What is Stiff Neck or Locked Neck?
A stiff neck or "locked neck" is a condition characterized by limited cervical mobility, pain with neck movement, and reduced range of motion, most commonly caused by muscle spasm following trauma or poor posture, though it can also indicate serious underlying pathology requiring urgent evaluation. 1
Clinical Definition and Presentation
Stiff neck refers to the inability to move the neck through its normal range of motion, typically accompanied by:
- Pain with attempted neck movement in any direction (flexion, extension, rotation, or lateral bending) 1
- Muscle spasm in the paraspinal muscles or sternocleidomastoid, which is the body's protective response to injury or inflammation 1
- Point tenderness over specific cervical vertebrae or soft tissues 1
- Reduced cervical mobility that may only become apparent near the terminal points of flexion or extension 1
Common Benign Causes
The most frequent causes of stiff neck include:
- Muscle strain from overuse of neck and upper back muscles or poor posture, which typically resolves within days to weeks 2
- Whiplash-associated disorders (WAD) following rapid acceleration-deceleration neck injury, attributed to injury of paraspinal muscles, facets, disks, and craniocervical ligaments 1
- Cervical proprioception impairment leading to sensorimotor control disturbances and muscle coordination problems 3
- Capsular ligament laxity causing excessive movement between cervical vertebrae and subsequent muscle spasm as a protective mechanism 4
Most cases of acute neck stiffness resolve spontaneously or with conservative treatment, though approximately 50% of individuals will experience residual or recurrent symptoms. 5
Serious Causes Requiring Urgent Evaluation
Critical "red flags" that distinguish benign stiff neck from serious pathology include:
- Constitutional symptoms such as fever, unexplained weight loss, or night sweats, which suggest infection or malignancy 6, 7
- Elevated inflammatory markers (ESR, CRP, WBC) indicating possible vertebral osteomyelitis, discitis, or inflammatory arthritis 6, 7
- Neurological deficits including weakness, sensory changes, or gait disturbance, suggesting cervical myelopathy or radiculopathy 6
- History of malignancy or immunosuppression, raising concern for metastatic disease 6
- Intractable pain despite appropriate conservative therapy 6
- Vertebral body tenderness on palpation, which is a red flag for metastatic disease or infection 6
Pediatric Consideration: Torticollis
In children presenting with stiff, tilted neck:
- Congenital muscular torticollis is the third most common pediatric orthopedic diagnosis, caused by sternocleidomastoid muscle tightness 8
- Nonmuscular torticollis must be differentiated, as it can indicate inflammatory, ocular, neurologic, or orthopedic diseases that may be life-threatening 8
- Physical examination and cervical spine radiographs are required for systematic work-up 8
Diagnostic Approach
For acute stiff neck without red flags (<6 weeks duration):
- Defer imaging and pursue conservative management, as most cases resolve spontaneously 6, 9
- Clinical examination should focus on identifying red flags rather than routine imaging 6
For stiff neck with red flags present:
- Obtain MRI cervical spine without contrast immediately, as it is the most sensitive modality for detecting soft tissue abnormalities, inflammatory processes, infection, tumor, or vascular pathology 6, 7
For persistent stiff neck beyond 6-8 weeks without red flags:
- Consider MRI cervical spine without contrast to evaluate for structural causes such as disc herniation or nerve root impingement 6, 9
Common Pitfall to Avoid
Do not order imaging immediately in the absence of red flags, as this leads to overdiagnosis of incidental degenerative changes that are present in 85% of asymptomatic individuals over 30 years and correlate poorly with symptoms. 6, 9 The diagnosis of benign stiff neck is primarily clinical, and imaging findings often do not change management in the absence of concerning features. 1, 5