Arthrocentesis is the removal of synovial fluid for analysis of pathologic processes. Small & medium joint arthrocentesis will be defined as the following joints: elbow, wrist, finger, ankle and toe. Ultrasound (US) and landmark (LM) small & medium joint arthrocentesis are both performed within the clinical setting. Both techniques are considered standard of care. Selection of which technique to use is dependent upon the physician's preference. There is currently limited data comparing the two methods. The investigators hope to determine if one modality is more effective in terms of success rate, number of attempts, and time to complete the procedure.

Patients presenting to the Emergency Department who are 18 years old or older, who do not belong to a vulnerable group, requiring small or medium joint arthrocentesis will be included in this trial. The investigators will randomize each patient into LM vs US. Data collected will include number of attempts to tap the joint, success rate, and time for procedure to be completed. The arthrocentesis will be performed by PGY-3 residents only. A 21 gauge needle will be used for the arthrocentesis.

Inclusion Criteria:

• All patients who require an arthrocentesis of a small and/or medium joint (defined previously)

Exclusion Criteria:

• Coagulopathic patients
• Patients on anticoagulants
• Patients with cellulitis overlying the joint.
• Patients with artificial joints
• Adults Unable to Consent
• Vulnerable Populations