Elbow muscles (wk8)

Question 1

Describe the function, origin and insertion of the muscles that create flexion at the elbow:
-Biceps brachii, brachialis, brachioradialis

Answer 1

• Biceps brachii -> O: Supraglenoid tubercule of scapula and apex coracoid process of scapula, I: Radial tuberosity and antebrachial fascia, F: Supinates forearm, flexes forearm at the elbow
• Brachialis -> O: Anterior aspect of distal half of humerus, I: Coronoid process and tuberosity of ulna, F: Flexes forearm at elbow joint
• Brachioradialis -> O: Superior of lateral supracondylar ridge of humerus, I: Lateral aspect of distal part of radius, F: Flexes forearm at elbow joint

Question 2

Describe the function, origin and insertion of the muscles that create extension at the elbow:
-Triceps brachii and anconeus

Answer 2

• Triceps brachii -> O: Posterior surface of humerus and infraglenoid tubercule of scapula, I: Olecranon process of ulna and adjacent antebrachial fascia, F: Extends forearm at elbow joint
• Anconeus -> O: Posterior side of lateral epicondyle of humerus, I: Olecranon (proximal end of body of ulna), F: Extends forearm at elbow joint

Question 3

Describe the function, origin and insertion of the muscles that create pronation of the forearm:
-Pronator quadratus and pronator teres

Answer 3

• Pronator quadratus -> O: Anterior aspect of distal ulna, I: Anterior aspect of distal radius, F: Pronates forearm at radioulnar joints
• Pronator teres -> O: Medial supracondylar ridge of humerus, via common flexor tendon and medial aspect of coronoid process of ulna, I: Middle third of anterolateral surface of radius, F: Pronates forearm at radioulnar joints

Question 4

Describe the function, origin and insertion of the muscles that create supination of the forearm:
-Biceps brachii and supinator

Answer 4

• Biceps brachii -> O: Supraglenoid tubercule of scapula and apex coracoid process of scapula, I: Radial tuberosity and antebrachial fascia, F: Supinates forearm, flexes forearm at the elbow
• Supinator -> Lateral epicondyle of humerus, supinator crest and supinator fossa of ulna, I: Anterior, lateral and posterior aspects of proximal surface of radius, F: Supinates forearm at radioulnar joints

Question 5

Describe how the movement of pronation/supination and explain how this is created:

Answer 5

• Pronation is created by an internal rotary movement of the radius on the ulna that results in the hand moving from the palm-up to the palm-down position
• Supination is created by an external rotary movement of the radius of the ulna that results in the hand moving from the palm-down to the palm-up position
  -The proximal radioulnar joint allows supination and pronation to occur. These are rotational movements that occur when the distal end of the radius moves over the distal end of the ulna by rotating the radius in the pivot joint formed by the circular head of the radius, the radial groove of the ulna and the annular ligament.