Learning Objectives
By the end of this section, the learner should be able to:
- Define the triangular space and describe its anatomical location.
- Identify the borders of the triangular space.
- List the contents that pass through the triangular space.
- Distinguish the triangular space from the triangular interval.
- Apply this knowledge to clinical and surgical contexts.
Overview
The triangular space is an anatomical passage located in the posterior aspect of the axilla. It serves as a conduit allowing neurovascular structures to pass between the axilla and the posterior scapular region.
Important distinction:
The triangular space should not be confused with the triangular interval, which lies inferior to it and transmits different structures.
Anatomical Orientation
- The triangular space is oriented with its base laterally and apex medially
- It is formed by the muscles of the posterior axillary wall
Borders of the Triangular Space
| Border | Structure |
|---|---|
| Lateral | Medial border of the long head of triceps brachii |
| Inferior | Superior border of the teres major |
| Superior | Inferior border of teres minor (or subscapularis) |
Contents
The triangular space transmits:
- Circumflex scapular artery
- Circumflex scapular vein
These vessels supply the posterior scapular region and contribute to the scapular anastomosis, an important collateral circulation pathway.
Avtivity
Clinical Correlation
- Knowledge of the triangular space is essential during axillary and shoulder surgery to avoid vascular injury.
- The circumflex scapular artery can provide collateral blood flow in cases of proximal arterial occlusion.
- Accurate identification helps prevent confusion with adjacent spaces, particularly the triangular interval, which transmits the radial nerve and profunda brachii artery.
Key Take-Home Points
- The triangular space connects the axilla to the posterior scapular region
- Borders are formed by the teres minor, the teres major, and the long head of the triceps
- Contents: circumflex scapular vessels
- Do not confuse with the triangular interval
