Macroscopic features of scurvy in human skeletal remains: A literature synthesis and diagnostic guide

Abstract The past two decades have seen a proliferation in bioarchaeological literature on the identification of scurvy, a disease caused by chronic vitamin C deficiency, in ancient human remains. This condition is one of the few nutritional deficiencies that can result in diagnostic osseous lesions. Scurvy is associated with low dietary diversity and its identification in human skeletal remains can provide important contextual information on subsistence strategy, resource allocation, and human‐environmental interactions in past populations. A large and robust methodological body of work on the paleopathology of scurvy exists. However, the diagnostic criteria for this disease employed by bioarchaeologists have not always been uniform. Here we draw from previous research on the skeletal manifestations of scurvy in adult and juvenile human skeletal remains and propose a weighted diagnostic system for its identification that takes into account the pathophysiology of the disease, soft tissue anatomy, and clinical research. Using a sample of individuals from the prehistoric Atacama Desert in Northern Chile, we also provide a practical example of how diagnostic value might be assigned to skeletal lesions of the disease that have not been previously described in the literature.


| INTRODUCTION
Scurvy, a condition caused by severe and prolonged vitamin C deficiency, has received increasing attention in the bioarchaeological literature in recent years. This proliferation of research began with the identification by Donald Ortner and colleagues of a suite of dry bone lesions which the authors argue can be intuitively linked to the unique pathophysiology of this disease (Ortner, Butler, Cafarella, & Milligan, 2001;Ortner & Ericksen, 1997;Ortner, Kimmerle, & Diez, 1999). Subsequent researchers have expanded on this work, both by extending Ortner's logical process of lesion identification to osseous changes at other sites in the skeleton and by integration of clinical radiographic and histological features of scurvy (Brickley & Ives, 2008;Geber & Murphy, 2012;Maat, 2004;Mays, 2008;Moore & Koon, 2017;Stark, 2014).
The identification of scurvy in past populations is meaningful for reasons that extend beyond the diagnosis of a pathological condition within the individual. Vitamin C deficiency is a condition associated with low dietary diversity and can be caused by general famine conditions or nutritional dependence on vitamin C poor staple foods, such as cereal crops (Cheung et al., 2003;World Health Organization, 1999). As such, identification of scorbutic individuals in the archeological record can contribute significantly to studies of the paleoenvironment, subsistence transitions such as agricultural intensification, and even cultural practices involving resource allocation and social inequality Crandall, 2014;Snoddy, Halcrow, Buckley, Standen, & Arriaza, 2017). Although Walker, Bathurst, Richman, Gjerdrum, & Andrushko, 2009). Traditionally, bioarchaeologists have relied upon paleofaunal and paleobotanical remains, as well as non-specific markers of physiological disruption in bone and teeth (e.g., Harris lines, linear enamel hypoplasia), to provide contextual evidence of dietary stress in past populations (Cohen & Armelagos, 1984;Cohen & Crane-Kramer, 2007;Huss-Ashmore, Goodman, & Armelagos, 1982). Advances in isotopic analysis of human remains have allowed the generalized reconstruction of trophic relationships and resource use in ancient human groups (Hedges & Reynard, 2007;Schoeninger, 2014). However, these analyses cannot provide direct information on the intake of individual micronutrients, such as vitamins and minerals, many of which are essential for maintaining basic metabolic function. As such, the identification of specific diseases of poor micronutritional intake in skeletal remains has the potential to contribute significantly to the creation of a holistic portrait of health, resource use, and human-environmental interactions in the ancient past Snoddy et al., 2017;Stark, 2014;Wilbur, Farnbach, Knudson, & Buikstra, 2008).
Micronutrient malnutrition disorders, such as vitamin C deficiency, rarely occur in isolation and because of this the identification of scurvy in ancient human remains can be an important proxy for population-wide nutritional status (Snoddy et al., 2017;Stark, 2014).
As discussed above, scurvy is associated with low dietary diversity, and can be found in individuals experiencing general undernutrition (e.g., starvation) or those relying on a few, micronutrient poor staple foods for caloric sufficiency (Snoddy et al., 2017;World Health Organization, 1999). Clinically, individuals suffering from scurvy are also usually deficient in a number of other micronutrients, such as folate or iron, which will not necessarily leave diagnostic osseous markers (Pimentel, 2003;Popvich, McAlhany, Adewumi, & Barnes, 2009). The development and consistent application of a robust diagnostic protocol for the identification of scurvy from human skeletal remains is therefore of importance to those who study the wider context of nutritional stress in ancient human groups.

| VITAMIN C IN HUMAN HEALTH
The role of vitamin C in human physiology has been reviewed in detail elsewhere (Levine & Padayatty, 2014), but a brief overview is presented here. Ascorbic acid functions as a reducing agent within the body, catalyzing enzymatic reactions and acting as a potent antioxidant by pairing with free radicals (Levine & Padayatty, 2014, p. 400).
Most mammals have the ability to endogenously synthesise ascorbic acid from glucose. However, primates, including humans, lack the hepatic enzyme gluconoactone oxidase, which is necessary for the synthesis of the ascorbic acid precursor (Drouin, Godin, & Page, 2011). These animals must therefore meet their physiological need through dietary intake of substances that are rich in pre-synthesized ascorbic acid (Du, Cullen, & Buettner, 2012, p. 444). All photosynthetic plants have the ability to synthesize ascorbic acid (Smirnoff & Wheeler, 2000). Fruits and dark green vegetables, particularly citruses, asparagus, broccoli, and kale, are rich sources of vitamin C (Levine, Rumsey, Daruwala, Park, & Wang, 1999, p. 1417. The livers of animals that are capable of endogenous synthesis of ascorbic acid (e.g., most terrestrial vertebrates and marine mammals) are also rich in this nutrient and can be an important complementary source of vitamin C for humans in environments where vegetation is scarce (Fediuk, Hidiroglou, Madère, & Kuhnlein, 2002;Geraci & Smith, 1979).

| CLINICAL MANIFESTATIONS OF DEFICIENCY
Scurvy is associated with a number of nonspecific symptoms, such as fatigue, irritability, and depression (Olmedo, Yiannias, Windgassen, & Gornet, 2006;Pimentel, 2003;Popvich et al., 2009). However, the majority of clinical signs are directly related to defective type II collagen synthesis. Ascorbic acid acts as an electron donor to two enzymes involved in the hydroxylation of the amino acids lysine and proline.
This hydroxylation process is necessary for the stabilization of the final triple helix structure of mature collagen, and if the structural integrity of collagen is compromised, widespread damage of connective tissues can occur (Hirschmann & Raugi, 1999 p. 899). The extracellular matrix of bone is largely composed of collagen (Boskey & Robey, 2013) and poor or non-existent osteoid formation is a hallmark of ascorbic acid deficiency, with the rapidly developing juvenile skeleton typically more severely affected than that of the adult (Fain, 2005;Joffe, 1961). Both adults and juveniles may exhibit generalized osteopenia and cortical thinning due to the cessation of osteoid formation, but this feature is not strongly diagnostic (Fain, 2005;Joffe, 1961;Weinstein, Babyn, & Zlotkin, 2001;Young, Schiliro, & Russo, 1979).
Likewise, subperiosteal hemorrhage can result in a radiographically visible lifting of the periosteum from the underlying cortex. However, subperiosteal new bone is generally only visible following the reintroduction of vitamin C and resumption of osteoid formation and must usually be extensive in order to be radiographically visualized (Brailsford, 1953;Joffe, 1961;Sprague, 1976;Young et al., 1979).
Musculoskeletal lesions occur in the majority of clinical cases of subadult scurvy and radiography of suspected scorbutic individuals is standard practice in differential diagnosis (Pimentel, 2003;Riepe, Eichmann, Oppermann, Schmitt, & Tunnessen, 2001;Verma et al., 2007;Young et al., 1979). The majority of radiographically visualized diagnostic lesions are metaphyseal and associated with defective endochrondral growth. Demineralization of the cortex of metaphyses results in a characteristic radiographic "ground glass" appearance (Jaffe, 1972;Riepe et al., 2001). Alternating radiolucent (Trümmerfeld zone) and radiopaque (White line of Frankel) bands, which represent defective bone matrix formation and poor resorption in the provisional zone of calcification respectively, may be evident in regions of active endochrondral growth (e.g., metaphyses of lone bones, sternal end of ribs) (Jaffe, 1972;Young et al., 1979). Wimberger's ring, a band of increased mineral density around epiphyses, is also caused by poor resorption of calcified cartilage (Jaffe, 1972;Popvich et al., 2009).
Clefting of the lateral metaphyses ("corner sign") may occur as the result of microfractures within the provisional zone of calcification (Riepe et al., 2001). When these microfractures heal, bony spurs may form on the lateral aspect of the metaphyses of lower long bones (Burk & Molodow, 2007). Most of these lesions remodel quite rapidly following reintroduction of vitamin C and are only present in active cases of severe deficiency, although lesions associated with increased mineral density may persist for years (Jaffe, 1972;Sprague, 1976).
One of the tissues most dramatically affected by ascorbic acid deficiency in both adults and children is the basement membrane of blood vessels, which functions in the connection and support of the vascular epithelial wall to the underlying endothelium (Popvich et al., 2009, p. 411;Saladin, 2014, p. 750-752). In scorbutic individuals, compromised integrity of the vascular wall causes widespread, chronic hemorrhage in response to minor trauma and normal muscular action, resulting in perivascular edema, petechia (pin-point cutaneous bruising), gingival bleeding, and subperiosteal hematomas (Hirschmann & Raugi, 1999;Olmedo et al., 2006;Popvich et al., 2009). Subperiosteal hemorrhage and bleeding into joint spaces (hemarthrosis) can cause intense pain and inflammation, and may lead to compromised mobility (Hirschmann & Raugi, 1999, p. 902). Gingival hemorrhage due to scurvy can cause secondary alveolar bone resorption, resulting in periodontal disease and antemortem tooth loss (Hirschmann & Raugi, 1999, p. 902). It is primarily the secondary effects of this chronic bleeding, particularly in the subperiosteal space of long bones, cranial vault, orbits, small facial bones and the alveolar bone of the mandible and maxilla, and at entheseal sites which is thought to lead to many of the lesions commonly employed by paleopathologists in the differential diagnosis of scurvy from skeletal remains (Brickley & Ives, 2008;Ortner, 2003; section 10). 5 | THE "ORTNER CRITERIA": PALEOPATHOLOGICAL INFERENCE USING KNOWN ANATOMICAL RELATIONSHIPS As discussed above, the majority of features employed by bioarchaeologists in the diagnosis of scurvy from skeletal remains have their foundation in the work of Ortner & colleagues. Using both anatomical (Ortner & Ericksen, 1997) and archaeological samples of non-adult remains (Ortner et al., 1999(Ortner et al., , 2001 these authors have identified a suite of macroscopic bony lesions which they argue can be intuitively linked to the hemorrhagic effects of scurvy, specifically low-grade bleeding due to the effects of minor muscular actions-such as masticatory movements-on weakened vasculature. The scorbutic lesions proposed by Ortner et al., as well with their anatomical associations and hypothesized mechanisms of formation, are outlined in Table 1 and described in detail in section ten. The majority of these are cranial, consisting of clustered, fine cortical porosity and are argued to be the result of bleeding of vasculature associated with the muscles of mastication, such as the temporalis and pterygoids (Ortner et al., 1999(Ortner et al., , 2001Ortner & Ericksen, 1997). Capillary proliferation is part of the inflammatory response to the presence of extravascular blood; these new vessels act as a delivery system for phagocytic cells of the innate immune system to aid in the removal of hemorrhagic material (Browder, Folkman, & Pirie-Shepherd, 2000). Ortner & others argue that this hypervascular (angiogenic) response to extravasated blood will result in fine (<1 mm across) abnormal porosity at sites of subperiosteal hemorrhage as new capillaries create pathways through the bony cortex (Klaus, 2017;Ortner et al., 2001; Figure 1). Once sufficient levels of vitamin C are restored for osteoid formation, islands of porous new bone may be deposited at these sites of subperiosteal bleeding (Ortner et al., 1999(Ortner et al., , 2001Riepe et al., 2001; Figure 2). Some bioarchaeologists have used this logic to interpret subperiosteal scorbutic lesions as "healing" individuals, although, as Klaus (2017) and others have pointed out, it is likely that relatively little vitamin C is needed for the resumption of osteoid formation and the formation of new bone should not necessarily be interpreted as a full return to health (Klaus, 2017;Stark, 2014).   Limited: Sprague, 1976 Suggestive SPNB = subperiosteal new bone. †structure not implicated by referenced author(s) but role is anatomically intuitive. VIs = vascular impressions. NA = not applicable. More than one diagnostic feature is required in a single individual for classification of probable scurvy and at least one diagnostic and multiple suggestive features are required for classification of possible scurvy. Visual examples of each listed lesion are provided in Supporting Information Table S1.
are typically found on long bones, particularly in the metaphyseal region of lower limbs, although intraocular and subdural hematomas have also been reported (Ingalls, 1936;Verma et al., 2007). Islands of subperiosteal new bone on the endocranial surface, the metaphyses of the lower limbs, and the orbital roof do therefore have clinical support as features associated with scurvy, although trauma should also be considered in differential diagnosis. Accounts from historic pathologists also provide some support for several of the bony lesions attributed to the hemorrhagic effects of scurvy by Ortner and subsequent researchers. Autopsies of scorbutic patients by Barlow and Möller revealed subperiosteal hematomas in the subspinous and infra spinous fossae of the scapula, on the ecto and endocranial surfaces of the parietal bones, the orbital roofs, and in the ethmoid (Barlow, 1883(Barlow, , 1894. Furthermore, Barlow noted "thickening" and "swelling" of the zygomatic region, maxillae, mandible, occipital, and parietals in living patients which he attributed to probable scorbutic subperiosteal hemorrhage (Barlow, 1883, p. 168-169).
Unlike subperiosteal new bone, direct clinical evidence for abnormal cortical porosity in scorbutic patients is exceedingly thin (cf. Park, Guild, Jackson, & Bond, 1935), although Barlow noted clustered porosity under a subdural hematoma in a scorbutic child (Barlow, 1883, p. 182). This is probably because this abnormal porosity is not radiographically visible and is not observable in living individuals.
However, as discussed above, the relationship between scorbutic hemorrhage and abnormal cortical porosity is logical when the pathophysiology of the disease is considered.

| CRITIQUES OF THE ORTNER CRITERIA
Several of the features noted by Ortner and colleagues, specifically the subperiosteal new bone of the orbital roof and cortical porosity of the greater wing of the sphenoid, as well as the ectocranial parietal, have been noted in documented cases of scurvy in an anatomical collection housed at the Royal College of Surgeons (Stark, 2014). However, the subperiosteal new bone in these anatomical examples is far more severe in expression than the lesions noted by Ortner and colleagues, leading some to critique the use of these features in the diagnosis of scurvy in undocumented skeletal remains (Melikian & Waldron, 2003;Waldron, 2009). However, as Stark (2014) has argued, these anatomical examples likely represent the extreme end of the scorbutic spectrum. The nature and location of the lesion is, in this instance, likely more important than the degree of expression. Additionally, the subtler expression of osseous changes makes identification of scurvy challenging in many cases, as the porotic and subperiosteal nature of the Ortner suite of lesions has considerable overlap with normal infant growth (Snoddy et al., 2017). Because of this, there is a danger that the Ortner criteria may lend itself to confirmation bias, a tendency to interpret new data in support of pre-existing expectations, especially in analysis of very young individuals who are undergoing rapid appositional and endochondral growth. In other words, subtle changes associated with normal osseous development may be recorded as pathological if the analyst is "looking" for disease. This potential problem has led some researchers to argue that the supposed hemorrhagic lesions described by Ortner and others, while theoretically plausible, should be avoided and that clinically described signs should be considered the only diagnostic features of scurvy in human remains (Melikian & Waldron, 2003). However, we would argue that the rapid clinical resolution of many of the radiographic features of juvenile scurvy following treatment means that most of these lesions would only be present in children who were actively scorbutic at the time of their death. The observation of radiographic features is further complicated by issues with preservation and completeness in archaeological human remains. Unfused epiphyses, for example, are frequently lost and metaphyses are often damaged in the post depositional environment. If these regions are unobservable a differential diagnosis considering clinical radiographic features is impossible. Stark (2014) attempted to overcome some of these issues by creating a framework for the study of juvenile scurvy in the past by integrating clinical radiographic features with macroscopic osseous pathology. This approach has the potential to critically evaluate the diagnostic robusticity of the hemorrhagic features described by Ortner & colleagues. Stark recommended this framework be applied to collections of juveniles who exhibit macroscopic porous and proliferative lesions. However, its application is not universally practical considering problems with preservation and completeness. Although interpretative caution is needed in order to avoid over diagnosis in all of which may also occur in adult vitamin D deficiency osteomalacia and age-related osteoporosis (Hirschmann & Raugi, 1999;Jaffe, 1972 ;Joffe, 1961). Subperiosteal new bone on the shafts of long bones, as well as evidence of hemarthrosis, has been radiographically observed in adults with this disease, but these features also occur in a number of other pathological conditions, including trauma and infectious disease (Jaffe, 1972;Joffe, 1961). As chronic hemorrhage occurs in both scorbutic adults and children, the macroscopic lesions reported by Ortner and others can theoretically be applied to adult individuals and well as subadults (Crandall & Klaus, 2014; e.g., Buckley et al., 2014;Geber & Murphy, 2012). Jaffe (1972) reports that autopsy findings of adults with scurvy include bloody discoloration of muscle bellies and attachments, which lends clinical credibility to this argument (Jaffe, 1972, p. 454). However, the osseous response to hemorrhage is expected to be milder in expression in individuals who have ceased active appositional growth (Crandall & Klaus, 2014). This makes the identification of scurvy in adult skeletal remains from macroscopic lesions difficult and, as with other metabolic bone diseases, juveniles are expected to comprise the largest cohort within a skeletal assemblage who exhibit clear evidence of the disease (see Brickley & Ives, 2008).  "If what we are doing in paleopathology is science, we must set out objective criteria for identifying disease in ancient human remains and make our identification procedures explicit" (Powell and Cook, 2016, p. 42) As noted, the recent proliferation of research on the paleopathology of scurvy is exciting and has the potential to contribute significantly to our collective understanding of subsistence strategy, humanenvironmental interactions, and the biological consequences of social inequality. However, a systematic approach to the diagnosis of this disease in skeletal remains and an exploration of the assignment of the diagnostic weight of individual lesions is needed in order to avoid over-diagnosis. Although much has been done in terms of methodological advancement over the last two decades (Brickley & Ives, 2006Ortner et al., 1999Ortner et al., , 2001, the application and diagnostic weight given to osseous features attributed to this disease has not always been uniform. Some researchers consider particular lesions (e.g., porosity of the greater wing of the sphenoid) pathognomonic or strongly diagnostic for this condition (Ortner et al., 1999(Ortner et al., , 2001Ortner & Ericksen, 1997), while others do not recognize any strongly diagnostic osseous features (Brickley & Ives, 2008)  However, the diagnostic weight given to various lesions is not explicitly justified by the authors and entire bones (e.g., sphenoid, maxillae), rather than specific osseous sites (e.g., lateral apect of the greater wing of the sphenoid, maxillary palate, etc) are cited (Brickley & Ives, 2008, p. 57 Brickley and Ives (2008). However, statistical means of assigning diagnostic value to "new" lesions requires a baseline of macroscopic features which are accepted to be associated with the disease. We therefore propose that the process of assigning diagnostic weight to features commonly attributed to scurvy in the bioarchaeological literature need not necessarily require statistical analysis (cf. section 6), but the line of reasoning for the diagnostic value assigned to these features must be made explicit by the researcher. For example, a feature assigned "diagnostic" value must not only be intuitive from an anatomical and pathophysiological standpoint, it must also have either the support of clinical observations or a large body of bioarchaeological evidence. A feature assigned "suggestive" value might be one that is anatomically intuitive but which does not have clinical support or has only be observed in a few (<5) bioarchaeological case-studies or case-series.
As research on the paleopathology of scurvy continues, diagnostic criteria will naturally evolve and require updating. For instance, features previously noted in small samples may be upgraded from suggestive to diagnostic after additional work with larger samples. An example of how this approach could be applied is provided below. (ca 13,000-9,000 BP), prior to the adoption of contemporary irrigation technology, populations were confined to coastal estuaries and river valleys fed by the seasonal melting of Andean snow (Arriaza, Standen, & Cassman, 2008;Rivera, 2008). The low terrestrial biodiversity and marginal ecology of this region is contrasted by a diverse and abundant marine biomass, fostered by the cold waters of the Pacific Humboldt current (Montecino & Lange, 2009;Tam et al., 2008). This provided the resources necessary for the rise of the Chinchorro Cultural Complex, a sedentary hunter-gatherer society, during the Archaic Period destruction, as well as lesion size, density, and shape. Access to radiographic equipment was limited but wherever possible, analog radiographs were obtained of any individuals exhibiting macroscopic skeletal lesions.
Differential diagnosis of scurvy was conducted using a modified version of Brickley and Ives (2008) system with lesions classified as diagnostic (D) or suggestive (G). This system was modified to include more recent paleopathological literature and additional clinical work (see Snoddy et al., 2017). Two or more D features in a single individual were required for a diagnosis of probable scurvy and at least one D feature and multiple G features were required for diagnosis of possible scurvy. from Brickley and Ives (2008). This feature has previously been noted in two individuals from 17th century San Croix Island (New France) (Crist & Sorg, 2014), and in a case study of a 6-to 8-year-old child from Colonial

| Results
Peru (Klaus, 2017). As both Crist and Sorg (2014) and Klaus (2017) have noted, this is an anatomically logical location as this region is the origin of the medial pterygoid muscle, which is involved in the common movements of mastication and facial expression (Standring, 2016; Figure 4(b)).
The medial pterygoid is involved in the elevation and contralateral (sideto-side) movement of the mandible (Drake, Vogl, & Mitchell, 2015). Exact logistic regression with an odds ratio (OR) output was conducted to test the strength of the association of each of these features with a diagnosis of probable or possible scurvy. A 2 × 2 OR  and pattern matching can make equal use of a similar visual framework or rubric to rank potential differential diagnoses to the progressive exclusion of unlikely diagnostic options." (Klaus, 2017, p. 101).
The following provides an anatomical guide and weighted diagnostic system for the identification of scurvy from macroscopic skeletal lesions. It consists of a summary of the macroscopic lesions most frequently attributed to scurvy in the paleopathological literature, along with their anatomical associations, and justification for their proposed diagnostic weight. As discussed above, radiographic, histological, and biomolecular methods should be incorporated into the analysis of pathological bone wherever possible. However, we have focused on the macroscopic lesions of scurvy here as these are likely to have the most diagnostic value for paleopathologists working in a field or limited laboratory setting. As with any paleopathological diagnostic system, this methodology is not intended to be exhaustive and will naturally evolve as research on the osseous lesions of scurvy continues to proliferate. Our intention here is to highlight the importance of considering anatomical relationships and the role of soft tissues in lesion formation as well as to illustrate a standardized approach to differential diagnosis.
The weighted diagnostic approach we take here can be summa- case. The nature of this system means that it is likely that some probable and possible cases of scurvy will be lost if the skeletal remains are incomplete (particularly if the cranium is missing). However, we believe that a conservative approach is necessary in order to avoid overdiagnosis. The complete system is outlined in Table 1.
Photographic examples of each feature are provided in Supporting Information Table S1. Each lesion and the justification for its inclusion in this system is described below.

Anatomical association
The temporal lines of the lateral parietal are the origin of the temporalis muscle. The squamous portion of the temporal bone underlies the belly and associated vasculature of this muscle (Drake et al., 2015; Figure 6).

Clinical support
Ectocranial new bone on the parietal was noted by Sir Thomas Barlow in anatomical material from individuals known to have suffered from scurvy, although these early examples are more extreme than those observed in subsequent paleopathological studies (Stark, 2014).

Paleopathological research
Ortner and colleagues have attributed this lesion to scorbutic hemorrhage from vasculature associated with the temporalis, which originates on the lateral aspect of the parietals (Ortner & Ericksen, 1997).

Proposed diagnostic strength
Diagnostic if bilateral and subperiosteal nature of new bone can be confirmed. Radiographs or SEM (Brickley & Ives, 2006) should be employed wherever possible to confirm the subperiosteal nature of the new bone.

Caveat
Lesions are expected to be bilateral if attributable to scurvy.

Feature
Subperiosteal new bone with vascular impressions and/or fine cortical porosity on the endocranial surface of the vault.

Anatomical association
Chronic or acute hemorrhage of the vasculature of the meninges can cause blood clots to form in the subdural space (subdural hematomas) (Yadav, Parihar, Namdev, & Bajaj, 2016).

Clinical support
Endocranial porosity underlying a hematoma was noted by Barlow (1883) in an autopsy of a scorbutic individual. Subdural hematomas are a clinically reported complication of scorbutic hemorrhage (Ingalls, 1936).

Paleopathological research
This feature has been noted in a number of archaeological individuals who exhibit other features diagnostic of scurvy (Brown & Ortner, 2011;Mays, 2008;Snoddy et al., 2017).

Proposed diagnostic strength
Despite its clinical association with scurvy, endocranial new bone and/or porosity have multiple etiologies (Lewis, 2004). As such, we propose that this feature be considered suggestive.

Differential diagnosis
Any condition that might result in localized inflammation of the meninges, including trauma and infection.

Feature
Abnormal cortical porosity and/or subperiosteal new bone in the orbital roofs/ lateral orbit.

Anatomical association
Indirect hemorrhage from vessels associated with the extrinsic muscles of the eye might cause blood to pool in this region.

Clinical support
Indirect: intraocular hematomas have been noted in cases of active scurvy by Barlow (1883) and Verma et al. (2007).
Proposed diagnostic strength: Diagnostic.
Caveat: Feature is expected to be bilateral if attributable to scurvy.
Caution is needed to differentiate cortical porosity from mild cribra orbitalia (trabecular expansion).

| Maxillae
Feature Abnormal cortical porosity and/or porous subperiosteal new bone on the anterior surface and/or in the region of the infraorbital foramina.

Anatomical association
The infraorbital artery runs through the infraorbital foramen and the buccinator originates on the alveolar process of the anterior maxillae (Drake et al., 2015; Figure 6).

Clinical support
None but anatomically intuitive.

Paleopathologial research
This feature was first described by Ortner et al. (1999), in 23 individuals who also exhibited abnormal porosity of the greater wing of the sphenoid. It has subsequently been observed in a number of archaeological individuals who exhibit other diagnostic features of scurvy (Brickley & Ives, 2006;Geber & Murphy, 2012;Snoddy et al., 2017).

Proposed diagnostic strength
Diagnostic.

Differential diagnosis
Any condition that might result in localized periosteal inflammation, including trauma and infection.

Caveat
Lesions are expected to be bilateral if attributable to scorbutic hemorrhage.

Feature
Abnormal cortical porosity and/or porous subperiosteal new bone on the posterior surface, superior to the alveolar margins.

Anatomical association
This region is the origin of the superficial head of the medial pterygoid muscle, which is supplied by the medial pterygoid branches of the maxillary artery (Drake et al., 2015).

Clinical support
None, but anatomically intuitive.

Paleopathological research
This feature was first noted by Ortner and Ericksen (1997). It has subsequently been noted in association with a number of other diagnostic features of scurvy in a large body of paleopathological work (Geber & Murphy, 2012;Klaus, 2014;Ortner et al., 1999Ortner et al., , 2001Snoddy et al., 2017).

Proposed diagnostic strength
Diagnostic.

Differential diagnosis
Porosity associated with alveolar resorption during dental eruption.

Caveat
This feature is expected to be bilateral if attributable to scorbutic hemorrhage and care is needed in juveniles to differentiate from normal porosity associated with eruption of the molars.

Feature
Abnormal cortical porosity and/or porous subperiosteal new bone on the maxillary palate, outside of the alveolar margins.

Anatomical association
The greater palatine artery supplies this region (Drake et al., 2015).

Clinical support
None but anatomically intuitive.

Paleopathological research
This feature was described by Ortner et al. (1999) in 17 individuals who also exhibited abnormal porosity of the greater wing of the sphenoid. It has subsequently been described in a large body of paleopathological work (Brickley & Ives, 2006;Crist & Sorg, 2014;Geber & Murphy, 2012;Halcrow et al., 2014;Ortner et al., 2001).

Proposed diagnostic strength
Diagnostic.

Caveat
Caution is needed in juveniles due to the normal porosity associated with dental eruption.

| Zygomata Feature
Abnormal cortical porosity and/or subperiosteal new bone on the lateral portion of the anterior surface.

Anatomical association
The zygomaticotemporal and zygomaticofacial arteries supply this region and are under indirect stress from orbicularis oculi (Drake et al., 2015; Figure 7).

Clinical support
None but anatomically intuitive.

Paleopathological research
This lesion has been described in two individuals who exhibited other diagnostic features of scurvy (Pitre, Stark, & Gatto, 2016;Snoddy et al., 2017).

Proposed diagnostic strength
Suggestive. Direct clinical support and/or demonstration of statistical association with diagnostic features in a larger sample is needed.

Caveat
Feature expected to be bilateral if attributable to scorbutic hemorrhage.

Feature
Abnormal cortical porosity on the internal/posterior surface.

Anatomical association
This region is supplied by the masseteric branches of the maxillary artery and is the origin of the masseter muscle (Drake et al., 2015). Hemorrhage from the orbital and facial branches of the superficial temporal arteries would also result in blood pooling here (Ortner et al., 2001).

Clinical support
None but anatomically intuitive.

Paleopathological research
This lesion has been described in a handful of paleopathological case studies of scurvy in association with other diagnostic features (Klaus, 2014;Ortner et al., 2001).

Proposed diagnostic strength
Suggestive. Direct clinical support and/or demonstration of statistical association with diagnostic features in a larger sample is needed.

Anatomical association
This region underlies the belly of the temporalis muscle and is supplied by the anterior deep temporal artery (Drake et al., 2015;Figure 6).

Clinical support
This feature has been reported in anatomical material from individuals known to have suffered from scurvy, although these examples are more extreme than has been observed in subsequent paleopathological studies (Stark, 2014). Ortner and colleagues have proposed that these lesions are indirectly caused by masticatory stress from the temporalis muscle on the anterior branch of the deep temporal artery (Ortner & Ericksen, 1997).

Paleopathological research
Ortner has argued that this lesion is strongly diagnostic for scurvy and this feature has been described in a large body of paleopathological work collectively comprising scores of individuals Geber & Murphy, 2012;Klaus, 2014;Ortner et al., 2001;Snoddy et al., 2017).

Proposed diagnostic strength
Diagnostic.

Feature
Subperiosteal new bone around the foramen rotundum.

Anatomical association
The vasculature associated with the maxillary branch of the trigeminal nerve (V2) passes through here (Drake et al., 2015).

Clinical support
None but anatomically intuitive.

Paleopathological research
This feature has been reported in 18% (78/412) of juvenile individuals exhibiting lesions within the Ortner suite in a large archaeological assemblage from 19th Century Ireland (N = 970; Geber & Murphy, 2012). This study demonstrated a statistically significant association between this lesion (Geber & Murphy, 2012) and previously published features the authors considered diagnostic (Brickley & Ives, 2008;Brown & Ortner, 2011;Ortner et al., 1999). It has also been observed in several smaller case series and case studies (Snoddy et al., 2017).

Proposed diagnostic strength
Tentatively diagnostic but association with scurvy should be statistically explored in other samples.

Feature
Abnormal cortical porosity on the lesser wings.

Anatomical association
These structures do not come into direct contact with muscles or vasculature, but the anterior cerebral artery, anterior communicating artery of the brain, and the orbital branch of the middle meningeal artery are transmitted through this region (Drake et al., 2015).

Clinical support
None, but anatomically intuitive.

Paleopathological research
This lesion was described in a single infant in a case-series by Brickley and Ives (2006).

Proposed diagnostic strength
Suggestive. Direct clinical support and/or demonstration of statistical association with diagnostic features in a larger sample is needed.

Feature
Abnormal cortical porosity and/or subperiosteal new bone in the pterygoid fossae.

Anatomical association
Lesion location is the origin of the medial pterygoid muscle (Drake et al., 2015; Figure 4(a)(b)).

Clinical support
None but anatomically intuitive.

Paleopathological research
See section nine.

Proposed diagnostic strength
Diagnostic; see section nine.

Caveat
Feature is expected to be bilateral if attributable to scorbutic hemorrhage.

| Occipital
Feature Abnormal cortical porosity on the inferior surface of pars basilaris (juveniles only).

Anatomical association
This lesion is found in the region of the insertion of the longus capitus muscle (Drake et al., 2015).

Clinical support
None, although neck pain has been reported in scorbutic patients (Olmedo et al., 2006).

Paleopathological research
This lesion has been reported in a small case-series (N = 9/10) of individuals who exhibited other lesions the authors considered diagnostic for scurvy (Moore & Koon, 2017).

Proposed diagnostic strength
Suggestive. Direct clinical support and/or demonstration of statistical association with diagnostic features in a larger sample is needed. The etiology of this feature has also been disputed by González et al. (2018).

Differential diagnosis
Normal growth.

| Mandible
Feature Abnormal cortical porosity and/or subperiosteal new bone on the interior surface of the rami/ coronoid process.

Anatomical association
The temporalis muscle inserts on the coronoid process and the inferior alveolar artery passes through the mandibular foramen on the medial aspect of the ramus (Drake et al., 2015).

Clinical support
None but anatomically intuitive.

Paleopathological research
This lesion was found in three individuals who also exhibited abnormal porosity of the greater wing of the sphenoid (Ortner et al., 1999) and has subsequently been described in association with other scorbutic lesions in a large body of paleopathological work (Geber & Murphy, 2012;Klaus, 2014;Schattmann, Bertrand, Vatteoni, & Brickley, 2016;Snoddy et al., 2017).

Proposed diagnostic strength
Diagnostic.

Caveat
Feature is expected to be present bilaterally if attributable to scorbutic hemorrhage.

Feature
Subperiosteal new bone along the mylohyoid line on the interior surface of the body.

Anatomical association
This region is the origin of the mylohyoid muscle, which is supplied by the inferior alveolar artery (Drake et al., 2015; Figure 5(a)(b)).

Clinical support
None but anatomically intuitive (see section nine).

Paleopathological research
Observed in four individuals who exhibited multiple diagnostic lesions for scurvy after Brickley and Ives (2008).

Proposed diagnostic strength
Suggestive. Direct clinical support and/or demonstration of statistically significant association with diagnostic features in a larger sample is needed.
10.2 | Axial skeleton (post cranial) Abnormal cortical porosity and/or subperiosteal new bone in the supra and/or infraspinous fossae (Figure 8).

Anatomical association
The supraspinatus muscle originates within the supraspinous fossa and scorbutic hemorrhage of the associated suprascapular artery could cause extravasated blood to pool here (Drake et al., 2015). Likewise, the infraspinatus and teres minor muscles both originate in the infraspinous fossa and scorbutic hemorrhage of the circumflex branch of the subscapular artery might be caused by lateral rotation of the arm (Drake et al., 2015).

Clinical support
Indirect; Barlow (1883) noted subperiosteal hematomas in these regions in autopsies of scorbutic children.

Paleopathological research
Ortner et al. (2001) noted these features in several individuals who also exhibited abnormal porosity of the greater wing of the sphenoid.

Proposed diagnostic strength
Diagnostic.

| Ribs
Feature Enlargement of the costochrondral junction (juveniles only).

Clinical support
This feature is part of the radiographic suite of lesions seen in pediatric scurvy and is caused by defective collagen formation at the sternal margins of the ribs (Jaffe, 1972). However, it is more strongly associated with rickets (Adams, 2011).

Proposed diagnostic strength
Despite its clinically demonstrated association with scurvy, we consider this feature suggestive as it is more frequently found in association with rickets and the paleopathological evidence for its association with scurvy is thin.

Feature
Subperiosteal new bone on the anterior/lateral surfaces of the shafts.

Clinical support
Limited; Barlow (1883) has described the presence of subperiosteal hematomas on the shafts of ribs in autopsied scorbutic children.

Paleopathological research
This feature has been described in two perinates exhibiting other lesions diagnostic for scurvy Snoddy et al., 2017).

Proposed diagnostic strength
Suggestive. This feature is associated with a number of other pathological conditions. Direct clinical support and/or demonstration of statistically significant association with diagnostic features in a larger sample is needed.

Caveat
Feature is expected to be bilateral and widespread.

| Vertebrae
Feature Biconcavity and osteopenia of bodies (adults only).

Clinical support
This feature has been clinically associated with adult scurvy (Joffe, 1961). However, it is also found in osteomalacia and age-related osteoporosis (Jaffe, 1972).

Paleopathological research
We have been unable to find published paleopathological research ascribing this feature to scurvy.

Proposed diagnostic strength
Despite its clinically demonstrated association with scurvy, we consider this feature suggestive due to its commonality across several metabolic bone diseases.

Caveat
Biconcavity due to metabolic bone disease rather than trauma is expected to be widespread throughout the vertebral column (Jaffe, 1972;Resnick, 1995).

| Ilia Feature
Abnormal cortical porosity and/or subperiosteal new bone, particularly on the visceral surface. Subperiosteal new bone may contain vascular impressions.

Anatomical associations
This region underlies the belly of the iliacus muscle, which is supplied by the internal iliac artery (Drake et al., 2015).

Clinical support
Indirect; Barlow (1883) noted subperiosteal hemorrhage on an ilium of an autopsied scorbutic child and subperiosteal fluid around the ilium and ischium has been visualized by MRI in a clinical case-report (Gongidi, Johnson, & Dinan, 2013).

Paleopathological research
This feature was first noted in a case-study by Brown and Ortner (2011) and has subsequently been described in several individuals by Geber and Murphy (2012).

Proposed diagnostic strength
Suggestive. Additional clinical support and/or demonstration of statistical association with diagnostic features in a larger sample is needed.

Anatomical associations
Multiple. The diaphysis/metaphyses of the appendicular long bones underlie the bellies of numerous muscles with a variety of vascular innervations. Widespread subperiosteal bleeding in the appendicular skeleton can occur due to minor soft tissue trauma in scorbutic individuals (Besbes et al., 2010;Jaffe, 1972;Joffe, 1961).

Clinical support
This feature has been clinically observed following the reintroduction of vitamin C and resumption of osteoid formation (Noordin et al., 2012;Riepe et al., 2001).

Paleopathological research
Ortner et al. (2001) noted this feature in several individuals who also exhibited abnormal porosity of the greater wing of the sphenoid. It has subsequently been noted in a large body of paleopathological work in association with other osseous features of scurvy (Brown & Ortner, 2011;Buckley et al., 2014;Geber & Murphy, 2012;Klaus, 2014;Snoddy et al., 2017;Van der Merwe et al., 2010).

Proposed diagnostic strength
Diagnostic if found in association with cranial lesions.

Caveat
Expected to be present bilaterally if attributable to scorbutic hemorrhage. Care is needed with interpretation in juveniles as this is also a feature of appositional growth.

Anatomical association
Multiple (see above).

Clinical support
As above, this feature has been clinically observed following the reintroduction of vitamin C and resumption of osteoid formation (Brailsford, 1953).

Paleopathological research
The paleopathological observations of this feature in association with scurvy come from adult individuals Maat, 2004;Van der Merwe et al., 2010).

Proposed diagnostic strength
Suggestive if bilateral, non-diagnostic if unilateral.

Clinical support
Limited; a case study by Sprague (1976) described metaphyseal cupping in a scorbutic individual several years following recovery. This lesion occurred due to epiphyseal slipping from the residual effects of scurvy on the provisional zone of calcification of the growth plate.

Paleopathological research
Schattmann and colleagues (2016) have described metaphyseal cupping in possible comorbid cases of scurvy and rickets.

Proposed diagnostic strength
Suggestive.

| Femora
Feature Subperiosteal new bone on the proximal and medial diaphysis, medial to the linea aspera.

Anatomical association
This region is the insertion of the adductor longus muscle, which is supplied by the profundus femoris artery (Drake et al., 2015).

Clinical support
None but anatomically intuitive.
Paleopathological research Buckley et al. (2014) in several individuals who exhibited other osseous features of scurvy.

Proposed diagnostic strength
Suggestive. Direct clinical support and/or demonstration of statistical association with diagnostic features in a larger sample is needed.

| SUMMARY AND CONCLUSIONS
The recent proliferation of research on scurvy in ancient human remains is promising and carries implications for how we study subsistence, resource allocation, and human-environmental interactions in the past.
However, the diagnostic criteria for scurvy employed by paleopathologists has not always been uniform. This article has provided a literature synthesis of the previous body of work on the identification of scurvy in archaeological human remains. Drawing from this foundation, we have proposed a standardized approach to differential diagnosis that assigns diagnostic value based on the strength of association between macroscopic osseous lesions, clinically observed features, and anatomical relationships. Using a well-preserved sample from the ancient Atacama Desert, we have also demonstrated an approach for assigning diagnostic weight to newly recognized lesions of this disease.
We encourage debate on this subject and consider this work a starting point for a larger academic conversation that will ultimately refine diagnostic protocol and increase the rigor of this system. Our intention here was to highlight the need for a standardized approach which considers the pathophysiology of the disease and soft-tissue anatomy. It is our hope that other researchers will carry this approach forward and continue to advance the study of this condition in pastpopulations.

ACKNOWLEDGMENTS
The authors thank Susana Monsalve and Anita Flores for their assistance with collections access at the Museo San Miguel de Azapa, Universidad de Tarapacá, Arica. They thank the reviewers for their comments. This project was supported by a Marsden Grant from the Royal Society of New Zealand (UOO1413), CONICYT Anillo (SOC1405) and Fondecyt (1171708) grants, and a University of Otago Doctoral Scholarship.