Thecal Sac Indentation at T6–T7

Inside your spine runs the thecal sac—a watertight sleeve of dura-mater that holds the spinal cord and the fluid that cushions it. When something crowds the spinal canal at the mid-thoracic level (between the sixth and seventh thoracic vertebrae, T6-T7) the sac can bow inward. Radiologists call that inward bowing an indentation. Mild dents may simply touch the sac; deeper dents can flatten it and squeeze the cord, sometimes leading to nerve or cord symptoms. MRI reports often mention it long before a person notices any problem. spineinfo.comradiopaedia.org

• Anatomy in a nutshell – The T6-T7 level sits roughly behind the shoulder-blade tips. The spinal canal is narrower here than in the neck or low back, and the spinal cord is still present (in the lumbar spine it ends). Even a small extra mass can reduce the wiggle-room for the cord. ncbi.nlm.nih.govbarrowneuro.org

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Types of Thecal-Sac Indentation

(Use of “mild / moderate / severe” or “central / lateral / foraminal” in MRI reports simply grades how much and where the sac is indented.)

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Common Causes

1. Central thoracic disc herniation – The soft middle of the disc leaks backward and presses on the sac.

2. Broad-based disc bulge – Age-related flattening of the disc’s edge encroaches on the canal.

3. Posterior osteophyte – A hard bony beak grows from the back of a vertebral body.

4. Ossification of the posterior longitudinal ligament (OPLL) – A spinal‐ligament slowly turns to bone, shrinking canal space.

5. Ligamentum flavum hypertrophy – The yellow ligament that forms the “roof” of the canal thickens with arthritis.

6. Compression fracture with retropulsion – A crushed vertebra sends broken bone into the canal.

7. Scheuermann’s kyphosis – Wedged vertebrae create a hump and pinch the front of the sac.

8. Scoliosis apex narrowing – A sideways curve rotates the canal and indents the sac.

9. Traumatic subluxation / dislocation – Bone slip after injury crowds the cord.

10. Epidural abscess – A pocket of pus expands in the canal.

11. Epidural hematoma – A blood clot forms after trauma or spine injection.

12. Spinal meningioma – A benign membrane tumor grows inward.

13. Schwannoma / neurofibroma – A nerve-sheath tumor balloons into the canal.

14. Metastatic vertebral tumor – Cancer eats bone and collapses it inward.

15. Primary bone tumor (e.g., hemangioma with soft-tissue extension) – A vascular bone growth invades the canal.

16. Posterior osteophyte from ankylosing spondylitis – Inflammatory bone overgrowth narrows the space.

17. Calcified thoracic disc (adult sequela of juvenile disc calcification) – Rock-hard disc material projects backward.

18. Thickened dura in spinal pachymeningitis – Inflammation makes the covering itself bulky.

19. Congenital short pedicles – Small “side walls” leave less room for the cord from birth.

20. Iatrogenic canal compromise – Surgical hardware or cement slightly protrudes into the canal after a fusion or vertebroplasty. spineinfo.com

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 Typical Symptoms

1. Mid-back pain – Inflamed disc or bone activates local pain fibers.

2. Band-like chest or rib pain – Compressed thoracic nerve roots refer pain around the trunk.

3. Electric shock sensations when bending – Cord stretch over the indent triggers paresthesia.

4. Numb patch around the nipple line – T6 root irritation maps to that dermatome.

5. Tingling in both legs – Cord indentation distorts ascending sensory tracts.

6. Leg heaviness or weakness – Descending motor tracts lose clear signaling.

7. Trouble standing long – Cord blood flow is impaired during extension.

8. Loss of fine toe movement – Small corticospinal fibers become vulnerable first.

9. Gait imbalance – Compressed dorsal columns blunt position sense.

10. Positive Romberg test – Eyes-closed sway indicates proprioceptive pathway injury.

11. Spastic leg stiffness – Upper-motor neurons are partially blocked.

12. Sudden giving-way of the knees – Cord clamp causes transient motor drop-out.

13. Hyper-reflexia in the patellar or ankle jerk – Reflex arcs lose descending inhibition.

14. Up-going Babinski sign – Classic early-myelopathy marker.

15. Sharp back pain with cough or sneeze – Intrathecal pressure spike hits the bulging disc.

16. Rib-cage tightness on deep breath – Costovertebral joints stiff from arthritic causes.

17. Difficulty taking a deep breath when lying flat – Extra mass can restrict cord movement during respiration.

18. Abdominal wall tingling or burning – Thoracic root sensory fibers fire abnormally.

19. Bowel or bladder urgency (late sign) – Long-tract compression disrupts autonomic signals.

20. Unexplained upper-abdominal cramps – Root irritation sometimes mimics visceral pain. ncbi.nlm.nih.govpmc.ncbi.nlm.nih.gov

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Diagnostic Tests and How They Help

A. Physical-Examination Tests

1. Inspection of posture & rib cage – Kyphosis, scoliosis, or post-traumatic deformity suggest a structural cause.

2. Palpation for spinous tenderness – Pin-point pain over T6-T7 may mean disc or fracture disease.

3. Active range-of-motion check – Reduced thoracic extension hints at stenosis pain.

4. Dermatomal pin-prick test – Dullness or hyper-sensitivity around T6-T7 dermatome spotlights root irritation.

5. Myotome power grading – Weakness in trunk or lower limb groups reveals cord involvement.

6. Deep-tendon-reflex assessment – Brisk knee/ankle jerk suggests upper-motor neuron compromise.

7. Babinski sign – Up-going big toe flags early myelopathy.

8. Clonus testing at the ankle – Sustained beats confirm cord hyper-excitability.

9. Gait observation (tandem walk) – Wide-based or spastic walk uncovers proprioceptive loss.

10. Romberg balance test – Eyes-closed sway shows dorsal-column dysfunction.

B. Manual / Orthopedic Special Tests

11. Thoracic slump test – Flexing spine and legs stretches the cord; symptom reproduction hints at disc pressure.

12. Seated thoracic compression – Downward axial load can aggravate facet or disc pain.

13. Kemp’s test (thoracic extension-rotation) – Posterolateral disc or facet stresses elicit localized pain.

14. Soto-Hall test – Passive cervical flexion applies tension through the thoracic cord.

15. Schepelmann’s sign – Side-bending pain differentiates disc (convex-side pain) from rib inflammation (concave-side pain).

16. Prone press-up – Extension pain reproduction supports posterior element compression.

17. Adam’s forward-bend test – Highlights scoliotic rib hump that may narrow the canal at its apex.

18. Beevor’s sign – Umbilicus shift during sit-up can localize a thoracic cord lesion.

C. Laboratory & Pathological Tests

19. Complete blood count (CBC) – Elevated white cells suggest infection causing an epidural abscess.

20. Erythrocyte sedimentation rate (ESR) & C-reactive protein (CRP) – High levels reinforce an inflammatory or infectious source.

21. Blood culture – Isolates bacteria if sepsis is suspected behind an abscess.

22. Serum calcium & vitamin-D – Low density bones fracture easily and retropulse fragments.

23. Tumor markers (e.g., PSA, CA-125) – Help track suspected metastatic lesions compressing the sac.

24. HLA-B27 typing – Supports ankylosing spondylitis diagnosis when ligament or bony overgrowth arises.

D. Electrodiagnostic Tests

25. Electromyography (EMG) – Detects chronic cord/root denervation changes in the trunk or legs.

26. Nerve-conduction study (NCS) – Rules-out peripheral neuropathy mimicking thoracic pain.

27. Somatosensory evoked potentials (SSEP) – Show slowed conduction through the compressed dorsal columns.

28. Motor evoked potentials (MEP) – Quantify corticospinal tract delay under indentation.

29. F-wave latency test – Prolonged values suggest proximal nerve or cord compromise.

30. H-reflex study – Early hyper-reflexia or latency changes flag sub-clinical myelopathy.

E. Imaging Tests

31. Plain thoracic X-ray – Screens for fractures, scoliosis, osteophytes.

32. Flexion / extension X-rays – Reveal hidden instability that narrows the canal only in certain positions.

33. Computed tomography (CT) – Best at showing bony canal diameter and calcified discs.

34. Magnetic resonance imaging (MRI) of T-spine – Gold standard to visualize sac, cord, and soft disc material.

35. Contrast-enhanced MRI – Lights up tumors or infection causing the indent.

36. CT myelogram – Iodine dye outlines the sac so even tiny dents are obvious when MRI is contraindicated.

37. Bone scan (scintigraphy) – Flags occult fractures or metastases active on bone turnover.

38. PET-CT – Highlights metabolically hot tumors or infection behind the indentation.

39. Ultrasound of paraspinal soft tissue – Rapid bedside tool for superficial abscess or hematoma assessment.

40. DEXA scan – Checks bone density if fragile-bone fractures are suspected in canal compromise. barrowneuro.orgradiopaedia.org

Non-Pharmacological Treatments

A. Physiotherapy & Electrotherapy Therapies

1. Manual Cervicothoracic Mobilization
   Gentle hands-on gliding of T6–T7 facets by a trained therapist to restore joint motion, reduce stiffness, and relieve sac pressure through improved alignment.

2. Thoracic Extension Traction
   Gradual, low-force stretching of the thoracic spine over a wedge or harness to widen the spinal canal, decreasing indentation and improving nerve gliding.

3. Transcutaneous Electrical Nerve Stimulation (TENS)
   Surface electrodes deliver pulsed currents to block pain signals at the spinal cord level and stimulate endorphin release, reducing discomfort around T6–T7.

4. Interferential Current Therapy
   Medium-frequency currents applied via four pads create a deep “beat” over the lesion, promoting blood flow, reducing muscle spasm, and easing pressure on the thecal sac.

5. Ultrasound Therapy
   High-frequency sound waves penetrate tissues at T6–T7 to generate heat, enhancing collagen extensibility in ligaments and reducing local inflammation.

6. Short Wave Diathermy
   Electromagnetic waves produce deep heating, improving circulation in paraspinal muscles and facets, thereby helping to off-load compression off the thecal sac.

7. Cold Laser Therapy
   Low-level laser light applied over T6–T7 stimulates cellular repair, reduces inflammatory mediators, and mitigates nerve irritation.

8. Spinal Traction Table
   Mechanical decompression pulls the thoracic segments apart gently, temporarily enlarging the spinal canal at T6–T7 to relieve indentation.

9. Kinesio Taping
   Elastic therapeutic tape applied paraspinally to support posture, reduce muscle fatigue, and indirectly off-load compressive forces on the thecal sac.

10. Therapeutic Heat Packs
    Moist heat applied locally increases tissue temperature, promoting muscle relaxation and improved flexibility around the compressed area.

11. Cryotherapy
    Intermittent ice applied to T6–T7 reduces local blood flow and nerve conduction, offering short-term relief of acute inflammation.

12. Soft Tissue Massage
    Myofascial release and trigger-point work in the erector spinae and rhomboids reduce paraspinal tension that can worsen sac indentation.

13. Cupping Therapy
    Suction cups create negative pressure to lift fascia, enhance local circulation, and reduce adhesions near the compressed thecal sac.

14. Instrument-Assisted Soft Tissue Mobilization (IASTM)
    Specially contoured tools glide over paraspinal musculature to break down scar tissue and improve segmental mobility at T6–T7.

15. Proprioceptive Neuromuscular Facilitation (PNF) Stretching
    Therapist-guided contract-relax stretches of paraspinal muscles improve thoracic extension and off-load pressure on the thecal sac.

B. Exercise Therapies

1. Thoracic Extension on Foam Roller
   Lying supine over a foam roller at T6–T7, extend arms overhead to open up the spinal canal and strengthen erector spinae.

2. Scapular Retraction with Resistance Band
   Pulling a band apart at shoulder height trains mid-upper back muscles to support proper thoracic alignment.

3. Cat–Camel Mobilization
   On all fours, alternate arching and rounding the back to gently mobilize intervertebral joints and reduce sac indentation.

4. Prone “Y”–“T” Lifts
   Lifting arms in Y and T positions while prone strengthens the lower trapezius and supports thoracic posture.

5. Wall Angels
   Standing against a wall, slide arms up/down in a “snow angel” motion to promote thoracic extension and relieve compressive forces.

C.  Mind-Body Therapies

1. Mindful Thoracic Breathing
   Slow, deep breaths focused on expanding the mid-back create gentle self-mobilization of T6–T7 and release paraspinal tension.

2. Guided Imagery for Pain Relief
   Visualization of a relaxed thoracic spine can downregulate pain centers in the brain and lessen perceived indentation discomfort.

3. Progressive Muscle Relaxation
   Sequential tensing/releasing of trunk muscles reduces overall muscle tone, decreasing compressive pull on the thecal sac.

4. Meditation with Posture Focus
   Sitting in an upright position while monitoring thoracic alignment builds awareness and reduces slouching that worsens indentation.

5. Yoga Cat Pose with Chest Opening
   Combining back arching with gentle chest stretching uses mind-body synergy to improve thoracic mobility.

D. Educational Self-Management Strategies

1. Ergonomic Thoracic Pillow Training
   Teaching correct pillow height and firmness to maintain neutral T6–T7 curvature during sleep and limit overnight indentation.

2. Posture Self-Monitoring App
   Using smartphone reminders and posture sensors to cue timely alignment breaks throughout the day.

3. Activity Pacing Education
   Learning to segment tasks with breaks prevents overloading the thoracic segments and reduces cumulative indentation stress.

4. Back-Safe Lifting Workshop
   Instruction in hip-hinge technique to protect thoracic structures when lifting objects, minimizing disc bulge risk.

5. Home Exercise Log & Goal Setting
   Tracking daily thoracic mobility and strength exercises improves adherence and long-term off-loading of the thecal sac.

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Evidence-Based Drugs

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Dietary Molecular Supplements

1. Omega-3 Fatty Acids (Fish Oil)
   – Dosage: 1–2 g EPA/DHA daily
   – Function: Reduces inflammatory cytokines around the disc
   – Mechanism: Competes with arachidonic acid to produce anti-inflammatory eicosanoids

2. Vitamin D₃
   – Dosage: 1000–2000 IU daily
   – Function: Supports bone health and immune modulation
   – Mechanism: Enhances calcium absorption and dampens pro-inflammatory T-cell activity

3. Vitamin B₁₂ (Methylcobalamin)
   – Dosage: 1000 µg sublingual daily
   – Function: Promotes nerve repair and myelin synthesis
   – Mechanism: Cofactor for methionine synthase in methylation pathways

4. Magnesium Citrate
   – Dosage: 200–400 mg daily
   – Function: Reduces muscle spasm and nerve excitability
   – Mechanism: Blocks NMDA receptors and regulates calcium flow

5. Alpha-Lipoic Acid
   – Dosage: 300–600 mg daily
   – Function: Antioxidant that protects nerve cells
   – Mechanism: Regenerates other antioxidants and chelates metals

6. Curcumin (Turmeric Extract)
   – Dosage: 500–1000 mg standardized extract daily
   – Function: Inhibits inflammatory mediators in the disc space
   – Mechanism: Blocks NF-κB signaling and COX-2 expression

7. Resveratrol
   – Dosage: 150–250 mg daily
   – Function: Anti-inflammatory and anti-fibrotic in spinal tissues
   – Mechanism: Activates SIRT1, reducing oxidative stress

8. Glucosamine Sulfate
   – Dosage: 1500 mg daily
   – Function: Supports cartilage and disc matrix integrity
   – Mechanism: Serves as substrate for glycosaminoglycan synthesis

9. Chondroitin Sulfate
   – Dosage: 800–1200 mg daily
   – Function: Promotes water retention in disc tissue
   – Mechanism: Inhibits degradative enzymes (MMPs)

10. Acetyl-L-Carnitine
    – Dosage: 500–1000 mg daily
    – Function: Enhances nerve energy metabolism and repair
    – Mechanism: Transports fatty acids into mitochondria for ATP production

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Regenerative & Advanced Drugs

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Surgical Procedures

1. Posterior Thoracic Laminectomy
   Removal of the lamina at T6–T7 to decompress the thecal sac directly.
   Benefits: Immediate relief of cord compression and reduction in neurological symptoms.

2. Hemilaminectomy
   Unilateral removal of half the lamina to preserve stability while relieving indentation.
   Benefits: Less postoperative pain and quicker recovery compared to full laminectomy.

3. Thoracic Discectomy
   Excision of herniated disc material through a posterior approach under microscopy.
   Benefits: Direct decompression of the thecal sac with minimal bone removal.

4. Microendoscopic Discectomy
   Endoscope-assisted removal of disc fragments via a small muscle-splitting incision.
   Benefits: Reduced muscle trauma and shorter hospital stay.

5. Transpedicular Corpectomy
   Removal of the vertebral body segment and disc at T6–T7 followed by cage placement.
   Benefits: Addresses both bone spurs and disc disease when both contribute to indentation.

6. Anterior Thoracoscopic Discectomy
   Minimally invasive removal of disc through small chest wall incisions using a camera.
   Benefits: Avoids paraspinal muscle dissection and preserves posterior elements.

7. Instrumented Posterior Fusion
   Laminectomy combined with pedicle screw fixation from T5–T8 to stabilize the segment.
   Benefits: Prevents postoperative instability after decompression.

8. Expandable Interbody Cage Placement
   After corpectomy, an expandable cage restores disc height and maintains canal diameter.
   Benefits: Promotes fusion and maintains sagittal alignment.

9. Costotransversectomy
   Resection of the rib head and transverse process to access the disc laterally.
   Benefits: Targets laterally placed herniations with minimal spinal cord manipulation.

10. Vertebral Body Tethering
    Novel technique using flexible tether to restore sagittal balance and off-load T6–T7.
    Benefits: Dynamic stabilization without rigid fusion.

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Prevention Strategies

1. Maintain neutral thoracic posture when sitting or standing.

2. Strengthen core and paraspinal muscles regularly.

3. Use ergonomic chairs and lumbar supports with thoracic contour.

4. Break up prolonged sitting every 30 minutes with extension stretches.

5. Lift objects using a hip-hinge technique, avoiding thoracic flexion.

6. Keep body weight within healthy range to reduce disc loading.

7. Avoid high-impact sports without proper conditioning.

8. Quit smoking to improve disc nutrition and healing capacity.

9. Ensure adequate daily hydration (2–3 L water) for disc turgor.

10. Get routine spine checkups if you have prior back injuries.

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When to See a Doctor

Seek medical attention if you experience:

• Sudden weakness or numbness in the legs or chest

• Loss of bladder or bowel control

• Persistent, severe mid-back pain unrelieved by rest or OTC meds

• Progressive difficulty walking or balance problems

• High fever or signs of infection (if preceded by surgery)

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Do’s and Don’ts

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Frequently Asked Questions

1. What causes thecal sac indentation at T6–T7?
   Most often caused by a herniated thoracic disc, bony overgrowth (osteophytes), or thickened ligaments that press into the sac’s space.

2. Can it heal on its own?
   Mild cases may improve with rest, physical therapy, and anti-inflammatory measures, but moderate to severe indentations usually require targeted treatment.

3. Is surgery always necessary?
   No. Many patients respond well to conservative care; surgery is reserved for those with neurologic deficits or refractory pain.

4. How long does recovery take?
   With conservative therapy, relief may appear within 6–12 weeks; post-surgical recovery varies from 3 months to a year depending on procedure extent.

5. Will I need long-term medication?
   Ideally no—most can taper off pain meds once physical therapy and strengthening reduce compression.

6. Are there risks to thoracic spine surgery?
   As with any spine operation, risks include infection, bleeding, nerve injury, and adjacent segment stress.

7. Can I prevent re-indentation?
   Yes—through posture correction, ergonomic adjustments, core strengthening, and avoiding high-risk activities.

8. Does age matter?
   Older adults may have slower healing and more bony changes, but appropriate treatment can still yield good outcomes.

9. Are injections helpful?
   Epidural steroid injections can reduce inflammation around T6–T7 and offer temporary relief in selected cases.

10. What imaging is best?
    MRI provides the most detail for soft-tissue compression; CT and X-ray can identify bony spurs.

11. Is the pain constant?
    Pain often fluctuates—worsening with flexion or prolonged sitting and easing with extension.

12. Can I fly after treatment?
    Short flights are usually fine once pain is controlled—long flights may require mid-flight mobility exercises.

13. What exercises should I avoid?
    Avoid heavy overhead lifting or forward-flexion activities that can increase indentation.

14. Will physical therapy hurt?
    A good therapist will tailor intensity; slight discomfort is normal, but sharp pain means back off.

15. When is it an emergency?
    Loss of bladder or bowel control, sudden paralysis, or severe chest pain with breathing changes mandates immediate care.

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: June 08, 2025.

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