Table 6.
List of osteological correlates of the origin and insertion of each muscle observed in the present study
| Standardized muscle name | Origin/Insertion | Lepidosauria | Testudines | Crocodilia | Aves |
|---|---|---|---|---|---|
| M. tibialis cranialis | Origin | Absent | Absent | Absent | The lateral expansion of the cranial cnemial crest and the dorsoventral expansion of the lateral cnemial crest |
| Insertion | A tubercle on each lateroplantar aspect of MTs II & III | A laterodorsal surface of each distal shaft of MTs I–IV | A tubercle on the medial margin of each proximal shaft of MTs II–IV | Tubercles on the dorsal aspect of the proximal tarsometatarsus (tuberositas m. tibialis cranialis) | |
| M. extensor digitorum longus | Origin | Absent | A rugose longitudinal sulcus on the dorsomedial margin of the tibia | A rugose surface on the proximal‐most portion of the dorsal aspect of the tibia | A broad surface between the cranial and the lateral cnemial crests |
| Insertion | Absent | A tubercle on the proximomedial end of MT I | A bulge on each dorsal aspect of MTs I and II | The proximodorsal lip of each phalanx of digits II–IV except proximal‐most phalanges | |
| M. peroneus longus | Origin | Absent | A slightly excavated dorsal surface on the distal half of the fibula | A laterodorsal surface of the fibula, between each longitudinal ridge on the dorsal and the lateral aspects of the shaft | Proximal margins of the cranial and the lateral cnemial crests |
| Insertion | A depression on the dorsolateral aspect of MT V | Absent | A flat surface on the proximolateral margin of MT V | Absent | |
| M. peroneus brevis | Origin | Absent | Absent | A flat laterodorsal surface on the distal two thirds of the fibular shaft | A laterodorsal surface of the distal two thirds of the tibial shaft and a dorsal surface of the distal half of the fibular shaft |
| Insertion | A process on the proximolateral margin of MT V (outer process) | Absent | Absent | A proximal surface near the lateral margin of the hypotarsus (tuberculum m. fibularis brevis) | |
| M. adductor hallucis dorsalis | Origin | A dorsolateral surface of the distal end of the fibula and the medial half of the proximolateral lip of the tarsal facet of the astragalocalcaneum | A depression on the distodorsal margin of the tibia | Absent | NA |
| Insertion | Absent | Absent | Absent | NA | |
| M. extensor digitorum brevis | Origin | A depression on the dorsal aspect of astragalocalcaneum | A depression on the dorsal aspect of DT IV | A depression on the dorsal aspect of the astragalus | NA |
| Insertion | The proximodorsal lip of each phalanx of digits III and IV (as well as digits I and II in some taxa) | The proximodorsal lip of each phalanx of digits III and IV | The proximodorsal lip of each phalanx of digits I–III | NA | |
|
M. extensor hallucis brevis |
Origin | Absent | Absent | The dorsal aspect of MT I, distal to the transverse ridge | Longitudinal depressions on the medial parts of the dorsal aspects of the tarsometatarsus and MT I |
| Insertion | The proximodorsal lip of each phalanx of digit I | The proximodorsal lip of I−2 | The proximodorsal lip of each phalanx of digit I | The proximodorsal lip of each phalanx of digit I | |
| M. extensor digiti II | Origin | Absent | Absent | Absent | NA |
| Insertion | The proximodorsal lip of each phalanx of digit II | The proximodorsal lip of each of II−2 and 3 | The proximodorsal lip of each phalanx of digit II | NA | |
| M. extensor digiti III | Origin | Absent | Absent | Absent | A slightly depressed rugose surface on the dorsal aspect of the distal half of the tarsometatarsus |
| Insertion | The proximodorsal lip of each phalanx of digit III | The proximodorsal lip of each of III−2, 3, and 4 | The proximodorsal lip of each phalanx of digit III | The proximodorsal lip of III−1 | |
| M. extensor digiti IV | Origin | Lateral half of the proximolateral lip of the tarsal facet of the astragalocalcaneum | Absent | Absent | NA |
| insertion | The proximodorsal lip of each of IV−2, 3, 4 and 5 | The proximodorsal lip of each of IV−2, 3, 4 and 5 | The proximodorsal lip of each phalanx of digit IV | NA | |
|
M. interosseous dorsalis digiti II |
Origin | A longitudinal rugosity along the lateral margin of MT I | A rugosity on the proximomedial margin of the dorsal aspect of MT I | A depression on the lateroplantar aspect of MT I | An oblique groove on the medial aspect of the tarsometatarsus and the fossa metatarsi I |
| Insertion | The proximodorsal lip of each phalanx of digit II | The proximodorsal lip of each phalanx of digit II | The proximodorsal lip of II−1 | A medioplantar tubercle on the proximal end of II−1 | |
| M. interosseous dorsalis digiti III | Origin | A longitudinal rugosity along the lateral margin of the proximal half of MT II | A rugosity on the proximomedial margin of the dorsal aspect of MT II | A rugosity on the proximolateral margin of each of dorsal and lateral aspects of MT II | NA |
| Insertion | The proximodorsal lip of each phalanx of digit III | The proximodorsal lip of each of III−2, 3, and 4 | The proximodorsal lip of III−1 | NA | |
| M. interosseous dorsalis digiti IV | Origin | A longitudinal rugosity on the lateral margin of the proximal half of MT III | A rugosity on the proximomedial margin of the dorsal aspect of MT III | A depression on the lateroplantar aspect of the proximal shaft of MT III | A sulcus laterally along the origin of m. extensor brevis digiti III |
| Insertion | The proximodorsal lip of each pahalnx of digit IV | The proximodorsal lip of each of IV−2 and 3 | The proximodorsal lip of IV−1 | A tuber on the medial aspect of IV−1 | |
| M. gastrocnemius | Origin | The medial and the lateral femoral epicondyles and distal portion of the tibial ventral crest | A rugose swelling on the medial margin of the dorsal aspect of the tibia, a blunt depression on the ventral aspect of the proximal tibia, and a depression on the lateroventral aspect of the distal femur | A depression on the lateroventral margin of the distal‐most portion of the shaft of the femur | A rugose depression on the lateroventral margin of the distal‐most portion of the femoral shaft, a shallow depression just proximal to the medial distal condyle of the femur, and the medial aspect of the cranial cnemial crest of the tibia |
| Insertion | The medial and the lateral plantar tubercles of MT V | A prominent tubercle on the lateral margin of the plantar aspect of MT V | The lateral flange of MT V | Longitudinal ridges on the medial and lateral margins of the plantar aspect of the hypotarsus and the tarsometatarsal shaft | |
| M. flexor hallucis longus | Origin | Absent | A shallow and broad depression on the lateroventral aspect of the femur | Absent | Several facets on the distal end of the fossa poplitea of the femur |
| Insertion | The flexor tubercle of each ungual of digits II–IV | The flexor tubercle of each ungual of digits I–IV | The flexor tubercle of each ungual of digits I–IV | The flexor tubercle of I−2 and the proximoplantar heel of each non‐ungual phalanx of digits II–IV | |
| M. flexor digitorum longus | Origin | A depression on the medial aspect of the fibula, just distal to the fibular attachment of m. popliteus | A distinct surface between the lateral margin of the shaft and the longitudinal ridge situated laterally on the ventral aspect of the fibula | A flat surface on the ventral aspect of the fibula, and depression on the ventral aspect of the proximal‐most tibial shaft | A flat surface on the dorsal aspect of the proximal one third and the lateral and ventral aspects of the distal two thirds of the fibular shaft |
| Insertion | The flexor tubercle of each ungual of digits II–IV | The flexor tubercle of each ungual of digits I–IV | The flexor tubercle of each ungual of digits I–IV | The flexor tubercle of each ungual of digits II–IV | |
| M. pronator profundus | Origin | A flat surface on the ventral aspect of fibula | A flat surface between two longitudinal ridges on the ventral aspect of the fibular shaft | A flat surface between longitudinal stout ridges on the dorsolateral and lateral margins on the ventral aspect of the tibial shaft | NA |
| Insertion | Rugose surfaces or swellings on the proximomedial margins of the plantar aspects of MTs I–III | Absent | Narrow and rugose swelling on the proximomedial margin of the plantar aspect of MT I | NA | |
| M. fibulocalcaneous | Origin | A smooth surface on the plantar aspect of the calcaneal tuber | NA | A flat surface on the ventral aspect of the distal one third of the fibula | NA |
| Insertion | Absent | NA | The dorsal surface of the calcaneal tuber | NA | |
| M. flexor digitorum brevis superficialis | Origin | Absent | Absent | Longitudinal ridge or bulge on the lateroplantar margin of MT V | NA |
| Insertion | The proximoplantar heel of each non‐ungual phalanx of digits I–IV | The proximoplantar heel of each of II−1, III−1, and IV−1 | The proximoplantar heel of each non‐ungual phalanx of digits I–III | NA | |
| M. flexor digitorum brevis profundus | Origin | A concavity on the medial aspect of MT V | NA | Medial and lateral margins of the calcaneal tuber and the concavity on the distomedial margin of the plantar aspect of MT V | NA |
| Insertion | The flexor tubercle of each ungual of digits I–IV | NA | The flexor tubercle of the unguals of digits I–III | NA | |
| Mm. lumbricales | Origin | Absent | Absent | Absent | NA |
| Insertion | The proximoplantar heel of each non‐ungual phalanx of digits III and IV | Absent | Absent | NA | |
| M. lumbricalis profundus | Origin | Absent | Absent | Absent | Absent |
| Insertion | The proximoplantar heel of each of II−1, III−1, and IV−1 | Absent | Absent | Absent | |
| M. flexor hallucis brevis | Origin | The plantar tubercle of DT IV | A depression on the plantar aspect of DT I | Absent | NA |
| Insertion | The proximoplantar heel of I−1 | The proximoplantar heel of I−1 | The longitudinal depression on the planter surface of MT I and the proximoplantar heel of I−1 | NA | |
| M. adductor digiti V | Origin | Absent | NA | NA | NA |
| Insertion | Absent | NA | NA | NA | |
| Mm. contrahentes | Origin | A small tubercle on the medial margin of the shaft of MT V | Absent | A depression on each plantar aspect of DTs III and IV and a tubercle on the distal end of MT V | NA |
| Insertion | Absent | Absent | The medioplantar surface of each of MTs II, III, and IV | NA | |
| M. adductor hallucis plantaris | Origin | The dorsomedial surface of the proximal shaft of MT II | A depression on the medial aspect of the proximal portion of MT II | A depression on the mediodorsal aspect of near the proximal end of MT II | The medial part of the sulcus flexorius of the tarsometatarsus |
| Insertion | Absent | Absent | A broad, shallow depression on the plantar aspect of MT I | The proximoplantar heel of I‐1 | |
| M. interosseous plantaris digiti II | Origin | The dorsomedial and medioplantar surfaces of the proximal shaft of MTIII | A depression on the medial aspect of MT III | Depressions on the dorsomedial and medioplantar aspects of near the proximal end of MT III | The central part of the distal sulcus flexorius |
| Insertion | The lateroplantar surface MT II | Absent | The lateroplantar surface of MT II | A small tubercle on the lateroplantar margin of the proximal end of II−1 | |
| M. interosseous plantaris digiti III | Origin | The medial and the plantar surfaces of proximal two thirds of MT IV | A depression on the medial aspect of MT IV | Depressions on the dorsomedial and medioplantar aspects near the proximal end of MT IV | NA |
| Insertion | The lateroplantar surface of MT III | Absent | The lateroplantar surface of MT III | NA | |
| M. abductor digiti IV | Origin | The dorsomedial surface of MT V | A depression on the distal aspect of the medial portion of MT V | The mediodistal margin of the dorsal aspect of MT V | The lateral portion of the sulcus flexorius |
| Insertion | Absent | Absent | A flat surface between the plantar ridge and the medial margin of MT IV | A tubercle projecting plantarly on the lateroproximal margin of IV−1 |
NA indicates the absence of the muscle itself.