Posterior Scapula Muscles - Gross Anatomy Flashcards

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Bones: Scapula Humerus Radius Ulna • The muscles of the posterior scapula are innervated by the brachial plexus Supraspinatus • Originates in the supraspinous fossa of the scapula • Inserts on the greater tubercle of the humerus (specifically,
Bones: Scapula Humerus Radius Ulna • The muscles of the posterior scapula are innervated by the brachial plexus Supraspinatus • Originates in the supraspinous fossa of the scapula • Inserts on the greater tubercle of the humerus (specifically, the superior facet of the tubercle) • Abducts the humerus. Infraspinatus • Originates in the infraspinous fossa of the scapula • Inserts on the greater tubercle of the humerus (specifically, the middle facet) • Laterally rotates the humerus. Teres minor • Originates on the lateral scapular border (specifically, the proximal 2/3rds of the lateral border) • Inserts on the greater tubercle of the humerus (specifically, the lower facet) • Laterally rotates the humerus. Teres major • Originates on the posterior surface of the inferior angle of the scapula • Inserts on the intertubercular groove of the anterior humerus (specifically, on the medial lip) • Adducts the humerus, and, because of its anterior insertion, medially rotates the arm. Long head of triceps brachii • Originates on the infraglenoid tubercle • Inserts on the olecranon process of the ulna (via common triceps brachii tendon). • Is an accessory adductor and extensor of the arm (it also works with the medial and lateral heads of triceps brachii to extend the forearm). Clinical correlations: • The posterior shoulder muscles are arranged so that discrete spaces are created, through which neurovascular structures pass. The quadrangular space comprises the space between: • Teres minor • Humeral neck • Teres major • The long head of triceps brachii. • The quadrangular space encompasses the axillary nerve and posterior circumflex artery. The triangular space comprises the space between: • Long head of triceps brachii • Teres major • Teres minor • The triangular space encompasses the circumflex scapular artery. Triangular interval comprises the space between: • Long head of triceps brachii • Humeral shaft • Teres major • The triangular interval encompasses the deep brachial artery and the radial nerve. Innervation: • The muscles of the posterior scapula are innervated by the brachial plexus Related Anatomy Muscles • Posterior aspect Teres major Infraspinatus Teres minor Supraspinatus • Anterior aspect Subscapularis Scapula