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Triangular Space

Triangular space lies between teres major, teres minor, and triceps long head for scapular vessels.

RegionUpper Limb
SystemMusculoskeletal System

The triangular space is a small anatomical interval in the posterior shoulder region. Unlike the adjacent quadrangular space, it transmits only a vascular structure — the scapular circumflex artery. It serves as a key surgical and anatomical landmark in posterior shoulder dissections.

Boundaries

BorderStructure
SuperiorTeres minor muscle
InferiorTeres major muscle
LateralLong head of triceps brachii

Contents

Relations

  • Medial to the quadrangular space
  • Superior to the triangular interval
  • Posterior to the scapulothoracic region, lying deep to the deltoid

Function / Significance

  • Allows the scapular circumflex artery to pass from the axilla into the scapular region
  • Forms part of the collateral circulation around the scapula

Clinical Significance

  • Scapular Collateral Circulation: In cases of axillary artery occlusion, the scapular circumflex artery provides an alternative route for blood to reach the distal limb
  • Surgical Landmark: Important in posterior surgical approaches and flap dissections (e.g., latissimus dorsi flap)
  • Not commonly involved in compressive syndromes like the quadrangular or triangular interval

Comparative Anatomy

The triangular space and its contained vessel are part of the human-specific vascular design that supports highly mobile scapulohumeral function. The scapular anastomosis plays a role in maintaining perfusion despite positional changes or vascular compromise.

Published on May 12, 2025
Last updated on May 12, 2025
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