Parts of the knucklebone

The ‘knuckbone’ is also called an Astragalus (or Talus in Humans).

I need to be able to describe the parts of the bone in order to describe the orientation of design and spues and other features of the individual coin specimens.

“Schematic diagram of the lateral outline of an astragalus rotating as a cam. The bold portion of the astragalar outline line shows the surface of the cam, comprising the lateral outline of the distal trochlea and the calcaneal (sustentacular) facet. The circle indicates the center of rotation at the transverse tarsal joint. Straight dashed lines indicate the distance between the axis of rotation and the calcaneus, which is represented by a simple rectangle. The system is shown in extreme dorsiflexion (A) and then in extreme plantarflexion (B) with resulting posterior displacement of calcaneus.”

From Barr, W.. (2014). Functional Morphology of the Bovid Astragalus in Relation to Habitat: Controlling Phylogenetic Signal in Ecomorphology. Journal of Morphology. 275. 10.1002/jmor.20279.

“**Bretzia pseudalces astragalus. UWBM 53066. A. anterior view, B. medial view, C. posterior view, D. lateral view. Scale bar equals 1 cm.**“

From Gustafson, Eric. (2015). An early Pliocene North American deer: Bretzia pseudalces, its osteology, biology, and place in cervid history. University of Oregon Museum of Natural History Bulletin. 25.

Astragalar terminology. (A) Photograph of a Samotherium major (GMM 2002) astragalus in dorsal view, with representative terminology. (B) Samotherium major (GMM 2002) astragalus in ventral view, with representative terminology. The scale bar represents 50 mm. doi:10.1371/journal.pone.0151310.g001

From: Solounias, Nikos & Danowitz, Melinda. (2016). Astragalar Morphology of Selected Giraffidae. PloS one. 11. e0151310. 10.1371/journal.pone.0151310.

“A sheep astragalus (L7 5 1034; crate 4) showing clear signs of acid etching — probably the result of partial digestion in an animal’s (perhaps a dog) stomach. “

From DAvIS, SJM & GOnçAlvES, MJOS & Gabriel, Sónia. (2008). Animal remains from a Moslem period (12th/13th century AD) lixeira (garbage dump) in Silves, Algarve, Portugal. Revista Portuguesa de Arqueologia. 11. 183-258.

So where does this leave me in my vocabulary. I think we can say on RRC 14/6 the knucklebone is shown on the plantar side, which we might also call the ventral or posterior view. I will consider the distinctive interarticular groove and related proximal triangular fossa to be indicative of the ‘top’ and use it as my primary reference point.

Interestingly this is by chance the second lowest scoring/most common throw in a game of chance.

Update 23 Apr 2024:

2 thoughts on “Parts of the knucklebone”

On a Roman agate intaglio, I saw all the faces of the knucklebone, likely representing a winning combination in a game, which is why there was a palm branch at the center of the composition (J. Boardman, Greek gems and finger rings, n. 543; Manifattura Paoletti, matrix in glass inv. MR 24357 n. 327 “Il gioco degli Aliossi dedicato a Venere”; Bertolami Fine Arts, Auction 66 – Part II, 10 July 2019, lot 382)