Ulna

Ulna and radius are two bones of the forearm. In contrast to the radius, the ulna is thicker in its proximal end, where it articulates with the trochlea of the humerus.


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The frontal and anterior oblique view of the bones of the forearm The dorosal and posterior oblique view of the ulna, radius and hand bones
Right forearm bones in situ.
In the standard anatomical position (with palms faced anteriorly), the ulna lies medially, but the radius is lateral.

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Anterior aspect of the radius in situ Frontal view of the radius with the latin terminology
The anterior aspect of the right ulna.

The list of terms: Incisiura trochlearis – Trochlear notch
Processus coronoideus – Coronoid process
Incisura radialis – Radial notch
Tuberositas ulnae – Ulnar tuberosity
Corpus ulnae – Body of ulna
Margo anterior – Anterior margin
Margo interosseus – Interosseous margin
Facies anterior – Anterior surface
Caput ulnae – Head of ulna
Circumferentia articularis – Articular circumference
Processus styloideus – Styloid process

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Posterior view of the radius Back view of the radius with the latin terminology comments
The posterior aspect of the right ulna relative to other upper limb bones.
Note the most prominent structure of ulna – the olecranon. It is an attachment site for the elbow joint's extensor muscles and could be easily palpated through the skin. When you find the olecranon, it is then possible to follow the entire bone by palpating its posterior surface up to the styloid process.
The list of terms: Olecranon
Crisita m. supinatoris – Supinator crest
Corpus ulnae – Body of ulna
Facies posterior – Posterior surface
Margo posterior – Posterior margin
Facies medialis – Medial surface
Margo interosseus – Interosseous margin
Caput ulnae – Head of ulna
Processus styloideus – Styloid process

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Bones of the elbow joint The humerus, ulna and radius. The lateral oblique view of the elbow joint
The bones of the elbow joint. The oblique postero-lateral view.
The elbow joint is the complex one, as it includes three bones enclosed into one capsule. The articulation between humerus and ulna provides the flexion and extension of the forearm, but the axial rotation of the radius is the base of the pronation-supination motion.
The list of terms: Epiphysis distalis humeri – Distal epiphysis of humerus
Epiphysis proximalis ulnae – Proximal epiphysis of ulna
Epiphysis proximalis radii – Proximal epiphysis of radius
Circumferentia articularis – Articular circumference
Olecranon
Incisura trochlearis – Trochlear notch
Processus coronoideus – Coronoid process
Incisura radialis – Radial notch
Crista m. supinatoris – Supinator crest

360° rotation of the ulna. All views are synchronized.

First published: 2/Jul/2020
Last updete: 05/10/2020