1867.] 



Mr. J. Wood on Variations in Human Myology. 



519 



remarked in former papers upon the apparent greater frequency of one 

 variety in the foot, viz. "the abductor ossis metatarsi quinti " in the 

 female subject. This increase is clearly maintained in the results of the 

 present investigation, and apparently extends to some other muscles also. 



To economize time, space, and the difEculties of tabulation, the expla- 

 nations necessary to understand the adjoined Table are taken, as before, 

 in the order of the columns therein given. 



The first three are appropriated to the muscular varieties of the Head 

 and Nech, numbering 31 instances, viz. 24 in the 22 males, and 7 in the 

 12 females, affecting 15 different muscles. Of these, the cleido-occipital, 

 trapezius, occipito- scapular, and levator anguli scapulae, amounting to 

 16 instances, are to be considered as belonging quite as much to the 

 upper extremity. This leaves 15 specimens affecting 11 muscles of the 

 head and neck exclusively. 



1. Cleido-occipital. — By this name is signified a muscle usually about 

 three-quarters of an inch wide, which, arising from the border of the 

 clavicle outside the cleido-mastoid portion of the sterno-cleido-mastoi- 

 deus, is placed parallel to the posterior border of the latter, and separated 

 from it by a more or less wide areolar interval. It is distinguished 

 from the cleido-mastoid proper by its insertion into the superior curved 

 line of the occipital bone on the same plane as the fibres of the sterno- 

 mastoid. It joins close up to the trapezius, with which its upper 

 fibres are sometimes united. The true cleido-mastoid, on the other 

 hand, is inserted deeper than the fibres of the ster no -mastoid into the 

 mastoid portion of the temporal bone. It has been recognized as an 

 occasional accessory portion of the sterno-cleido-mastoideus, by Meckel, 

 Kelch, ScBmmerring,and Henle. In animals it forms an important part 

 of the muscle called the GepJialo-hvmeral. There were in the 34 subjects 

 examined no less than 12 specimens, all on both sides. In subject 21 it 

 was very large, broad, and double, with a superficial slip of communi- 

 cation with the cleido-mastoid. Last session the proportion of specimens 

 was strikingly similar, viz. one-third of the whole number of subjects. 



2. Omohyoid. — One of the five specimens of abnormality in this muscle 

 was found in the hinder belly arising from the whole length of the 

 middle third of the clavicle covering the subclavian artery (No. 17). In 

 the four others the anterior belly was implicated. In No. 6 it received a 

 muscular slip from the sterno-hyoid. In JSTo. 19 it contributed a large 

 slip to the same muscle, the latter being double also at its origin, and 

 giving off a muscular bundle to its fellow on the opposite side across the 

 median line. In No. 20 the anterior belly was double, the posterior 

 portion being attached by fascia to the stylo-hyoid muscle, which did 

 not reach the hyoid bone. In No. 27 the anterior belly was triple, the 

 middle portion becoming the normal insertion, the front one being in- 

 serted into the cervical fascia, and the hinder one implanted into the 

 upper horn of the thyroid cartilage.. 



VOL. XV. 2 u 



