Tag Archives: biology

Identification – cattle hock bone

Photo of the calcaneus.

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.

Diagrom to show position of hock in cattle leg

The hock bone (calcaneus) is shown by no. 32 (bottom right). 31 shows the ankle joint and 30 shows the knuckles of the toes. 27 shows the knee joint (bottom middle). Image credit: reference 1.

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).

Diagrams showing skeletons of the cattle and human foot.

15-21 are the ankle bones, 23 and 24 are the metatarsals, and 26-28 show the three phalanges in each toe. The same bones are labelled in the human foot on the right. Image credits: references 2 and 3.

(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.)

Photo of the calcaneus.

The original bone I was asked to ID. © Saffron Walden Museum.

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.

This photo is pretty much a close-up of the photo above, from the bottom end. © Saffron Walden Museum.

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.

 

References

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

Object of the Month – August 2018

Red squirrel - August object of the month

August’s Object of the Month is a red squirrel. The mammal was chosen as Object of the Month by Sarah Kenyon, Natural Sciences Officer.

This red squirrel was found dead at Saffron Walden, Essex in August 2003. It had been run over by a car in Landscape View. A member of the Uttlesford group of Essex Wildlife Trust gave it to Saffron Walden Museum to be preserved. The body was mounted, or stuffed, by a taxidermist. This red squirrel has russet red fur on its body and tail, with white fur on its chest and belly. Male and female squirrels look identical.

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