open access

Vol 78, No 2 (2019)
ORIGINAL ARTICLES
Published online: 2018-10-03
Submitted: 2018-05-06
Accepted: 2018-06-24
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Accessory head of the flexor pollicis longus muscle: anatomical study and clinical significance

D.R. Ballesteros, P.L. Forero, L.E. Ballesteros
DOI: 10.5603/FM.a2018.0091
·
Pubmed: 30299534
·
Folia Morphol 2019;78(2):394-400.

open access

Vol 78, No 2 (2019)
ORIGINAL ARTICLES
Published online: 2018-10-03
Submitted: 2018-05-06
Accepted: 2018-06-24

Abstract

Background: The accessory head of the flexor pollicis longus (AHFPL) has an oblique trajectory from medial to lateral aspect of the forearm below the flexor digitorum superficialis muscle and then joins the flexor pollicis longus muscle. When the anterior interosseous nerve (AIN) courses underneath the muscle belly of the AHFPL an entrapment neuropathy may occur, known as anterior interosseous nerve syndrome (AINS). 

Materials and methods: This descriptive cross-sectional study evaluated 106 fresh upper extremities. When the AHFPL was present, its fascicle was traced up to evaluate the origin site. The morphometric variables were measured using a digital micrometre (Mitutoyo, Japan). The relationship between the AHFLP and the AIN was evaluated. 

Results: The AHFPL was found in 34 (32.1%) of the 106 forearms. The AHFPL arose from the flexor digitorum superficialis muscle in 16 (47.1%) forearms, the medial epicondyle of the humerus in 10 (29.4%) forearms and the coronoid process of ulna in 8 (23.5%) forearms. The average total length of the AHFPL was 94.11 ± ± 10.33 mm. The AIN was located lateral to the AHFPL in 3 (8.8%) forearms, posterolateral in 7 (20.6%) forearms and posterior in 24 (70.6%) forearms.

Conclusions: This study performed in a South American population sample revealed a prevalence of the AHFPL in a lower range compared to previous studies in North Americans and Asians. The AIN coursed more frequently underneath the muscle belly of AHFPL. This finding has clinical significance in the onset of the AINS and the subsequent surgical procedure for the AIN decompression. 

Abstract

Background: The accessory head of the flexor pollicis longus (AHFPL) has an oblique trajectory from medial to lateral aspect of the forearm below the flexor digitorum superficialis muscle and then joins the flexor pollicis longus muscle. When the anterior interosseous nerve (AIN) courses underneath the muscle belly of the AHFPL an entrapment neuropathy may occur, known as anterior interosseous nerve syndrome (AINS). 

Materials and methods: This descriptive cross-sectional study evaluated 106 fresh upper extremities. When the AHFPL was present, its fascicle was traced up to evaluate the origin site. The morphometric variables were measured using a digital micrometre (Mitutoyo, Japan). The relationship between the AHFLP and the AIN was evaluated. 

Results: The AHFPL was found in 34 (32.1%) of the 106 forearms. The AHFPL arose from the flexor digitorum superficialis muscle in 16 (47.1%) forearms, the medial epicondyle of the humerus in 10 (29.4%) forearms and the coronoid process of ulna in 8 (23.5%) forearms. The average total length of the AHFPL was 94.11 ± ± 10.33 mm. The AIN was located lateral to the AHFPL in 3 (8.8%) forearms, posterolateral in 7 (20.6%) forearms and posterior in 24 (70.6%) forearms.

Conclusions: This study performed in a South American population sample revealed a prevalence of the AHFPL in a lower range compared to previous studies in North Americans and Asians. The AIN coursed more frequently underneath the muscle belly of AHFPL. This finding has clinical significance in the onset of the AINS and the subsequent surgical procedure for the AIN decompression. 

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Keywords

flexor pollicis longus; anterior interosseous nerve; nerve compression syndromes; anatomic variation; orthopaedic procedures

About this article
Title

Accessory head of the flexor pollicis longus muscle: anatomical study and clinical significance

Journal

Folia Morphologica

Issue

Vol 78, No 2 (2019)

Pages

394-400

Published online

2018-10-03

DOI

10.5603/FM.a2018.0091

Pubmed

30299534

Bibliographic record

Folia Morphol 2019;78(2):394-400.

Keywords

flexor pollicis longus
anterior interosseous nerve
nerve compression syndromes
anatomic variation
orthopaedic procedures

Authors

D.R. Ballesteros
P.L. Forero
L.E. Ballesteros

References (27)
  1. al-Qattan MM. Gantzer's muscle. An anatomical study of the accessory head of the flexor pollicis longus muscle. J Hand Surg Br. 1996; 21(2): 269–270.
  2. Azar FM, Canale ST, Beaty JH. Campbell’s Operative Orthopaedics. 13th ed. Philadelphia: Elsevier. 2016: 3213.
  3. Caetano EB, Sabongi JJ, Vieira LÂ, et al. Gantzer muscle. An anatomical study. Acta Ortop Bras. 2015; 23(2): 72–75.
  4. Cihák R. Ontogenesis of the skeleton and intrinsic muscles of the human hand and foot. Ergeb Anat Entwicklungsgesch. 1972; 46(1): 5–194.
  5. Degreef I, De Smet L. Anterior interosseous nerve paralysis due to Gantzer's muscle. Acta Orthop Belg. 2004; 70(5): 482–484.
  6. Dellon AL, Mackinnon SE. Musculoaponeurotic variations along the course of the median nerve in the proximal forearm. J Hand Surg Br. 1987; 12(3): 359–363.
  7. El Domiaty MA, Zoair MM, Sheta AA. The prevalence of accessory heads of the flexor pollicis longus and the flexor digitorum profundus muscles in Egyptians and their relations to median and anterior interosseous nerves. Folia Morphol. 2008; 67(1): 63–71.
  8. Gantzer KF. Dissertatio anatomica musculorum varietates sistens: quam consensu gratiosi medicorum ordinis. Berolini: Typis Joannis Friderici Starckii. 1813; 13: 14.
  9. Gunnal SA, Siddiqui AU, Daimi SR, et al. A Study on the Accessory Head of the Flexor Pollicis Longus Muscle (Gantzer’s Muscle). J Clin Diagnostic Res. 2013; 7(3): 418–421.
  10. Hemmady MV, Subramanya AV, Mehta IM. Occasional head of flexor pollicis longus muscle: a study of its morphology and clinical significance. J Postgrad Med. 1993; 39(1): 14–16.
  11. Jones M, Abrahams PH, Sañudo JR, et al. Incidence and morphology of accessory heads of flexor pollicis longus and flexor digitorum profundus (Gantzer's muscles). J Anat. 1997; 191 (Pt 3): 451–455.
  12. Kara A, Elvan O, Yildiz S, et al. Accessory head of flexor pollicis longus muscle in fetuses and adult cadavers and its relation to anterior interosseous nerve. Clin Anat. 2012; 25(5): 601–608.
  13. Mahakkanukrauh P, Surin P, Ongkana N, et al. Prevalence of accessory head of flexor pollicis longus muscle and its relation to anterior interosseous nerve in Thai population. Clin Anat. 2004; 17(8): 631–635.
  14. Mangini U. Flexor pollicis lungus muscle. Its morphology and clinical significance. J Bone Joint Surg Am. 1960; 42-A: 467–470.
  15. Nagano A. Spontaneous anterior interosseous nerve palsy. J Bone Joint Surg. British volume. 2003; 85-B(3): 313–318.
  16. Oh CS, Chung IH, Koh KS. Anatomical study of the accessory head of the flexor pollicis longus and the anterior interosseous nerve in Asians. Clin Anat. 2000; 13(6): 434–438.
  17. Pai MM, Nayak SR, Krishnamurthy A, et al. The accessory heads of flexor pollicis longus and flexor digitorum profundus: Incidence and morphology. Clin Anat. 2008; 21(3): 252–258.
  18. Park IJ, Roh YT, Jeong C, et al. Spontaneous anterior interosseous nerve syndrome: clinical analysis of eleven surgical cases. J Plast Surg Hand Surg. 2013; 47(6): 519–523.
  19. Roy J, Henry BM, Pękala PA, et al. The prevalence and anatomical characteristics of the accessory head of the flexor pollicis longus muscle: a meta-analysis. PeerJ. 2015; 3: e1255.
  20. Riveros A, Olave E, Sousa-Rodrigues C. Estudio Anatómico del Fascículo Accesorio del Músculo Flexor Largo del Pulgar y su Relación con el Nervio Interóseo Anterior en Individuos Brasileños. Int J Morphol. 2015; 33(1): 31–35.
  21. Sharma M, Chabbra U, Kaushal S, et al. Accessory Head of Flexor Pollicis Longus Muscle. J Exerc Sci Physiother. 2008; 4(1): 15–18.
  22. Shirali S, Hanson M, Branovacki G, et al. The flexor pollicis longus and its relation to the anterior and posterior interosseous nerves. J Hand Surg Br. 1998; 23(2): 170–172.
  23. Spinner M. The anterior interosseous-nerve syndrome, with special attention to its variations. J Bone Joint Surg Am. 1970; 52(1): 84–94.
  24. Standring S. Gray’s Anatomy: The Anatomical Basis of Clinical Practice. 41st ed. Elsevier; 2016: 837–861.
  25. Tabib W, Aboufarah F, Asselineau A. Compression du nerf interosseux antérieur par le muscle de Gantzer. Chirurgie de la Main. 2001; 20(3): 241–246.
  26. Ulrich D, Piatkowski A, Pallua N. Anterior interosseous nerve syndrome: retrospective analysis of 14 patients. Arch Orthop Trauma Surg. 2011; 131(11): 1561–1565.
  27. Uyaroglu FG, Kayalioglu G, Erturk M. Incidence and morphology of the accessory head of the flexor pollicis longus muscle (Gantzer`s muscle) in a Turkish population. Neurosciences (Riyadh). 2006; 11(3): 171–174.

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