Ulna Bone of animals
Ulna Bone of animals is a long bone and longer than the radius. It situated on the posterolateral aspect of the radius.
Ulna bone of Ox
Ulna Bone of Ox is a long bone and longer than the radius. It situated on the posterolateral aspect of the radius. It is fused with the radius in the adult, except at the two inter-osseous spaces above and below.
Shaft of ulna
Shaft of ulna is complete, three sided and strongly curved. Its proximal part contains the medullary cavity, which extends somewhat into the proximal end.
The dorsal face is rough except at two places where it is smooth and is applied to the volar aspect of the radius, the medial face is wide and the lateral face presents the radio-ulnar groove between it and the radius.
Proximal extremity of ulna
Proximal extremity of ulna forms the major part of the bone and is made up of the semilunar notch and the olecranon process.
The olacranon processis quadrilateral in shape directed upward and backward. The medial surface is concave and smooth while the lateral is convex and rough above. The anterior border bear on its middle a pointed projection the anconeus process that is for anconeus and during extreme extension of the elbow joint it passes into the olecranon fossa of the humerus. The posterior border is thick and concave. The summit of the olecranon process forms the point of the elbow and gives attachment to triceps.
The semilunar notch is placed below the anconeus process and articulates with the posterior part of the medial division of the articular area of the humerus. Below the notch are two facets for articulation with the like facets on the posterior face of the proximal extremity of the radius.
Distal extremity of ulna
Distal extremity of ulna is fused with the radius. It projects below the level of the radius forming the styloid process of ulna, which furnishes a part of the facet for the ulnar carpal.
Ulna bone of Sheep and Goat
Shaft of the ulna in sheep and goat is more slender especially in the distal half. Fusion with the radius occurs in the later part of the life and the fusion is much less extensive than the ox.
Ulna bone of Horse
Ulna of horse is shorter, reaching only the distal third of the radius. It forms only the proximal radio-ulnar arch. There is no articulation with the ulnar carpal.
Ulna bone of Pig
The proximal extremity of ulna of pig is large and the olecranon process is prominent. The distal extremity is small and tapers to a blunt point.
Ulna bone of Dog
Ulna of dog is well developed and crosses the volar face of the radius medio-laterally closing a narrow interosseous space.
The olecranon is grooved and shows three prominences of which the posterior one is large and rounded. Below the semilunar notch is concave surface for the radius. The styloid process articulates dorso-medially with radius and low with ulnar and the accessory carpals.
Ulna bone of Rabbit
Ulna of Rabbit is similar to that of dog.
Ulna bone of Fowl
Ulna of fowl is larger and thicker than the radius. It is curved in it’s length.
The proximal extremity has two concave articular areas and olecranon process is short.
The distal extremity is expanded and presents a trochlea and articulates with radial and ulnar carpal bones.
