Hybrid Muscles of the Upper Limb: Coracobrachialis, Teres Major & Latissimus Dorsi

1. Coracobrachialis:

- Origin: Coracoid process of the scapula

- Insertion: Medial aspect of the humerus (coracobrachialis fossa)

- Action: Flexion and adduction of the arm; assists in shoulder joint stabilization

2. Teres Major:

- Origin: Inferior angle of the scapula

- Insertion: Lateral aspect of the humerus (intertubercular sulcus)

- Action: Adduction and external rotation of the arm

3. Latissimus Dorsi:

- Origin: Thoracolumbar fascia, spinous processes of lower thoracic and lumbar vertebrae, iliac crest, and lower ribs

- Insertion: Intertubercular sulcus of the humerus

- Action: Adduction, extension, and internal rotation of the arm

4. Pectoralis Major:

- Origin: Clavicle (medial half), sternum, and costal cartilages

- Insertion: Crest of the greater tubercle of the humerus

- Action: Flexion, adduction, and internal rotation of the arm

5. Rhomboids:

- Major and Minor

- Origin: Spinous processes of thoracic vertebrae

- Insertion: Vertebral border of the scapula

- Action: Adduction and elevation of the scapula

6. Levator Scapulae:

- Origin: Transverse processes of upper cervical vertebrae

- Insertion: Superior angle and vertebral border of the scapula

- Action: Elevation and slight rotation of the scapula