<s>[INST] context: Origin-Lateral surfaces of upper 8 to 9 ribs and deep fascia overlying the related intercostal spaces Inseion-Costal surface of medial border of scapula Innervation-long thoracic nerve (C5,6,7) Function-protraction and rotation of scapula, keeps medial border and inferior angle of scapula opposed to thoracic wall Winging of scapula: -As long thoracic nerve passes down the lateral thoracic wall on external surface of serratus anterior muscle just deep to skin & subcutaneous tissue, it is vulnerable to damage. -Loss of function of this muscle cause medial border, paicularly inferior angle of scapula, to elevate away from thoracic wall | (Resulting in) "winging" of scapula (on pushing forward with arm) - Normal elevation of arm a no longer possible. Trapezius: supplied by motor spinal pa of accessory nerve (X1); sensory (proprioception) anterior rami of C3 & C4 Function: powerful elevator of scapula, rotates scapula during abduction of humerus above Horizontal. Middle fibers = retract scapula Lower fibers = depress scapula Latissimus dorsi: supplied by thoraco- dorsal nerve (C6, C7, C8) Function: adduction, medial rotation & extension of arm at glenohumeral joint. Pectoralis major: innervated by medial & lateral pectoral nerves. [/INST] question: Winging of scapula is due to paralysis of (FMGE Dec 2018) | options: A: Trapezius B: Serratus anterior C: Latissimus dorsi D: Pectroralis major | answer: B </s>