The digital tendon locking mechanism of the avian foot (Aves)
- 425 Downloads
- 31 Citations
Summary
Representatives of all avian orders were studied in order to establish that the tendon-locking mechanism (TLM), consisting of local specialization of the flexor tendons and the adjacent portion of the flexor tendon sheath, is by no means rare, but rather, constitutes the prevalent condition in a large majority of the avian species sampled. The areas of tubercles on the tendons and the adjacent sheath plications intermesh with one another thereby forming a true tendon-locking mechanism that maintains the distal and other interphalangeal joints of the digits in the flexed position. The TLM seems to function not only in perching, but in a wide variety of other activities of the avian foot including swimming, wading, prey-grasping, clinging, hanging, and tree climbing. The basic structural components of the mechanism are remarkably similar in the divergent avian groups adapted for these activities. Ultrastructural detail of the TLM was studied by means of scanning and transmission electron microscopy. Interdigital variation in distribution of the TLM in all of the digits of individuals were made as were comparisons of the interspecific distribution of the TLM. An analysis of the biomechanics involved in engaging the elements of the TLM and how they produce locking of the flexed joints of the digits includes a consideration of the roles of the podothecal pads, ungual flexor processes, and the elastic flexor and extensor ligaments of the toes. The components of the TLM are differentiated in early fetal development establishing that the TLM components are not acquired adventitiously in response to such factors as posthatching mechanical stresses.
Keywords
Avian Species Flexor Tendon Tendon Sheath Interphalangeal Joint Prevalent ConditionPreview
Unable to display preview. Download preview PDF.
References
- Baumel JJ, King AS, Lucas AM, Breazile JE, Evans HE (eds) (1979) Nomina Anatomica Avium, an annotated dictionary of birds. London New York, Academic PressGoogle Scholar
- Beckham C, Greenlee TK (1975) Chick vincula: elastic structures with a check-rein mechanism. J Anat 119 (2):295–308Google Scholar
- Bent AC (1940) Life histories of North American goatsuckers, Hummingbirds and Their Allies, Washington, US Govt Printing Office, pp 147–252Google Scholar
- Bent AC (1963) Life histories of North American marsh birds. New York, Dover Publ, pp 356–366Google Scholar
- Berger AJ (1966) The musculature. In: George JC, Berger AJ (eds) Avian myology. New York, London, Academic Press, pp 224–473Google Scholar
- Bock WJ (1965) Experimental analysis of the avian passive perching mechanism. Am Zool (5):681Google Scholar
- Cracraft J (1971) The functional morphology of the hind limb of the domestic pigeon, Columba livia. Bull Am Mus Nat Hist 144(3):173–268Google Scholar
- Cramp S (ed) (1977) Handbook of the birds of Europe, the Middle East, and North Africa, vol 1. Oxford, Oxford Univ Press, pp 78–88Google Scholar
- Goslow GE (1972) Adaptive mechanisms of the raptor pelvic limb. Auk 89:47–64Google Scholar
- Hudson GE (1937) Studies on the muscles of the pelvic appendage in birds. Am Midl Nat 18:1–108Google Scholar
- Lennerstedt I (1975) A functional study of papillae and pads in the foot of passerines, parrots, and owls. Zool Scr 4:111–123Google Scholar
- Lucas AM, Stettenheim PR (1972) Avian anatomy: Integument, Part I. Washington, US Govt Printing Office, pp 69–71Google Scholar
- Morony JJ, Bock WJ, Farrand J (1975) Reference list of the birds of the World. New York, Am Mus Nat HistGoogle Scholar
- Quinn TH, Baumel JJ (1983) An SEM study of a locking mechanism on avian pedal flexor tendons. Anat Rec 205(3):156AGoogle Scholar
- Raikow RJ (1970) Evolution of diving adaptations in the stifftail ducks. Univ Calif Berkeley Publ Zool 94:1–52Google Scholar
- Raikow RJ (1973) Locomotor mechanisms in North American ducks. Wilson Bull 85:295–307Google Scholar
- Raikow RJ (1978) Appendicular myology and relationships of the New World nine-primaried oscines. Bull Carneg Mus Nat Hist 7:1–43Google Scholar
- Raikow RJ (1985) Locomotor System. In: King AS, McLelland J (eds) Form and function in birds, vol 3. London-New York, Academic Press, pp 57–147Google Scholar
- Ranvier LA (1889) Sur les tendons des doigts chez les oiseaux. CR Acad Sci Paris 13:167–169Google Scholar
- Richardson F (1942) Adaptive modifications for tree-trunk foraging birds. Univ Calif Berkeley Publ Zool 317–378Google Scholar
- Schaffer J (1903) Über die Sperrvorrichtung an den Zehen der Vögel. Z Wiss Zool 73:377–428Google Scholar
- Schaffer J (1905) Anatomisch-histologische Untersuchungen über den Bau der Zehen bei Fledermäusen und einigen kletternden Säugetieren. Z Wiss Zool 83:231–284Google Scholar
- Scharnke H (1930) Physiologisch-anatomische Studien am Fuss der Spechte. J Ornithol 78(3):308–327Google Scholar
- Shepherd JD (1981) An analysis of proposed avian perching mechanisms. Thesis, University of Connecticut Diss Abstr Int B 41(9):3352Google Scholar
- Stolpe M (1932) Physiologisch-anatomische Untersuchungen über die hintere Extremität der Vögel. J Ornithol 80(2):161–247Google Scholar
- Storer RW (1960a) The fossil loon Colymboides minutus. Condor 58:413–426Google Scholar
- Storer RW (1960b) Evolution in diving birds. Proc Int Ornithol Congr 12:694–707Google Scholar
- Watson M (1869) On the mechanisms of perching in birds. J Anat 3:379–384Google Scholar