title: Comparison of autogenous cancellous bone grafts obtained from the sternum and proximal portion of the tibia of llamas.
abstract: OBJECTIVE
  To describe the anatomy of the sternum in llamas, define the surgical approach to the sternum for collection of cancellous bone graft tissue, and compare the histologic appearance of graft tissue obtained from the sternum with that obtained from the proximal portion of the tibia.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  12 llamas, 3 to 19 years old, that had been submitted for necropsy.
  
  
  METHODS
  Radiographs were taken of the sternum and left tibia of the llamas. Measurements of the sternum were determined from the radiographs and adjusted for magnification. Sternebrae volumes were estimated from these measurements. Anatomic dissections to the center of the fourth sternebra and the proximal portion of the tibia were made, and a surgical approach to the sternum was developed. Cancellous graft tissue was obtained from each site and submitted for histologic evaluation.
  
  
  RESULTS
  Sternebrae 3, 4, and 5 were significantly larger in volume than the other sternebrae. The ventral aspect of the fourth sternebra was readily accessed for removal of graft tissue by making a 6-cm-long ventral midline incision centered 17 cm craniad to the xipnoid. Mean soft tissue thickness overlying the ventral aspect of the fourth sternebra was 3.1 cm. More tissue was obtained from the sternal (mean, 9.11 g) than from the tibial (mean, 5.16 g) sites. Sternal graft tissue consisted of trabecular bone spicules with predominantly hematopoietic marrow, whereas tibial tissue consisted of trabecular bone spicules with only fatty marrow.
  
  
  CONCLUSIONS
  The fourth sternebra in llamas is readily accessible for obtaining autogenous cancellous bone graft tissue that consists of predominantly hematopoietic marrow.
authors.affiliation: Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis 97331-4803, USA.
authors.forename: A J
authors.initials: AJ
authors.lastname: Kaneps
authors.forename: M J
authors.initials: MJ
authors.lastname: Huber
authors.forename: S P
authors.initials: SP
authors.lastname: Snyder
mesh_terms: D000818:Animals; D016025:Bone Transplantation / Q000502:physiology / Q000662:veterinary*; D002161:Camelids, New World / Q000033:anatomy & histology* / Q000601:surgery; D006651:Histocytochemistry; D011446:Prospective Studies; D011859:Radiography; D013249:Sternum / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000601:surgery; D013977:Tibia / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000601:surgery; D014182:Transplantation, Autologous / Q000662:veterinary