Search results
Results from the WOW.Com Content Network
The ulna or ulnar bone (pl.: ulnae or ulnas) [3] is a long bone in the forearm stretching from the elbow to the wrist. It is on the same side of the forearm as the little finger, running parallel to the radius, the forearm's other long bone. Longer and thinner than the radius, the ulna is considered to be the smaller long bone of the lower arm.
medial (ulnar) boundary – lateral border of pronator teres muscle originating from the medial epicondyle of the humerus. lateral (radial) boundary – medial border of brachioradialis muscle [2] originating from the lateral supraepicondylar ridge of the humerus. apex – it is directed inferiorly, and is formed by the meeting point of the ...
Of these, the lateral, triangular, articulates with the scaphoid bone; the medial, quadrilateral, with the lunate bone. The articular surface for the ulna is called the ulnar notch ( sigmoid cavity ) of the radius; it is narrow, concave, smooth, and articulates with the head of the ulna.
A long bone is one that is cylindrical in shape, being longer than it is wide. However, the term describes the shape of a bone, not its size, which is relative. Long bones are found in the arms (humerus, ulna, radius) and legs (femur, tibia, fibula), as well as in the fingers (metacarpals, phalanges) and toes (metatarsals, phalanges).
Lower arm bones (4 bones in total, 2 on each side) left bone Ulna (2) (Lined up with pinky) Radius (2) (Lined up with thumb) Hand (54 bones in total; 27 in each hand) Carpals. Scaphoid bone (2) Lunate bone (2) Triquetral bone (2) Pisiform bone (2) Trapezium (2) Trapezoid bone (2) Capitate bone (2) Hamate bone (2) Metacarpals (10 bones in total ...
Its base is continuous with the body of the bone, and of considerable strength. [1] Its apex is pointed, slightly curved upward, and in flexion of the forearm is received into the coronoid fossa of the humerus. Its upper surface is smooth, convex, and forms the lower part of the semilunar notch.
The styloid process of the ulna projects from the medial and back part of the ulna. It descends a little lower than the head. 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 muscle.
The accurate adaptation of the trochlea of the humerus, with its prominences and depressions, to the trochlear notch of the ulna, prevents any lateral movement. Flexion in the humeroulnar joint is produced by the action of the biceps brachii and brachialis , [ 3 ] assisted by the brachioradialis , with a tiny contribution from the muscles ...