11.3 The Elbow

Question 1

What are the functions/ranges of motion of the elbow joint?

Answer 1

ROM:
- Flexion/extension
- Pronation/supination

Functions:
- Picking things up
- Enables greater function of hands
- Balance (weight distribution)

Question 2

What are the names of the surfaces of the ulnar and the humerus that articulate with one another?

Answer 2

• Trochlea of the humerus
• Articulates with trochlear notch of the ulna

Question 3

What are the two processes on the proximal end of the ulnar?

Answer 3

• Olecranon process (most proximal; where you rest elbow on table)
• Coronoid process

Question 4

What are the names of the surfaces of the radius and humerus that articulate with one another?

Answer 4

• Capitulum; head (distal humerus)
• Radial head (slightly concave)

Question 5

Describe the attachments of the radius and ulna that allow for the pronation and supination of the forearm

Answer 5

• Proximally, the radial head articulates on the radial notch of the ulnar
• Distally, the ulnar head articulates on the ulnar notch of the radius

Question 6

List each of the ligamentous structures of the elbow, and describe their function

Answer 6

• Joint capsule (contains synovial fluid, continuation of the periosteum of arm bones)
• Radial and ulnar ligaments (protect against varus and valgus stress respectively)
• Annular ligament (wraps around radial head, stabilising during pronation and supination, like a labrum)

Question 7

List the pronator and supinator muscles of the elbow

Answer 7

Pro: Pronator teres/quadratus

Soup: Supinator (biceps also helps)

Question 8

Origin and insertion of pronator teres

Answer 8

Origin: medial humeral condyle (humeral head) and proximal ulna (ulnar head)

Insertion: Middle of shaft of radius

Question 9

Describe the joints of the radius and ulnar distal to the proximal radioulnar joint

Answer 9

• Interosseus membrane
• Triangular Fibrocartilage Complex (triangular ligament), articular disk, a/p ligaments

Question 10

What are the borders of the cubital fossa?

Answer 10

(Upside down triangle)

Superior: Line between epicondyles
Medial: Pronator teres
Lateral: brachioradialis

Question 11

List four structures that pass through the cubital fossa

Answer 11

1. Brachial artery
2. Brachial vein
3. Median nerve
4. Biceps brachii tendon

Question 12

Explain the pronation/supination action of brachioradialis

Answer 12

• When brachioradialis contracts, it wants to make the lateral distance between the humerus and wrist as short as possible
• Therefore, it brings the hand 90°, to the “handshake” position; this enables it to act as a pronator OR a supinator

Question 13

Origin and insertion of anconeus What is its action?

Answer 13

Originates at lateral humerus, inserts at proximal ulna.

Action: extensor and stabiliser

(on posterior side)