A Study of the Accessory Muscles in the Flexor Compartment of the Forearm 564-567
G-1, Staff Quarters, Chennai Medical College Hospital &
Research Centre, Irungalur, Trichy, India -621105.
Aim: To ascertain the prevalence of the accessory muscles in the flexor (anterior) compartment of the forearm. A wide array of the supernumerary muscles has been described in the anatomical, surgical and radiological literatures. In a vast majority of the cases, the accessory muscles are asymptomatic and they represent incidental findings at surgery or imaging. Hence, this study was taken up to access the occurrence of the accessory muscles in the flexor compartment of the forearm.
Materials and Methods: This descriptive study was conducted in the Department of Anatomy, Chennai Medical College Hospital and Research Centre, Trichy and in the Sri Ramachandra University, Chennai, India. This study was conducted from 2006 to 2012 for a period of seven years in the Department of Anatomy. During the routine cadaveric dissection for undergraduate teaching in one hundred cadavers for a period of seven years, we studied the presence of abnormal variations in the muscular pattern of the anterior compartment of the forearm. All the upper limbs were dis-articulated and were tagged for their respective sexes and numbers. Among the 100 cadavers, 90 belonged to the male sex, whereas 10 belonged to the female sex. In a total of 200 upper limbs: 100 limbs to the right side and 100 limbs to the left side. Upper limbs which exhibited fractures both pre mortem as well post mortem, those with an obscuring pathology, previous surgical scars, and congenital deformities and partially amputated limbs were excluded from our study.
Methods: During the routine undergraduate dissection, we studied the muscular pattern in all the upper limbs. After making an incision in the skin, the superficial fascia and the deep fascia were reflected, thus exposing the flexor muscle compartment. A thorough investigation was carried out to verify all the two layers of muscles, both the superficial layer and the deep layer. The investigation included the questions (a) whether the muscles for that compartment were present or not (absence), and if present its both proximal and distal attachments, (b) if there is any acessory muscles present, its attachments. Results: In our study, we found that only in two different limbs, unilaterally, there was a presence of (a) an Additional Head of the Flexor Pollicis Longus (AHFPL-Gantzerâ€™s muscle) and in a another limb (b) an Accessory Palmaris Longus was found and both belonged to the male sex.
Conclusion: Only 2% of the limbs in our study exhibited an abnormal pattern of the muscles. This study will supplement our knowledge on the possible variations of the muscles in this region, which would be useful for hand surgeons, orthopaedic surgeons, general surgeons, physicians and plastic surgeons, as it would probably compress the neuro- vascular bundle because of its close relationship, leading to both vascular and neural symptoms.