Pondering These Knees
Most animal legs
will have some knees.
Including birds,
including bees,
including dogs
like Pekinese,
including cats
like Siamese.
There’s also apes
like chimpanzees
and watery-mammal
manatees.
And most of them all
have kneecaps, two.
Including us,
the gnu, the shrew
and even frogs
have kneecaps too.
But NONE are found
on a kangaroo.
https://www.realclearscience.com/blog/2019/04/02/four_fascinating_facts_about_kneecaps.html
The patella, or kneecap, is one of the most incredible bones in your body. As a sesamoid bone, it is embedded within a tendon, where the quadriceps and patellar tendons meet. There, the rounded, triangular bone protects the knee joint and acts like a pulley, allowing the tendon to transmit more force with smoother motion.
Frogs may have evolved the first kneecaps. In 2017, researchers from Argentina discovered primitive, soft kneecaps in eight species of frog. “One implication of the discovery is that kneecaps like this began to evolve in the Devonian period 400 million years ago,” Andy Coghlan wrote for NewScientist.
http://kneesafe.com/fun-facts-animal-knees/
Fun facts about animal knees
AUG 10, 201718036 VIEWS
In some ways, animals are even more similar to us than we could imagine, yet the animal world is filled with strange and mesmerizing characteristics like these few listed above that illustrate perfectly how colorful the whole animal kingdom really is.
https://www.ncbi.nlm.nih.gov/pubmed/2297078
Absence of an osseous patella and other observations in Macropodidae stifle.
Holladay SD1, Smith BJ, Smallwood JE, Hudson LC.
Abstract
The patella is a large sesamoid bone that typically develops in the tendon of insertion of the large extensor muscles of the stifle joint. Although present in almost all species of mammals and birds, it has been found to be absent in the red kangaroo and two wallaby species (family Macropodidae). In its place is a fibrocartilage pad, located in the tendon of the quadriceps femoris muscle. This structure is visible grossly, is palpable, and has the form normally expected of a bony patella. In addition, the femoral trochlea is shallow and asymmetric, and the lateral gastrocnemius sesamoid is unusually prominent. These and other related modifications in the area of the Macropodidae stifle are presented.
I love learning things from your poems, Celia! Fascinating!