**7. Ankle**

*Tendons*

**6.4 Iliopsoas tendon**

inserts at the lesser trochanter of the femur.

that represents adipose tissue of the fascia [28].

anterior inferior aspect of the iliac spine [30].

during this MRI sequence.

**6.5 Hamstring tendons**

The psoas major and iliacus muscles form the iliopsoas tendon complex. The psoas major originates at the transverse processes of L1-L5 vertebrae; while the iliacus muscle has various origins, including the superior two thirds of the iliac fossa, the anterior sacroiliac ligaments, and the anterior sacral ala. This tendon complex

The iliopsoas tendon has an echogenic sonographic imaging appearance, with anterior extension in relation to the anterior-superior acetabular labrum [28]. On MRI sequences, the iliopsoas tendon complex is characteristically identified as two parallel homogeneously hypointense structures, separated by a hyperintense region

Snapping iliopsoas tendon is characterized by an audible or palpable painful snap with movement of the hip. Repetitive movements of the hip serve as predisposition to develop a snapping tendon, such as those performed by young athletes in different sports, with ballet dancers being the most commonly affected [30]. Iliopsoas tendon as the source of a snapping hip is classified as an internal cause of the broader term snapping hip syndrome. It may get trapped during movement due to a prominent iliopectineal eminence, an insertion site osseous projection or the

Dynamic evaluation of the hip joint with US and MRI allows the identification of the source of snapping iliopsoas tendon. Sonographic evaluation is performed with a high-frequency transducer (linear 5–12 MHz) placed in the transverse oblique plane, above the hip joint and parallel to the pubis [28]. The patient is in the supine position, with initial static evaluation performed following the iliopsoas tendon until reaching its insertion at the lesser trochanter. Dynamic evaluation is performed while the ipsilateral leg is moved from the "frog leg" position (extension, adduction, and internal rotation) to the neutral position (flexion, abduction, and external rotation). The position of the iliopsoas tendon can be traced along the anterior compartment of the hip as the leg is moved from the aforementioned positions and snapping occurs. Regarding MRI examination for this particular pathology, fast GRE sequence allows dynamic evaluation of the iliopsoas tendon during movement [28]; change from "frog leg" to neutral position is also performed

The hamstring tendon complex is located at the posterior compartment of the

hip, formed by three muscles groups: biceps femoris, semimembranosus and semitendinosus. The biceps femoris is composed of a short and a long head. Origin of the short head is at the lateral linea aspera of the posterior femur, the lateral supracondylar line and the intermuscular septum [31]. The long head shares origin with the semitendinosus tendon at the inferomedial facet of the ischial tuberosity to form a conjoint tendon. Distal biceps femoris tendon inserts at the lateral fibular head and lateral condyle of proximal tibia, while the semitendinosus inserts at the anteromedial aspect of the tibia, sharing insertion with the gracilis and sartorius muscles to form the pes anserinus tendons [32]. The semimembranosus tendon originates at the superolateral ischial tuberosity and has several insertion sites through tendinous arms [31]. The anterior, direct, and inferior arms insert at the medial condyle of the tibia. The capsular arm inserts at the posterior oblique ligament. There is also insertion into the posterior joint

capsule and arcuate ligament through the oblique popliteal ligament.

**28**
