BICEPS BRACHII MUSCLE: AN ANATOMICAL AND MORPHOLOGICAL STUDY
Ashraf H. Abd El-Hakeem*, M.A. Sayed Ahmed** and M.L. Al-Otaibi***
Departments of Anatomy, Faculties of Medicine, Assiut* and Zagazig** Universities Department of Orthopedic Surgery***, Faculty of Medicine, King Khalid University, Abha, Saudi Arabia
Introduction and aim of the work: The biceps brachii is the most powerful muscle of the anterior brachial region. This study provides the evaluation of biceps muscle volume, the size of the tendon of long head of biceps and its attachment, and the incidence and form of third head of the biceps brachii muscle. In addition, it describes the biceps tendon insertion and defines the external osteology features of the bicipital groove and bicipital tuberosity. Material and methods: Both upper extremities of 38 formalin fixed cadavers, 90 dry humeral bones and 100 radii were examined. Results: 40% to 65% of the fibers of the long head of biceps tendon (LHBT) arose from the superior glenoid labrum and the remaining fibers were attached to the supraglenoid tubercle. Postero-inferior fibers of the long head arises from the glenoid labrum more often postero-superior, while, the antero-superior fibers arises from the supraglenoid tubercle. Average volume of biceps brachii muscle is 139.2 cm3. Length of the muscle is 29.1 cm and the length of the LHBT is 10.8 cm. The cross-sectional area of the tendon and its shape change along its course. Three heads of biceps were observed bilaterally in male cadaver (2.6 %). The third head arises from the tendon of long head of biceps brachii at the level of bicipital groove as a unique case not reported before. The length of the bicipital groove is 7.7 cm.The width of the bicipital groove at its midpoint is 8.5 mm. The mean value found for the angle is 117°. The insertion site of biceps is typically a thin, semilunar area along the extreme ulnar margin of the bicipital tuberosity. The average length and width of the biceps insertion is 21.1 mm and 5.2 mm respectively. The majority of radii examined has a single ridge, which is either of the small, medium or large type. The smooth morphology was 7%. A bifid ridge was seen in 8 % of specimens. Conclusion: A clear understanding of these anatomic relationships is vital for planning of the biceps surgery.