Olecranon

The olecranon is a large bony prominence at the proximal end of the ulna. Itis palpable at the posterior aspect of the elbow. 

Summary

• location
  • proximal end of the ulna
  • articulates with the olecranon fossa of the humerus
• blood supply
  • ​deep nutrient branch of the ulnar artery
• relations
  • posteriorly the olecranon bursa 
  • anteriorly the semilunar notch
  • attachments
    • triceps brachii muscle attached over the superior surface
    • posterior and oblique bands of the ulnar collateral ligament
    • ulnar part of the flexor carpi ulnaris muscle

Gross anatomy

Location

The olecranon has a beak-like structure and is bent forwards into the olecranon fossa of the humerus during extension of the elbow. It is present over the posterior surface of the elbow and forms the palpable 'point' of the elbow during its full extension. 

Articulations

The olecranon articulates with the humerus via the olecranon fossa on the humerus, which is situated over the posterior surface of the humerus.  

It is continuous with the coronoid process of the ulna via the trochlear or semilunar notch anteriorly. This forms the attachment site for the humerus over the ulnar surface. 

Relations

• olecranon bursa is situated posterior to the olecranon, in between the joint capsule and the tendon of the triceps brachii muscle
• the radial notch of the ulna articulates with the radius, located over the lateral surface of the olecranon
• anteriorly, the elbow joint capsule is attached to the olecranon surface
• ulnar collateral ligament and the flexor carpi ulnaris muscle attach to the medial surface
• distally, it attaches to the flexor digitorum profundus muscle
• laterally, it attaches to the anconeus muscle
• the ulnar nerve passes in between the olecranon and the medial epicondyle of the humerus ¹

Blood supply

The blood supply of the olecranon comes from a deep nutrient branch of the ulnar artery ².

Innervation

The nerve supply of the olecranon comes from the radial nerve and ulnar nerve ³.

History and etymology

The term olecranon originates from the Greek words olene meaning elbow and kranon meaning head.

Related Pathology

• olecranon fracture
• olecranon bursitis
• gout of the olecranon bursa