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Brachial bone
Last reviewed: 23.04.2024
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The humerus is a long tubular bone. Distinguish the body of the humerus (corpus humeri) and the two ends: the upper and lower. The upper end (proximal) is thickened and forms the spherical head of the humerus (caput humeri). The head is turned medially and slightly back. At the edge of the head is a groove - an anatomical neck (collum anatomicum). Immediately behind the anatomical neck are two tubercles. The large tuberculum maius lies laterally, and the small tuberculum minus is anterior to the large tuberculum. From each hillock comes a crest to the bottom: a crest of a large tubercle (crista tuberculi majoris) and a crest of a small tubercle (crista tuberculi minoris). Between the tubercles and between the crests is the intertubercular furrow (sulcus intertubercularis), intended for the tendon of the long head of the biceps brachii muscle.
The narrowest point between the head of the humerus and its body is called the surgical neck (collum chirurgicum). The body of the humerus in the upper part has a cylindrical shape, downwards it becomes trihedral. At this level, distinguish the posterior surface (facies posterior), the medial front surface (facies anterior medialis) and the lateral anterior surface (facies anterior lateralis). Somewhat higher than the middle of the body of the bone, on its lateral front surface is the deltoid tuberosity (tuberositas deltoidea), to which the deltoid muscle is attached. Below the deltoid tuberosity, a furrow of the radial nerve (sulcus nervi radialis) spirals along the posterior surface of the bone. It starts at the medial edge of the bone, bends the bone from behind and ends at the lateral margin below. The lower end of the humerus is enlarged, slightly curved anteriorly and ends with a condylus humeri. The medial part of the condyle forms a humerus block (trochlea humeri) for articulation with the ulnar bone of the forearm. The lateral block is the head of the condyle humeri (capitulum humeri) for articulation with the radius. In front of the block of the humerus is a coronoid fossa (fossa coronoidea), which is included in the elbow bend in the ulnar process of the ulna. Above the head of the condyle of the humerus there is also a depression - a radial fossa (fossa radialis). Behind the block of the humerus is the fossa of the elbow process (fossa olecrani).
From the medial and lateral sides of the humerus above the condyles, elevations are visible: the medial epicondylus (epicondylus medialis) and the lateral epicondylitis (epicondylus lateralis). The furrow of the ulnar nerve (sulcus nervi ulnaris) passes on the posterior surface of the medial epicondyle. Above, this epicondyle turns into the medial nadrum of the crista supracondylars medialis, which in the region of the body of the bone forms its medial margin (margo medialis). The lateral epicondyle extends upward into the lateral supracondylar crest (crista supracondylaris lateralis), which forms on its bones the lateral margin (margo lateralis).
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