Lacerations continue to be a leading cause of emergency department visits. Minor wound management should reduce the likelihood of infection and be performed to achieve minimal scarring . It is especially critical that lip lacerations are repaired correctly to preserve the cosmetic appearance and functionality of the lip. When interacting with people, our vision is immediately directed towards the eyes and lips highlighting the aesthetic importance of lip structure. The lip also serves a critical role in speech articulation, food ingestion, and tactile sensation. Most lacerations can be repaired by the emergency clinician; however, there are rare circumstances where specialist referral may be necessary.
When evaluating trauma to the face and lip care should be taken to evaluate the patient for other traumatic injuries and the clinician should follow Advanced Trauma Life Support (ATLS) protocol. The patient should undergo primary assessment of airway, breathing, circulation, disability and neurologic function prior to secondary survey for additional injuries.
The lip is a unique structure in the body and in cross section is composed of three layers: the mucosal layer (within the oral cavity), the middle muscular layer (orbicularis oris muscle), and the outer mucosal layer consisting of the wet vermillion (internal oral) and the dry vermillion (external oral) or the “red lip” (figure 1). The cosmetic outline of the lip where the facial skin meets the vermillion is referred to as the vermillion border. Aesthetically the vermillion border is crucial as light reflects at this juncture and misalignment by 1 mm will cause a noticeable scar.
The blood supply to the lip arises from the superior and inferior labial arteries which are branches of the facial artery (figure 2).
The lip is innervated by the infraorbital and inferior alveolar nerves which arise from the trigeminal nerve (cranial nerve V) (figure 3).