Background: The advantages of lower limb orthopedic procedures under spinal anesthetic are quick onset, preservation of spontaneous breathing, relaxation of the required muscles for the procedure, and affordability. It also has the benefit of not carrying the hazards associated with pulmonary aspiration and intubation. Objective: This study aimed to compare the effects of intrathecal versus intravenous dexmedetomidine added to bupivacaine on characteristics of spinal blocks in patients undergoing lower limb orthopedic surgery. Patients and methods: Sixty patients scheduled for lower limb orthopedic surgeries under spinal anesthesia were included in this prospective randomized comparative study. We evaluated the degree of sedation, the onset and duration of sensory and motor block, the quality of intra-operative anesthesia, postoperative analgesia, and adverse effects on patient hemodynamics. Results: Administering dexmedetomidine intravenously or intrathecally shown to be a safe supplement to bupivacaine spinal anesthesia. Intrathecal dexmedetomidine was a better adjuvant. It offered less overall side effects, improved perioperative analgesia, increased augmentation to sensory and motor block, and more stable hemodynamics. During the intraoperative phase, a higher dose of sedation is provided via intravenous dexmedetomidine. In order to validate the outcomes of this work, more research with a greater number of patients is necessary. Conclusion: Administration of dexmedetomidine intravenously or intrathecally shown to be a safe supplement to bupivacaine spinal anesthesia. When comparing intravenous dexmedetomidine to spinal bupivacaine, intrathecal dexmedetomidine was a better adjuvant.