The tongue is a muscular organ that sits on the floor of the oropharynx. It is enveloped by mucosa and contains glands, sensory organs, and 4 pairs of extrinsic muscles. The tongue is essential for several important functions, including jaw articulation, taste, manipulation of food, swallowing, and the production of speech. See image below.
From anterior to posterior, the tongue has 3 surfaces: tip, body, and base. The tip is the highly mobile, pointed anterior portion of the tongue. Posterior to the tip lies the body of the tongue, which has dorsal (superior) and ventral (inferior) surfaces. For more information about the relevant anatomy, see Tongue Anatomy.
Injuries to the tongue, are often treated in the emergency department or other acute care settings. A tongue laceration is often the result of a fall, seizure, or other blunt force mechanism.  Piercings, intoxication, and iatrogenic cause are also commonly associated with tongue injury. [2, 3, 4] Lacerations secondary to seizures are most often found to the side of the tongue.  Because of the tongue’s generous blood supply, most tongue lacerations do not become infected and many heal well without repair. However, repair is required when the injury has certain characteristics (see Indications).
The goals of laceration repair of the tongue are to attain adequate closure, minimize complications, preserve mobility, and optimize articulation and deglutition.
While uncommon, practitioners should keep in mind that such injuries can be the result of physical abuse, especially in children. 
Wounds larger than 1 cm
Avulsion or amputation injuries (The tongue may be primarily closed if the defect is less than 30% of the tongue.)
Most tongue lacerations do not require sutures. Small flaps may be simply excised. Tongue lacerations in children are known to heal well without intervention.  Simple linear lacerations, especially if centrally located, heal with minimal risk of infection. Mouth protectors and tooth guards are also noninvasive modalities to assist tongue healing. 
A case report has demostrated the efficacy of using 2-octyl cyanoacrylate (Dermabond) for a pediatric tongue laceration. 
Any of the following anesthesia techniques may be used:
Topical anesthesia with lidocaine 4% on gauze for 5 minutes (See Anesthesia, Topical for more information.)
Local infiltration with lidocaine 1% (See Local Anesthetic Agents, Infiltrative Administration for more information.)
Lingual nerve block for the anterior two thirds of the tongue
The pain associated with local anesthesia injections can be diminished if the practitioner uses a smaller gauge needle and administers the anesthetic slowly. 
Personal protective equipment is as follows:
Anesthesia equipment is as follows:
Syringe, 10 mL
Needle, 27 gauge (ga)
Needle, 18 ga
Irrigation equipment is as follows:
Saline or water
Syringe or irrigation device
Suture material is as follows:
Absorbable sutures (eg, plain gut, chromic gut), 4-0
Other equipment is as follows:
Side mouth gag (eg, Denhardt, Dingman)
Gauze, 4 X 4 in
The supine position is preferable for most repairs. The patient may sit in an ENT chair, if available.
Once the patient is anesthetized, inspect the wound carefully. Some through-and-through lacerations may not be obvious without gentle probing.
Always check for chipped, missing, or mobile teeth in mouth injuries. Tooth fragments may be lodged inside the wound and, if not removed, may serve as a nidus for infection.
Intraoral wounds are prone to considerable contamination, and thorough irrigation is necessary.
The major difficulty in closing a tongue laceration is maintaining control of the area being sutured. To stabilize and hold in protrusion for repair, the tip of the tongue can be grasped with gauze or a towel clip or punctured and withdrawn with a large suture.
A bite block may be used to protect both the patient and physician, as necessary.
Through-and-through lacerations may be closed in 1-3 layers.
As long as the muscular layer is closed, bleeding is sufficiently controlled, motor function is returned, and the mucosal layers heal rapidly. See the images below.
The frequent movements of the tongue often untie the sutures. This can be avoided by burying the stitches or tying many knots. Avoid nylon in the mouth and tongue.
Using 4-0 absorbable sutures, first close the muscular mucosa.
The inferior mucosa is then sutured.
The repair is then extended up and around the lateral aspect of the tongue to close the superior mucosa. See images below.
Use one stitch to approximate half the thickness of the tongue superiorly.
Use another stitch to approximate half the thickness inferiorly.
Close the edges of the tongue.
Sutures do not have to be buried. See image below.
Some suggest using a deep absorbable suture to close only the muscular layer, leaving the other layers open to heal without sutures.
This technique is successful because of the rapidly healing superficial mucosa. See image below.
After repair, the patient should eat a soft diet for 2-3 days.
Daily dilute peroxide mouth rinses should be used.
Healing occurs very rapidly.
Update the patient's tetanus vaccination, if necessary.
The use of prophylactic antibiotics for tongue injury is controversial, but they should be used in any contaminated wound.  Ultimately, as one current review of the literature concluded, "treatment decisions must be guided by clinical and scientific rationale rather than evidence-based medicine."  For more information, see Medscape article Human Bite Infections.
Complications can include the following: