OIA Shoulder Joint Muscles PDF Anatomy Study Guide

OIA Shoulder joint **1. Pectoralis Major (Upper Fibers)** - **Origin**: Medial half of anterior surface of clavicle - **Insertion**: Lateral lip of intertubercular groove of humerus - **Actions**: - Internal rotation (Transverse plane) - Horizontal adduction (Transverse plane...

OIA Shoulder joint **1. Pectoralis Major (Upper Fibers)** - **Origin**: Medial half of anterior surface of clavicle - **Insertion**: Lateral lip of intertubercular groove of humerus - **Actions**: - Internal rotation (Transverse plane) - Horizontal adduction (Transverse plane) - Diagonal adduction (Diagonal plane) - Flexion (Sagittal plane) - Abduction (Frontal plane) - **Palpation**: From the medial clavicle to the intertubercular groove of the humerus during flexion and adduction - **Innervation**: Lateral pectoral nerve (C5, C6, C7) **2. Pectoralis Major (Lower Fibers)** - **Origin**: Anterior surface of costal cartilages of first six ribs, adjoining portion of sternum - **Insertion**: Lateral lip of intertubercular groove of humerus - **Actions**: - Internal rotation (Transverse plane) - Horizontal adduction (Transverse plane) - Diagonal adduction (Diagonal plane) - Extension from flexed position (Sagittal plane) - Adduction (Frontal plane) - **Palpation**: From the lower ribs and sternum to the intertubercular groove of the humerus during resisted extension - **Innervation**: Medial pectoral nerve (C8, T1) A skeleton with a red chest muscles AI-generated content may be incorrect. **3. Subscapularis** - **Origin**: Entire anterior surface of subscapular fossa - **Insertion**: Lesser tubercle of humerus - **Actions**: - Internal rotation (Transverse plane) - Adduction (Frontal plane) - Extension (Sagittal plane) - **Palpation**: Mostly inaccessible; lateral portion may be palpated with active internal rotation - **Innervation**: Upper and lower subscapular nerves (C5, C6)  **4. Coracobrachialis** - **Origin**: Coracoid process of scapula - **Insertion**: Middle of medial border of humeral shaft - **Actions**: - Horizontal adduction (Transverse plane) - Diagonal adduction (Diagonal plane) - **Palpation**: High on the medial arm, posterior to the short head of the biceps brachii - **Innervation**: Musculocutaneous nerve (C5, C6, C7) **5. Deltoid (Anterior Fibers)** - **Origin**: Anterior lateral third of clavicle - **Insertion**: Deltoid tuberosity on lateral humerus - **Actions**: - Abduction (Frontal plane) - Flexion (Sagittal plane) - Horizontal adduction (Transverse plane) - Internal rotation (Transverse plane) - Diagonal adduction (Diagonal plane) - **Palpation**: From the clavicle to the anterior humerus during resisted flexion - **Innervation**: Axillary nerve (C5, C6) **6. Deltoid (Middle Fibers)** - **Origin**: Lateral aspect of acromion - **Insertion**: Deltoid tuberosity on lateral humerus - **Actions**: - Abduction (Frontal plane) - Horizontal abduction (Transverse plane) - **Palpation**: Lateral border of the acromion to deltoid tuberosity during resisted abduction - **Innervation**: Axillary nerve (C5, C6) **7. Deltoid (Posterior Fibers)** - **Origin**: Inferior edge of spine of scapula - **Insertion**: Deltoid tuberosity on lateral humerus - **Actions**: - Abduction (Frontal plane) - Horizontal abduction (Transverse plane) - External rotation (Transverse plane) - Diagonal abduction (Diagonal plane) - **Palpation**: Lower lip of scapular spine to posterior humerus during resisted extension - **Innervation**: Axillary nerve (C5, C6) A diagram of the muscles of the ribs AI-generated content may be incorrect. **8. Supraspinatus** - **Origin**: Medial two-thirds of supraspinous fossa - **Insertion**: Greater tubercle of humerus - **Action**: Abduction (Frontal plane) - **Palpation**: Above spine of scapula in supraspinous fossa during initial abduction - **Innervation**: Suprascapular nerve (C5)  **9. Latissimus Dorsi** - **Origin**: Posterior crest of ilium, sacrum, spinous processes of lumbar & lower six thoracic vertebrae, lower three ribs - **Insertion**: Medial side of intertubercular groove of humerus - **Actions**: - Extension (Sagittal plane) - Adduction (Frontal plane) - Internal rotation (Transverse plane) - Horizontal abduction (Transverse plane) - **Palpation**: Posterior axillary wall, upper lumbar/lower thoracic area during extension - **Innervation**: Thoracodorsal nerve (C6, C7, C8) A skeleton with muscles and text AI-generated content may be incorrect. **10. Teres Major** - **Origin**: Posteriorly on inferior third of lateral border of scapula - **Insertion**: Medial lip of intertubercular groove of humerus - **Actions**: - Extension (Sagittal plane) - Adduction (Frontal plane) - Internal rotation (Transverse plane) - **Palpation**: Just above the latissimus dorsi on the posterior scapula surface - **Innervation**: Lower subscapular nerve (C5, C6)  **11. Infraspinatus** - **Origin**: Infraspinous fossa of scapula - **Insertion**: Greater tubercle of humerus - **Actions**: - External rotation (Transverse plane) - Horizontal abduction (Transverse plane) - Extension (Sagittal plane) - Diagonal abduction (Diagonal plane) - **Palpation**: Below spine of scapula, lateral to humerus during external rotation - **Innervation**: Suprascapular nerve (C5, C6) A human skeleton with muscles AI-generated content may be incorrect. **12. Teres Minor** - **Origin**: Posteriorly on upper and middle aspect of lateral border of scapula - **Insertion**: Greater tubercle of humerus - **Actions**: - External rotation (Transverse plane) - Horizontal abduction (Transverse plane) - Extension (Sagittal plane) - Diagonal abduction (Diagonal plane) - **Palpation**: Above teres major on posterior scapula surface - **Innervation**: Axillary nerve (C5, C6)  **Additional Muscles Involved** - **Biceps Brachii**: Assists in flexion, horizontal adduction, diagonal adduction - **Triceps Brachii (Long Head)**: Assists in extension, adduction, horizontal abduction, diagonal abduction