Elbow Joint/Muscles

Question 1

Describe the two epicondyles of the humerus i.e location/shape

Answer 1

Medial epicondyle - Located @ the distal end of the medial supracondylar ridge of the humerus. It is a projection that is more prominent than the lateral epicondyle

Lateral epicondyle - Located @ the distal end of the lateral supracondylar ridge of the humerus. It’s projection is less prominent than the medial epicondyle

Question 2

What are the two fossas of the distal humerus and what are their functions?

Answer 2

Radial fossa - small depression found above the capitulum of the humerus. It accommodates the head of the radius during flexion

Coronoid fossa - small depression found above the trochlea of the humerus. It accommodates the head of the ulna (coronoid process) during flexion.

Question 3

What is the olecranon and what is it’s function?

Answer 3

Olecranon - Sits posteriorly. It is a large, superior projection on the proximal part of the ulna. It curves at the top, fitting into the olecranon fossa.

• It is an attachment site for the Triceps

Question 4

What are the ligaments of the elbow joint? Functions?

Answer 4

Radial (lateral) collateral ligament - Major joint stabilizer that has two heads attaching from the lateral epicondyle to the anterior head of the radius and the posterior supinator crest of the ulna

Ulnar (medial) collateral ligament - Major joint stabilizer with fibers in many directions. Attaches from medial epicondyle to the ulna

Question 5

What are the ligaments and CT structures of the radioulnar joint? Functions?

Answer 5

Quadrate ligament - Connects the radius and the ulna proximally and provides stability for the radioulnar joint and some flexibility during supination and pronation

Annular ligament - Attaches from the radial notch and wraps around the ulna, holding it against the radius; it allows the head of the radius to rotate within the ligament during pronation/supination

Question 6

What are the elbow flexors? Origins and insertions?

Answer 6

Long Head of Biceps Brachii - Origin @ the supraglenoid tubercle of the scapula, runs over the joint, through the intertubercle groove, and inserts @ the radial tuberosity

Short Head of Biceps Brachii - Origin @ the coracoid process of the scapula and inserts @ the radial tuberosity of the humerus

Brachialis - Origin @ the anterior aspect of the distal half of the humerus and inserts @ the coronoid process and tuberosity of the ulna

Brachioradialis - Origin @ the lateral supracondylar ridge of the humerus and inserts @ the lateral aspect of the distal part of the radius

Question 7

What are the elbow extensors? Origins and insertions?

Answer 7

Triceps Brachii - Origin @ the posterior surface of the humerus and the infraglenoid tubercle of the scapula. Inserts @ the olecranon of the ulna

Anconeus - Origin @ the posterior aspect of the lateral epicondyle of the humerus and inserts @ the olecranon of ulna

Question 8

What are the elbow pronators? Origins and insertions?

Answer 8

Pronator Quadratus - Origin @ the anterior aspect of the distal 1/4th of the ulna and inserts @ the anterior aspect of the distal 1/4th of radius

Pronator Teres - Origin @ the medial supracondylar ridge of the humerus, via the common flexor tendon, and the medial aspect of the coronoid process of ulna. Inserts @ the middle 1/3rd of the anterolateral aspect of the radius

Question 9

What are the elbow supinators? Origins and insertions?

Answer 9

Long Head of Biceps Brachii - Origin @ the supraglenoid tubercle of the scapula, runs over the joint, through the intertubercle groove, and inserts @ the radial tuberosity

Short Head of Biceps Brachii - Origin @ the coracoid process of the scapula and inserts @ the radial tuberosity of the humerus

Supinator - Origin @ the lateral epicondyle of the humerus, spinator crest, and supinator fossa of the ulna. Inserts @ the anterior, lateral, and posterior aspects of proximal 1/3rd of radius