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.
Right forearm bones in situ.
In the standard anatomical position (with palms faced anteriorly), the ulna lies medially, but the radius is lateral.
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
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
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: 18/Jan/2021