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The tibialis posterior muscle (TPM) is the primary inverter of the foot and can assist in powerful plantar flexion. Its functional evaluation is particularly useful in patients with foot drop (caused by paralysis of the muscles that lift the foot) to differentiate between peroneal neuropathy and L5 radiculopathy. Electromyography (EMG) needle insertion in the TPM is typically performed through either an anterior or a posterior approach. However, several authors still consider EMG needle placement in this muscle to be difficult, with less than 10% accuracy even with electrical stimulation. The aim of this paper is to illustrate and compare anterior and posterior approaches for ultrasound (US)-guided needle insertion into the TPM, which is considered a key muscle in the etiological diagnosis of foot drop. Both the anterior and posterior approaches for performing US-guided EMG of the TPM are valid and safe. With US guidance, practitioners must clearly identify the TPM and avoid puncturing the neurovascular structures of the leg and other adjacent muscles. This requires not only a good understanding of the US anatomy of the leg but also a rigorous technique for bimanual manipulation and aseptic insertion of the EMG needle.