A prime mover of thigh flexion is the:
a. Rectus femoris
b. Iliopsoas
c. Vastus muscles
d. Gluteus maximus

Verified step by step guidance

1. Step 1: Understand the term 'prime mover' in anatomy. A prime mover, or agonist, is the muscle primarily responsible for producing a specific movement at a joint.
2. Step 2: Identify the movement in question, which is thigh flexion. Thigh flexion refers to the action of lifting the thigh forward at the hip joint.
3. Step 3: Review the functions of each muscle option: Rectus femoris assists in thigh flexion but mainly extends the knee; Iliopsoas is a major hip flexor; Vastus muscles primarily extend the knee; Gluteus maximus is mainly responsible for thigh extension, not flexion.
4. Step 4: Determine which muscle is the main contributor to thigh flexion by comparing their primary actions. The Iliopsoas is known as the strongest and most important muscle for hip (thigh) flexion.
5. Step 5: Conclude that the prime mover of thigh flexion is the Iliopsoas based on its anatomical function and role in hip movement.

Key Concepts

Thigh Flexion

Thigh flexion refers to the movement that decreases the angle between the thigh and the pelvis, typically lifting the leg forward. It is a fundamental motion in activities like walking, running, and climbing stairs.

Iliopsoas Muscle

The iliopsoas is a deep muscle group composed of the psoas major and iliacus muscles. It is the primary and most powerful flexor of the thigh at the hip joint, playing a crucial role in lifting the leg.

Role of Other Muscles in Thigh Movement

The rectus femoris assists in thigh flexion but mainly extends the knee; vastus muscles primarily extend the knee; gluteus maximus is the main thigh extensor. Understanding their functions helps identify the prime mover in thigh flexion.