What causes muscle spasms in the anterior neck and jaw?

Causes of Muscle Spasms in Anterior Neck and Jaw

Muscle spasms in the anterior neck and jaw result from multiple etiologies including post-surgical complications (particularly after neck dissection or radiation), mechanical cervical spine pathology, neurological conditions affecting cranial nerves, inflammatory processes, and musculoskeletal strain.

Post-Treatment and Iatrogenic Causes

Cervical dystonia represents a critical cause of painful dystonic spasms in cervical muscles, occurring after neck dissection, radiation therapy, or both. 1 This condition specifically affects head and neck cancer survivors and requires:

• Assessment for painful dystonic spasms of cervical muscles at each follow-up visit 1
• Referral to rehabilitation specialists for comprehensive neuromusculoskeletal management 1
• Treatment with nerve-stabilizing agents (pregabalin, gabapentin, duloxetine) or botulinum toxin type A injections into affected muscles for pain management and spasm control 1

Neurological Causes

Hemifacial spasm results from vascular compression of the facial nerve, causing unilateral hyperactivity and spasm of facial musculature including jaw muscles. 1 This occurs most commonly within the centrally myelinated portion of the nerve. 1

Facial nerve pathology can cause jaw and anterior neck spasms through:

• Brainstem lesions (infarction, vascular malformations, tumors, multiple sclerosis) affecting facial nuclei 1
• Lesions along the facial nerve course (schwannomas, meningiomas, inflammation, trauma) 1
• Extracranial facial nerve involvement from parotid tumors, skull base pathology, or inflammatory disease 1

Mechanical and Musculoskeletal Causes

Mechanical pain originating from the cervical spine and supporting structures represents the majority of nontraumatic neck pain cases. 1 Key considerations include:

• Cervical radiculopathy as the primary mechanical pain etiology 1
• Degenerative disc disease, though correlation with symptoms is poor as degenerative changes are common in asymptomatic individuals 2
• Muscle strain from poor positioning during activities (studying, smartphone/tablet use) 3
• Joint inflammation and muscle spasm from musculoskeletal conditions 4

Inflammatory and Infectious Causes

Elevated inflammatory markers (CRP, ESR, WBC) combined with neck pain and spasms indicate potential inflammatory or infectious processes requiring urgent investigation. 1, 2 Red flags include:

• Constitutional symptoms (fever, weight loss) 1
• Recent lymphadenopathy with pain on swallowing 2
• History of immunosuppression or IV drug use 1
• Inflammatory arthritis 1

Systemic and Other Causes

Additional etiologies to consider include:

• Tumor involvement (malignancy, perineural spread) 1
• Vascular causes 1
• Autoimmune conditions (rheumatoid arthritis, dermatomyositis, temporal arteritis) 4
• Trigger points and tendinitis 4
• Neurogenic inflammation 4

Critical Diagnostic Approach

When red flags are present (elevated inflammatory markers, constitutional symptoms, neurological deficits, or minimal response to conservative therapy), MRI of the cervical spine without contrast is the appropriate next imaging step. 2 This is superior for evaluating:

• Soft tissue abnormalities contributing to symptoms 2
• Inflammatory processes or infection not visible on plain radiographs 2
• Tumor or vascular pathology 1, 2

Important caveat: Loss of cervical lordosis on radiographs does not reliably indicate muscle spasm, as straight cervical spines occur in 42% of normal populations and are more common in women. 5 This finding should not be used to diagnose muscle spasm as the cause of neck pain.

Treatment Considerations

For acute painful musculoskeletal conditions with muscle spasm, cyclobenzaprine is indicated as an adjunct to rest and physical therapy for relief of muscle spasm, but should only be used for short periods (up to 2-3 weeks). 6 It is not effective for spasticity associated with cerebral or spinal cord disease. 6

Most acute cervical neck pain resolves spontaneously or with conservative treatment, but the presence of red flags warrants thorough investigation before assuming a benign course. 2