1. Myology 2 (HS 201)
Lecture 3
Myology of the
Elbow

2. Distal Humerus Anatomy:
Capitulum: rounded knob that articulates with the head of the radius
Radial fossa: anterior depression that receives the head of the radius when the forearm is flexed
Trochlea: spool-shaped surface that articulates with the ulna
Coronoid fossa: anterior depression that receives the coronoid process when the forearm is flexed
Olecranon fossa: posterior depression receiving the olecranon process of the ulna when the forearm is extended
Medial and lateral epicondyles: projections on either side for attachment of many forearm muscles.

3. Anatomical Review Distal Humerus

4. Ulna Ulna located on the medial forearm Longer than the radius
Anatomy:
Olecranon process: large process on the proximal end of the elbow
Coronoid process: an anterior projection of bone that with the olecranon receives the trochlea of the humerus
Ulnar tuberosity: ridge of bone inferior to the coronoid process
Trochlear (semilunar) notch: large curved area between the olecranon and the coronoid process
Radial notch: depression on the lateral humerus that receives the head of the radius
Head: rounded distal end of the ulna
Styloid process: small projection distal to the head of the ulna

5. Radius Located on the lateral side of the forearm Anatomy:
Head: disc shaped proximal end of the radius which articulates with the capitulum of the humerus.
Neck: constricted area distal to the head
Radial tuberosity: roughened area on the proximal medial shaft for attachment of the biceps brachii muscle
Shaft: widens distally to articulate with the scaphoid and lunate bones of the wrist
Styloid process: small bony projection at the distal end of the radius
Ulnar notch: depression on the medial side of the radius for articulation with the distal end of the ulna

6. Anatomical Review Proximal Ulna and Radius

7. Articular Anatomy of the Elbow
Elbow is a hinge joint formed by the articulation of the distal humerus and proximal radius and ulna
Made up of three joints:
Humeroradial: joint between the capitulum and the head of the radius
Humeroulnar: joint between the trochlea and the trochlear notch of the ulna
Radioulnar: joint between the head of the radius and the radial notch of the ulna

8. Soft Tissue of the Elbow
Interosseous Membrane: A broad, flat fibrous connective tissue that joins the shafts of the radius and ulna
Articular Capsule: Extends from distal humerus to proximal radius and ulna (enveloping the entire joint)
Ulnar Collateral Ligament: Thick triangular ligament extending from medial epicondyle of the humerus to the coronoid process and olecranon of the ulna

9. Soft Tissue of the Elbow
Radial Collateral Ligament: Strong
triangular ligament extending from
the lateral epicondyle of the humerus
to the annular ligament of the radius
and radial notch of the ulna
Radial Annular Ligament: Ligament
encircling the head/neck of the radius and
radial notch of the ulna
Olecranon Bursa: Fluid filled sac lining
the olecranon process. Lubricates the
joint

10. Elbow Ranges of Motion
Each student should be able to describe and demonstrate the following movements:
Elbow flexion
Elbow extension
Pronation
Supination

11. Palpation of the elbow
Olecranon Process: Sitting; Shake hands with your partner and palpate large prominence of the
elbow. Passively flex and extend the elbow observe how the olecranon moves.
Olecranon Fossa: Sitting; Locate the olecranon process again. Roll your finger proximally around
the top of the process, pressing through the triceps tendon and into the fossa.
Humeral epicondyles: Sitting; Again locate the olecranon process. Slide your fingers medially and
laterally off the olecranon feeling the prominences. Note that the medial is larger.
Supracondylar ridges: Sitting; Locate the epicondyles, slide your fingers proximally toward the
shoulder feeling the medial and lateral supracondylar ridges. Roll your fingers back and forth to feel
the edges.
Shaft of the ulna: Sitting; Again, locate the olecranon process and then slide your hand distally
along the shaft of the ulna (remember the ulna is medial). Follow it along the length of the forearm.
Ulnar Head: Sitting; Slide your finger along the shaft of the ulna. Just proximal to the wrist the shaft
will bulge to become the ulnar head.
Ulnar styloid process: Sitting; Find the posterior aspect of the ulnar head then slide distally off the
head and palpate the ulnar styloid process.

12. Palpation of the elbow (cont.)
Radial Head: Sitting; Locate the lateral epicondyle and slide distally. Notice a small depression
between the humerus and radius. The distal side of the depression is the radial head. Have your
partner pronate and supinate the forearm feeling the radial rotate.
Radial Shaft: Sitting; Supinate and flex your partner’s elbow, find the radial head again and slide
your fingers distally along the radial shaft.
Radial styloid process: Sitting: Find the distal radial shaft to the end feeling the lateral side of the
radius to the tip of the styloid process.

13. Muscles that move the Elbow
Biceps Brachii
Brachialis
Brachioradialis
Triceps Brachii
Anconeus
Pronator Teres
Pronator Quadratus
Supinator

14. Biceps Brachii O: Long Head: Supraglenoid tubercle of the scapula
Short Head: Corocoid process of the scapula
I: Radial tuberosity
A: Shoulder: Flexes the arm
Elbow: Flexes the elbow and assists in supination when power is required.
**Note: the long head can cause abduction of the arm, while the short head can cause adduction
N: Musculocutaneous nerve

15. Brachialis O: Anterior aspect of the humeral shaft
I: Coronoid process of the ulna
A: Flexion of the forearm
N: Musculocutaneous nerve
Brachialis is located deep to the
biceps brachii

16. Brachioradialis O: Lateral supracondylar ridge of the humerus
I: Styloid process of the radius
A: Flexion of the elbow in the neutral
position (shaking hands). Also
assists in supination and pronation
of the forearm.
N: Radial nerve

17. Triceps Brachii O: Long Head: Infraglenoid tubercle of the scapula
Lateral Head: Posterior aspect of the shaft of the humerus (proximal ½)
Medial Head: Posterior aspect of the shaft of the humerus (distal ½)
I: Olecranon Process of the Ulna
A: Shoulder: Extends the arm
Elbow: Extends the elbow
** Note: the long head can cause adduction of the arm
N: Radial nerve

18. Anconeus O: Lateral epicondyle of the humerus
I: Olecranon process of the
ulna
A: Extension of the elbow
(weak)
N: Radial nerve

19. Pronator Teres O:
Humeral Head: medial epicondyle (via common flexor tendon) of the humerus
Ulnar Head: Coronoid process of the ulna
I: Lateral aspect of the shaft of
the radius
A: Pronates the forearm and flexes the elbow. Assists in flexion of the elbow
N: Median nerve

20. Pronator Quadratus O: Distal ¼ of the Ulna I: Distal ¼ of the Radius
A: Pronation of the forearm
N: Median nerve

21. Supinator O: Lateral epicondyle of the humerus and proximal ulna
I: Proximal anterior radius
A: Supination of the forearm (for slow non-resisted supination the supinator is sufficient. When speed or resistance is required, the biceps brachii is recruited.
N: Radial Nerve