Cattle right-side calcaneus (heel bone)
The calcaneus in humans is the heel bone, and is the first point of contact with the floor when we walk. However, cattle are ‘nail-walkers’ – walking on the very tips of their toes with the rest of the foot held off the ground. This means the first joint from the ground on the hind leg is the ankle (hock), not the knee, which is why it bends in the opposite direction to our knee. The knee is further up the leg, almost hidden by the leg muscles, while the hip is very high up, just below the base of the tail.
The bovine foot has 15 bones, grouped into 7 tarsals (talus, calcaneus, and five others), 2 metatarsals (running from the tarsals to thethe two toes). These correspond to the 3rd and 4th metatarsals in human feet The big toe has the first metatarsal). The cow has 6 phalanges (three in each toe).
For comparison, humans have 26 foot bones, comprising 7 tarsals, 5 metatarsals (one leading to each toe) and 14 phalanges (two for the big toe and three for every other toe).
(The image above actually shows the front leg of a cow, with the wrist and not the ankle bones, but the other bones are generally the same.)
In life, this cattle calcaneus is from the right hock and has the smooth side faces outward to the right, as in the photo above. The shaft of the bone is then pointing up and back, toward the tail of the animal, to form the distinctive point of the hock in the cow’s leg (no. 32 in the first diagram). The top of the bone is the attachment point for the large muscles of the lower leg. These are the gastrocnemius and soleus, (the ‘calf muscles’ in humans).
Some of the more fragile edges of this calcaneus are missing, but you can still see the main features.
In the photo, the letter A shows a smooth articular surface for the 3rd and 4th metatarsals, and B is one of the articular surfaces with the talus. C is a dome-shaped articular surface for the lateral malleolus, a bone on the outer edge of the hock. The roughened depression (D) in the centre of the plate is called the tarsal sinus, and is mirrored by a similar area on the talus. This cavity houses blood vessels, fat, nerves, and a series of ligaments which hold the tarsal bones together.
The talar shelf (E), is at the near end of the shaft, and helps support the talus bone which sits above it. There is also a groove (F) for the tendon of the flexor digitorum lateralis muscle, which bends the toes.
The calf muscles which attach to the top of the bone help straighten the leg when walking and running, while the length of the bone acts as a lever to amplify their effect and increase make the movement more efficient This is especially important in animals such as cattle, whose ancestors and wild relatives migrate across continents and run to escape predators.
– James Lumbard, Natural Sciences Officer.
1. Domestic_animals;_ _history_and_description_of_the_horse,_mule,_cattle,_sheep,_swine,_poultry,_and_farm_dogs,_(1858)_(14598393827)
By Internet Archive Book Images – https://www.flickr.com/photos/internetarchivebookimages/14598393827/Source book page: https://archive.org/stream/domesticanimalsh00alle/domesticanimalsh00alle#page/n51/mode/1up, No restrictions, https://commons.wikimedia.org/w/index.php?curid=44520464
2. Cattle hock skeleton diagram © https://www.dcfirst.com/cow_skeletal_anatomy_poster.html Accessed 31.3.2020.
3. BruceBlaus. :Blausen.com staff (2014). “Medical gallery of Blausen Medical 201”. WikiJournal of Medicine 1 (2). DOI:10.15347/wjm/2014.010. ISSN 2002-4436. / CC BY 3.0