WILLISTON: RESTORATION OF ORNITHOSTOMA (PTERANODON). 45 
articulation. It is hardly possible that the process gives attach- 
ment to any shoulder muscle; certainly its chief use can not be for 
a deltoid muscle, and the name deltoid as applied to it is, I believe, 
improper. Below the process the bone suddenly narrows to its 
least width, which is distinctly above the middle. From this con- 
tracted place the bone again widens gradually to the extremity. 
The ulnar border of the bone is nearly straight throughout. 
On the anterior ulnar side, immediately beyond the head, there 
is a large process, directed inferiorly and anteriorly, which is 
doubtless for the attachment of pectoral muscles, and may be 
known as the pectoral process. It does not extend so far as does 
the radial process, and is not so large; usually it is crushed flat to 
the shaft of the bone. 
At the distal extremity there is a large, oval, articular surface on 
the radial side, inclined anteriorly, for articulation with the radius. 
Back of this there are two articular surfaces, separated by a pit or 
depression. The anterior one, the smaller one, is seen from the 
anterior side, while the posterior is on the posterior side, concealed 
by a process at the distal extremity of the humerus, which is 
Strongly convex on the inferior margin, straight on the distal. 
Cdcrnendntnoy Sahohoatvanicr aul brkzheicnhoksy NG aia re MERGER ety a vay coy 
Greatest diameter proximal articular surface......... 50 
Greatest transverse diameter of same surface........ 30 
Width of bone 110 mm. below upper extremity...... 39 
Greatest. width through, radial process... wie. vs. 4. 04s TOO 
MVATCID rot CG Cen eset tats Gian canine yee olan Ohi)! BC 
Ulna. 
The ulna is the larger bone of the forearm, At the proximal end 
there are two concave articular surfaces, meeting each other in an 
angle, which is lodged in an excavation in the humerus. In life 
the ulna overlapped the radius to some extent when seen from in 
front. The bone is narrowed at the middle, expanding distally, 
More especially on the radial side. The distal extremity has two 
articular facets, of which the lower one is the larger. On its radial 
border the margin is expanded for about an inch and a half above 
the articulation, and is roughened. Near the distal end, between 
the two articular facets, there is a large pneumatic foramen. 
1951. 2217, 1960. 
RSG Fo diwasaritiodiear es soy ete asaniale gies or tha Waa ce Saha > aimee 
Width to ahaul aah APNE Rae NCO UOE S| 0} 60 62 
Mvddthndigtal extremity, sik ci. vee ee 81 77 
DN MMURIS uM Te Pe ay ce bute greta wets ace ice 48 45 
