<s>[INST] context: In exposed positions the former sign may be elicited by directly grasping the segments of the bone and moving either upon the other; in other cases (fracture of the surgical neck of the humerus) the surgeon must be satisfied with determining that the motions (rotation) of one fragment (the shaft) are not imparted to the other, as indicated by the immobility of one of its bony points (the greater tuberosity) Again, abnormal mobility near a joint may simulate abnormal mobility of the joint itself, and special care be necessary to differentiate between fracture and dislocation. is the grating sensation heard or felt when the two rough bone ends rub against each other?
The intervention of soft parts between the bone ends, of course, prevents crepitus, which may, on the other hand, be simulated by the crackling of coagulated blood, by roughened joint-surfaces, by tenosynovitis, and by emphysema.
Finally, be it espe cially noted that although abnormal mo bility and crepitus are pathognomonic, they are often by no means necessary to the diagnosis of fracture, and the manip ulations which they require may be not only extremely painful, but also, by pro ducing further lacerations of the soft parts, positively harmful to the patient. [/INST] question: A diagnostic sign of a fracture | options: A: Abnormal mobility at fracture site B: Pain at the fracture site C: Tenderness D: Swelling | answer: A </s>