**Core Concept**
The lesser trochanter of the femur is an important anatomical landmark for the attachment of various muscles and ligaments. The structure is crucial for hip stability and movement. The muscles and ligaments attached to the lesser trochanter play a significant role in hip flexion and rotation.

**Why the Correct Answer is Right**
The iliopsoas muscle, the psoas major, and the psoas minor muscles are attached to the lesser trochanter through the lesser trochanteric ridge. The iliopsoas muscle is a powerful flexor of the hip joint, and its attachment to the lesser trochanter enables it to produce this movement. The psoas major and psoas minor muscles also contribute to hip flexion and lumbar spine stabilization.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not provided, but if it were, we would need to evaluate its accuracy. However, since it's not given, we'll proceed with the other options.

**Option B:** The obturator externus muscle is actually attached to the trochanteric fossa of the femur, not the lesser trochanter. This muscle rotates the femur laterally during hip flexion.

**Option C:** The gluteus minimus muscle is attached to the greater trochanter of the femur, not the lesser trochanter. This muscle assists in hip abduction and external rotation.

**Option D:** The tensor fasciae latae muscle is attached to the anterior superior iliac spine (ASIS) and the iliotibial tract, not the lesser trochanter. This muscle assists in hip abduction and flexion.

**Clinical Pearl / High-Yield Fact**
Remember that the iliopsoas tendon, which attaches to the lesser trochanter, can be a source of hip pain in patients with conditions such as iliopsoas tendinitis or snapping hip syndrome. This highlights the importance of considering the anatomy of the lesser trochanter in diagnosing and managing hip-related disorders.

**Correct Answer:** B. The obturator externus muscle is attached to the trochanteric fossa of the femur, not the lesser trochanter.