It is concave from before backward, and its prominent extremities serve for the attachment of the annular ligament. The ulnar shaft has three borders (anterior, posterior, and interosseous) and three surfaces (anterior, posterior, and medial). : a single bone in the forelimb of an amphibian (such as a frog) that represents fusion of the separate radius and ulna of higher vertebrate forms First Known Use of radio-ulna 1897, in the meaning defined above History and Etymology for radio-ulna Cross-section through the middle of the forearm, showing the two bones and the muscles, nerves and blood vessels surrounding them. At birth, the ends are cartilaginous. Ulna, inner of two bones of the forearm when viewed with the palm facing forward. ulna: Legal dictionary [home, info] ulna: Financial dictionary [home, info] Computing (1 matching dictionary) ulna: Encyclopedia [home, info] Medicine (8 matching dictionaries) Ulna: MedTerms.com Medical Dictionary [home, info] ulna: online medical dictionary [home, info] Ulna: Anatomy of the Human Body [home, info] The proximal end or extremity of the ulna articulates with the trochlea of the humerus. At the junction of this surface with the front of the body is a rough eminence, the tuberosity of the ulna, which gives insertion to a part of the brachialis; to the lateral border of this tuberosity the oblique cord is attached. 7). The top end of the ulna has a distinguishing feature that sets it apart from other bones, including the similar radius. The ulna (latin: os ulna) is one of the two bones forming the skeleton of the forearm. Therefore the radius is considered to be the larger of the two. A part of the brachialis muscle inserts on this tuberosity. Its base is continuous with the body of the bone, and of considerable strength. Synonym: elbow bone 7). Near the wrist, the ulnar, with two eminences; the lateral and larger is a rounded, articular eminence, termed the head of the ulna; the medial, narrower and more projecting, is a non-articular eminence, the styloid process. (anatomy) The bone of the forearm that extends from the elbow to the wrist on the side opposite to the thumb, corresponding to the fibula of the hind limb. Scientific American The medial and lateral heads originate on the upper-arm bone and attach on the ulna , which is one of the forearm … ... the longer bone of the two bones in the lower part of the arm between the elbow and the wrist, on the side opposite the thumb see also radius (3) Topics Body c2. The apex of this process is received into the olecranon fossa of the humerus in flexion of the forearm. The radial notch is a narrow, oblong, articular depression on the lateral side of the coronoid process; it receives the circumferential articular surface of the head of the radius. The superior surface of the olecranon serves for the attachment of the triceps brachii muscle. The compact layer is continued onto the back of the olecranon as a plate of close spongy bone with lamellæ parallel. Structure This nerve is one of the branches of the brachial plexus, and it arises from the C8 and T1 nerve roots. What made you want to look up ulna? About the middle of either side of this notch is an indentation, which contracts it somewhat, and indicates the junction of the olecranon and the coronoid process. ulna meaning: 1. a long, thin bone in the lower part of your arm 2. a long, thin bone in the lower part of your…. About the fourth year or so, a center appears in the middle of the head, and soon extends into the ulnar styloid process. ulna: [ ul´nah ] ( L. ) the inner and larger bone of the forearm, on the side opposite the thumb. Definition of ULNA in the Definitions.net dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more. The upper epiphysis joins the body about the sixteenth, the lower about the twentieth year. Frequently, the flexor pollicis longus arises from the lower part of the coronoid process by a rounded bundle of muscular fibers. This notch allows for the radius to move smoothly and fre… It is on the side opposite the thumb, extends from the elbow to the wrist, and runs parallel to the radius, which it exceeds in length and size. The ulna is usually slightly longer than the radius, but the radius is thicker. And distally, the ulna articulates with the radius, forming the distal radioulnar joint. It articulates with the humerus and with the head of the radius at its proximal end; with the radius and bones of the carpus at the distal end. Its posterior surface, directed backward, is triangular, smooth, subcutaneous, and covered by a bursa. ‘Moving on to the ulna, which is the medial bone of the forearm, the radial notch may be seen clearly, articulating with the head of the radius at the superior radio-ulnar joint.’ ‘Displacement of the ulna from the trochlea, with humeroradial joint dislocation, is usually achieved only in a patient who has received general anesthesia.’ The head is separated from the styloid process by a depression for the attachment of the apex of the triangular articular disk, and behind, by a shallow groove for the tendon of the extensor carpi ulnaris. Learn more. Ossification begins near the middle of the body of the ulna, about the eighth week of fetal life, and soon extends through the greater part of the bone. https://en.wikipedia.org/w/index.php?title=Ulna&oldid=991365880, Wikipedia articles incorporating text from the 20th edition of Gray's Anatomy (1918), Creative Commons Attribution-ShareAlike License, medial surface on middle portion of coronoid process (also shares origin with, olecranon process and posterior surface of ulna (also shares origin with medial epicondyle of the humerus), coronoid process (also shares origin with medial epicondyle of the humerus and shaft of the, anteromedial surface of ulna (also shares origin with the, posterior surface of ulna (also shares origin with the posterior surface of the, posterior surface of distal ulna (also shares origin with the interosseous membrane), This page was last edited on 29 November 2020, at 17:52. radius (def. The coronoid process of the ulna is a triangular eminence that projects forward from the anterior proximal part of the ulna. Ulna: The larger of the two long bones within the forearm. The ulna is a long bone found in the forearm that stretches from the elbow to the smallest finger, and when in anatomical position, is found on the medial side of the forearm. Its apex is pointed, slightly curved upward, and in flexion of the forearm is received into the coronoid fossa of the humerus. The ulna is a long bone in the forearm. The ulna is one of two bones that give structure to the forearm. Vertical section through the articulations at the wrist, showing the synovial cavities. Specifically, the ulna joins (articulates) with: Conservative management is possible for ulnar fractures when they are located in the distal two-thirds, only involve the shaft, with no shortening, less than 10° angulation and less than 50% displacement. The long, narrow medullary cavity of the ulna is enclosed in a strong wall of cortical tissue which is thickest along the interosseous border and dorsal surface. The ulna has three segments: a proximal end, a shaft, and a distal end. The upper end of the ulna presents a large C-shaped notch—the semilunar, or trochlear, notch—which articulates with the trochlea of the humerus (upper arm bone) to form the elbow joint. Its superior surface is of quadrilateral form, marked behind by a rough impression for the insertion of the triceps brachii; and in front, near the margin, by a slight transverse groove for the attachment of part of the posterior ligament of the elbow joint. Three long bones form the framework of the arm: the humerus of the upper arm, and the radius (outer bone) and ulna (inner bone) of the forearm. grid radius grid focus. Its antero-inferior surface is concave, and marked by a rough impression for the insertion of the brachialis. 2. in anatomy, the bone on the outer or thumb side of the forearm. Below the coronoid process there is a small area of compact bone from which trabeculæ curve upward to end obliquely to the surface of the semilunar notch which is coated with a thin layer of compact bone. Anatomy. The ulna is a long bone found in the forearm that stretches from the elbow to the smallest finger, and when in anatomical position, is found on the medial side of the forearm. From the Cambridge English Corpus A subadult left ulna measures 185 mm in length, suggesting an adolescent of 9 to 15 years. At the extremities the compact layer thins. Near the elbow, the ulna has two curved processes, the olecranon and the coronoid process; and two concave, articular cavities, the semilunar and radial notches. The ulna (latin: os ulna) is one of the two bones forming the skeleton of the forearm. Definition of ulna noun in Oxford Advanced Learner's Dictionary. The ulna is usually slightly longer than the radius, but the radius is thicker. The remaining portion of the ulnar head is directed laterally, it is narrow, convex, and received into the ulnar notch of the radius, forming the distal radioulnar joint. Essential landmarks of the proximal ulna are the olecranon, coronoid process, trochlear notch, radial notch, and the tuberosity of the ulna. It also articulates with the radius at the proximal radioulnar joint. It receives the circumferential articular surface of the head of the radius at the proximal radioulnar joint. Free. Its lateral surface presents a narrow, oblong, articular depression, the radial notch. Doublet of ell. a corresponding bone in the forelimb of other vertebrates. Frequently, the flexor pollicis longus muscle arises from the lower part of the coronoid process. The olecranon can be palpated as the most pointed portion of the elbow. Ulna medical definition, flashcards and ICD-10 codes. The styloid process of the ulna projects from the medial and posterior part of the bone, and its rounded end gives attachment to the ulnar collateral ligament of the wrist joint. Proximally, it articulates with the humerus at the elbow joint. arm bone - a bone in the arm olecranon, olecranon process - process of the ulna that forms the outer bump of the elbow and fits into the fossa of the humerus when the arm is extended Based on WordNet 3.0, Farlex clipart collection. The ulna is located on the opposite side of the forearm from the thumb. The olecranon is a large, thick, curved bony projection of the ulna that extends proximally behind the elbow, forming a part of the trochlear notch. Learner's definition of ULNA [count] medical: the bone in the lower part of your arm on the side that is opposite to your thumb — see picture at human. The ulnar nerve, sometimes called the ‘funny bone,’ is one of the three main nerves in the human arm. For questions regarding business inquiries. The ulnar nerve is a long nerve, running through the whole arm. It is also referred to as the ulnar shaft or body. Include any comments and questions you have about this word. It lies medially and parallel to the radius, the second of the forearm bones.The ulna acts as the stabilising bone, with the radius pivoting to produce movement.. Proximally, the ulna articulates with the humerus at the elbow joint. Distally, the shaft of the ulna becomes narrower. The ulna forms part of the wrist joint and elbow joints. Close to the wrist, the ulna has a styloid process. (The other, shorter bone of the forearm is the radius.) (anatomy) The bone of the forearm that extends from the elbow to the wrist on the side opposite to the thumb, corresponding to the fibula of the hind limb. 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