Arm Muscles Anatomy PDF

The brachium, or arm, extends from the shoulder to the elbow. The deep fascia of the arm, in the form of lateral and medial intermuscular septae, creates two muscular compartments. The anterior compartment contains exor muscles and is innervated by the musculocutaneous nerve. Th...

The brachium, or arm, extends from the shoulder to the elbow. The deep fascia of the arm, in the form of lateral and medial intermuscular septae, creates two muscular compartments. The anterior compartment contains exor muscles and is innervated by the musculocutaneous nerve. The posterior compartment contains extensor muscles and is innervated by the radial nerve. The biceps brachii muscle has two heads of origin: ◦ The short head originates from the coracoid process of the scapula. ◦ The long head originates from the supraglenoid tubercle of the scapula. The insertion of the biceps brachii muscle is at the radial or bicipital tuberosity. The muscle is innervated by the musculocutaneous nerve. The primary function of the biceps brachii is to supinate the forearm, and when the forearm is supinated, it also exes the forearm. The blood supply to the biceps brachii comes from the muscular branches of the brachial artery. The biceps tendon re ex test is used to assess the integrity of the musculocutaneous nerve and the C5–C6 spinal cord segments. An excessive, diminished, or prolonged (hung) response to the test may indicate central or peripheral nervous system disease or a metabolic disorder. To perform the test, gently ex the arm at the elbow and tap the biceps tendon with a re ex hammer. Locating the tendon with your thumb and striking your thumb with the hammer can help ensure accuracy during the test. The brachialis muscle originates from the anterior surface of the humerus. Its insertion is at the coronoid process and the ulnar or brachial tuberosity of the ulna. The muscle is innervated by the musculocutaneous nerve. Its primary function is to ex the forearm. The brachialis muscle receives blood supply from the radial recurrent artery. The coracobrachialis muscle originates from the coracoid process of the scapula. Its insertion is at the medial surface of the humerus. The muscle is innervated by the musculocutaneous nerve. Its function is to ex and adduct the arm. The blood supply comes from the muscular branches of the brachial artery. The musculocutaneous nerve pierces the coracobrachialis muscle. The triceps brachii muscle has three heads of origin: The long head originates from the infraglenoid tubercle of the scapula. The lateral head originates from the posterior surface of the humerus. The medial head also originates from the posterior surface of the humerus. The insertion of the triceps brachii muscle is at the olecranon process of the ulna. The muscle is innervated by the radial nerve. fl fl fl fl fl fl fl Its primary function is to extend the forearm. The blood supply comes from the muscular branches of the brachial artery. The olecranon bursa is located between the olecranon and the triceps tendon. The anconeus muscle originates from the lateral epicondyle of the humerus. Its insertion is at the olecranon process of the ulna. The muscle is innervated by the radial nerve. Its function is to assist the triceps brachii muscle. The blood supply to the anconeus muscle comes from the posterior interosseous recurrent artery.