einstein. 2008; 6(2):229-33 MEDICAL ADVANCES Differential diagnosis of calf pain by ultrasonography Diagnóstico ultra-sonográfico diferencial entre as causas de dor na panturrilha Luciano Augusto Botter 1 , George Rachid Oliveira 2 , Érika Suenaga 3 , Rubens Mitsuo Tanaka 4 , Ricardo Tadao Yonezaki 5 , Marco Antonio de N. Germano 6 , Marcelo Rocha Correia da Silva 7 , Miguel José Francisco Neto 8 , Marcelo Buarque de Gusmão Funari 9 ABSTRACT This paper aims to evaluate the recent and numerous applications of ultrasonography in the differential diagnosis of conditions that affect the popliteal fossa and lower limbs, resulting in calf pain. Popliteal cysts and their ruptures, aneurysms, hematomas, cellulitis, abscesses, soft tissue tumors and other fluid collections are easily identified by this technique. Moreover, post-trauma and inflammatory conditions affecting muscles and tendons, muscle necrosis, deep venous thrombosis and superficial thrombophlebitis are very well demonstrated by the ultrasonographic screening. Keywords: Lower extremity/ultrasonography; Diagnosis, differential RESUMO Este trabalho tem como finalidade analisar as recentes e numerosas aplicações da ultra-sonografia no diagnóstico diferencial das doenças que afetam a fossa poplítea e a extremidade inferior dos membros, com expressão clínica de dor na panturrilha. Cistos poplíteos e suas rupturas, aneurismas, hematomas, celulites, abscessos, neoplasias de partes moles e outras coleções líquidas são facilmente identificadas por esta técnica. Em associação desordens pós-traumáticas e inflamatórias afetando os músculos e tendões, necrose muscular, trombose venosa profunda e tromboflebite superficial são muito bem demonstradas pelo rastreamento ultra- sonográfico. Descritores: Extremidade inferior/ultra-sonografia; Diagnóstico diferencial INTRODUCTION Calf pain usually results from diseases involving the popliteal fossa and the dorsal aspect of the leg – such as the knee joint, the popliteal-tibial-fibular arterial complex, superficial and deep veins, soleus and gastrocnemius muscles and adjacent soft tissues. The range of diseases involved in the differential diagnosis is as follows (1) . CAUSES FOR CALF PAIN AND ULTRASOUND IDENTIFICATION Baker’s cyst Baker’s Cyst is a liquid distension of the gastrocnemius- semitendinious synovial pouch that communicates with the knee joint in 50% of normal adults. It results from synovial diseases or any intra-articular process leading to excessive fluid production that may leak to that region. Medially located in the popliteal fossa, between the tendon of the semitendinous muscle and the medial head of the gastrocnemius. It is visualized as a cystic, anechoic pouch of regular contours (Figure 1A), except the cases, in which there is also synovial proliferation, hemorrhages or infection, when it can assume a heterogeneous aspect with a solid-cystic appearance or forming fluid-fluid level (2) . The rupture of a Baker’s 1 Graduate student of Hospital Israelita Albert Einstein – HIAE, São Paulo (SP), Brazil. 2 Graduate student in ultrasonography by Hospital Israelita Albert Einstein – HIAE, São Paulo (SP), Brazil. 3 MD; Radiologist of Hospital Israelita Albert Einstein – HIAE, São Paulo (SP), Brazil. 4 MD; Radiologist of Hospital Israelita Albert Einstein – HIAE, São Paulo (SP), Brazil. 5 MD; Radiologist of Hospital Israelita Albert Einstein – HIAE, São Paulo (SP), Brazil. 6 MD; Radiologist of Hospital Israelita Albert Einstein – HIAE, São Paulo (SP), Brazil. 7 MD; Radiologist of Hospital Israelita Albert Einstein – HIAE, São Paulo (SP), Brazil. 8 PhD; Coordinator of the Ultrasonography Department at the Hospital Israelita Albert Einstein – HIAE São Paulo (SP), Brazil; Assistant physician at Instituto de Radiologia do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo – INRAD/HC-FMUSP, São Paulo (SP), Brazil. 9 PhD; Coordinator of the Imaging Department at the Hospital Israelita Albert Einstein – HIAE São Paulo (SP), Brazil; Assistant physician at Instituto de Radiologia do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo – INRAD/HC-FMUSP, São Paulo (SP), Brazil. Corresponding author: Luciano Augusto Botter – Rua Arthur de Azevedo, 142 – apto 64 – Pinheiros – CEP 05404-012 – São Paulo (SP), Brasil – Tel.: 11 3891-2197 – e-mail: la.botter@uol.com.br Received on May 16, 2007 – Accepted on Jan 15, 2008