ABSTRACT
Background: During surgery of the shoulder region the identification of musculocutaneous nerve (MCN) and its variation is important because it is vulnerable to injury from surgical instruments. The MCN is formed as the continuation of lateral cord of brachial plexus. The MCN travels obliquely below the coracoid process and enters the coracobrachialis (CB) muscle. The MCN supplies the muscles of front of arm, namely the CB, the Biceps brachii and Brachialis muscles. Methods: The Morphological study included 25 cadavers aged between 21 to 70 years. Both the right and the left upper limbs of each cadaver, 50 limbs were studied and documented. The MCN showed variations in their course, branching pattern and communication with MN (median nerve). Results: The lateral cord gives a direct branch to CB, then pierces the muscle in 2 cases (8%) unilaterally. MCN does not pierce the CB but communicates with median nerve in 3 cases (12%) unilaterally, whereas communication between MCN and MN seen in 5 cases (20%). Conclusion: The Knowledge of Variation in origin, course, branching pattern, termination and communication of MCN in the arm have the significance in shoulder injuries and reconstructive surgeries.
ABSTRACT
Introduction: The superior transverse scapular ligament (STSL) is present above the suprascapular notch . It joins the two superior corners of this notch and converts it into suprascapular foramen through which passes the suprascapular nerve , while the suprascapular artery and vein usually pass above the ligament . The anterior coracoscapular ligament (ACSL) runs in the suprascapular notch, below the superior transverse scapular ligament. Narrowed bony foramen by ossification of STSL and ACSL is one of the predisposing factor of suprascapular nerve entrapment as well as with an injury to the suprascapular nerve in arthroscopic procedures. Aim: The aim of present study was to know the prevalence of suprascapular foramen in Indian dry scapulae and provide a knowledge on the variations along the course of suprascapular nerve which is essential to understanding the source of entrapment syndrome. Methods and Results: The present study was carried out on 73 dried human scapulae irrespective of age and sex. Visual observation revealed that 3 scapulae (4.1%) had completely ossified superior transverse scapular ligament and 2 scapulae (2.7 %) had partially ossified STSL. The incidence of ossified anterior coracoscapular ligament is 1.3 % ( 1 scapula ) in our study. Conclusion: The knowledge of variations in the suprascapular region and ossification of STSL & ACSL is important for anatomists, orthopaedicians, radiologists and neurosurgeons to obtain a safe zone which would be useful to avoid iatrogenic nerve lesion and for better diagnosis and management of the nerve entrapment syndrome.