Volume 1
On the anatomy, physiology, and pathology of the chimpanzee / by Charles F. Sonntag.
- Sonntag, Charles F. (Charles Frederick), -1925
- Date:
- 1923
Licence: In copyright
Credit: On the anatomy, physiology, and pathology of the chimpanzee / by Charles F. Sonntag. Source: Wellcome Collection.
25/118 page 345
![The pectoralis minor appears to vary considerably both in origin and insertion. In mv specimen it arises by three well-marked slips from the lower borders of the second, third, and fourth costal cartilages. Its long, but strong, tendon passes through a fibrous and synovial sheath over the coracoid process, and it is inserted into the upper and back part of the capsule of the shoulder joint. The sheath is adherent to the inner and upper parts of the coracoid process. Champneys (11) gives its origin from the first four ribs and its insertion into the capsule of the shoulder joint close to the supra-spinatus tendon, and Humphry (26) mentions it as extending across to the great tuberosity of the humerus. Bland-Sutton (4) describes an insertion similar to that in my specimen, but gives its origin as ribs three, four, and five. Wilder (53) and Gratiolet (22) record tendons inserted into both the coracoid process and capsule of the shoulder joint, and the latter gives the origin as ribs two to five inclusive. So if several animals are examined the muscle appears to write its evolutionary history. The serratus magnus arises by eleven digitations from the first eleven ribs, the first one being very small, but it has a remark- ably rich supply of nerves (text-fig. 48). The first nine arise from the outer surfaces of the ribs, but the tenth and eleventh arise from the lower borders. The digitations arising from the fifth to the eleventh ribs interdigitate with the external oblique. The muscle is thick at its insertion into the deep aspect of the vertebral border of the scapula. The part arising from the first four ribs is much thinner than the remaining part of the muscle. Champneys (11) has given the origin as from the first ten ribs, and described the muscle as consisting of three parts, which he describes in great detail, but Wilder (53) describes two parts, and gives the origin from all the ribs. The subclavius arises from the upper border of the first costal cartilage immediately internal to the rib. It is inserted into the under surface of the second quarter of the clavicle from the inner end. It is enveloped as in Man by the costo-coracoid membrane. The costo-coracoid membrane is attached to the first costal cartilage round the tendon of origin of the subclavius, to the inferior surface of the sterno-clavicular joint, to the under sur- face of the clavicle by two layers which enclose subclavius as in Man, and to the anterior surface of the clavicle lateral to the subclavius. The costo-coracoid ligament is well marked. Several authors have recorded the latter. The clavi-pectoral fascia ex- tending downwards from the costo-coracoid ligament splits to enclose the pectoralis minor, and at the same time it sends a process inwards to the neuro-muscular bundle in the axilla. External to the pectoralis minor the fascia passes to the deep fascia of the axilla, and it passes mesially to the deep fascia covering the serratus magnus between the pectoralis major and latissimus dorsi. The membrane is pierced by the external [23]](https://iiif.wellcomecollection.org/image/b2982123x_0001_0025.jp2/full/800%2C/0/default.jpg)
