Background and Aim: Genu varum and genu valgum are two most common deformities of the knee joint in children and adults. In these deformities knee muscles function maybe affected by the alteration in mechanical axis of lower limb. The aim of this survey was to provide some basic knowledge about the function of knee muscles in patients with genu varum and genu valgum deformities.

Materials and Methods: Studies were identified by searching in the Pub-Med, Science Direct, Google Scholar databases and authoritative references available on the internet and library for articles and books published after 1990,with the key words such as genu varum, genu valgum, knee muscles, bow leg, knock knee and knee frontal angle.

Results: Among 102 papers and 10 books resulted from the first search, only 30 papers and 5 books were related to this literature review and just10 papers and 2 books among them were about changes in knee muscles.

Conclusion: The results of this survey indicated that patients with genu varum and genu valgum deformities have architectural and functional alteration in their knee muscles. According to the results most of these studies have noticed the basic changes in quadriceps muscle function and architecture. It is necessary to study more about the function of other knee muscles.

Key words: Genu varum, Genu valgum, Bow leg, Knock knee, Knee muscles.

Background and Aim: Muscle fascicle length and pennation angle can be non-invasively studied by applying methods like ultrasonography. The aim of this study was to introduce fascicle length and fascicle angle for the estimation of the strength of skeletal muscle by using ultrasonography.

Materials and Methods: The data of this study have been driven from pubmed and authoritative references available on the internet and in libraries. In all fifteen full text articles and 30 abstracts have been collected and reviewed. Keywords such as: muscle, fascicle, pennation angle, force and ultrasonography were searched to fulfill the purpose of this study.

Results : Detailed information about the angles of pennation and fascicles length are important to predict muscle force. It has been suggested that changes in muscle pennation angles are positively correlated to the length of fascicle in a muscle contraction. While muscle thickness may in some case be remained constant in this relation.

Conclusion: Real-time ultrasonography is a noninvasive procedure to monitor the architecture of the living muscle at rest and during static and dynamic sets. It is a valuable measurement tool to estimate muscle force by measuring the muscle architecture parameters such as angle of pennation and fascicle length.

Keywords : Muscle, Fascicle, Pennation angle, Force, Ultrasonography