Surg Radiol Anat (2017) 39:843–848
Topographical relations between the Gantzer’s muscle
and neurovascular structures
· Soo‑Jung Jung
· Hyunsu Lee
· In‑Jang Choi
· Jae‑Ho Lee
Received: 14 July 2016 / Accepted: 19 December 2016 / Published online: 13 March 2017
© Springer-Verlag France 2017
Keywords Gantzer’s muscle · Flexor pollicis longus ·
Flexor digitorum profundus
Among the anatomical variations of the muscles of the
forearm, Gantzer’s muscle (GM) is an additional muscle
in the forearm as the accessory head of the ﬂexor pollicis
longus (FPL) and accessory head of ﬂexor digitorum pro-
fundus (FDP). Its prevalence and morphological variations
have been described in the previous studies [7, 13, 15, 16,
20]. Although the prevalence of the accessory head of FPL
(aFPL) and FDP (aFDP) varies in these studies, it is con-
sistently reported in 50% of the Asian population [13, 15].
The various origins of the GM have been described in pre-
vious studies: the medial humeral epicondyle, the coronoid
process or dual origin from the medial epicondyle and the
coronoid process [1, 13, 15]. The insertions of the aFPL
and aFDP have been consistently reported in the ulnar bor-
der of the FPL and in the tendon of the FDP at the wrist
level, respectively [1, 16, 19].
The anterior interosseous nerve (AIN) is a branch of the
median nerve (MN) and it innervates the FPL, FDP, prona-
tor quadratus, and the GM. Although a variable topologi-
cal relationship has been reported between the AIN and the
aFPL, the more frequent course of the AIN is posterior to
the aFPL [13, 15, 20]. Owing to its anatomical position, the
aFPL has been assumed as one of the causes of AIN com-
pression, the so-called “AIN syndrome” [8, 21, 22].
Considering the inﬂuence of the anatomical variation on
the nerve branching in a previous study , it has been
postulated that the GM may also aﬀect the branching point
of the AIN from the MN. However, the inﬂuence of the
GM on the adjacent anatomical structures remains obscure.
Purpose Gantzer’s muscle (GM) is an additional muscle
in the forearm, which develops as an accessory head of the
ﬂexor pollicis longus or the ﬂexor digitorum profundus.
The study aimed to determine the topography of the GM
and to deﬁne the topographical relationship between the
GM and the neurovascular structures surrounding it.
Methods After conﬁrming the presence of GM, its topog-
raphy and the neurovascular structures were analyzed to
determine the correlation between them in 73 upper limbs.
Results The incidence of GM was 47.95% (35/73)
and the average insertion point of GM was identiﬁed at
49.33 ± 7.47‰ (119.82 ± 20.80 mm) on the reference line
between the medial epicondyle and the pisiform bone. And
the branching points of the median nerve and the ulnar
artery were located 19.91 ± 11.23‰ (52.21 ± 24.67 mm),
17.45 ± 8.39‰ (42.53 ± 20.54 mm) on the reference line,
respectively. The presence of GM had no signiﬁcant cor-
relation with the position of the nerve branches. On the
other hand, the branching point of the ulnar artery was
distally located in the cases with the presence of the GM
(17.35 ± 8.65 vs 19.42 ± 10.87, p = 0.031). There was a sig-
niﬁcant positive correlation between the point of arterial
bifurcation and the length of the GM (r = 0.407, p = 0.015).
Conclusions This study suggested that the GM has a top-
ographical relation with the arterial structures, perhaps for
K. Yang and S.-J. Jung contributed equally to this work.
* Jae-Ho Lee
Department of Anatomy, School of Medicine, Keimyung
University, 2800, Dalgubeoldaero, Dalseo-Gu, Daegu,
Republic of Korea