OCR Text |
Show 1881.] OF CERCOPITHECUS CALLITRICHUS. 813 continuous with the postero-internal margin of the anterior belly of the muscle1. Sterno-mastoid united above with cleido-mastoid ; cleido-occipital inserted close to, hut not united with, trapezius ; omo-hyoid small, without tendinous intersection. Trapezius inserted into the whole length of the spine of the scapula, also into the outer extremity of the clavicle. Pectoralis major arises from almost the whole length of the clavicle and from the sternum as far as the xiphoid cartilage. Pectoralis minor consists of two separate parts : the anterior, from the cartilages of the third to the sixth rib, is inserted into the capsular ligament of the shoulder-joint ; the posterior, from the aponeurosis of the external oblique, is inserted by an aponeurosis into the outer margin of the bicipital groove, being connected with the insertion of the anterior part into the capsular ligament. These divisions do not touch each other, but pass separately and parallel to their insertions. Levator clavicula double, from the atlas, forms two large muscles which are inserted, one behind the other, under cover of the trapezius, into the acromion and anterior third of the spine of the scapula; from the inferior margin of the anterior muscle a small slip of muscular fibres is detached and inserted into the outer extremity of the clavicle. Levator anguli scapula and serratus magnus are so intimately connected at their insertions, that it is difficult to say where the origin of one begins or the other ends. The former appears to be represented by two perfectly separate muscles, of which one arises from the transverse process of the atlas, and is inserted into the posterior border of the scapula near its angle ; the ether, from the axis, is inserted immediately in front of the preceding; then follow two other muscular slips arising respectively from the third and fifth cervical vertebrae, which are continuous at their insertions with the serratus magnus. The three scaleni are well developed : the posterior is very large, and inserted by two divisions as far backwards as the fifth rib; the inferior division passing under cover of the external oblique to its insertion, the superior is inserted into, and becomes directly continuous with the fibres of that muscle, which may thus be said to extend from the neck to the pelvis. Bectus abdominis et sternalis is very broad ; its fibres end abruptly anteriorly along an oblique line extending from the sternum behind the articulation of the fifth rib to the commencement of the osseous part of the third rib, where it is inserted into a fibrous aponeurosis, attached internally to the sternum and anteriorly to the first rib. From the outer margin of this aponeurosis (which equals the rectus in width, and looks like its continuation forwards, but its fibres are directed obliquely forwards and outwards) a thin fiat muscle, the sterno-costalis, arises. The deltoid is well developed; its inferior margin is connected 1 See m y paper, " O n the Tendinous Intersection of the Digastric," Proc Eoy. Soc. 31st March 1881. |