Features of the Femoral Proximocaudal Joint Capsule Insertion Among Canids

Abstract

This observational study was conducted to evaluate the anatomic relationship between the proximocaudal femoral joint capsule insertion and the femoral caudolateral curvilinear osteophyte (CCO), across ancient and modern domestic and non‐domestic canids. Museum specimens of proximal femora were screened for presence of remnant enthesophytes of the caudal joint capsule insertion (first inclusion criterion) and then for the CCO (second inclusion criterion). The initially screened population included 267 dry bone specimens: Six Canis species, hybrid coyote × domestic dog, and five vulpines (three Vulpes species, one Urocyon, and one Nyctereutes). Proximocaudal joint capsule insertion remnant enthesophytes were limiting at n = 19 specimens: Seven ancient domestic dogs, four modern coyotes, two ancient coyotes, two modern hybrid coyote × dog, two modern red foxes, and two modern raccoon dogs. The joint capsule enthesophytes are associated with inflammation, but are observed far less frequently than the CCO. The CCO is seen radiographically but is visible more frequently by direct inspection. The primary inclusion criterion necessarily was a visible caudal joint capsule insertion; spatial relationships of the CCO can be assigned with confidence only when a capsule insertion line can be recognized clearly. We demonstrate that the anatomic CCO associates with the joint capsule insertion being nonspecific and species‐independent. A joint capsule insertion‐CCO spatial relationship across species is an important new observation, strongly indicating that both are pathological features. Our data indicate need for new research to characterize the canid coxofemoral joint and its overt and incipient pathology in a phylogenetic context. Anat Rec, 302:2164–2170, 2019. © 2019 American Association for Anatomy

Skeletal remains of five blue foxes (Vulpes lagopus) from St. Paul Island, Pribilof Islands, Alaska: A view of differential diagnosis

“…Skeletal components that were available from each of the foxes are shown in Supporting Information S1. Skeletal observations were divided into categories: pathology that is unique to the circumstances of these five foxes (Conlogue et al, 1979; Kucklick et al, 2002; Ogden & Conlogue, 1981; Spraker & White, 2017; Whalen et al, 1977) and pathology that can be observed on skeletal components of many foxes and other canids (Lawler, Becker, et al, 2016; Lawler & Evans, 2016; Lawler et al, 2012, 2017, 2019; Mustonen et al, 2017) (Table 1). The volume and detail of both observation categories necessitate presentation as a Supporting Information S2.…”

“…Axial skeletal features that are observed on many vulpine remains (Lawler et al, 2012, 2017, 2019; Mustonen et al, 2017) variously included evidence of alveolar, perialveolar, periodontal, and/or periosteal disease (porous bone, bone covering empty alveoli or tooth roots, tooth damage or loss, inter‐root bone peaks, receding alveolar margins, and perialveolar boney rims along dental arcades) (Figures 1 and S1). Vertebrae variously revealed mild boney proliferation, rough irregular bone, porous or rough ventral vertebral body, and focal‐to‐multifocal spondylosis.…”

“…Appendicular skeletal features that are observed on many vulpine forelimb or hind limb remains (Lawler et al, 2012, 2017, 2019; Mustonen et al, 2017) variously included articular surface eburnation or fibrillation, periarticular fibrillar bone, articular porous margin or boney rims, healed fracture, rough or porous articular bone surface, periarticular or encircling rough bone or boney proliferation, acetabular fossa osteophytes, and osteophytes impinging articular surface margins. Additional femoral features included joint capsule insertion osteophytes, circumferential femoral head osteophyte, caudolateral curvilinear osteophyte, and osteophyte‐rimmed round ligament attachment.…”

“…However, there are significant caveats that impact archaeological diagnosis in particular, and several additional differential diagnoses also must be considered. By comparison, those pathological changes that can be observed on many or most fox skeletal remains could reflect the rigorous lives of carnivores or conserved traits (Lawler et al, 2012, 2017, 2019; Mustonen et al, 2017). For an expanded view of bone minerals homeostasis, see Supporting Information S3.…”

The nature of coxofemoral joint pathology across family Canidae

“…We ask whether "osteoarthritis" is a valid universal descriptor of jointassociated dry bone features, absent of histological evaluations that allow visualizing of living cells, additional sub-classifying observations (Blom et al, 2004;Junker et al, 2016;Roelofs et al, 2020;van Lent et al, 2004), or analytical assessment of their unique biochemical properties (Xu et al, 2017). Furthermore, depending on the location of a given individual boney feature, is "osteophyte-like" a more appropriate general descriptor, given that features on dry bone can represent (a) enthesophyte (Lawler et al, 2019); (b) osteophyte (Roelofs et al, 2020); (c) pyrophosphate (pseudogout, chondrocalcinosis, Gibson & Roenigk, 1972;Woodard et al, 1982;Heimann et al, 1990;De Haan & Andreasen, 1992;Frank et al, 2002;Forsyth et al, 2007;Miksanek & Rosenthal, 2015;Bertram et al, 2019;Catelli et al, 2020;Henschen et al, 2020); (d) postdevelopmental boney remnant (Lawler et al, companion in this issue); (e) calcified fibrous remnant; (f) exostosis (Gambardella et al, 1975;Gee & Doige, 1970;Jacobson & Kirberger, 1996;Owens, 1982); (g) neoplasm (Kim et al, 2005;Owens, 1982;Scherrer et al, 2005;Valentine et al, 2002); (h) developmental or mechanical multi-tissue impingement (not well-researched in dogs); or (i) idiopathic? It must be recognized that underlying or incipient pathophysiology, and therefore the individual, population, and phylogenetic implications across these differential diagnoses, can be variable (Henschen et al, 2020;Litwic et al, 2013;Miksanek & Rosenthal, 2015;Roelofs et al, 2020;…”