A Variation of Flexor Carpi Ulnaris Muscle: A Case Report.
Flexor carpi ulnaris muscle (FCUM) is an important muscle in the forearm belonging to the anterior flexor compartment, and it provides strength to wrist flexion and ulnar adduction. Besides, it is used for flap surgery (1).
The prevalence of anomalies related to FCUM is rare. No anomalies of the FCUM were found among 5000 cadaver specimens which were surveyed (1). However, a number of reported FCUM anomalies have been established via ultrasound, during surgery, or cadaver dissection (2, 3). Therefore, the knowledge of possible major anomalies which may give rise to misidentification of anatomical structures during surgical procedures on the forearm and wrist is of crucial importance (4).
A variation of FCUM on the left forearm of an adult male cadaver was observed during anatomical dissection. The cadaver belonging to the Anatomy Laboratory of Dokuz Eylul University, School of Medicine was fixed with %10 formalin solution.
The anomalous FCUM was arising with the common tendon from the medial epicondyle; however, the belly of the muscle was split into two parts proximally at the forearm, and extended with two tendons through the distal forearm (Figure 1). The fibers of these tendons were attached to the pisiform, the hamate and proximal of the fifth metacarpal bone anterior to flexor retinaculum (Fig. 2). Ulnar nerve and artery were located lateral to the tendon of the variant muscle (Figure 2). We did not observe any other variations on the left upper extremity of the cadaver. This case was examined morphologically, and photographed.
The flexor carpi ulnaris muscle (FCUM), positioned most medially in the forearm, belongs to the superficial flexor group of muscles (5). FCUM is a genuinely bipennate muscle and possesses an independent nerve and has its own vascular supply (6). Its humeral head is small, and originates from the medial epicondyle; the origin of the ulnar head is extensive, and it attaches to the medial margin of the olecranon and proximal two-thirds of the posterior border of the ulna. At its anterolateral border, in its distal half, it forms a thick tendon which is attached to the pisiform, and extends to the hamate and fifth metacarpal (5).
Soft tissue defects of the posterior elbow may develop secondary to trauma and wound dehiscence due to burns, chronic inflammation, and bursitis (7-9). The larger ulnar and smaller humeral heads comprising the FCUM are both able to affect independently with one being confined for wrist flexion and ulnar deviation strength while the other is for tendon transfer or soft tissue coverage of the region (10, 11).
The rare anatomic variations which exist emphasize the importance of appropriate preoperative planning, and the need for the consideration of alternative reconstructive options (12).
These anomalies may be clinically asymptomatic, and may be detected incidentally during anatomical dissections or surgical treatment of lacerations (13). They may rarely be accompanied with pain, mass in forearm, or with symptoms of ulnar nerve compression (2). Bhardwaj et al. (13) propose a system for the classification of FCUM variations based on reviews of literature, and they define three major groups of anomalies:
Type 1: Single muscle with two tendons (split tendon): the presence of a single muscle with two separate tendons.
Type 2: Each head forming separate muscle and tendon (Digastric FCU): the presence of two heads each forming a separate muscle and tendon.
Type 3: Extra muscle in addition to normal FCUM (accessory FCU): the presence of an extra muscle in alongside the normal FCUM
Ciftcioglu et al. (14) reported a FCUM that possessed only a humeral head; another muscle belly originating from medial epicondyle lying between flexor digitorum superficialis and FCUM and was attached to triquetral, hamate bones, and flexor retinaculum.
Sawant et al. (15) reported a FCUM which had separate humeral and ulnar heads, and combined tendons just before their insertion to pisiform. In both of these studies the muscular anomalies observed were classified as type 2 described by Bhardwaj et al. (13).
We observed the anomalous FCUM which has a separate muscle belly extending from the proximal part of the forearm, and form a separate tendon inserting to the to the pisiform, the hamate and proximal of the fifth metacarpal bone. We interpreted it as type 2 (Fig. 1 and 2) according to classification described by Bhardwaj et al. (13).
The detection of FCUM variations is significantly important not only in the treatment of pressure related symptoms which they cause but also in reconstructive and orthopedic surgery.
Informed Consent: Written informed consent was obtained from patient who participated in this case
Peer-review: Externally peer-reviewed.
Author Contributions: Concept - MG; Design - MG; Supervision - MG, GNY; Literature Search - GNY, SC, SS, CE; Writing - GNY, SC; Critical Reviews - GNY, MG; Cadaver Dissection - GNY, SC, SS, CE
Conflict of Interest: The authors declare that there are no conflicts of interest.
Financial Disclosure: This study has received no financial support
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Goksin Nilufer Yonguc (1), Sibel Cirpan (1), Salih Sayhan (1), Canan Eyuboglu (1), Mustafa Guvencer (1)
(1) Dokuz Eylul University School of Medicine, Department of Anatomy, Izmir, Turkey
Address for Correspondence: Mustafa Guvencer, E-mail: firstname.lastname@example.org
Received: 11.27.2017; Accepted: 12.18.2017; Available Online Date: 30.05.2018
Cite this article as: Yonguc GN, Cirpan S, Sayhan S, Eyuboglu C, Guvencer M. A Variation of Flexor Carpi Ulnaris Muscle: A Case Report. J Basic Clin Health Sci 2018; 2:57-59.
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|Title Annotation:||Case Report|
|Author:||Yonguc, Goksin Nilufer; Cirpan, Sibel; Sayhan, Salih; Eyuboglu, Canan; Guvencer, Mustafa|
|Publication:||Journal of Basic and Clinical Health Sciences|
|Date:||May 1, 2018|
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