top ortho blogs 100 medallionHorses and cattle, along with deer, goats, and sheep, walk on their tiptoes. This makes their limbs are as long as possible, allowing them to run fast and escape canine and feline predators, which run on their digits planted flat.

Slide1Another limb-lengthening and speed-enhancing adaptation of these toe trotters is their cannon bone, named for its tube-like structure. It is an extra long bone in each forelimb in addition to the upper arm and forearm bones and in each hind limb in addition to the thigh and leg bones. To understand a cannon bone’s location, we can sing about the toe trotters’ forelimb anatomy: The arm bone is connected to the forearm bone, … is connected to the wrist bones, … are connected to the cannon bone, … is connected to the finger bones. Similarly for the hind limbs: The thigh bone, … leg bone, … ankle bones, … cannon bone, …  toe bones. 

Slide9In these hoofed animals, the cannon bone replaces

the five largest bones that humans have in each hand (metacarpals) and in each foot (metatarsals). It is actually two elongated metacarpal/tarsal bones fused together. The cleft on the end of the bone suggests this fusion, and an X-ray clarifies it.

Although ancient hunters discarded them because there was little marrow inside and no flesh outside, cannon bones have had second lives in many forms. This is due to the combination of their straight shape, substantial length and thickness, and ubiquity. Enterprising craftspeople in many different cultures have shaped them them into worldly goods.

Slide2Indigenous people living on sea coasts had easy access whale bones in abundance, which were their go-to source for a hard durable material to craft tools and weapons. For inlanders, cannon bones were readily available. When broken obliquely, they became awls and daggers. With one end beveled, they were strong enough to chisel wood. Sawed in half longitudinally, they scraped hides and skated (sort of) on ice. As civilization advanced, cannon bones even met the call for cored apples.

If you have doubts that the implements mentioned so far came from cannon bones, note that each object depicted above has a deeply clefted, spool-like end. These features are unique to cannon bones. However, when the bones were cut into pieces that were used as a material rather than as objects, their origin becomes less obvious; but signs are there.

Slide6In the Middle Ages, bone was used for making buttons and rosary beads. (See details in this previous post.) In Constanz, Germany, industrial-sized piles of bone scraps from this endeavor accumulated. The remnants include the ends of the distinctly shaped cannon bones and the blanks from which spheres were drilled.

About the same time in Italy, Baldassare Embriachi oversaw large workshops that turned out jewelry boxes and altar panels covered with flat segments of intricately carved bone. (See details in this previous post.) These segments numbered in the thousands and all measured approximately 1.5″ x 6″. They could have come only from bovine cannon bones.

Slide7The same is true for the bone beads that were wildly popular among some Native Americans tribes in the late 1800s. (See details in this previous post.) The Armour meat packing plant in Chicago sent cow leg bones to New York, where they were sawed, turned, and drilled to become 4 inch long, 1/2 inch thick beads. Once again, only a steer’s cannon bone can meet these dimensions.

Slide5Although other bones might suffice, cannon bones were also the most likely source for pins, needles, spoons, belt buckles, whistles, handles, spindles, needle cases, and similar household items.



Of course when craftsmen had fully accessorized their kitchens and workshops, it was time to play. Chess pieces, whose diameters and heights often exceed a cannon bone’s dimensions, were made in segments and screwed together. Musicians strung multiple cannon bones together to make music. Cannon bone musical virtuosity? Who knows? Cannon bone versatility? You bet!


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4 thoughts on “The versatile cannon bone. What is it?

    1. Hi Av, Good to hear. The vets have us beat on cannon bones. Even more to learn in due time: penis bones in dogs, wolves, walruses, etc!
      Best wishes, Roy

  1. Welcome to the BHB group on LinkedIn. The only thing I know about bones is how badly it hurt the one time I broke one. I look forward to learning!

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