DR. J. MURIE ON THE ANATOMY OF THE SBA-LION. D907 
through the medium of the scapula as a fixed point, the triceps, dorsi epitrochlear, and 
flexor ulnaris muscle as combined levers, with the enlarged olecranon as a fulcrum. 
The fibres at the bend of the elbow (or here broad cubital region) form a well-marked 
arch, traversing crosswise from the anterior condyloid edge to the posterior olecranon 
border. From this downwards to the wrist there is a continuation of aponeurotic 
tissue which covers almost wholly the inner surface of the forearm. This fascia at the 
anterior or outer radial border forms a thick ligamentous-like band, which proceeds 
onwards to the carpus, joming the tendon of the extensor ossis metacarpi and pollicial 
moiety of the deep palmar fascia—ultimately being inserted, beneath the tendon of the 
ulnaris, into the proximal and plantar surface of the first metacarpal bone. On the 
ulnar side the fascia is weaker, adherent to and conterminous with that of the palmaris 
secundus. 
Deltoid.—This muscle is composed of two layers, the superficial one of which is by 
far the larger of the two. The first portion (Pl. LXX. fig. 15, D') arises from the 
whole length of the spine of the scapula, its posterior border covering the infra- 
spinatus muscle as its fibres proceed downwards. With somewhat of a flattened-arch 
contour in front, and a straight edge behind, this first part of the deltoid, becoming 
pointed below, proceeds to be inserted into the deltoid ridge. A narrow roundish slip, 
almost like a separate muscle, is moreover continued (fig. 27) down the front and out- 
side of the forearm, and ultimately joins the tendon of the supinator longus. 
The deeper second and smaller layer or portion of the deltoid is only perceptible as 
a broadish, but very thin and sparse, band of muscular fibres arising from the shoulder- 
joint, and inserted on the outer but deep side of the deltoid prominence (fig. 27, D*). 
On the opposite (right) side of the same animal no distinct slip of fibres constituting 
the above second part could be detected. It may have been incorporated with the 
cephalo-humeral; but no definite line of demarcation existed. 
Action. The powerful deltoid, with extensive origin and slanting direction of fibres 
attached low on the humeral shaft, drags backwards the limb whilst rotating it outwards. 
The supraspinatus (S.sp, figs. 20, 26) is, in relation to the infraspinatus, the broader 
muscle of the two. It has the usual origin from the supraspinous fossa, and insertion 
by a very strong broad tendon into the outer humeral tuberosity. What may be 
described as a second portion of this muscle, is the part which more directly arises 
from the superior and anterior edge of the bone. This portion, although barely 
divisible in the fleshy part (or so-called belly) of the muscle, has nevertheless a more 
or less separate insertion of a muscular kind into the inner border of the radial 
tuberosity. 
This latter-mentioned division has, moreover, a still further separation, and into 
what, with more propriety, might be considered an individual muscle episubscapularis 
(figs. 26, 27, Ep.s). The origin of this portion or muscle is in close union with that 
portion described above as the second part of the supraspinatus. It arises, therefore, 
