Which nerve is involved in this deformity:

Ans. B. Long thoracic nerveThe deformity shown is Winging of scapula due to Paralysis of serratus anterior.The paralysis of serratus anterior muscle following an injury to long thoracic nerve by stab injury or during removal of the breast tumor leads to the following effects:(a) Protraction of scapula is weakened.(b) Inferior angle and medial border of scapula become unduly prominent particularly when patient pushes his hands against the wall, producing a clinical condition called winging of the scapula.