You flex your hips by bending your trunk forward and you extend your knees when you straighten your legs. Walking, running and lifting objects from the floor all require your to flex your hips and extend your knees. The iliopsoas, tensor fascia latae, pectineus and quadriceps all flex the hip, but the quadriceps is the only one to extend the knee.
The iliacus and the psoas major are located in the pelvis and they merge to form the iliopsoas muscle, which is the main hip flexor. The iliacus begins at the top of the hip bone, called the iliac crest, and at the sacrum, which is the bone at the base of your spine. The psoas major starts along the sides of the lumbar vertebrae. The muscles combine in the iliopsoas and run together to attach on the femur, which is your thigh bone. The iliopsoas muscle is responsible for hip flexion and it helps to stabilizes your posture by helping maintain the normal curve of your lumbar spine.
Tensor Fasciae Latae
The fleshy part of the tensor fasciae latae muscle is attached to side of your hip bone. It has a long tendon that extends down to the knee to insert into the tibia, which is the larger of your two lower leg bones. Tensor fasciae latae work together with the iliopsoas and part of the quadriceps to flex the hip. It also helps to stabilize your thigh bone when you’re standing.
The pectineus is a flat muscle located on the front and top part of your thigh. It’s attached to the pubic bone located above your crotch and runs to the top of the femur. It helps the other muscles flex the thigh and also adducts the thigh to bring it toward the midline of the body.
The quadriceps femoris is the large muscle that forms the front of your thigh. It has four sections. The rectus femoris, vastus lateralis and vastus medialis are attached to the hip bone. The vastus intermedius portion is attached to the femur. All four parts run down toward the knee where they form the quadriceps tendon that covers the front of your knee. The quadriceps tendon contains the kneecap and attaches to the top of the tibia. All four parts extend the knee joint and the rectus femoris also helps flex the hip.
- Clinical Anatomy by Regions, Eighth Edition; Richard S. Snell
- Essential Clinical Anatomy, Fourth Edition; Keith L. Moore
Sheri Kay has a master's degree in human nutrition. She's the co-author of two books and has been a nutrition and fitness writer since 2004.
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