L4 Arm Muscles Anatomy PDF

Systemic Anatomy of the Human Body Upper Limb 2: Muscles of The Arm ACB 2200B Emily Danciu [email protected] Learning Objectives 1. Osteology of the humerus, radius and ulna 2. Describe the muscles that cross the shoulder joint and move the arm 3. Describe the...

Systemic Anatomy of the Human Body Upper Limb 2: Muscles of The Arm ACB 2200B Emily Danciu [email protected] Learning Objectives 1. Osteology of the humerus, radius and ulna 2. Describe the muscles that cross the shoulder joint and move the arm 3. Describe the attachments, functions and innervation of each muscle 4. Describe the anterior and posterior compartments of the arm, their muscular components, actions, and innervation 5. Review the brachial plexus and nerve branches Osteology Osteology of Humerus Anterior Posterior Humerus Osteology  1. Head of the humerus 2. Anatomical neck 3. Surgical neck 4. Intertubercular groove 5. Medial lip 6. Lateral lip 7. Greater tubercle 8. Lesser tubercle 9. Deltoid tubercle 10. Medial condyle 11. Lateral condyle 12. Medial supracondylar ridge 13. Lateral supracondylar ridge 14. Capitulum 15. Trochlea 16. Coronoid fossa 17. Radial fossa 18. Spiral groove 19. Olecranon fossa Humerus Osteology Elbow Joint Osteology Elbow Joint Osteology 1. Olecranon process 2. Olecranon fossa 3. Medial condyle 4. Lateral condyle  Anterior Muscles That Move the Arm Pectoralis Major Origin Clavicular head: Medial half of clavicle Sternocostal head: sternum, superior 6 costal cartilages and aponeurosis of external oblique Insertion: Lateral lip of intertubercular groove Innervation: Lateral and medial pectoral nerves Action: Flexion, adduction and medial rotation of shoulder Coracobrachialis Origin: Coracoid process Insertion: Mid shaft of humerus, Medial side Innervation: Musculocutaneous nerve Action: Flexion and adduction of the arm Posterior Muscles That Move the Arm Latissimus Dorsi Origin: Spinous processes of T6-T12, thoracolumbar fascia, iliac crest and inferior 3-4 ribs Insertion: Intertubercular groove of humerus Innervation: Thoracodorsal nerve Action: Extension, adduction and medial rotation of the shoulder Teres Major Origin: Dorsal surface of the inferior angle of the scapula Insertion: medial lip of intertubercular groove Innervation: Lower subscapular nerve Action: Extension, adduction and medial rotation of the arm A Scandalous Story The lady that lies between 2 majors Deltoid Origin: lateral 1/3 of clavicle, acromion and spine of scapula Insertion: deltoid tuberosity Innervation: Axillary nerve Action Anterior Fibers: flexion and medial rotation of the arm Middle Fibers: abduction of the arm Posterior Fibers: extension and lateral rotation of the arm Summary Anterior Pectoralis major and coracobrachialis both flex the arm at the shoulder joint Posterior Latissimus dorsi and teres major both extend the arm at the shoulder The deltoid flexes, extends and abducts the arm at the shoulder Muscles of The Arm Biceps Brachii Origin Short head: coracoid process Long head: supraglenoid tubercle Insertion: radial tuberosity and bicipital aponeurosis Innervation: Musculocutaneous nerve Action: Forearm supination and elbow flexion Brachialis Origin: distal ½ of anterior surface of humerus Insertion: coronoid process of ulna Innervation: Musculocutaneous nerve Action: forearm flexion Triceps Brachii Origin Long head: infraglenoid tubercle Medial head: posterior humerus below radial groove Lateral head: posterior humerus above radial groove Insertion: proximal end of olecranon process and forearm fascia Innervation: Radial nerve Action: Extension of the arm, long head steadies head of abducted humerus Teres Major Triceps Brachii Compartments Compartments Dense and fibrous connective tissue divides the muscles of the limbs into anatomical compartments. Muscles in the same compartment have similar actions and innervation The muscles in opposite compartments act as agonist and antagonist pairs Compartment Syndrome The abnormal increase of interstitial pressure in a closed fascial compartment. Results in; Microvascular compromise Impaired myoneural function Necrosis Innervation of The Upper Limb Nerves of the Arm Musculocutaneous Nerve Radial Nerve Axillary Nerve Brachial Plexus Clinical Case Brady is a stunt double who was doing a scene where he needed to jump through a window. He didn’t land properly and landed on his arm. Although his arm appears normal, he was unable to flex it at the elbow. What happened to Brady?  Any Questions? Email me at [email protected] All Cadaveric images are sourced from Rohen’s Atlas and all digital anatomy images are from Anatomy Standard Thank you! Lecture Feedback Form [email protected]