Part 292

This section consists necessarily only of a brief statement of the most important differences in the joints of the other animals.

Footnote 40:

These movements are best seen in man, in whom the back of the hand may be turned forward (pronation) or backward (supination).

Footnote 41:

The student will note in dissection that transition forms occur; also that the same sheath may belong to two or more tendons in common, e. g., the sheath of the two flexors on the back of the carpus. In such cases the synovial membrane is reflected from one tendon to the other, and may form a secondary mesotendon.

Footnote 42:

This muscle is probably the homologue of the sternal portion of the sterno-cleido-mastoid of man. On account of the differences in its insertion in the various animals, it seems desirable to adopt the name sterno-cephalicus.

Footnote 43:

The upper part of this maybe separated from the scalenus proper, and is then termed the cervicalis ascendens or ilio-costalis cervicis—a continuation in the neck of the transversalis costarum.

Footnote 44:

This seems due to pressure produced by pathological changes in the supra-atloid bursa, which are frequently extensive in dissecting-room subjects.

Footnote 45:

The lumbar part of this muscle is subject to variation. It may, in quite exceptional cases, extend as far as the ilium.

Footnote 46:

The muscle as here described includes the spinalis and semispinalis components, as the separation of these is largely artificial in the horse.

Footnote 47:

The function of the intercostal muscles is still a subject of much discussion. The statements made above seem to represent the view most commonly held in regard to their action.

Footnote 48:

It should be noted, however, that in the embryo the diaphragm appears as a paired structure, extending from the lateral walls of the cœlom to fuse with the septum transversum.

Footnote 49:

In order to get a clear idea of the relative positions of these foramina and of the form of the diaphragm, the thoracic surface of the latter should be examined while the abdominal viscera remain in situ.

Footnote 50:

It is narrow and slit-like in the natural condition, but may appear oval in the dissecting-room, especially if the hind limb is drawn back and abducted.

Footnote 51:

It must be admitted that the term “ring” is rather misleading as applied to the abdominal opening of the canal, since normally it is a mere dilatable slit. The ring-like constriction which exists here in the male is constituted by the peritoneum, which descends into the canal to form the tunica vaginalis. This peritoneal ring is termed the =vaginal ring= (Annulus vaginalis), and must not be confused with the subperitoneal ring, i. e., the internal inguinal ring.

Footnote 52:

As might be expected, the cremaster usually undergoes more or less atrophy, and is paler in the castrated subject. In the mare the muscle is small, and ends in the connective tissue in the lower part of the inguinal canal.

Footnote 53: