Upper triangular space-
1. Boundaries:
• Laterally- Long head of triceps brachii muscle
• Inferiorly- Teres major muscle
• Superiorly- Teres minor muscle
2. Content:
• Circumflex scapular vessels
Boundaries | Upper triangular space | Lower triangular | Quadrangular space |
Lateral | LH of triceps | Shaft of | Shaft of the humerus |
Inferior | Teres major | Teres major muscle | Teres major muscle |
Superior | Teres minor | X | Teres minor muscle |
Medial | X | LH of triceps brachii muscle | LH of triceps brachii muscle |
Quadrangular space-
1. Boundaries-
• Medially- Long head of triceps brachii muscle
• Laterally- Shaft of the humerus
• Inferiorly- Teres major muscle
• Superiorly- Teres minor muscle
2. Content:
• Axillary nerve (It supplies to Deltoid and Teres minor muscle)
• Posterior circumflex humeral artery
Lower triangular space-
1. Boundaries-
• Medially- Long head of triceps brachii muscle
• Laterally- Shaft of the humerus
• Inferiorly- Teres major muscle
2. Content-
• Profunda brachii artery (Deep brachial artery)
• Radial nerve