Hydrocele is a collection of serous fluid in the tunica vaginalis of the scrotum. The document discusses the surgical anatomy of the scrotum, defines hydrocele and discusses its classification and causes. It also covers the clinical examination for hydrocele including inspection, palpation and transillumination of the scrotum. Common investigations like ultrasound and treatments like eversion of the sac are mentioned. Complications of hydrocele surgery are also listed.