1895. | NEW YORK ACADEMY OF SCIENCES. 241 
b a 
£ y x y 
Fic. 9. Reduction variation; Origin Fic. 10. Reduction variation; Origin 
reduced; Insertion retained. reduced; Insertion retained. 
the insertion, or of both, is eliminated, necessitating, under 
some conditions, a change in the direction of the muscular fibres. 
These variations are represented schematically by Figs. 3-10, 
it being of course evident that the arbitrarily selected points a 
and b, and x and y, may be placed anywhere along the lines of 
origin and insertion respectively. 
In defining the following variations in the human Biceps I pre- 
fer to accentuate this relation to a fundamental vertebrate type- 
plan, and, at the expense of introducing an additional term into 
the complex reversional nomenclature, I will speak of them as 
“ Myo-typical Reversions.” 
In man the Biceps is composed of the Gleno-radial and Coraco- 
radial divisions, combined with a superficial ulnar fasciculus, 
possessing a fascial insertion along the ulnar border of the fore- 
arm by means of the semilunar fascia. 
We may group the variations which concern us here with 
reference to the derivation and destination of the accessory 
portions. representing additional glenoid and coracoid heads, 
which have lost their distal ulnar attachment. 
I. GLENO-ULNAR HEAD. 
Appears in the following forms: 
1. CAPSULO-PECTORAL TENDON. 
Diagnosis: Tendinous fibres in the form of scattered bundles, 
or more compactly arranged as distinct tendon-bands, arising in 
conjunction with the capsular ligament from the glenoid margin of 
the scapula, differentiating from the capsule at the upper border of 
the intertubercular groove and extending downwards over the 
TRANSACTIONS N. Y. AcAD. S¢t., Vol. XIV., Sig. 16, August 28, 1895. 
