Atlanto-occipital fusion and spondylolisthesis in an Anasazi skeleton from bright angel ruin Grand Canyon National Park Arizona.код для вставкиСкачать
AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 67:381-391(1985) Atlanto-Occipital Fusion and Spondylolisthesis in an Anasazi Skeleton From Bright Angel Ruin, Grand Canyon National Park, Arizona CHARLES F. MERBS AND ROBERT C. EULER Department ofAnthropbgy, Arizona State Uniuersity, Tempe, Arizona 85287 KEY WORDS Paleopathology, Atlanto-occipital fusion, Spondylolisthesis, Depression fracture, American Southwest The skeleton of a middle-aged female showing a n unusual ABSTRACT pattern of congenital, traumatic, and degenerative pathology was recovered from a small Kayenta Anasazi site located near the confluence of Bright Angel Creek with the Colorado River in the Inner Gorge of Grand Canyon. The atlas is fused with the base of the skull and C2 is fused with C3. The cervical region was subjected to hyperextension, perhaps through use of a tumpline, with resultant reduction of the neural canal to 8 mm, a condition that quite likely led to neurological problems. The skeleton also includes a depression fracture of the lateral condyle of the left tibia. Complete, bilateral spondylolysis of L5 led to a n olisthesis of approximately 15 mm. The disc between L5 and S1 then ossified, most likely from staphylococcus bacteremia, making the olisthesis permanent and thereby creating a unique archaeological specimen. Although spondylolysis is usually viewed as a stress fracture, the general pattern of pathology in this individual makes it necessary to consider a n etiology of acute trauma. ARCHAEOLOGICAL CONTEXT Near the confluence of Bright Angel Creek and the Colorado River in the Inner Gorge of Grand Canyon is a small Kayenta Anasazi ruin (Ariz. B:16:1) that was occupied ca. A.D. 1050-1150. The site was first noted in 1869 by Major John Wesley Powell (1875: 87) during his initial voyage down the Colorado River, but it was not recorded by professional archaeologists until 1953 (Taylor, 1958: 25). In 1969, the National Park Service contracted with the School of American &search to excavate the site (Schwartz et al., 1979), but no human skeletal material was recovered. However, in January of 1982, during the course of digging by a construction crew, two burials (Ariz. B:16:1A) associated with the pueblo were accidently discovered. Work was immediately halted, fortunately, before major damage occurred, and excavation was undertaken by Robert C. Euler, assisted by A. Trinkle Jones and Lisa D. Madsen. The bodies had been interred in the only boulder-f:ee sandy area of the entire delta, on the west side of Bright Angel Creek, ap0 1985 ALAN R. LISS, INC. proximately 300 m west of the pueblo, 50 m west of the present course of the creek, and 90 m north of the Colorado River. Burial 1 contained the skeleton of a n adult woman a t a depth of approximately 1m below present ground surface in unconsolidated sand. The original ground surface was not ascertainable. The skeleton was lying on its back in a loosely flexed position with its skull to the south on fairly compact white flecked sand. Near the right iIium was a Tusayan Corrugated jar, the only cultural item in association with the burial. Burial 2, located a t the same subsurface level and approximately 80 cm west of burial 1,contained the somewhat disarticulated, partial skeleton of a juvenile. Although the skull was lacking, the body had probably been oriented with its head to the northwest. The only artifact in association was a bracelet on the left wrist consisting of one olivella shell and eleven fine- Received September 25, 1984; revised March 12, 1985; accepted March 25,1985. 382 C.F. MERBS AND R.C. EULER grained siltstone beads. This skeleton is too fragmentary to warrant, further discussion in this paper. DESCRIFTION OF ADULT SKELETON The skeleton of the adult (burial 1)is relatively complete except for the face and mandible. The only facial parts present are the left zygomatic, a portion of the left maxilla, and a portion of the right zygomatic. The occipital shows postmortem damage near the left mastoid process, but the cranium is otherwise well-preserved. All major postcranial parts are present, but many show postmortem damage, and in a few cases the damage is extensive. The only parts actually missing, however, are very small bones such as carpals and phalanges. The skull has large mastoid processes and moderately well developed supraorbital ridges, and it could easily be judged as male. Evidence from the postcranial skeleton, however, strongly indicates female. The greater sciatic notch of the pelvis (preserved on both sides) is broad and shallow, and the pubic element (preserved on left side) is elongated. A well-defined preauricular sulcus is present, and the acetabulum is small relative to the overall size of the pelvis. The lengths of the long bones and their overall gracility also strongly suggest the sex of the skeleton to be female. Considering the reliability of the various criteria and their intensity of expression in this skeleton, a judgement of female can be made with high reliability. The application of standard aging criteria to this skeleton suggests an approximate age of 37 years at time of death with individual criteria producing ages as young as 30 years and as old as 48 years. Estimates of stature for the skeleton are based upon the maximum length of the right femur taken by itself, and upon the maximum lengths of all long bones (except the tibia) from the left side considered as a group. Using the method of Genoves (1967), which is based upon modern Mexicans of predominantly Indian origin, this individual is estimated to have been slightly less than 156 cm (5 feet 1inch) in height. The cranium is flattened a t lambda (actually centered 20 mm to the left of lambda) and markedly asymmetrical. Although the lambdoidal suture is complicated and contains tiny “inclusions,” no actual wormian bones are present. The cranium contains unusually large, irregularly shaped tympanic dehiscences (Fig. l), but no auditory exostoses. The dehiscence on the left side, which is slightly larger than that on the right, measures 9.5 mm by 5.5 mm. A “button osteoma,” measuring approximately 12 mm in diameter, and protruding 2 mm from the surface of the frontal bone, is centered just above the right supraorbital ridge. Dorsal to the foramen magnum and to the right of the midline on the occipital is a contact facet measuring 12 x 8 mm (Fig. 2). There is little indication of a corresponding facet on the spinous process of the axis, but this part has sustained postmortem damage making observation difficult. Two examples of cervical vertebral fusion are present. The first involves the atlas, which is fused to the occipital (Figs. 1, a), a condition usually referred to as occipitalization of the atlas, or atlas assimilation. Although well formed and basically normal in appearance, the atlas nevertheless exhibits some unusual features. First, the transverse processes of the vertebra lack foramina; second, the inferior articular facets are unusually large and somewhat more convex in sagittal section than normal; and third, the left side of the posterior arch has been flattened against the base of the skull. The usual atlanto-occipital articulations do not exist, and the remainder of the atlas, except for the transverse processes and a portion of the anterior arch to the right of the midline, is solidly fused to the occipital. The second example of cervical fusion involves C2 and C3 (Fig. 3). Except for their separated transverse processes, these two vertebrae form a single unit, a so-called block vertebra. All foramina, including the intervertebral foramina defined by the two vertebrae, are well-formed, and the same is generally true of other parts of the vertebrae. There is one exception, however, this being the odontoid process, which shows distinct beveling toward its apex, especially on the right side. The odontoid has also been deeply impressed where it contacted the anterior arch of the atlas during extension of the neck, and a step has formed between this surface and the nonarticular surface below. A facet on the superior surface of the spinous process of C4 extends back approximately 10 mm from the edge of the neural canal (Fig. 41, while the opposing facet on C3 is much smaller and poorly defined. The inferior surface of C4 contains a small facet similar to that on C3. Just below the superior ATLANTO-OCCIPITALFUSION AND SPONDYLOLISTHESIS Fig. 1. Fusion of first cervical vertebra with base of skull. Note large tympanic dehiscences (dehiscence on right side indicated by arrow). Fig. 2. Base of skull with facet (arrow) indicating contact with spinous process of second cervical vertebra. 383 384 C.F. MERBS AND R.C. EULER Fig. 3. Fusion of second and third cervical vertebrae. Fig. 4. Fourth cervical vertebra showing osteophyte development into neural canal, facet on superior surface of spinous process, and deep impression below left articular facet. articular facets of C4 are impressions produced by contact with the inferior articular processes of C3, the condition being especially pronounced on the left side. These two vertebrae also exhibit osteophyte development extending from the margins of their opposing bodies dorsally into the neural canal and laterally over the pedicles. This development is more prominent on C4 and has a markedly pitted appearance. Only two cervical vertebrae below C4 were recovered and both are fragmentary. Twelve thoracic vertebrae were recovered, but all have damaged transverse and spinous processes. In addition, units 1-3 lack bodies. All nine of the recovered bodies, T4-Tl2, show slight to moderate osteophyte development on their anterior margins. In addition, the body of T11 has been slightly compressed, an estimated 2 mm having been lost from its anterior height. Five lumbar vertebrae were recovered, but only the first and last are relatively complete. The last unit (L5) is separated into two parts (spondylolysis), the separation having occurred between the superior and inferior articular processes (pars interarticularis) (Fig. 5). The portion of L5 containing the body, pedicles, and superior articular processes, continuous with the vertebral column above this point, shows evidence of having shifted forward approximately 15 mm (spondylolisthesis) (Fig. 6). The shifted portion of L5, but not the separated neural arch, then became fused to the sacrum through ossification of the intervertebral disc (L5/S1),thus making the olisthesis a permanent part of the osteological record (Fig. 7). There are large areas of contact between the spinous processes of L3 and L4 (18 x 9 mm), and between those of L4 and L5 (18 x 11 mm), and the inferior articular processes of L4 have been broadened and flattened into facets (approximately 14 mm in diameter) that articulate with the separated edges of the pars interarticularis of L5 (Fig. 8). The spinous process of L4 has been beveled posteriorly through contact with that of L3 (Fig. 8). All of the contact facets have irregular surfaces and margins, and some contain small circular pits. Evidence of disc degeneration (osteophyte formation) is present on the superior margin of the L3 body, but this area is too damaged to make similar observations for L4, L5, or the sacrum. All facets composing the L4-5 apophyseal articulations show evidence of degenerative joint disease (osteoarthritis), and the sacro-iliac articulations have also developed a rim of new bone indicative of joint degeneration. Evidence of degenerative joint disease is present in the bones of both elbows. The lat- ATLANTO-OCCIPITALFUSION AND SPONDYLOLISTHESIS Fig. 5. Fifth lumbar vertebra and sacrum, dorsal view, showing spondylolysis (complete, bilateral) through pars interarticularis of L5 (separation on right side indicated by arrow). Fig. 6. Fifth lumbar vertebra, superior view, showing olisthesis (arrow) of L5 relative to S1. 385 386 C.F. MERBS AND R.C. EULER Fig. 7. Fifth lumbar vertebra and sacrum, ventral view, with ossification of disc (arrow) between L5 and S1. Fig. 8. Fourth lumbar vertebra. A. Inferior view, showing faceting of spinous process and inferior articular processes. B. Right view, showing beveling of spinous process from contact with L3. ATLANTO-OCCIPITALFUSION AND SPONDYLOLISTHESIS 387 Fig. 9. Left tibia, proximal end, showing depression fracture of lateral condyle. era1 trochlear ridge of the right humerus shows surface erosion, while that of the left humerus shows deep pitting, which extends dorsally as lipping between the trochlea and capitulum. Although the capitulum itself is free of pathology on both sides, the head of the left radius contains a small area of erosion, while that of the right radius is too damaged to allow observation. Both radii show arthritic lipping at their distal ends with that on the left side being slightly greater than that on the right. A middle manual phalanx contains evidence of a lytic lesion (osteomyelitis) at its proximal end. The lateral condyle of the left tibia has sustained marked depression with three fracture lines evident-two straight and one curvilinear Wig. 9). One extends from the posterolateral corner of the condyle to the approximate center of the intercondyloid eminence; another from the approximate midpoint of the first to the anterior margin of the condyle; and the third, curvilinear in shape, from the lateral margin of the condyle to the intercondyloid eminence, where it meets the first. The third line lies several millimeters inside the anterior margin of the condyle over most of its route and crosses the second line. Pronounced callus development is evident along the second fracture line with only traces visible along the first and third. The fracture area covers two-thirds of the left condyle and has produced a maximum depression of approximately 7 mm in its surface. The patellar surface of the lateral condyle on both femora contains an area of roughened, porous bone, typical of degenerative joint disease, with that on the left side covering approximately twice the area of that on the right. The superior margin of the patellar surface also shows considerably more osteophyte development on the left side than the right. The patellae, themselves, also contain roughened, porous areas, but here involvement is greater on the right side than the left. The proximal articular surfaces of the tibiae show no evidence of degenerative change, but small “squatting facets” are present at the distal ends. In addition, a small bony spur extends from the margin of the proximal articular facet of a pedal phalanx. DISCUSSION Some features of the pathology described here would not be considered unusual in an Anasazi Pueblo woman. Asymmetrical deformation centered near lambda, for example, is typical of Anasazi crania, with the condition usually attributed to the use of a cradleboard in infancy. The presence of “squatting facets” on the tibiae is also not unusual in Anasazi remains, but attributing them to the flexion of the lower extremity that occurs during habitual squatting (Ubelaker, 1978: 388 C.F. MERBS AND R.C. EULER 74) may be inappropriate here. The faceting in Southwest Pueblo women is more likely due to the hours they spend kneeling before their metates while grinding maize and other foods, and the condition in this group would thus more appropriately be termed “kneeling facets.” The evidence for joint degeneration (osteoarthritis) in both elbows of the Bright Angel woman is concentrated in the flexionextension rather than the rotational aspect of this joint. This pattern has been identified more frequently in women than men among Eskimos and has been attributed primarily to movements and stresses involved in skin preparation for clothing (Merbs, 1983). Associating the condition with food grinding in Baja California, Merbs (1980) introduced the term “metate elbow” as a female analog to Angel’s (1966) well-known “atlatl elbow” in males. Other features of the pathology noted in this woman are even more general in nature and probably reflect her age more than anything else. In this category is the osteophyte development indicative of disc degeneration in the thoracic region of the vertebral column and the slight compression of the T11 body. The bony spur on the pedal phalanx, probably the result of tendon damage in a toe, may also be included here. The most interesting features of pathology in the Bright Angel skeleton are those that are unusual in themselves, and that in combination provide this individual with a unique profile. Included here is the vertebral fusion in the cervical region, the spondylolisthesis and disc ossification a t the thoracolumbar junction, the fracture in the left knee, and, possibly, the Iytic lesion in the manual phalanx. The fusion of the atlas with the occipital may be attributed to a failure of fetal sclerotomes to separate properly in the formation of intervertebral spaces and discs, and the condition would have been present a t birth. Rare in skeletal series, and not always discernible in the living, population frequencies are difficult to establish. However, a n incidence a t birth of approximately 0.5% has been recorded by Correia (Gunderson et al., 1976: 497). Fusion of C2/3, also attributable to maldevelopment of fetal sclerotomes, frequently accompanies atlanto-occipital fusion (McRae, 1960). Fusion of C2/3 is included under the eponym “Klippel-Feil syndrome,” a term which remains popular despite the recognition that it encompasses more than one etiologic and clinical entity. Estimates of frequencies vary enormously, from .002% (Luftman and Weintraub, 1951) to .429% (Shands and Bundens, 1956). The condition has been reported for a number of North American skeletal series, including some from the Southwest (see Wade, 1981:123). Wade describes 5 cases of C2/3 fusion in 29 skeletons from several closely related archaeological sites dating between A.D. 600 and 1200 in northeastern Arizona. However, none of Wade’s five affected cases, all males, combine the fusion of C2/3 with atlanto-occipital fusion. Congenital vertebral fusion frequently follows a familial pattern of occurrence, and genetic inheritance is strongly suggested. Both autosomal dominant and autosomal recessive models have been postulated, but it is clear that the actual mode of inheritance is far from understood. Incomplete penetrance and variable expressivity are frequently invoked to account for a lack of conformity to a simple, trustworthy Mendelian model (Wade, 1981: 117). Environmental influences must also be considered. Atlanto-occipital fusion has been associated with a low hairline and a short neck, and some restriction of movement may be experienced. In approximately 20% of cases, the condition is associated with other developmental problems including anomalies of the jaw, incomplete development of the nasal cartilage, cleft palate, congenital deformation of the external ear, cervical ribs, abnormal vertebral number, and anomalies of the urethra and urinary tract (Rothman and Simeone, 1975). Unfortunately, the Bright Angel skeleton does not lend itself to the observation of any of these traits because they are limited to soft tissue or because the relevant skeletal parts are missing or too fragmentary for study. Clinical information on tympanic dehiscences is lacking, but given the occasional association of ear anomalies with atlanto-occipital fusion, the possibility that the unusually large dehiscences in this individual may be related to the fusion cannot be ruled out. The combination of atlanto-occipital fusion and fusion of C2/3 places greater than normal demands on the atlanto-axial articulation, particularly in flexion and extension. This may be observed in the Bright Angel adult in the greater than normal convexity ATLANTO-OCCIPITALFUSION AND SPONDYLOLISTHESIS of the inferior articular facets of the atlas. The faceting on the occipital and on several of the cervical spinous processes, the deep impressions on C4 produced by the inferior articular processes of C3, and the development of osteophytes on the dorsal margins of the bodies of C3 and C4 are all indications of extreme hyperextension of the neck. This pattern of osteological change is compatible with the use of a tumpline across the forehead for carrying heavy objects, the tumpline tending to pull the head backward, thus placing considerable stress on the dorsal aspects of the upper cervical vertebrae. In the case of the Bright Angel skeleton, the pathological results of tumpline usage have been exacerbated by the loss of neck mobility through vertebral fusion. Given the variation that exists between the appearance of a condition and how a person is actually affected, attempts to reconstruct this relationship from prehistoric skeletal remains must be viewed as speculative at best. The vertebral contact and resultant degenerative changes produced by pronounced extension of the neck would certainly be expected to cause local pain, but did the vertebral fusions also lead to impingement upon the spinal cord or other nerves which could have resulted in more widespread neurological problems? McRae and Barnum (1953) associate the development of neurological signs from atlanto-occipital fusion with an odontoid process of abnormal sue, in abnormal position, or with abnormal mobility. The odontoid process of the Bright Angel woman is somewhat unusual in terms of shape, but it is not unusually large, and its position relative to the base of the skull (and thus the base of the brain) is well within the range of normality. Its mobility in life is difficult to judge. McRae and Barnum (1953)found neurological involvement in individuals in which the effective diameter of the neural canal, measured from the odontoid process to the closest bony point behind it (margin of the foramen magnum or posterior arch of the atlas), was 19 mm or less. Other authors Poznanski, 1974) suggest that a slightly smaller diameter can be tolerated with few or no symptoms. This measurement in the Bright Angel woman is 14 mm. However, McRae and Barnum’s standard was established on typical present-day patients, not small, prehistoric Pueblo Indians. Since the measurement considered is not among those taken in gen- 389 eral osteological studies, standards of normality for Pueblo Indians do not exist. However, a Sinagua woman of approximately equal size from the site of Nuvakwewtaqa (Chavez Pass), Arizona, with a normal atlanto-occipital region, measures only 15 mm across the neural canal. Pueblo women thus appear to be smaller in this dimension than most present-day patients, and the Bright Angel skeleton, with a diameter of 14 mm, is still probably within the range of normality for its population. However, given the extreme extension of the neck already discussed, and the natural narrowing of the neural canal it would produce, the true minimal diameter of the canal may be obvious only during this extension. The various indications of vertebral contact during maximum extension allow the reconstruction of this position quite accurately as well as the measurement of the canal at various levels. In so doing, the minimal diameter is found to be no more than 8 mm (between C3 and C4), a narrowing that very likely did produce observable neurological changes. Adding to the problem is the fact that the part of C4 that would have impinged upon the spinal cord in this individual, the anterior margin of the neural arch, has an unusually sharp edge. The osteophyte development between C3 and C4 is also impinging upon the space of the fourth cervical nerve, a situation which may have further aggravated the neurological situation. Among the symptoms associated with reduction of the neural canal and bony impingement upon the spinal cord, according to McRae and Barnum (19531, are numbness and pain in the arms, weakness of the legs, muscle control problems in both limbs, occipital headache, blurring of vision, and double vision. McRae and Barnum add that head or neck trauma may play some role in the onset of these symptoms in a condition that may otherwise have been asymptomatic since birth. The depression fracture of the left tibia appears to have been caused by acute trauma, most likely produced by a fall, with the lateral condyle of the femur acting as a hammer and the opposing tibia1 condyle as an anvil. The femur itself shows no evidence of trauma. The fracture would most likely have taken place while the left leg was extended, perhaps even hyperextended, with the full impact of the shock passing through the knee while it was in a position extremely vulner- 390 C.F. MERBS AND R.C. EULER able to fracture. The lack of remodeling in the fracture area indicates that the unaffected posterolateral one-third of the condyle served as the sole lateral support for the femur, and that disruption of normal movement in the knee was probably not major. However, the unaffected portion of the condyle does contain a n area of roughened bone (9 x 4 mm), applied to the smooth articular surface, which is indicative of some joint disfunction. The osteoarthritic degeneration involving the patellar surface of the femur and the patella itself is very likely related to the trauma. Both knees are affected, but overall the pathology is distinctly more advanced on the left side than the right. The complete, bilateral spondylolysis affecting the last lumbar vertebra in the Bright Angel woman is not unusual (Coyne, 1981: 153; Merbs, 1983: 35-42), nor is the olisthesis that followed it. However, the bony ankylosis of the affected body to the sacrum below through ossification of the intervertebral disc has never been reported for a n archaeological specimen (T. Dale Stewart, personal communication) and is extremely rare clinically (Leon L. Wiltse, personal communication). Since the degree of olisthesis is established by the relative positions of two osseous units to each other, held in place by soft tissue (ligaments and disc), it, is a difficult condition to reconstruct in archaeologically derived material devoid of soft tissue. When such reconstruction is possible, it is based upon the matching of osteophytes on the bodies of adjacent vertebrae, or other secondary osseous changes in the region of the separation, and it is a n estimate a t best (Merbs, 1980).In the case of the Bright Angel woman, however, the ossification of the disc formed a bony connection that provides a permanent and accurate picture of the olisthesis that occurred. Spondylolisthesis ranges from cases that are barely detectable to those in which the column slips completely off the vertebral body below. The shifting in the Bright Angel woman measures 15 mm, or slightly more than one-third the width (estimated) of the sacral body, a degree of slippage that would place her in terms of severity in the upper 20% of individuals with this condition (Harris, 1959). The reason for the ossification of the disc is not readily apparent, especially since spondylolisthesis tends to decrease the stability of the region and thus decrease the likelihood of immobility and fusion. The most likely cause, however, is discitis. Tuberculosis, one possible cause of discitis, has been identified in prehistoric Southwestern skeletal remains (El-Najjar, 19791, but with this disease bony ankylosis is usually preceded by massive bone destruction. There is no indication of this kind of destruction in the Bright Angel skeleton. Nor is there any evidence of ankylosing spondylitis or rheumatoid arthritis in the region of the ossified disc, or in any other part of the skeleton. Evidence of generalized osteopenia leading to traumatic collapse in the affected region is also absent. Staphylococcus bacteremia is a much more likely cause of infectious discitis and ultimate fusion, according to Wiltse (personal communication), but other bacteria cannot be ruled out. The bacteremia could have developed from a n infected foot or hand that continued to be used. In a few days or weeks the bloodstream might then have become heavily infested with the bacteria that could produce multiple areas of sepsis, or lodge in a single place. The intervetebral disc is a favorite place for them to lodge, according to Wiltse, perhaps more so if the disc is subjected to inflammation and degeneration from spondylolisthesis. This type of fusion takes only a year to 18 months to occur. In this context, it is tempting to see the pathological middle manual phalanx of the Bright Angel woman as representing the point of entry for the bacteria that eventually led to the ossification of the disc, but this is nothing more than speculation. It is also possible that the fusion was caused by a noninfectious discitis. Wiltse reports that he has seen these spontaneous fusions many times in patients who did not have spondylolisthesis. Reviews of these patients’ histories disclosed no indication of infection, or at least nothing severe enough to make the patient sick. CONCLUSIONS In terms of cranial features and general body form, the adult skeleton from Bright Angel Ruin is typical of Pueblo Indian females. Accentuating this picture are skeletal changes consistent with the use of a cradleboard during infancy, the carrying of heavy objects with a tumpline, and the use of a mano and metate in food preparation. The skeleton also shows evidence of a congenital problem, fusion of the first cervical vertebra with the base of the skull, and fusion of the second and third cervical vertebrae. This fusion (actually a failure of developing vertebrae to separate) increased ATLANTO-OCCIPITAL FUSION AND SPONDYLOLISTHESIS the amount of movement occurring between the first and second cervical vertebrae. In combination with the habitual hyperextension evidenced in the upper cervical vertebrae, the result was considerable reduction in the size of the neural canal, allowing a sharp edge of bone to impinge upon the spinal cord, and very likely producing neurological problems affecting the arms and legs, and vision. The Bright Angel skeleton also shows evidence of trauma, a depression fracture of the left knee, a compression fracture of a lower thoracic vertebra, and spondylolysis of the last lumbar vertebra. The spondylolysis was followed by spondylolisthesis and ossification of the intervertebral disc between the affected unit and the sacrum, thus fusing these two units in their position of olisthesis. The fusion appears to have been caused by a discitis, most likely owing to staphylococcus bacteremia, and possibly initiated by a n infected finger. The fractured knee and compressed thoracic vertebra are compatible with a fall, with both possibly representing the same traumatic event. Although spondylolysis is generally attributed to gradual bone separation, a “fatigue fracture” resulting from repeated or habitual stress (Wiltse et al., 1975), the other evidence for a fall in the Bright Angel woman makes it necessary to consider acute trauma as the possible cause of the spondylolysis in this skeleton. Incomplete separation (Merbs, 1983)may be interpreted as a fatigue fracture “in progress,” but once the separation has become complete, it is unlikely that the alternative etiologies may be distinguished from their skeletal appearance. In other words, the fractured tibia and the spondylolysis, and possibly all three fractures, may have resulted from a single traumatic event such as a severe fall. All that can be established with respect to the timing of the three fractures is that they occurred some time (perhaps years) before the death of the individual, allowing for secondary degenerative changes to take place. Although not related etiologically, the congenital condition and the fractures-may have had a n effect upon each other. The neurological problems associated with the cervical fusions may have prompted the fall that produced the fractures, for example, or the trauma produced by the fall may have aggravated the neurological conditions. In any event, the profile of pathology reconstructed from the skeleton of this ancient occupant of 391 the Grand Canyon indicates that her life was indeed a harsh one. LITERATURE CITED Angel, JL (1966) Early Skeletons from Tranquility, California. Smithsonian Contributions to Anthropology, Vol. 2, No. 1. Washington. Coyne, S (1981) Variations and pathologies in the vertebral columns of Gran Quivira Indians. In AC Hayes (ed) Contributions to Gran Quivira Archeology. National Park Service Publications in Archeology 17, Washington. El-Najar, MY (1979) Human treponematosis and tuberculosis: Evidence from the New World. Am. J. Phys. Anthropol. 5It599-618. Genoves, S (1967) Proportionality of the long bones and their relation to stature among Mesoamericans. Am. J. Phys. Anthropol. 265-78. Gunderson, CH, Greenspan, RH, Glaser, GH, and Lubs, HH (1976) The Klippel-Feil syndrome: Genetic and clinical reevaluation of cervical fusion. Medicine 46t491-512. Harris, RI (1959) Congenital anomalies. In R Nassim and H J Burrows (eds): Modern Trends in Diseases of the Vertebral Column. New York: Hoeber, pp. 29-66. Luftman, 11, and Weintraub, S (1951) Klippel-Feil syndrome in a full term stillborn infant. N.Y., J. Med. 5Ir2035. McRae, DL (1960) The significance of abnormalities of the cervical spine. Am. J. Roentgen. 84:3-25. McRae, DL, and Barnum, AS (1953) Occipitalization of the atlas. Am. J. Roentgen. 70:23-46. Merbs, CF (1980) The pathology of a La Jollan skeleton from Punta Minitas, Baja California. Pacific Coast Archaeological Society Quarterly 16:37-43. Merbs, CF (1983)Patterns of Activity-Induced Pathology in a Canadian Inuit Population. National Museum of Man Mercury Series, Archaeological Survey of Canada Paper No. 119. Ottawa. Powell, JW (1875) Exploration of the Colorado River of the West and its Tributaries. Washington: U S . Government Printing Office. Poznanski, AK (1974) Congenital anomalies of the cervical spine. In RW Bailey (ed):The Cervical Spine. Philadelphia: Lea and Febiger, pp. 47-90. Rothman, RH, and Simeone, FA (1975) The Spine (2 Volumes). Philadelphia: W.B. Saunders. Schwartz, DW, Marshall, MP, and Kepp, J (1979) Archaeology of the Grand Canyon: The Bright Angel Site. Santa Fe: School of American Research Press. Shands, AR, Jr., and Bundens, WD (1956) Congenital deformities of the spine: An analysis of the spines of 700 children. Bull. Hosp. Joint Dis. 17:llO. Taylor, WW (1958) Brief Survey Through the Grand Canyon of the Colorado River. Museum of Northern Arizona Bulletin 30. Flagstaff. Ubelaker, D (1978) Human Skeletal Remains. Chicago: Aldine. Wade, WD (1981) Klippel-Feil syndrome in a prehistoric population of Northern Arizona. In JS Cybulski (ed): Contributions to Physical Anthropology, 1978-1980. National Museum of Man Mercury Series, Archaeological Survey of Canada Paper No. 106, pp. 115-126. Ottawa. Wiltse, LL, Widell, EH, Jr., and Jackson, DW (1975) Fatigue fracture: The basic lesion in isthmic spondylolisthesis. J. Bone Joint Surg. 57-A:17-22.