Background The aim of this study was to assess the passive stiffness of the medial and lateral gastrocnemius (MG and LG), Achilles tendon (AT), and plantar fascia (PF) at different ankle and knee positions. Material/Methods Stiffness was assessed using a portable hand-held device (MyotonPRO). In 30 healthy participants (15 males, 15 females) with the knee fully extended or flexed 90°, stiffness of the MG, LG, AT, and PF was measured at 50° plantar flexion, 0° (neutral position), and 25° dorsiflexion (not for AT) of the ankle joint by passive joint rotation. Results With the knee fully extended, passive dorsiflexion caused significant increase in muscle stiffness ( P <0.001), whereas AT and PF stiffness increased with passive ankle dorsiflexion regardless of knee position ( P <0.001). Increased stiffness was observed in MG compared to LG ( P <0.001) and at the 3-cm site of AT compared to the 6-cm site ( P <0.05). Stiffness was greater in LG compared to MG at −50° plantar flexion ( P <0.001) and was greater in MG compared to LG at 25° dorsiflexion ( P <0.05). Stiffness of AT increased in a distal-to-proximal pattern: 0 cm >3 cm >6 cm ( P <0.001). Conclusions Stiffness assessed by use of the MyotonPRO was similar assessments using other techniques, suggesting that the MyotonPRO is capable of detecting the variations in stiffness of MG, LG, AT, and PF at different ankle and knee positions.

Rationale: Perivascular epithelioid cell tumor (PEComa) is a mesenchymal tumor that arises from perivascular epithelioid cells and can differentiate into melanocytes and smooth muscle cells. Malignant renal perivascular epithelioid cell tumor is extremely rare. Due to the lack of specific clinical manifestations and imaging features, diagnosing PEComa depends on postoperative pathology and immunohistochemistry. Surgery is the primary treatment for malignant PEComa because the efficacy of radiotherapy and chemotherapy is uncertain. There is still a lack of unified diagnostic criteria and treatment guidelines for renal malignant PEComa, especially with vascular invasion. Hence, the treatment experience depends on a small number of cases reported worldwide.

BACKGROUND Penetrating neck injuries require prompt recognition, diagnosis and management of critical airways. This case demonstrates an emergent situation that a “medical negligence” was avoided with the aid of end-tidal carbon dioxide (ETCO 2 ) waveform. CASE SUMMARY We report a case of malposition of the endotracheal tube into the right hemithoracic cavity for cervical knife trauma, resulting in pneumothorax. Tube placement was not confirmed during emergency airway management, and the patient was directly transferred to the emergency operation room. Assisted by ETCO 2 and imaging examinations, the anesthetist timely noticed the absence of ETCO 2 waveform and resolved this urgent situation before anesthesia induction. CONCLUSION This case emphasizes the necessity of ETCO 2 waveform and/or X-ray confirmation of endotracheal intubation even in emergent situations.