Deltoid Muscle Anterior Posterior

Supraspinatus Muscle occupies the supraspinous fossa

Superior Transverse Scapular Ligament closes off suprascapular notch into a foramen

Suprascapular Nerve passes UNDER superior transverse scapular ligament

Suprascapular Vessels - Artery

Suprascapular Vessels – Artery (cartoon) passes OVER superior transverse scapular ligament

Suprascapular Vessels – Vein

Infraspinatus Muscle occupies the infraspinous fossa

Suprascapular n., a., v. passing the Greater Scapular Notch Note they descend posterior to the infraspinatus muscle

Teres Major Muscle Anterior Posterior

Teres Minor Muscle

Long Head of the Triceps Brachii Muscle

Triangular Space Formed by: the medial margin of the long head of the triceps brachii muscle; the superior margin of the teres major muscle; and the inferior margin of the subscapularis muscle.

Quadrangular Space Formed by: the inferior margin of the subscapularis muscle; the surgical neck of the humerus; the superior margin of the teres major muscle; and the lateral margin of the long head of the triceps brachii muscle.

Triangular Interval Formed by: the lateral margin of the long head of the triceps brachii muscle; the inferior margin of the teres major muscle; and the medial margin of the humerus

Triangular Space, Quadrangular Space, and Triangular Interval… Why should I care?

Triangular Space, Quadrangular Space, and Triangular Interval… Why should I care?

Axillary Nerve

Posterior Circumflex Humeral Artery passing through the quadrangular space posteriorly supplies the deltoid m. and arm muscles near the surgical neck of the humerus

Posterior Circumflex Humeral Vein passing through the quadrangular space posteriorly

Circumflex Scapular Artery passing through the triangular space supplies teres major, minor, and infraspinatus m.

Serratus Anterior

Pectoralis Minor

Latissimus Dorsi

Axillary Vein Passes into the axilla through the deltopectoral/ clavipectoral triangle Also note the Posterior circumflex humeral v Subscapular v Circumflex scapular v Internal jugular above, joins subclavian, becomes left brachiocephalic.

Deltopectoral Triangle Formed by: pectoralis major muscle, deltoid muscle, Clavicle Axillary vein passes enters the axilla here

Axillary Vein (in deltopectoral triangle) dives through fascia just inferior to the clavicle