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Understanding Frozen Shoulder

(True Adhesive Capsulitis vs Muscular & Tendinous Shoulder Dysfunction)

Portrait of sporty woman putting her hand on red spots on while has sport injury in her sh

Not all stiff shoulders are true frozen shoulder. Learn the difference between adhesive capsulitis and rotator cuff or tendon-related pain in Horsham.

Why Many “Frozen Shoulders” Aren’t Actually Frozen

It’s common for people to self-diagnose a stiff, painful shoulder as frozen.

But a true frozen shoulder — adhesive capsulitis — is very specific.
In clinic, many restricted shoulders are actually driven by:

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  • Rotator cuff tendinopathy

  • Subscapularis overactivity pulling the humerus forward

  • Anterior deltoid inflammation

  • Biceps tendon irritation

  • Mild brachial plexus neural irritation

  • Thoracic restriction and postural overload

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These feel restrictive.They can be painful.

But they are not capsular freezing.

 

Correct differentiation changes treatment completely.

What Defines a True Frozen Shoulder?

A genuine adhesive capsulitis involves:
 

  • Inflammation of the joint capsule

  • Capsular thickening

  • Adhesion formation

  • Global restriction of passive AND active movement

  • Marked loss of external rotation

 

The key feature is capsular end-feel restriction.

 

If passive range is still available beyond what you can actively achieve, it is unlikely to be true frozen shoulder.

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The Over-Reaching Pattern: A Common Misdiagnosis

One of the most common presentations mistaken for frozen shoulder involves repetitive forward reaching often from:

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  • Desk work

  • Driving

  • Gym pressing movements

  • DIY or overhead work

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In this pattern:

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  • The subscapularis becomes dominant

  • The humeral head migrates slightly anteriorly

  • The anterior deltoid becomes inflamed

  • The long head of the biceps tendon becomes irritated

  • The rotator cuff tendons become overloaded

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The shoulder feels tight and restricted.

But the capsule is not frozen.

It is mechanically overloaded.

→ Read more information in the Blog post

Subscapularis & Anterior Shoulder Pull

The subscapularis internally rotates the shoulder.

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When chronically shortened, it can:

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  • Draw the humeral head forward

  • Reduce external rotation

  • Increase anterior joint compression

  • Create a “blocked” feeling

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Clients often assume this loss of rotation means frozen shoulder.

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In reality, it is muscular dominance.

Rotator Cuff Tendinopathy & Deltoid Inflammation

Overreaching and forward loading can cause:

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  • Supraspinatus irritation

  • Infraspinatus overload

  • Anterior deltoid inflammation

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The head of the deltoid can become reactive and tender, especially with repeated lifting.

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Pain with reaching overhead does not equal adhesive capsulitis.

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It often equals tendon overload.

Gerdy Tubercle & Femoral Epicondyle Explained

The IT band inserts at Gerdy’s tubercle.
Friction often occurs near the lateral femoral epicondyle.

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But irritation there is usually:

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  • Compression under load

  • Repetitive tracking dysfunction

  • Not “tight fascia”

Why Foam Rolling Feels Good (But Doesn’t Solve It)

Foam rolling:

  • Improves short-term blood flow

  • Temporarily reduces neural tone

  • Changes pain perception

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It does NOT:

  • Correct pelvic imbalance

  • Restore glute activation

  • Change structural load patterns

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It’s symptom management, not root correction.

Clinical Approach to Resolving It

Treatment may include:

  • QL rebalancing

  • Glute med facilitation

  • TFL decompression

  • Hip rotational control

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And occasionally, yes some IT band interface work.

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But it’s never the only focus.

Biceps Tendon Involvement

The long head of the biceps runs through the anterior shoulder groove.

When anterior translation of the humeral head occurs:

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  • Biceps tendon strain increases

  • Localised front-of-shoulder pain develops

  • Clicking or aching may appear

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Again — this mimics frozen shoulder, but the pathology is different.

Mild Brachial Plexus Irritation

Forward head posture and rounded shoulders may also:

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  • Increase tension through the brachial plexus

  • Cause diffuse aching

  • Produce mild neural sensitivity

  • Create “arm heaviness” sensations

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This neural component can amplify perceived stiffness.

 

But it is not capsular adhesion.

True Frozen Shoulder vs Muscular Restriction

True adhesive capsulitis:

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  • Passive movement restricted

  • Firm capsular end feel

  • Significant loss of external rotation

  • Gradual staged progression

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Muscular / tendinous pattern:​

  • Painful but variable range

  • Passive range often better than active

  • Trigger points present

  • Postural influence evident

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Differentiation requires assessment not guesswork.

FAQ: Frozen Shoulder Clarified

  • Can rotator cuff tendinitis feel like frozen shoulder?

Yes. Rotator cuff irritation can limit movement due to pain, creating a perceived “block.”

  • Why does my shoulder feel locked when I reach behind my back?

Internal rotation dominance and subscapularis tightness commonly restrict this movement.

  • Can biceps tendon pain mimic frozen shoulder?

Yes. Anterior shoulder pain from the long head of the biceps can limit lifting and reaching.

  • How do you test for true frozen shoulder?

By assessing passive range of motion and identifying capsular end-feel restriction, especially in external rotation.

  • Can nerve irritation make the shoulder feel stiff?

Mild brachial plexus tension can contribute to diffuse discomfort and protective guarding.

  • Does posture play a role?

Absolutely. Forward head posture and rounded shoulders increase anterior joint loading.

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