=Extensor Minimi Digiti= (Fig. 73, 10; Fig. 74, 15, 16; Fig. 75, 14, 15).--This muscle, _the lateral extensor of the phalanges_ of veterinary anatomy, situated on the external surface of the forearm, behind the common extensor of the digits, arises, as a rule, from the epicondyle (dog, cat), or from the external surface of the superior extremity of the radius (horse). The tendon succeeding to the fleshy body appears towards the lower third of the forearm, and at the level of the wrist lies in a groove analogous to that which in man is hollowed out for the passage of the corresponding tendon at the level of the inferior radio-ulnar articulation. This groove corresponds to the same articulation in animals in which the ulna is well developed, such as the dog and the cat; but it belongs to the radius when the inferior extremity of the ulna does not exist--for example, in the horse. Indeed, in this animal the groove in question is found on the external surface of the carpal extremity of the radius. In the dog, the tendon is divided into three parts, which, crossing obliquely the tendons of the common extensor of the digits, pass to the three external digits, to be inserted by blending with the corresponding tendons of the latter into the third phalanges of those digits. Thus is explained the name of _common extensor of the three external digits_ which is sometimes given to this muscle. In the cat, there is a fourth tendon, which passes to the index-finger, so that the name _common extensor of the four external digits_ is in this case legitimate, and the lateral extensor of the phalanges is also a common extensor, as is the anterior extensor of the phalanges, or common extensor of the digits. In the pig, the tendon, which is single, is inserted into the external digit, for which reason it has received the name of the _proper extensor of the small external digit_. This muscle is, then, really the homologue of that which exists in the human species. In the ox, it is called the _proper extensor of the external digit_; it is as thick as the common extensor. Finally, in the horse, the muscle is little developed. Its fleshy body, thin and flattened from before backwards, becomes distinctly visible only below the middle of the forearm. Above, it is enclosed in a limited space, bounded in front by the common extensor of the digits, and behind by the posterior ulnar; there these two muscles approach each other so closely that from the point of view of external form they seem to be nearly in contact. The tendon, after receiving the small fasciculus from the common extensor (Fig. 75, 16), as well as a fibrous band emanating from the external surface of the carpus (Fig. 75, 17), is situated at the external side of the tendon of the anterior extensor of the phalanges, and is inserted into the anterior surface of the superior extremity of the first phalanx.