor tendon at the greater tuberosity. J Ultrasound 3:407–410. https://doi.org/10.1007/s40477-019-00414-0
Samuel P, Blanchard JP (1984) Rotator cuff syndrome caused by an anomaly of the insertion of the pectoralis minor. Rev Chir Orthop Reparatrice Appar Mot 70:401–404
Sicarda (1930) Pectoralis minor muscle termination anomaly. Its significance. Ann Anat path, VII, 352-355 in Anat Rericht, XXVI, abs 1462 352–355
Simovitch RW, Bal GK, Basamania CJ (2006) Thoracic outlet syndrome in a competitive baseball player secondary to the anomalous insertion of an atrophic pectoralis minor muscle: a case report. Am J Sports Med 34:1016–1019. https://doi.org/10.1177/0363546505284386
Stewart TD (1936) The musculature of the anthropoids. I. Neck and trunk. Am J Phys Anthropol 21:141–204
Testut L, Latarjet A (1948) Traite d’anatomie humaine. Tome premier Osteologie-Arthrologie-Myologie. Doin, Paris
Tubbs RS, Oakes WJ, Salter EG (2005) Unusual attachment of the pectoralis minor muscle. Clin Anat NYN 18:302–304. https://doi.org/10.1002/ca.20113
Uzel AP, Bertino R, Caix P, Boileau P (2008) Bilateral variation of the pectoralis minor muscle discovered during practical dissection. Surg Radiol Anat 30:679–682
Huntington GS (1903) Present problems of myological research and the significance and classification of muscular variations. Am J Anat 2:157–175
Brodie CG (1890) Note on the transverse-humeral, coraco-acromial, and coracohumeral ligaments, &c. J Anat Physiol 24:247
Lander KF (1918) The pectoralis minor: a morphological study. J Anat 52:292
Dinnes J, Loveman E, McIntyre L, Waugh N (2003) The effectiveness of diagnostic tests for the assessment of shoulder pain due to soft tissue disorders: a systematic review. Health Technol Assess. https://doi.org/10.3310/hta7290
Goldman E, Vasan C, Lopez-Cardona H, Vasan N (2016) Unilateral ectopic insertion of the pectoralis minor: clinical and functional significance. Morphologie 100:41–44
Low SCS, Tan SC (2010) Ectopic insertion of the pectoralis minor muscle with tendinosis as a cause of shoulder pain and clicking. Clin Radiol 65:254–256
Higgins MA, Tambe A (2012) Aberrant pectoralis minor tendon and surgery around the coracoid process. Shoulder Elb 4:117–118
Zvijac JE, Zikria B, Botto-van Bemden A (2009) Isolated tears of pectoralis minor muscle in professional football players: a case series. Am J Orthop 38:145–147
Moineau G, Cikes A, Trojani C, Boileau P (2008) Ectopic insertion of the pectoralis minor: implication in the arthroscopic treatment of shoulder stiffness. Knee Surg Sports Traumatol Arthrosc 16:869–871
Kolts I, Busch LC, Tomusk H et al (2000) Anatomy of the coracohumeral and coracoglenoidal ligaments. Ann Anat-Anat Anz 182:563–566
Musso F, Azredo RA, Tose D (2004) Marchiori JGT (2004) Pectoralis minor muscle: an unusual insertion. Braz J Morphol Sci 21:139–140
Pandey V, Madi S, Maddukuri S et al (2016) A case of bilateral aberrant pectoralis minor insertion with absent coracohumeral ligament: Clinical relevance and controversies. J Clin Orthop Trauma 7:76–79. https://doi.org/10.1016/j.jcot.2016.06.013
Patten CJ (1934) Bilateral capsular insertion of part of the tendon of the pectoralis minor. J Anat 68:427
Kartelov Y, Jelev L, Hinova-Palova D, Paloff A, Ovtscharoff W (2012) Unusual insertion of the pectoralis minor muscle. Acta Morphol Anthropol 19:107–108
Yoo JC, Lim TK, Koh KH, Park WH (2010) Arthroscopic perspective of the tendinous insertion of the pectoralis minor and correlation with MRI: a case report. J Shoulder Elbow Surg 19:e19–e23
Funding
Authors declare no financial support received.
Author information
Authors and Affiliations
Contributions
Adil Asghar: Conceptualization, Search strategies, Statistical analysis, Manuscript Preparation. Ravi Kant Narayan: Literature search, Shortlisting of manuscripts, Risk of bias, Manuscript Preparation. Abhigyan Satyam: Literature search, Collection of literature, Shortlisting of manuscripts, Risk of bias. Shagufta Naaz: Risk of Bias, Statistical Analysis, Manuscript preparation, Manuscript editing.
Corresponding author
Ethics declarations
Conflict of interet
Authors declare no conflict of interest.
PROSPERO Registration: CRD42020173217 dated 28.04.2020.
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Asghar, A., Narayan, R.K., Satyam, A. et al. Prevalence of anomalous or ectopic insertion of pectoralis minor: a systematic review and meta-analysis of 4146 shoulders. Surg Radiol Anat 43, 631–643 (2021). https://doi.org/10.1007/s00276-020-02610-8
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00276-020-02610-8