Ulna

Question 1

Anatomical location

Answer 1

Long bone in forearm

Lies medially

Question 2

Proximal portion

Answer 2

Articulates with trochlea of humerus
Olecranon - large projection forming part of trochlea notch, palpated as tip of elbow, attachment of triceps brachii on superior surface
Coronoid process - ridge of bone projects outwards anteriorly, part of trochlea notch
Trochlea notch - wrench shaped, formed by coronoid process and olecranon, articulates with trochlea
Radial notch - located on lateral surface of trochlear notch, articulates with head of radius
Tuberosity of Ulna - roughening distal of coronoid process, attachment of brachialis muscle

Question 3

Shaft

Answer 3

Triangular shape with 3 surfaces and 3 borders

Question 4

3 surfaces of shaft

Answer 4

Anterior - site of attachment for pronator quadratus muscle distally
Posterior - site of attachment for many muscles
Medial - unremarkable

Question 5

3 borders of shaft

Answer 5

Posterior - palpable along entire length of forearm posteriorly
Interosseous - attachment for interosseous membrane, which spans the distance between the two forearm bones
Anterior - unremarkable

Question 6

Distal portion

Answer 6

Terminates in a rounded head with distal projection - the ulnar styloid process
Head articulates with the ulnar notch of radius to form distal radio-ulnar joint

Question 7

Fracture of ulna alone

Answer 7

Occurs as a result of a direct hit
Shaft is the most likely point of fracture
Muscle tone will pull proximal ulna posteriorly

Question 8

Olecranon process fracture

Answer 8

Patient falling on flexed elbow

Triceps brachii displace part of the fragment proximally

Question 9

Monteggia’s Fracture

Answer 9

Usually caused by force behind ulna

Proximal shaft fractured and head of radius dislocates anteriorly at elbow