Table 1.
Variables of the jaw muscle of Myiopsitta monachus
| Jaw muscle | M ± SE | PCSA | Fin | MA0° | MA54° | Fout 0° | Fout 54° |
|---|---|---|---|---|---|---|---|
| TP | 0.014* | – | – | – | – | – | – |
| PPtQ | 0.031 ± 0.011 | 4.543 | 1.136 | – | – | – | – |
| Ptv(pa) | 0.135 ± 0.010 | 24.156 | 10.167 | 0.146 | 0.123 | 1.483 | 1.251 |
| Ptv(pt) | 0.119 ± 0.024 | 16.512 | |||||
| Ptd | 0.150 ± 0.014 | 23.118 | 5.780 | 0.174 | 0.159 | 1.007 | 0.918 |
| EM | 0.152 ± 0.018 | 21.812 | 5.453 | 0.515 | 0.370 | 2.811 | 2.019 |
| Pss | 0.042 ± 0.002 | 9.324 | 2.331 | 0.370 | 0.255 | 0.862 | 0.595 |
| AMEp | 0.090 ± 0.006 | 14.321 | 3.580 | 0.294 | 0.174 | 1.053 | 0.624 |
| AMEs + PM | 0.075 ± 0.014 | 14.464 | 3.616 | 0.291 | 0.272 | 1.053 | 0.985 |
| AMP | 0.029 ± 0.008 | 7.399 | 1.850 | 0.056 | 0.055 | 0.103 | 0.101 |
| DMs | 0.084 ± 0.016 | 9.254 | 2.314 | – | – | – | – |
| DMi + DMp | 0.014 ± 0.006 | – | – | – | – | – | – |
Mass value for only one muscle measured.
AMEp, m. adductor mandibulae externus profundus; AMEs, m. adductor mandibulae externus superficialis; AMP, m. adductor mandibulae posterior; DMi, m. depressor mandibulae pars intermedia; DMp, m. depressor mandibulae pars profunda; DMs, m. depressor mandibulae pars superficialis; EM, m. ethmomandibularis; Fin, input-forces (in Newtons); Fout, output-forces (in Newtons) calculated by the multiplication of Fin with MA 0° (beak closed) and 54° (maximum gape angle); MA, mechanical advantage (the ratio between the in-lever arm and the out-lever arm); M, muscle mean mass (in grams); PCSA, physiological cross-sectional area (in mm2); PM, m. pseudomasseter; PPtQ, m. protractor pterygoideus et quadrati; Pss, m. pseudotemporalis superficialis; Ptd, m. pterygoideus dorsalis; Ptv(pa), m. pterygoideus ventralis pars palatina; Ptv(pt), m. pterygoideus ventralis pars pterygoidea; SE, standard error (df: n-1).