Topic Overview

Facts to Remember – Scapular Region

• Scapular region contains deltoid, rotator cuff muscles (SITS), teres major, triceps (long head).

• Deltoid → chief abductor of arm (15°–90°), supplied by axillary nerve.

• Rotator cuff muscles (SITS) stabilize shoulder joint.

  • Supraspinatus → initiates abduction (0–15°).

  • Infraspinatus → lateral rotation.

  • Teres minor → lateral rotation.

  • Subscapularis → medial rotation, adduction.

• Quadrangular space → axillary nerve + posterior circumflex humeral artery.

• Upper triangular space → circumflex scapular artery.

• Lower triangular space (interval) → radial nerve + profunda brachii artery.

• Axillary nerve injury → loss of abduction beyond 15°, deltoid wasting, regimental badge anesthesia.

• Suprascapular nerve injury → loss of initiation of abduction and weak lateral rotation.

• Scapular anastomosis maintains blood supply if axillary artery is ligated proximal to subscapular artery.

• Common site of rotator cuff tears = supraspinatus tendon.

• Posterior axillary fold formed by latissimus dorsi and teres major.

• Painful arc syndrome → 60–120° abduction due to supraspinatus impingement.

• Safe site for deltoid injection → 2–3 cm below acromion.

Clinicoanatomical Problems – Scapular Region

1. Axillary Nerve Injury

• Case: After fracture of surgical neck of humerus, patient cannot abduct arm beyond 15°.

• Diagnosis: Axillary nerve palsy → deltoid & teres minor paralysis.

2. Rotator Cuff Tear

• Case: A 55-year-old with painful abduction between 60–120°.

• Diagnosis: Supraspinatus tendon tear (commonest).

3. Quadrangular Space Syndrome

• Case: Athlete presents with shoulder pain, weakness of abduction, paresthesia over deltoid.

• Diagnosis: Axillary nerve compression in quadrangular space.

4. Suprascapular Nerve Entrapment

• Case: Patient with weakness of initiation of abduction and external rotation.

• Diagnosis: Suprascapular nerve compression at suprascapular notch.

5. Radial Nerve Injury in Triangular Interval

• Case: Fracture of humeral shaft causes wrist drop.

• Diagnosis: Radial nerve damaged in triangular interval.

6. Shoulder Dislocation (Inferior)

• Case: Post-dislocation, patient shows deltoid paralysis and sensory loss over regimental badge area.

• Diagnosis: Axillary nerve injury.

7. Subscapularis Test (Lift-off Test)

• Case: Patient unable to lift hand off back.

• Diagnosis: Subscapularis tear/weakness.

8. External Rotation Weakness

• Case: Loss of external rotation but deltoid intact.

• Diagnosis: Infraspinatus and teres minor injury.

9. Surgical Neck Fracture with Vessel Injury

• Case: Humeral fracture with massive shoulder swelling.

• Diagnosis: Posterior circumflex humeral artery injury.

10. Collateral Circulation

• Case: Ligation of 1st part of axillary artery → arm still receives blood supply.

• Diagnosis: Collateral flow via scapular anastomosis (suprascapular ↔ circumflex scapular