01.09.2014 Views

Boyer diss 2009 1046..

Boyer diss 2009 1046..

Boyer diss 2009 1046..

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

trochleae of the proximal phalanges. The dorsal and ventral margins extend proximally<br />

roughly equal distances, relative to the proximodistal axis of the shaft. However, the<br />

ventral margin is usually slightly more proximally projecting, which makes the proximal<br />

articular surface face slightly dorsally, relative to the shaft axis. The proximal end is<br />

usually slightly greater in its dorsoventral depth than its proximodistal width, with a<br />

couple of exceptions for certain manual elements. The ventral surface is marked by<br />

prominent tubercles that project ventrally. These appear to be either the flexor sheath<br />

tubercles or insertion points for the flexor digitorum superficialis tendons. Beyond the<br />

proximal end, the shaft shape is similar to that of proximal phalanges, narrowing in its<br />

mediolateral dimension until roughly the proximodistal midpoint of the shaft, and<br />

narrowing in its dorsoventral dimension for the entire length of the shaft. For much of the<br />

shaft length, the dorsoventral dimension is greater than the mediolateral dimension. The<br />

shafts are essentially straight, except for the three longest (probably pedal) elements,<br />

which show the slightest amount of dorsal convexity (<strong>Boyer</strong> and Bloch, 2008). The distal<br />

ends of the intermediate phalanges have a single groove down the center of their distal<br />

articular surface, rather than two grooves, as in the case of proximal phalanges. In lateral<br />

profile it can be seen that distal articular surface has a fairly constant radius of curvature<br />

and ~180° of arc to it, although one phalanx (Fig. 4.21G) appears to have well over 180°.<br />

Furthermore, in dorsal and lateral view it can be seen that the articular surfaces have a<br />

greater amount of ventral-facing area than dorsal-facing area, although they are not as<br />

retricted in the amount of dorsal area as the proximal phalanx distal articlar facets.<br />

Function.—The dorsoventrally deep shafts of the intermediate phalanges suggest<br />

that they were resistant to parasagittal stresses experienced due to body weight during<br />

322

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!