True about serratus anterior ?
Serratus anterior causes protraction of scapula.It is supplied by long thoracic nerve (Nerve of Bell).It forms medial boundary of axilla.Serratus anteriorOrigin : Outer surface of upper 8 ribs by 8 digitations (multipennate muscles).Inseion : Medial border of scapula and inferior angle.Nerve supply : Long thoracic nerve (nerve of bell).Actions : Action of serratus anterior are -Rotates the scapula so that glenoid cavity is raised upward & forward - Helps in Veical over head abduction (in this action assisted by trapezius).Draws the scapula forward around the throcic wall so paralysis leads to winging of scapula.degAlso used when arm is pushed forward in horizontal position as in forward punch (helped by Pectoralis minor in this action)e.Steadies the scapula during weight carrying.Helps in forced inspiration.2 (Accessory muscle of inspiration).Because of greater pull exeed on the inferior angle, inferior angle passes laterally and forward and the glenoid cavity is raised upward & forward; in this action the muscle is assisted by trapezius.
Causes protraction
Causes lateral rotation
Supplied by thoracodorsal nerve
Forms lateral boundary of axilla