On a group of varieties of the muscles of the human neck, shoulder, and chest : with their transitional forms and homologies in the Mammalia / by John Wood ; communicated by Dr. Sharpey.

Wood, John, 1825-1891.

Date:: [1869]

Credit: On a group of varieties of the muscles of the human neck, shoulder, and chest : with their transitional forms and homologies in the Mammalia / by John Wood ; communicated by Dr. Sharpey. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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$former, and ended below by dividing opposite the last cervical vertebra into two, which were both implanted by separate short tendons into the fascia covering the serratus posticus superior (s), the innermost near the junction of its tendon and fleshy belly. The other was exactly similar to the smaller one (s) described in the last figure, and was inserted, like it, into the serratus magnus close to its insertion into the base of the sca- pula opposite the spine. All the abnormal slips of muscle just described were apparently developed in the fascia covering the hinder surfaces of the splenii, levator anguli scapulae, and serrati muscles. The one marked A in fig. 3 had an origin quite similar to that of the occi- pito-scapular found on the right side in the subject of fig. 2 (d); its insertion, however, took place upon the surface of the serratus posticus superior instead of upon the rhom- boid or more superficial muscular layer, which it had, as it were, failed to reach. The other slips (s and y) were directly connected with the scapula through the insertion of the serratus magnus, as was also the slip (f) found in the subject of fig. 4. In the subject of the next illustration (Plate IX. fig. 5), a muscular male, were found muscular slips (s and v) of a precisely similar character, but connected rather with the front surface of the levator anguli than with the back. The upper and longer one (v\) arose with the third digitation of the levator anguli scapulae, but in front of it, and passed downwards, in front also of the fourth slip of origin of that muscle, as a fusiform muscle about 8 inches long, which was inserted by a falciform tendon into the lower part of the base of the scapula, between the insertions of the rhomboideus major (R) and the serratus magnus (S). The other slip (s) was similar in its upper attachment to that marked with the same letter in the previous figures, but was inserted below into the serratus posticus superior (s), instead of into the serratus magnus, as was the case with the others. In two other subjects, both females, were found also slips of muscle connected with and lying upon the front surface of the levator anguli scapulae. In one it was found on the right side only, arising from the third cervical transverse process, as a fusiform muscle, which was inserted into the hinder surface of the upper digitation of the serratus magnus near its scapular attachment. In the other, the subject of fig. 6 (Plate IX.), the muscular slip (v) arose from the second cervical transverse process, was placed in front of the levator anguli scagmlce, and was inserted also in front of the upper digitation of the serratus magnus, upon the fascia covering which its tendon was lost in the axillary space; it was likewise fusiform in shape and about 6 inches in length. I have now followed these curious transitional slips of muscle in the changes of their upper attachment from the superior curved line of the occipital bone, through the splenius capitis and colli, to the hinder surface, and, at last, to the front surface of the vertebral origin of the levator anguli scapulae. At their lower attachments we can trace them also from the base of the scapula, through the insertion of the rhomboids and the serratus posticus superior, to the back surface, and, at last, to the front surface of the serratus magnus. Here we link on a human muscular abnormality, also connected with the front surface of the levator anguli'$