Ulna

Description

Ulna anatomy labeled

PA and lateral radiographs of the forearm labeled

The proximal ulna is labeled

Distal ulna and distal radioulnar joint with TFCC

Name

• Ulna
• Forearm Bone

General

• Medial bone of the forearm
• Proximal end articulates with the humerus at the elbow joint and with head of radius at the proximal radioulnar joint
• Distal end articulates with radius at distal radioulnar joint
• Ulna is separated from wrist joint by an articular disc
• The proximal and large end of ulna is the olecranon process forming the prominence of the elbow

Anatomic Description

• Trochlear notch is on the anterior surface of ulna and it articulates with trochlea of humerus
• Coronoid process is located below the trochlear notch
• Radial notch is located on the lateral surface of the coronoid process and it serves for articulation with the radius
• Supinator crest is located below the radial notch and it gives origin to the supinator muscle
• The shaft of ulna goes from above down
• The shaft has a sharp interosseous border laterally for interosseous membrane attachment
• The ulna posterior border is rounded and subcutaneous
• The head of the ulna is located at its distal end
• The styloid process is a projection from the medial aspect of ulnar head

Annular Ligament

• Extends from the surface of the ulna both anterior and posterior to the radial notch and wraps the head of the radius
• Holding it in the radial notch of the ulna
• Helps to form the pivot type joint known as the proximal radio-ulnar joint.

Ulnar Collateral Ligament

• Located in the medial side of the elbow
• Attached to the humerus and to the ulna
• Consists of three bands anterior, posterior and transverse it plays an important role in elbow stability.

Articulations

• Elbow Joint: Articulates with Humerus to allow flexion and extension
• Proximal Radioulnar Joint: allows for pronation/supination
• Distal Radioulnar Joint: allows for pronation/supination
• Ulnocarpal Joint: articulates with lunate, triquetrum to contribute to wrist joint

Muscle Attachments: Elbow

• Brachialis
• Biceps Brachii
• Triceps Brachii
• Anconeus

Muscle Attachments: Forearm

• Pronator Teres
• Pronator Quadratus
• Supinator

Muscle Attachments: Hand, Wrist and Thumb

• Extensor Carpi Ulnaris
• Extensor Indicis
• Extensor Pollicis Longus
• Extensor Digitorum
• Extensor Digiti Minimi
• Flexor Carpi Ulnaris
• Flexor Digitorum Superficialis
• Flexor Digitorum Profundus
• Abductor Pollicis Longus

Vascular Supply

• Primarily Ulnar Artery
• Also, Common Interosseous Artery

Innervation

• Ulnar Nerve

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Clinical Significance

• Distal Ulna Fracture
• Isolated Ulna Fracture
• Radius Ulna Fracture
• Monteggia Fracture
• Ulnar Impingement Syndrome

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See Also

Elbow

• Elbow Anatomy Main
• Elbow Pain Main
• Physical Exam Elbow

Forearm

• Forearm Anatomy
• Forearm Pain (Main)

Wrist

• Hand And Wrist Anatomy
• Wrist Pain (Main)
• Physical Exam Wrist

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