Gerald J. Conlogue

Radiology of Postnatal Skeletal development: The proximal humerus

Twenty-three pairs of proximal humeri obtained from human cadavers ranging in age from fullterm stillborn to fourteen years were studied morphologically and radiographically. Roentgenograms of the specimens demonstrated the osseous and cartilaginous portions of the epiphyses, using air/cartilage interfacing. Comparable clinical simulations were obtained by using water immersion of the specimens. The metaphyseal cortex remained thin and trabecular near the physis. Histologically this area had multiple fenestrations, which provide a potential pathway for childhood osteomyelitis into the subperiosteal space, and may also affect the biomechanics of this region (i.e., susceptibility to Salter epiphyseal fractures). As skeletal maturity was reached, thicker cortical (osteonal) bone extended toward the physis. The epiphyseal secondary ossification centers form an osseous connection shortly after the appearance of greater tuberosity ossification center, although this may not be radiologically evident until the child is older. The major intent of this roentgenographic survey is to provide a reference index of proximal humeral development for the adequate interpretation of shoulder radiography in children who have not yet attained skeletal maturity.

Correlative roentgenography and morphology of the longitudinal epiphyseal bracket

Detailed examination of a complete chondro-osseous specimen from a patient with duplication of the first ray of the foot revealed the involved metatarsal had a trapezoid-shaped, diaphyseal-metaphyseal osseous unit that was longitudinally bracketed along the lateral side by a functioning physis, epiphysis, and secondary (epiphyseal) ossification center. The physis extended as an arc from the medial proximal side toward and along the lateral side and then back to the medial side distally. The medial side of the diaphysis had a normal periosteum. The longitudinal epiphyseal ossification bracket was a composite of initially separate proximal and distal secondary ossification centers that had progressively extended toward each other and finally coalesced along the laterally placed epiphyseal cartilage. We have termed this deformity the “longitudinal epiphyseal bracket” (LEB). The macroscopic and microscopic anatomy relevant to initial diagnosis and evaluation of sequential roentgenographic changes will be considered.

CAPILLARIA HEPATICA (BANCROFT) IN SELECT RAT POPULATIONS OF HARTFORD, CONNECTICUT, WITH POSSIBLE PUBLIC HEALTH IMPLICATIONS

Capillaria hepatica was found in 82% of 86 Norway rats (Rattus norvegicus) trapped in Hartford, Connecticut between February and November 1975. Adults were parasitized more frequently than juveniles and infection rate did not differ between sexes. Rats demonstrated a low intensity of infection, with 9% having extensive liver involvement. A seasonal variation in infection rate may have been a manifestation of environmental factors, cannibalism, and predation.

PATHOBIOLOGY OF SEPTIC ARTHRITIS AND CONTIGUOUS OSTEOMYELITIS IN A LEATHERBACK TURTLE (Dermochelys coriacea)1

Analysis of a case of presumed hematogenous septic arthritis and osteomyelitis involving the elbow, distal humerus, and proximal radius and ulna in a leatherback turtle (Dermochelys coriacea) showed the chondro-osseous response to be similar to the diseases in skeletally immature humans and terrestrial mammals (both spontaneous and experimental). This particular reptile has bone that is similar to mammalian bone. The infection had partially destroyed the distal humeral, proximal ulnar and proximal radial joint surfaces and epiphyseal cartilages. The elbow was filled with a fibrovascular pannus that had caused a partial ankylosis of the joint.

Parasites of the Dall's porpoise (Phocoenoides dalli True).

The prevalences of three helminths, Campula oblonga, Halocercus dalli and Crassicauda sp., recovered from Dalls porpoises which were net-entrapped incidentally in the vicinity of the western Aleutian Islands in the northwest Pacific are reported. Specimens of Campula oblonga were found within the bile ducts of 46% of 127 livers examined. The prevalence of hepatic trematodiasis increased with the age of the host. Pulmonary nodules associated with Halocercus dalli were noted in 71% of the Dalls porpoises. Adult H. dalli were recovered from the main stem bronchi of heavily infected lungs. Younger animals exhibited a relatively higher prevalence. Specimens of Crassicauda sp. were found within the main lactiferous canal of 69% of 29 mammary glands examined. The prevalence was highest in mature porpoises. Possible detrimental effects and the modes of transmission of the three species of parasites are also considered.

FRACTURES OF THE RADIUS AND ULNA IN A SKELETALLY IMMATURE FIN WHALE 1

A naturally-occurring fracture of the distal radius and ulna in a skeletally immature fin-whale, Balaenoptera physalus, appeared to be failing to heal. When compared to the response to fracture in the skeletally immature human and to other terrestrial mammals, this animal did not show any endosteal and only minimal subperiosteal callus, even though the fractures appeared to be several weeks, if not months old. This suggests that the larger ceteceans may not be able to respond appropriately to skeletal injury in the major structural units of the flipper.

JUVENILE RICKETS AND HYPERPARATHYROIDISM IN THE ARCTIC FOX1

Three of seven Arctic fox kits, Alopex lagopus, trapped on St. Paul Island, Alaska, had evidence of rickets and hyperparathyroidism. Radiographic, morphologic and histologic examination confirmed the diagnosis. The disease was presumed to be a juvenile-onset disease due to calcium-deficient intake following weaning. The possibility of insufficient exposure to sunlight could not be determined. No other abnormalities (e.g., genitourinary) were found. Skeletal involvement was quite varied. All growth plates exhibited columnar hyperplasia compatible with rickets, while the metaphyses showed decreased trabeculation and cortical thinning compatible with osteodystrophia fibrosa. One fox had bilateral metaphyseal fractures through this osteodystrophic bone.

Spontaneous rickets in the wild arctic fox Alopex lagopus

Normal and rachitic, skeletally immature arctic foxes (Alopex lagopus) were subjected to physical examination, roentgenographic studies, and in some cases histologic studies. The involved animals had active rickets coupled with antecedent normal diaphyseal bone formation. Evaluation of all the long bones showed highly variable manifestations of the disease, which undoubtedly reflect different rates of physeal endochondral transformation and metaphyseal remodeling. Histologic examination showed distinct patterns of widening of the physes and variable osteodystrophy in the trabecular and cortical bone of the metaphyses and epiphyseal ossification centers. These aforementioned factors certainly would necessitate different regional calcium needs and, therefore, different regional responses to an overall calcium deficiency. The physes involved in the most rapid growth rates in this period showed the most widening of the growth plate, and the most dystrophic changes in the metaphysis. Skeletal injuries, including metaphyseal fractures and slow-down of longitudinal growth (particularly in the ulna) were also evident. Because of apparent dietary differences in the affected and normal fox kits, this juvenile-onset disease was presumed due to calcium-deficient intake following weaning. To the best of our knowledge this is the first report of spontaneously occurring rickets in a wild animal in its natural habitat. There are several possible mechanisms for the variable widening of the physis and the loss of bone mineralization in these fox kits: calcium-deficient diet, binding of calcium in the bowel by high phosphorus intake, secondary hyperparathyroidism, and vitamin A toxicity.