severe bleeding disorders.Thrombocytopenia,regardless of severity,is not a contraindication.(See'Contraindications'above.) Aspiration/biopsy sites-The following anatomical sites can be used for bone marrow aspiration.(See'Choice of aspiration or biopsy site'above.) Posterior at which bot woRgygyoegeoeacanteEg .Stemum.Marrow may be aspirated from the sternum by experienced clinicians;biopsy at this site is contraindicated. .Other sites include the tibia,femur,vertebral bodies,ribs.Surgical considered,espe cially for Complications of the procedure-Complications of bone marrow aspiration/biopsy are uncommon(estimated at 0.05 to 0.07 percent in two series).(See 'Complications'above.) .The most commonly encountered complications include pain, discomfort,and/or bleeding at the site of the procedure. .Complications of sternal aspiration can be serious and are discussed in detail above.(See'Stemal aspiration'above.) ACKNOWLEDGMENT The editors of UpToDate acknowledge the contributions of Stanley LSchrier,MD as Section Editor on this topic,his tenure as the founding Editor-in-Chief for UpToDate in Hematology,and his dedicated and longstanding involvement with the UpToDate program. Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1.Malempati s.Joshis.Lai s.et al.Videos in clinical medicine.Bone marrow aspiration and biopsy.n EnalJ med 2009:361e28 2.Foucar K.Bone Marrow Pathology,2nd ed,ASCP Press,Chicago 2001. 3.Ryan DH,Cohen HJ.Bone marrow aspiration and morphology.In:Hema tology:Basic Principles and Practice,3rd ed,Hoffman R,Benz EJ,Shatt il SJ,et al.(Eds),Churchill Livingstone,Philadelphia 2000.p.2460. 4.Bain BJ.Bone marrow aspiration.J Clin Pathol 2001:54:657. 5.Subramanian R.Basu D,Badhe B.Dutta TK.Role of bone marrow trephine biopsy in the diagnosis of marrow involvementin Hodgkin's disease.Indian Pathol Microbiol 2007:50:640. 6.Ozkalemkas F.Ali R,Ozkocaman V,et al.The bone marrow aspirate and biopsy in the diagnosis of unsuspected nonhematologic malignancy:a clinical study of 19 cases.BMC Cancer 2005:5:144. severe bleeding disorders. Thrombocytopenia, regardless of severity, is not a contraindication. (See 'Contraindications'above.) Aspiration/biopsy sites — The following anatomical sites can be used for bone marrow aspiration. (See 'Choice of aspiration or biopsy site' above.) ●Posterior (preferred) or anterior iliac crest. The iliac crest is the only site at which both aspiration and biopsy may be safely performed in the adult. ●Sternum. Marrow may be aspirated from the sternum by experienced clinicians; biopsy at this site is contraindicated. ●Other sites include the tibia, femur, vertebral bodies, ribs. Surgical consultation is advisable when such sites are considered, especially for open biopsies Complications of the procedure — Complications of bone marrow aspiration/biopsy are uncommon (estimated at 0.05 to 0.07 percent in two series). (See 'Complications' above.) ●The most commonly encountered complications include pain, discomfort, and/or bleeding at the site of the procedure. ●Complications of sternal aspiration can be serious and are discussed in detail above. (See 'Sternal aspiration' above.) ACKNOWLEDGMENT The editors of UpToDate acknowledge the contributions of Stanley L Schrier, MD as Section Editor on this topic, his tenure as the founding Editor-in-Chief for UpToDate in Hematology, and his dedicated and longstanding involvement with the UpToDate program. Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. Malempati S, Joshi S, Lai S, et al. Videos in clinical medicine. Bone marrow aspiration and biopsy. N Engl J Med 2009; 361:e28. 2. Foucar K. Bone Marrow Pathology, 2nd ed, ASCP Press, Chicago 2001. 3. Ryan DH, Cohen HJ. Bone marrow aspiration and morphology. In: Hema tology: Basic Principles and Practice, 3rd ed, Hoffman R, Benz EJ, Shatt il SJ, et al. (Eds), Churchill Livingstone, Philadelphia 2000. p.2460. 4. Bain BJ. Bone marrow aspiration. J Clin Pathol 2001; 54:657. 5. Subramanian R, Basu D, Badhe B, Dutta TK. Role of bone marrow trephine biopsy in the diagnosis of marrow involvement in Hodgkin's disease. Indian J Pathol Microbiol 2007; 50:640. 6. Ozkalemkas F, Ali R, Ozkocaman V, et al. The bone marrow aspirate and biopsy in the diagnosis of unsuspected nonhematologic malignancy: a clinical study of 19 cases. BMC Cancer 2005; 5:144