A fractured mandible, commonly known as a broken jaw, is a serious orthopedic injury to the lower jawbone (mandible). Although the mandible is the largest and strongest bone in the face, significant trauma can cause it to break. Due to its U-shape, a single forceful blow often results in fractures occurring in two different places. A broken jaw is always considered a medical emergency because of its proximity to the airway and its vital role in breathing, speaking, and swallowing. Immediate medical attention is necessary to prevent complications like airway obstruction or severe blood loss.
Primary Sensations of the Injury
The initial sensation is typically intense, sharp pain localized to the area of impact, which quickly becomes a throbbing ache. This pain is exacerbated by any attempt to move the jaw, such as speaking, swallowing, or closing the mouth. Because jaw muscles continue to exert force, movement at the fracture site creates discomfort.
A specific sign of a break is malocclusion, the feeling that the teeth no longer fit together correctly when the mouth is closed. Even slight misalignment of the bone fragments causes the teeth to feel “off” or shifted from the normal bite. This feeling is often accompanied by grinding, clicking, or popping within the fracture site, a sensation known as crepitus.
Nerve damage can cause numbness or tingling in the lower lip and chin, known as paresthesia. This altered sensation results from trauma to the inferior alveolar nerve, which runs through the center of the mandibular bone. The nerve can be compressed or damaged by fractured bone fragments, leading to a loss of feeling in the areas it supplies. This numbness indicates a displaced fracture that has impacted the nerve pathway.
Visible Signs and Functional Limitations
The external presentation includes rapidly developing soft tissue swelling around the face, especially along the jawline, cheeks, and neck. Bruising (ecchymosis) often appears beneath the chin or on the outside of the jaw, caused by ruptured blood vessels. In severe cases, the jaw may appear visibly deformed or asymmetrical, sometimes shifting the chin toward the side of the injury.
Internally, a fracture communicating with the mouth can cause lacerations to the gums or inner cheek lining, leading to bleeding. Bleeding from the gums or around loosened teeth is common, especially if the break is near the dental arch. Bruising may also be visible under the tongue, indicating the trauma extended to the floor of the mouth.
Functional limitations are immediate and pronounced, often resulting in an inability to open the mouth fully, a condition called trismus. The jaw may feel “locked” or stiff, making movement nearly impossible without severe pain. Patients often experience difficulty swallowing (dysphagia) or speaking clearly, as both actions require coordinated jaw movement. Drooling may occur because the inability to fully close the mouth or swallow saliva compromises oral competence.
Essential Immediate Actions
If a broken jaw is suspected, the most important immediate action is to stabilize the head and neck and seek emergency medical services. The injured person must avoid moving their jaw to prevent further displacement of bone fragments or soft tissue damage. Any suspected head or spinal injury must be assumed until medical professionals assess the situation.
To provide temporary support, the jaw can be gently immobilized using a soft cloth, bandage, or tie wrapped under the jaw and tied over the head. The goal of this temporary support is to keep the jaw stable and limit movement without forcing it into a specific position. If there is bleeding inside the mouth, the individual should let the blood drain out rather than swallowing it, which can cause choking.
Monitoring the person’s airway is important, as severe swelling or a displaced fracture can cause the tongue to move backward, potentially obstructing breathing. Applying a cold compress or ice pack wrapped in a cloth to the outside of the jaw helps manage swelling and provides pain relief while waiting for medical help. Do not apply ice directly to the skin or attempt to forcefully realign the jaw.