IDENTIFICATION OF A NASOCONCHAL PARANASAL SINUS IN THE WHITE RHINOCEROS ( CERATOTHERIUM SIMUM).

African rhinoceros are poached for their horns using indiscriminate and aggressive methods. Rhinoceros that survive these attacks often have severe facial trauma, and treatment is limited by a lack of understanding and published information of the normal anatomy. This study was performed to investigate and describe the anatomy of the most commonly injured area of the head of the white rhinoceros ( Ceratotherium simum). Two white rhinoceros cadaver heads were imaged by computed tomography and grossly dissected. A combined dorsal conchal sinus and nasal sinus (named the nasoconchal sinus) was identified and confirmed to be readily exposed by horn removal. The nasoconchal sinus communicates via a relatively large opening with the middle nasal meatus of the nasal cavity. Awareness of the combined sinus space and its single communicating pathway will assist with accurate assessment and treatment of trauma to the dorsal facial region of the white rhinoceros.

Goat horn-induced intracranial emphysema and orbital injury.

This is a case description of a male patient found to have orbital and intracranial emphysema, specifically with air in his cavernous sinuses bilaterally following penetrating trauma to the medial orbit from a goat's horn. There were no orbital or skull base fractures. Although the presence of traumatic intracranial emphysema is not uncommon, it is typically the result of direct communication of the cranial vault with the paranasal sinuses in the setting of associated fracture or, alternatively, from direct penetration and inoculation. We present a rare case of orbital emphysema with traumatic intracranial emphysema without these previously described associations and postulate a mech``anism behind its development.

Adult orbital trapdoor fracture.

Trapdoor fractures occur almost exclusively in the pediatric population. The authors describe an adult with an entrapped inferior rectus muscle sheath in a trapdoor fracture. A 37-year-old man presented with persistent diplopia 3 weeks after blunt right orbital trauma. The only abnormal findings on clinical examination were limited vertical ductions. No bony defect or displacement was evident on CT. However, several small pockets of air were visible adjacent to the inferior rectus muscle. On surgical exploration, a linear nondisplaced orbital floor fracture was confirmed, and the entrapped inferior rectus muscle was released. One month postoperatively, extraocular motility had improved with no diplopia in primary or reading positions. This case demonstrates that trapdoor fractures can occur in adults and should be considered when suggestive findings are encountered. Clinicians should be aware of this because timely diagnosis and treatment might achieve more favorable outcomes.

Repair of horn and frontal bone avulsion in a forest buffalo (Syncerus caffer nanus) with a polymethylmethacrylate dressing.

A 2-yr-old female forest buffalo (Syncerus caffer nanus) presented with acute trauma to the right horn following a fight with a conspecific resulting in fracture and avulsion of the frontal bone, cornual process, horn, and juxtaposed skin. The animal was sedated for wound care and debridement followed by placement of an antibacterial-impregnated polymethylmethacrylate (PMMA) dressing. The dressing was noted to be intact on examination at day 7 post-injury, but had become dislodged and had to be replaced at day 11 postinjury. The replacement dressing ultimately fell off 68 days post-injury, revealing a healed circular scar. The use of PMMA in this case provided optimal wound care. In the 6 yr since the injury, the animal has grown a nearly normal-appearing horn, suggesting that the noncornual skin and associated skull structures may retain the ability to differentiate into a near-normal appearing horn because the entire horn apparatus in this case was avulsed.

Traumatic rupture of the globe caused by cow horns.

PURPOSE: We investigated the epidemiology, clinical findings and functional outcome of open-globe injuries caused by cow horns over a 50-year period in eastern Switzerland. METHODS: We retrospectively evaluated the files of cases with ruptures of the globe caused by cow horns between 1950 and 1999. RESULTS: We found 59 cases with ruptures of the globe by cow horns, accounting for 5% of all open-globe injuries. The incidence of these accidents did not change during the observation period. Twenty-two eyes (37%) were enucleated. Only 7 eyes (12%) retained a vision of > or = 0.1. Between 1950 and 1989 only 2/43 eyes (5%) reached a vision of > or = 0.1. In the 1990's, with the introduction of vitreous surgery 5/16 eyes (31%) had a vision of > or = 0.1. Four patients (7%) had blinding eye disease in the partner eye, and three (5%) had a second open-globe trauma. CONCLUSIONS: In rural regions, with cattle breeding, open-globe injuries by cow horns are relatively common and the frequency is still the same as 50 years ago. The visual prognosis of these eyes is still guarded, but functional results have improved with the introduction of vitreous surgery. Patients who have had a rupture of the globe appear to have an increased risk for partner eye trauma. Therefore, all efforts are justified to preserve even limited vision in severely injured eyes.

Eye injuries caused by cow horns.

PURPOSE: To assess ocular injuries caused by cow horns; to investigate clinical findings, treatment, and visual outcome in a population of dairy farmers; and to propose possible preventive measures. METHODS: A retrospective review was conducted to identify patients seen over a 45-month period with cow horn-inflicted eye injuries. Eleven patients were identified and their charts reviewed for demographics, mechanism of injury, initial and final visual acuity, surgeries performed, and anatomic outcome. RESULTS: The mean age of the patients was 64 years. Seven patients had open-globe injuries with vitreous hemorrhage. In five cases, pars plana vitrectomy was performed. Final best-corrected visual acuity was < or = hand motion in five patients, between 20/160 and 20/80 in three patients, and better than 20/32 in three patients. CONCLUSION: The majority of the cow horn injuries studied caused severe permanent impairment of vision. Owing to the blunt nature of the horns, a significant amount of energy is imparted into the eye. To prevent these injuries, coagulation of the horns should be performed 2 weeks after a calf's birth or farmers should be advised to wear safety glasses.

Invasive malignant fibrous histiocytoma in a cow.

An invasive malignant fibrous histiocytoma associated with the left cornual process, and causing lysis of the frontal bone, was diagnosed in a cow. The mass compressed the left cerebral hemisphere focally and extended into the frontal sinus and ethmoid and nasal turbinates. It was composed of pleomorphic to spindle-shaped cells with ultra-structural evidence of fibroblastic, myofibroblastic, and fibrohistiocytic differentiation. Trauma and chronic inflammation may be predisposing factors for development of neoplasia in cattle.

Horn aberrations in Dall's sheep (Ovis dalli) from Yukon Territory, Canada.

Horn aberrations in Dall's sheep from the Kluane Lake area of Yukon Territory were of two basic types. In the more prevalent type, the horn was severed at an annual growth check and the terminal segment of the remaining portion formed a short conical protuberance. The second type had characteristics of the first, but in addition, underwent extreme twisting or torquing during subsequent growth. Sheep with aberrant horns represented 2% of the Kluane Lake population or 14% of harvestable rams (greater than or equal to 6 yr old). Deformed horns, occurring in ewes and rams, were generally observed in animals 6 yr or older. Aberrations followed necrosis of the terminal segment of the horn core: cavitation of the sheath between successive periods of growth or the sequestering of portions of necrotic core within the sheath resulted. All sheep examined (eight) had a normal complement of 54 chromosomes.

The epidemiology of cancer in animals.

The principles of epidemiology are applicable to the study of the distribution and determinants of cancer in both human and animal populations. There are many examples of epidemiologic factors (host, environment, agent and time) related to cancer in animals. Certain host characteristics such as age, sex and breed are related to risk of developing cancer. Some environmental influences are illustrated by differences in the geographical distribution of certain types of animal cancer. Aggregations of cancer cases have been reported in herds, families and households. However, the usual distribution of cases in a population does not resemble epidemics typical of infectious diseases. Several factors (radiological, chemical, dietary, parasitic, mechanical, genetic and viral) have been identified as influences that affect the development of animal tumors. Animal species that have been domesticated live longer and consequently malignant disease develops in more of them. Cancer incidence rates now available from data compiled by an animal neoplasm registry in Alameda and Contra Costa counties, California, indicate that some of the frequent sites of cancer in man (skin, breast and the hemic and lymphatic systems) are among the most frequent sites in dogs and cats, man's closest animal associates.