Ulna

Question 1

What is the ulna?

Answer 1

A long bone in the forearm

Question 2

Where does the ulna lie?

Answer 2

Medially and parallel to the radius, and second of the forearm bones

Question 3

What does the ulna act as?

Answer 3

The stabilising bone, with radius pivoting it to produce movement

Question 4

What does the ulna articulate with?

Answer 4

Proximally, the humerus

Distally, the radius

Question 5

What is formed when the ulna articulates with the humerus?

Answer 5

The elbow joint

Question 6

What is formed when the ulna articulates with the radius?

Answer 6

The distal radio-ulnar joint

Question 7

What does the proximal portion of the ulna articulate with?

Answer 7

The trochlea of the humerus

Question 8

What enables movement at the elbow joint?

Answer 8

The specialised structure of the ulna, with bony prominences for muscle attachment

Question 9

What are the important landmarks of the proximal ulna?

Answer 9

The olecranon
 Coronoid process
 Trochlear notch
 Radial notch
 Tuberosity of ulna

Question 10

What is the olecranon?

Answer 10

A large projection of bone

Question 11

Where does the olecranon extend?

Answer 11

Proximally

Question 12

What does the olecranon form?

Answer 12

Part of the trochlear notch

Question 13

Where can the olecranon be palpated?

Answer 13

As the ‘tip’ of the elbow

Question 14

What attaches to the olecranon?

Answer 14

The triceps brachii, at its superior surface

Question 15

What is the coronoid process?

Answer 15

A ridge of bone that projects outwards in an anterior manner

Question 16

What does the coronoid process form?

Answer 16

Part of the trochlear notch

Question 17

What is the trochlear notch formed by?

Answer 17

Olecranon

Coronoid process

Question 18

What shape is the trochlear notch?

Answer 18

Wrench shaped

Question 19

What does the trochlear notch do?

Answer 19

Articulates with the trochlea of the humerus

Question 20

Where is the radial notch located?

Answer 20

On the lateral surface of the trochlear notch

Question 21

What does the radial notch do?

Answer 21

Articulates with the head of the radius

Question 22

What is the tuberosity of the ulna?

Answer 22

A roughening immediately distal of the coronoid process

Question 23

What is the purpose of the tuberosity of the ulna?

Answer 23

It is where the brachialis muscle attaches

Question 24

What shape is the ulnar shaft?

Answer 24

Triangular

Question 25

What does the ulnar shaft have?

Answer 25

Three borders and three surfaces

Question 26

What happens as the ulnar shaft moves distally?

Answer 26

It decreases in width

Question 27

What are the three surfaces of the ulnar shaft?

Answer 27

Anterior  Posterior  Medial

Question 28

What is the importance of the anterior surface of the ulnar shaft?

Answer 28

It is the site of attachment for the pronator quadratus muscle distally

Question 29

What is the importance of the posterior surface of the ulnar surface?

Answer 29

It is the site of attachment for many muscles

Question 30

What are the three borders of the ulnar shaft?

Answer 30

Posterior Interosseous  Anterior

Question 31

Where is the posterior border of the ulnar shaft palpable?

Answer 31

Along the entire length of the forearm posteriorly

Question 32

What is the importance of the interosseous border of the ulnar shaft?

Answer 32

It is the site of attachment for the interosseous membrane

Question 33

What does the interosseous membrane do?

Answer 33

Spans the distance between the two forearm bones

Question 34

How does the distal portion of the ulna differ from the proximal end?

Answer 34

It is much smaller in diameter

Question 35

How does the distal portion of the ulna terminate?

Answer 35

In a rounded head, with a distal projection

Question 36

What is the distal projection on the rounded head of the ulnar called?

Answer 36

The ulnar styloid process

Question 37

What does the ulnar head articulate with?

Answer 37

The ulnar notch of the radius

Question 38

What is formed when the ulnar head articulates with the ulnar notch?

Answer 38

The distal radio-ulnar joint

Question 39

How does a fracture of the ulnar alone usually occur?

Answer 39

As a result of the ulna being hit by an object

Question 40

Where is the most likely site of ulnar fracture?

Answer 40

The shaft

Question 41

What happens in a shaft fracture of the ulna?

Answer 41

The normal muscle tone will pull the proximal ulna posteriorly

Question 42

What can less commonly be fractured in the ulna?

Answer 42

The olecranon process

Question 43

What causes olecranon process fractures?

Answer 43

The patient falling on a flexed elbow

Question 44

What happens when the olecranon process fractures?

Answer 44

The triceps brachii can displace part of the fragment proximally

Question 45

How are the ulna and radius attached?

Answer 45

Interosseous membrane

Question 46

What is the result of the interosseous membrane regarding fractures?

Answer 46

The force of trauma to one bone can be transmitted to the other via the membrane, and therefore fracture of both the forearm bones are not uncommon

Question 47

What are the two classical fractures of both forearm bones?

Answer 47

Monteggia’s fracture | Galeazzi’s fracture

Question 48

What causes Monteggia’s Fracture?

Answer 48

Force from behind the ulna

Question 49

What happens in Monteggia’s Fracture?

Answer 49

The proximal shaft of the ulna is fractured, and the head of the radius dislocates anteriorly at the elbow

Question 50

What is Galaezzi’s fracture?

Answer 50

A fracture to the distal radius, with the ulna head dislocating at the distal radio-ulnar joint