Relation to the Tracheal form on the Dogs (On the mongrel Dogs of about 10kg b.w.)

Measurement of the trachea of 10 mongrel dogs (8 males and 2 females), each weighing 10 kg, was carried out to study the general length of the trachea and the amount as well as the lengthwise and breadthwise diameters of the cartilagines trachealis. Observation was also made on the appearance of the endotracheal tube using radiograph and endoscope.The results are outlined below:1. Study was made to discover a constant in the ratio of the length of the trachea in comparison with the body weight, the body length, the body height, the circumference of the neck and shoulders, and the length of the neck. A constant of 0.6 to 0.7 was obtained on the ratio of the body weight to the length of the trachea. However, a constant ratio on other comparisons was not possible. Moreover, the number of cartilagines trachealis varied widely from 33 to 46 in the animals.The breadthwise diameter of the cartilagines trachealis gradually increased in size from the 1st to the 5th and 9th, which were the largest, then gradually decreased in size. As to the lengthwise diameter of the cartilagines trachealis, the 1st was the largest with subsequent ones gradually decreasing in size toward the tracheal-biffureation.From the foregoing, it can be concluded that an endotracheal tube with an exterior diameter of 10 mm is suitable for the trachea of dogs weighing 10 kg.2. Observation using radiograph and endoscope indicates the area between the 1st to the 12th cartilagines trachealis as being the position suitable for the placement of the call. Moreover, to obtain airtight sealing point, a minimum Gaff air pressure of 2 to 3 ml was found to be suitable.