Cervical Thecal Sac Indentation at C2–C3

Cervical thecal sac indentation at C2–C3 is a finding often reported on cervical spine magnetic resonance imaging (MRI). It refers to pressure on the thecal sac—the protective membrane sheath that surrounds the spinal cord and cerebrospinal fluid—at the level between the second (C2) and third (C3) cervical vertebrae. This indentation can occur due to various factors such as a bulging disc, bony overgrowths, or ligament thickening. Understanding this condition is essential because, while mild indentation may be symptom-free, significant compression can lead to neck pain, nerve irritation, and even myelopathy (spinal cord dysfunction) if left untreated Spine InfoSpine Info.

The thecal sac is the dural membrane that encases the spinal cord and cerebrospinal fluid (CSF). “Indentation” or “effacement” of the thecal sac means that an external structure is pressing into this sac, causing it to lose its normal rounded shape. At the C2–C3 level, this indentation is visible on MRI when tissues such as herniated discs or osteophytes (bone spurs) encroach on the space. In mild cases, the spinal cord and nerves remain uncompressed, causing minimal or no symptoms; in moderate to severe cases, nerve roots or the cord itself may be affected, leading to neurological signs Spine InfoSpine Info.

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Anatomy of the Thecal Sac and C2–C3 Region

• Structure & Location: The thecal sac extends from the foramen magnum at the base of the skull down to approximately the S2 vertebra in the lumbar spine. At C2–C3, it lies just posterior to the intervertebral disc and anterior to the ligamentum flavum and laminae of the cervical vertebrae Spine-health.

• Attachments (Origin/Insertion): The dural sac attaches cranially at the foramen magnum and caudally anchors to the coccyx via the filum terminale. Along the way, it is tethered by denticulate ligaments to the inner surface of the vertebral canal Spine Info.

• Blood Supply: The dura mater receives small arterial branches from the vertebral and radicular arteries; venous drainage flows into the internal vertebral (epidural) venous plexus.

• Nerve Supply: Sensory innervation is provided by meningeal (recurrent) branches of spinal nerves, especially from the cervical dorsal rami.

• Key Functions:

  1. Protects the spinal cord and nerve roots from mechanical injury.

  2. Contains CSF, which cushions neural tissue.

  3. Maintains consistent intracranial and intraspinal pressure.

  4. Serves as a barrier to infection and toxins.

  5. Provides a medium for nutrient and waste exchange via CSF.

  6. Acts as an anatomical guide for nerve root exit points Deuk Spine.

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Types of Thecal Sac Indentation at C2–C3

Indentation can be classified by direction and severity:

• Directional Subtypes:

  • Ventral (anterior) indentation – often from disc bulge.

  • Dorsal (posterior) indentation – typically from ligamentum flavum hypertrophy or osteophytes.

  • Lateral indentation – may impinge nerve roots.

• Severity Grades (based on anteroposterior [AP] compression ratio):

  • Mild: < 30% sac deformation, usually asymptomatic PubMed.

  • Moderate: 30–50% deformation, often with nerve root irritation.

  • Severe: > 50% deformation, high risk of myelopathy and neurological deficits.

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Causes

1. Cervical disc herniation or bulging Spine Info

2. Osteophyte (bone spur) formation from spondylosis Spine Info

3. Ligamentum flavum hypertrophy Spine Info

4. Cervical spinal stenosis (congenital or acquired)

5. Ossification of the posterior longitudinal ligament (OPLL)

6. Cervical spine trauma (fracture, dislocation)

7. Rheumatoid pannus formation at atlantoaxial joint

8. Epidural hematoma (traumatic or anticoagulant-induced)

9. Epidural abscess (infection)

10. Synovial cysts of facet joints

11. Arachnoid cysts

12. Spinal tumors (meningioma, schwannoma)

13. Metastatic lesions

14. Paget’s disease of bone

15. Diffuse idiopathic skeletal hyperostosis (DISH)

16. Iatrogenic scarring (post-surgical fibrosis)

17. Degenerative endplate changes (Modic changes)

18. Inflammatory arthritis (ankylosing spondylitis)

19. Spontaneous intracranial hypotension (CSF volume shift)

20. Congenital dural ectasia

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Symptoms

1. Neck pain or stiffness Spine Info

2. Radicular pain down the arm Scoliosis Reduction Center®

3. Numbness or tingling in shoulders, arms, hands

4. Muscle weakness in upper limbs

5. Fine motor skill loss (e.g., buttoning shirts)

6. Gait imbalance or unsteady walking

7. Hyperreflexia (overactive reflexes)

8. Clonus (rhythmic muscle contractions)

9. Spasticity (increased muscle tone)

10. Bowel or bladder dysfunction (severe cases)

11. Sensory changes (paresthesia)

12. Headaches (occipital region)

13. Dizziness or vertigo

14. Lhermitte’s sign (electrical shock sensation on neck flexion)

15. Falls due to limb weakness

16. Muscle cramps or spasms

17. Fatigue from chronic pain

18. Neck muscle atrophy (late stage)

19. Loss of coordination (ataxia)

20. Neuropathic pain (burning, shooting sensation)

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Diagnostic Tests

1. MRI of the cervical spine – gold standard for visualizing thecal sac indentation Spine Info

2. CT scan – better for bony detail

3. Plain X-ray (lateral view) – assesses alignment, osteophytes

4. CT myelogram – when MRI is contraindicated

5. Electromyography (EMG) – tests nerve/muscle function

6. Nerve conduction studies (NCS)

7. Somatosensory evoked potentials (SSEPs) – evaluate spinal cord conduction

8. Flexion-extension X-rays – detect instability

9. Bone scan – rules out infection or tumor

10. Discography – provocative test for discogenic pain

11. Blood tests: CBC, ESR, CRP (to detect infection/inflammation)

12. CSF analysis (via lumbar puncture) – if infection suspected

13. Ultrasound of neck vessels – excludes vascular causes of neck pain

14. Gait analysis – quantifies functional impairment

15. Reflex testing – clinical strength of verdict

16. Balance testing (e.g., Romberg’s sign)

17. CT angiography – for vascular compressive lesions

18. Cervical spine ultrasound – limited but can guide injections

19. Physical examination – Spurling’s test for radiculopathy

20. Pain pressure threshold algometry – quantifies tenderness

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Non-Pharmacological Treatments

1. Physical therapy with focus on cervical stabilization

2. Cervical traction (mechanical or manual)

3. Posture correction education

4. Ergonomic workstation adjustments

5. Heat therapy (hot packs)

6. Cold therapy (ice packs)

7. Transcutaneous electrical nerve stimulation (TENS)

8. Ultrasound therapy

9. Acupuncture Dr. Devashish Sharma

10. Massage therapy

11. Chiropractic spinal manipulation

12. Yoga for neck flexibility

13. Pilates for core and neck support

14. Stretching exercises for levator scapulae, SCM

15. Strengthening exercises for deep neck flexors

16. Cervical collar (short-term use)

17. Hydrotherapy or aquatic exercises

18. Inversion therapy

19. Dry needling

20. Kinesiology taping

21. Ergonomic pillow and mattress selection

22. Sleeping position modification (supine with support)

23. Weight management to reduce axial load

24. Smoking cessation to slow degenerative changes

25. Stress management and relaxation techniques

26. Biofeedback for muscle tension control

27. Postural biofeedback devices

28. Cervical stabilization brace (night use)

29. Laser therapy (low-level laser)

30. Ergonomic driving seat adjustments

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Medications

1. NSAIDs (ibuprofen, naproxen) for pain and inflammation

2. Acetaminophen for mild pain relief

3. Muscle relaxants (cyclobenzaprine, methocarbamol) Dr. Devashish Sharma

4. Neuropathic pain agents (gabapentin, pregabalin)

5. Tricyclic antidepressants (amitriptyline) for neuropathic pain

6. SNRIs (duloxetine)

7. Oral corticosteroids (prednisone taper)

8. Epidural steroid injections (cervical transforaminal)

9. Opioids (tramadol for short-term severe pain)

10. Topical NSAIDs (diclofenac gel)

11. Capsaicin cream

12. Baclofen (for spasticity)

13. Tizanidine (for muscle spasms)

14. Anti-seizure drugs (carbamazepine for neuropathic pain)

15. Steroid-sparing immunosuppressants (in rheumatoid pannus)

16. Calcitonin (rarely, for bone pain)

17. Bisphosphonates (if osteoporosis contributes)

18. Vitamin D and calcium supplements

19. Sedatives (short-term for sleep disturbance)

20. IV antibiotics (for epidural abscess)

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Surgical Options

1. Anterior cervical discectomy and fusion (ACDF) Dr. Devashish Sharma

2. Posterior cervical laminectomy

3. Laminoplasty

4. Posterior foraminotomy

5. Cervical disc replacement (arthroplasty)

6. Corpectomy with strut grafting

7. Posterior cervical fusion with instrumentation

8. Microendoscopic decompression

9. Anterior cervical corpectomy and fusion (ACCF)

10. Minimally invasive tubular decompression

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 Preventive Measures

1. Maintain proper posture (neutral cervical spine)

2. Regular neck-strengthening exercises

3. Ergonomic workstation adjustments

4. Practice safe lifting techniques (avoid forward head flexion)

5. Use supportive pillows and mattresses

6. Avoid prolonged static neck positions

7. Engage in regular aerobic exercise

8. Maintain a healthy weight to reduce spinal load

9. Quit smoking to slow degenerative changes

10. Adopt a balanced diet rich in calcium and vitamin D

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When to See a Doctor

• Progressive weakness or numbness in arms or legs

• Loss of coordination, frequent falls, or gait changes

• Bowel or bladder control problems

• Severe, unremitting neck pain not relieved by conservative care

• Signs of infection (fever, chills, elevated blood tests)

• History of major trauma to the neck

• Rapidly worsening neurological symptoms

• Radicular pain unresponsive to 6–8 weeks of conservative treatment

• Any suspected tumor or unexplained weight loss

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Frequently Asked Questions

1. What does “thecal sac indentation” mean on my MRI?
   It means there is pressure on the dural sac encasing your spinal cord, often from a disc bulge or bony growth. The sac may look flattened or indented on imaging Spine Info.

2. Is cervical thecal sac indentation at C2–C3 serious?
   Mild indentation (< 30%) often causes no symptoms. Moderate to severe indentation risks nerve or spinal cord compression and needs evaluation PubMed.

3. Can thecal sac indentation improve on its own?
   Yes—if due to mild disc bulge or inflammation, physical therapy and anti-inflammatories can reduce indentation over weeks to months.

4. Which specialist should I see?
   Start with a spine-focused orthopedic surgeon or neurosurgeon, and involve a physiatrist or pain specialist for non-surgical care.

5. What non-surgical treatments are most effective?
   A tailored physical therapy program emphasizing cervical stabilization and traction often yields the best results.

6. When is surgery necessary?
   Surgery is considered for severe, progressive neurological deficits or pain unresponsive to 6–12 weeks of conservative therapy.

7. Are there risks to spinal injections?
   Risks include infection, bleeding, nerve injury, or temporary headache, but serious complications are rare.

8. How can I prevent cervical spine indentation?
   Maintain good posture, strengthen neck muscles, and avoid heavy lifting with poor technique.

9. Will I need a neck brace?
   A soft collar may be used short-term (days to weeks) to reduce movement and pain, but long-term use is discouraged.

10. Can I work if I have indentation?
    In most mild to moderate cases, yes—modifying activities and ergonomic adjustments are key.

11. What imaging is best?
    MRI is the gold standard for soft tissue detail and measuring thecal sac indentation; CT better shows bone.

12. Does age affect outcomes?
    Older patients may have slower recovery due to degenerative changes but still benefit from targeted therapy.

13. Are steroid injections addictive?
    No—cervical epidural steroid injections use local steroids to reduce inflammation, not systemic opioids.

14. Can children get thecal sac indentation?
    Rarely—when it occurs, it’s often due to congenital stenosis or trauma rather than degeneration.

15. How long is recovery after surgery?
    Most patients recover arm strength and relief within 3–6 months; full fusion (in ACDF) can take up to a year.

Disclaimer: Each person’s journey is unique, treatment plan, life style, food habit, hormonal condition, immune system, chronic disease condition, geological location, weather and previous medical  history is also unique. So always seek the best advice from a qualified medical professional or health care provider before trying any treatments to ensure to find out the best plan for you. This guide is for general information and educational purposes only. Regular check-ups and awareness can help to manage and prevent complications associated with these diseases conditions. If you or someone are suffering from this disease condition bookmark this website or share with someone who might find it useful! Boost your knowledge and stay ahead in your health journey. We always try to ensure that the content is regularly updated to reflect the latest medical research and treatment options. Thank you for giving your valuable time to read the article.

The article is written by Team Rxharun and reviewed by the Rx Editorial Board Members

Last Updated: May 02, 2025.

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