This chapter examines those aspects of the aetiology and classification of wounds that relate specifically to the external surface and its associated structures. Since wounds have a wide variety of aetiologies and their patterns of tissue trauma vary considerably, it follows that the clinician’s ability to appreciate the cause, likely progression, options for treatment and possible complications are of paramount importance. The following topics are covered: Wound classification; Wound complications and assessment; Incisional injuries and lacerations; Abrasions; Degloving and avulsion wounds; Shearing injuries; Puncture wounds; Burns; Pressure sores; and Cast- and bandage-related wounds.