The muscle indicated is the iliacus muscle.
The iliacus originates in the iliac fossa on the inside of the pelvic bone. The iliacus combines with the psoas major to enter the anterior compartment of the thigh and insert via a common tendon on the lesser trochanter of the femur. The iliacus and psoas are thus collectively referred to as the iliopsoas muscle – they act synergistically to flex the thigh at the hip joint, as well as acting to cause lateral rotation of the thigh. The iliopsoas muscles are the strongest hip flexors.
Origin: Iliac fossa
Insertion: Base of the lesser trochanter of the femur
Innervation: Femoral nerve
Action: Flexion of the thigh at the hip joint. Lateral rotation of the thigh.
Learn more about the iliacus muscle and the muscles of the anterior compartment of the thigh in this anatomy tutorial.