[21] Ventri, because inserted into the inferior part of the spine of the scapula, towards the acromion--that is, on the ventral side--by contrast with the trapezius, which is attached higher up (dorsal side) on the same process.
[22] Among the many names given to this muscle, Arloing and Lesbre recommend the adoption of the name 'transverse scapular' given by Straus-Durckheim, or 'transverse of the shoulder' (Arloing and Lesbre, 'Suggestions for the Reform of Veterinarian Muscular Nomenclature,' Lyons, 1898).
The omo-trachelian muscle is found in all mammalia, man alone excepted. It is, however, sometimes found in the human being; but it then constitutes an anomaly.
In the dog, pig, and ox, it arises from the inferior part of the spine of the scapula, in the region of the acromion, and terminates on the lateral portion of the atlas.
In the cat it is attached besides to the base of the occipital bone. It is visible in the space limited by the trapezius and the mastoido-humeral, the direction of which it crosses obliquely.
In the horse it appears to be blended in clearly defined fashion with the mastoido-humeral. Attached below, like this latter, to the anterior border of the humerus, it covers the scapulo-humeral angle; and is attached by its upper portion to the transverse processes of the first four cervical vertebræ.
We remember that the transverse processes are often, from their relation with the trachea, known as the tracheal processes. Hence the word 'trachelian,' which forms part of the name of the muscle with which we are now dealing.
By its contraction it helps to draw the anterior limb forwards.
When this muscle, as an abnormality, exists in man, it arises from the clavicle or the acromion process, traverses the supraclavicular fossa, and is inserted into the transverse processes of the atlas or axis, or of both these vertebræ, or of the cervical vertebræ below these latter. It is then known by the names of the _elevator of the clavicle_ or _elevator of the scapula_, and, finally, as the _cleido-omo-transversalis_ (Testut).[23]
[23] L. Testut, 'Les anomalies musculaires chez l'homme expliquées par l'anatomie comparée,' Paris, 1884, p. 97. A. F. Le Double, 'Traité des variations du système musculaire de l'homme et de leur signification au point de vue de l'anthropologie zoologique,' Paris, 1897, t. i., p. 235.