There are a number of facial muscles that make up the musculature of the face. These muscles function by enabling facial expression and movement of the ears, cheeks, mouth, mandible, lips, nose, eyelids, scalp, and jaw.

Muscle injury and failure of movement of the facial muscles include: trauma, gunshot wounds, surgery, or blasts.

Injury to this muscle group may result in limitations related to mastication due to cheek, jaw, mouth and mandible dysfunction. In addition, limitation in the movements of the eyelids, lips, nose, ears, eyebrows, and scalp are likely outcomes. Mastication symptoms may be severe, and patients may report significant disturbances of sleep and appetite, as well as other lifestyle changes. Other manifestations include: limited jaw opening; the shifting of the jaw to one side on opening; and limitation and pain in side-to-side movement of the jaw. Pain may be presented on palpation of the temporomandibular joint (TMJ) area or the associated muscle and soft tissues.

A physical examination is usually done, but it may be difficult due to pain. Muscle strength is tested and graded on a scale of 0 (none) to 5 (normal). Evaluations of motor strength and muscle deterioration are done. Creatine kinase (CK-MM) laboratory tests may be done to determine muscle injury. Electromyogram (EMG) may also be done.

Physical therapy is one of the major treatments used to restore and maintain muscle function. In addition, transcutaneous electrical nerve stimulation (TENS), and ultrasound may be helpful. Anti-inflammatory drugs and muscle relaxants may also be used in cases that involve muscle spasm secondary to inflammation. Initially, hard to chew foods would be avoided.

Physical capabilities require certain functioning muscles to perform activities of daily living (ADL). The extent of muscle injury that is caused by trauma, gunshot wounds, or blasts may result in scars (see Diagnostic Code: 7804 Scars, superficial, painful on examination).

• Evaluate functional impairment as seventh (facial) cranial nerve neuropathy (diagnostic code 8207), disfiguring scar (diagnostic code 7800), etc. Minimum, if interfering to any extent with mastication—10%.

Notes

• None.