Anatomy and Cell Biology

Korean Association of Anatomists (대한해부학회)
권호 표지
DOI QR코드

DOI QR Code

Morphological classification, anatomical variations, innervation patterns, musculocutaneous nerve relation of the coracobrachialis muscle: anatomical study and clinical significance

  • Ashraf Youssef Nasr (Department of Clinical Anatomy, Faculty of Medicine, King Abdulaziz University) ;
  • Rawan Ashraf Youssef (Department of Neurology, Faculty of Medicine, Zagazig University)
  • Received : 2024.02.02
  • Accepted : 2024.04.07
  • Published : 2024.06.30
Download PDF
⟨ Previous Next ⟩

Abstract

The anatomical variations of coracobrachialis muscle (CBM) are of great clinical importance. This study aimed to elucidate the morphological variations, innervation patterns and musculocutaneous nerve (MCN) relation to CBM. Upper limbs of fifty cadavers (30 males and 20 females) were examined for proximal and distal attachments, innervation pattern of CBM and its relation to MCN. Four morphological types of CBM were identified according to number of its heads. The commonest type was the two-headed (63.0%) followed by the single belly (22.0%), three-headed (12.0%) and lastly four-headed (3.0%) type. Moreover, an abnormal insertion of CBM was observed in four left limbs (4.0%); one inserting into the medial humeral epicondyle, the second into the upper third of humeral shaft, the third one in the common tendon of biceps, and the fourth one showing a bifurcated insertion. Also, four different innervation patterns of CBM were identified including MCN (80.0%), lateral cord (14.0%), lateral root of median nerve (4.0%), and median nerve itself (2.0%). The course of MCN was superficial to the single belly CBM (19.0%) and in-between the heads in the other types (71.0%). Measurements of the length and original distance of CBM muscular branches originating from MCN revealed no sex or side significant difference. Awareness of the anatomic variations, innervation patterns, and MCN relation of CBM is imperative in recent diagnostic and surgical procedures to obtain definite diagnosis, effective management and good outcome.

Keywords

Acknowledgement

The research was done at Department of Clinical Anatomy, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia.

References

  1. Johnson D, Collins P. Pectoral girdle and upper limb. In: Standring S, editor. Gray's Anatomy: The Anatomical Basis of Clinical Practice. 41st ed. Elsevier; 2016. p.783-7. 
  2. El-Naggar MM, Al-Saggaf S. Variant of the coracobrachialis muscle with a tunnel for the median nerve and brachial artery. Clin Anat 2004;17:139-43. 
  3. Georgiev GP, Landzhov B, Tubbs RS. A novel type of coracobrachialis muscle variation and a proposed new classification. Cureus 2017;9:e1466. 
  4. Georgiev GP, Tubbs RS, Landzhov B. Coracobrachialis longus muscle: humeroepitrochlearis. Cureus 2018;10:e2615. 
  5. Szewczyk B, Polguj M, Paulsen F, Podgorski M, Duparc F, Karauda P, Olewnik L. A proposal for a new classification of coracobrachialis muscle morphology. Surg Radiol Anat 2021;43:679-88. 
  6. el-Naggar MM. A study on the morphology of the coracobrachialis muscle and its relationship with the musculocutaneous nerve. Folia Morphol (Warsz) 2001;60:217-24. 
  7. Olewnik L, Zielinska N, Karauda P, Duparc F, Georgiev GP, Polguj M. The co-occurrence of a four-headed coracobrachialis muscle, split coracoid process and tunnel for the median and musculocutaneous nerves: the potential clinical relevance of a very rare variation. Surg Radiol Anat 2021;43:661-9. 
  8. Loukas M, Aqueelah H. Musculocutaneous and median nerve connections within, proximal and distal to the coracobrachialis muscle. Folia Morphol (Warsz) 2005;64:101-8. 
  9. Piagkou M, Tsakotos G, Triantafyllou G, Koutserimpas C, Chytas D, Karampelias V, Pantekidis I, Triantafyllou A, Natsis K. Coracobrachialis muscle morphology and coexisted neural variants: a cadaveric case series. Surg Radiol Anat 2023;45:1117-24. 
  10. Ilayperuma I, Nanayakkara BG, Hasan R, Uluwitiya SM, Palahepitiya KN. Coracobrachialis muscle: morphology, morphometry and gender differences. Surg Radiol Anat 2016;38:335-40. 
  11. Zielinska N, Duparc F, Polguj M, Borowski A, Olewnik L. A proposal for a new classification of the Coracobrachialis longus: a rare case or a new, distinct muscle? Ann Anat 2022;239:151825. 
  12. Zielinska N, Olewnik L. Six-headed coracobrachialis muscle. Folia Morphol (Warsz) 2022;81:809-13. 
  13. Filippou D, Piagkou M, Natsis K, Chytas D, Kostare G, Triantafyllou G, Kostares E, Koutserimpas C, Totlis T, Salmas M, Karampelias V, Tsakotos G. A rare bilateral variant of the coracobrachialis muscle with supernumerary heads and coexisted variant branching patterns of the brachial plexus and the axillary artery. Surg Radiol Anat 2023;45:277-82. 
  14. Larrotta DRB, Porras PLF, Acuna LEB. Anatomic variations in relation to the origin of the musculocutaneous nerve: absence and non-perforation of the coracobrachialis muscle. Anatomical study and clinical significance. Int J Morphol 2018;36:425-9. 
  15. Benes M, Kachlik D. Atypical branching of the musculocutaneous and median nerves with associated unusual innervation of muscles in the anterior compartment of the arm: case report and plea for extension of the current classification system. Surg Radiol Anat 2021;43:671-8. 
  16. Guerri-Guttenberg RA, Ingolotti M. Classifying musculocutaneous nerve variations. Clin Anat 2009;22:671-83. 
  17. Remerand F, Laulan J, Couvret C, Palud M, Baud A, Velut S, Laffon M, Fusciardi J. Is the musculocutaneous nerve really in the coracobrachialis muscle when performing an axillary block? An ultrasound study. Anesth Analg 2010;110:1729-34. 
  18. Tsakotos G, Triantafyllou G, Olewnik L, Georgiev GP, Koutserimpas C, Karampelias V, Zielinska N, Piagkou M. A bilateral symmetric accessory coracobrachialis muscle combined with an interconnection of the musculocutaneous nerve with the median nerve. Cureus 2023;15:e43496. 
  19. Saltzman BM, Harris JD, Forsythe B. Proximal coracobrachialis tendon rupture, subscapularis tendon rupture, and medial dislocation of the long head of the biceps tendon in an adult after traumatic anterior shoulder dislocation. Int J Shoulder Surg 2015;9:52-5.