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A Morphometric Analysis of Fibularis Tertius Muscle in Eastern Indian Population |
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Gyanaranjan Nayak 1. Assistant Professor, Department of Anatomy, I M S and SUM Hospital, SOA University, Bhubaneswar, Odisha, India. |
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Correspondence Address : Dr. Gyanaranjan Nayak, Flat No-111, Manorama Metro Complex, Malasahi, Mangalabag, Cuttack-753001, Odisha, India. E-mail: drgrn82@gmail.com |
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| ABSTRACT |  | ||||||||||||||||||||||||||||||||||||||||
: Morphometry of body and neural arch of lumbar vertebrae is very crucial in manufacturing screws, interspinous implants as well as preoperative planning of surgeries involving dorsolumbar spine. Aim: To determine various dimensions of typical and atypical lumbar vertebrae. Materials and Methods: A descriptive osteological study was carried out which included 66 intact adult dry human lumbar vertebrae (53 typical and 13 atypical) which were free of any deformity or pathological features. All the 53 typical vertebrae were randomly obtained. The following parameters were measured with slide callipers- superior transverse diameter and superior antero-posterior diameters of vertebral foramen; transverse diameter, antero-posterior diameter and anterior height of vertebral body; width, height of pedicles; interpedicular distance; maximum thickness of lamina; length of transverse process; maximum length, maximum height and maximum central thickness of spinous process. The data was tabulated and analysed using Microsoft Excel software. Mean and standard deviation was calculated for each parameter. Unpaired t-test was applied and p-value was derived for parameters like width and height of pedicles, thickness of lamina and length of transverse process. The p-value<0.05 were considered as significant. Results: The vertebral foramen (superior transverse diameter- 20.41±2.54 mm, superior antero-posterior diameter- 13.3±2.04 mm); vertebral body (transverse diameter- 44.43±5.91 mm, antero-posterior diameter- 30.17±3.19 mm, anterior height- 24.01±1.84 mm); pedicle (width- 10.85±3.94 mm on left side and 11.04±4.01 mm on right side, height- 13.84±4.01 mm on left side and 13.8±1.93 mm on right side, interpedicular distance- 29.17±5.06 mm); lamina (thickness- 6.6±1.36 mm on left side and 6.85±1.34 mm on right side); transverse process (length- 20.94±4.01 mm on left side and 21.51±4.5 mm on right side); spinous process (maximum length- 26.01±3.73 mm, maximum height- 19.92±4.03 mm, maximum central thickness- 6.42±1.41 mm). The mean transverse diameter and antero-posterior diameter of vertebral foramen of atypical lumbar vertebrae were higher than those of the typical lumbar vertebrae and these differences were significant (p-value of 0.0001 for transverse diameter and p-value of 0.005 for antero-posterior diameter). Conclusion: Most of the parameters of atypical lumbar vertebrae were found to be more compared to those of typical lumbar vertebrae. This inference should be kept in mind during fixation of lumbar inter-spinous implants, designing of pedicular screws and spinal grafting. | |||||||||||||||||||||||||||||||||||||||||
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| Keywords : Lower limb, Myocutaneous flap, Tendoplasty, Variations | |||||||||||||||||||||||||||||||||||||||||
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| INTRODUCTION |
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Fibularis tertius is a muscle of the anterior compartment of leg. It is absent in hominid apes and found exclusively in humans (1). The fibularis tertius is considered as the fifth tendon of extensor digitorum longus. It arises from the medial surface of fibula, interosseous membrane of leg and and anterior crural intermuscular septum. The insertion of the muscle is usually onto the base of the fifth metatarsal (2),(3). The muscle acts as a dorsiflexor and evertor of the foot. The everting action of the muscle along with fibularis longus and brevis elevates the foot and helps the toes to clear the ground thus improving the economy of bipedal mode of locomotion (2),(4),(5). The muscle can sense sudden inversion and contracts reflexly to prevent damage to the anterior tibio-fibular ligament which usually gets sprained in ankle injuries (6). Appearance of fibularis tertius is related to the development of extensor digitorum longus. The fibularis tertius gets progressively separated from extensor digitorum longus until it is inserted laterally onto the fifth metatarsal (7). Alternatively, it is described as the migrated part of extensor digitorum brevis of little toe [8,9]. Some researchers also opine that the muscle represents extensor digiti minimi with displaced insertion to the base of the fifth metatarsal (1). Presence of fibularis tertius in human beings and its absence in non human primates hints towards the evolution of the muscle and establishes its role in terrestrial bipedalism. Thus, the muscle is very important from an evolutionary point of view. Literature describes various variations of fibularis tertius muscle. These are as follows-the muscle may be absent (in about 18% cases), duplicated or it may give additional slip to the fascia of fourth interosseous muscle of foot or extensor aponeurosis of little toe (3),(4),(9). Variable insertion of fibularis tertius muscle may be responsible for causation of fractures such as Jone’s fracture (10). Fibularis tertius is useful in plastic and orthopaedic surgeries. It is used for performing tendoplasty, tendon transfer and resection surgeries of the foot. Flap from the muscle and its tendon are used for transposition, correcting any laxity in the ankle joint and transplantation surgeries on foot (11). As the fibularis tertius muscle is highly significant from evolutionary and surgical points of view, the present study was conducted to find the measurements and variations of the muscle. | |||||||||||||||||||||||||||||||||||||||||
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| TABLES AND FIGURES |
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Original article / research
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