Brachial Plexus: Variations in Infraclavicular Part and their Significance

ABSTRACT

Introduction: Brachial plexus extends from the neck to the axilla and gives motor and sensory nerves to the upper limb. Thebrachial plexus has two parts supraclavicular and infraclavicular parts.Material and Methods: The present study was carried out on 15 adult human cadavers (15 specimens of the right and leftside of the upper limb) in the Department of Anatomy, Government Medical College and Hospital, Chandigarh. All the cadaverswere male.Observations Of 30 cases, one specimen (3.34%) had variation in the arrangement of all cords (lateral, medial, and posterior)respective to the 3rd part of axillary artery, i.e., all three t cords lie lateral to 3rd part of axillary artery. In one case (3.34%), it wasobserved that lateral cord gave separate branch to coracobrachialis muscle. Musculocutaneous nerve passes straight downwardplaced between biceps brachii and brachialis. Musculocutaneous nerve continues as lateral cutaneous nerve of forearm. Inanother two cases (6.66%), there is communication between musculocutaneous and median nerve. Five cases (16.66%) hadvariations in the formation of median nerve. Here, median nerve was formed from three roots of two roots were originating fromlateral cord and one root from medial cord. In three cases (10%), there is higher origin of median nerve by joining of its tworoots. In one case (3.34%), there are two upper subscapularis nerves from the posterior cord. Other branches of this cord arelower subscapular, nerve to latissimus dorsi, radial, and axillary nerve which is normal in their positions.Discussion: Development of brachial plexus starts at 34th–35th day of intrauterine life and definitive adult pattern is visible by46th–48th day of intrauterine life. The growing axons are regulated by chemoattractants and chemorepulsants in a site-specificfashion. Changes in the signaling pattern between mesenchymal cells and neuronal growth cones can lead to variations.Conclusion: These variations are important for surgeons, neurosurgeons, and plastic surgeons in their respective field inknowing area of loss, loss of muscle power as well as in designing various surgeries.