Pelvic Elevation and Hip Flexion Study

Study Notes

Pelvic Elevation, Hip Flexion, and Extension

Objectives: Students will be able to identify primary muscles involved in pelvic elevation, hip flexion, and extension; identify the range of motion for these actions; and describe the effects of weakness in hip flexion and extension.
Content: The content covers primary muscles, range of motion, and effects of weakness for pelvic elevation, hip flexion, and extension.

Pelvic Elevation Motion

Primary Muscles: Quadratus Lumborum
Range of Motion: In a standing position, the pelvis can be raised on one side until the foot is off the ground (reverse action of quadratus lumborum).
Factors Limiting Range of Motion: Tension of spinal ligaments on the opposite side and contact of the iliac crest with the thorax.
Anatomy of Quadratus Lumborum: Originates from the iliac crest and iliolumbar ligament; inserts into transverse processes of L1-L4, the iliolumbar ligament, and the inferior border of the 12th rib. Innervated by anterior primary rami of T12, L1, L2, and L3.

Hip Flexion Motion

Primary Muscles: Psoas major and Iliacus
Range of Motion: Hip flexion with the knee flexed allows approximately 115-125 degrees of motion.
Factors Limiting Range of Motion: Contact of the thigh on the abdomen (when the knee is flexed) and tension of hamstring muscles (when the knee is extended).
Accessory Muscles: Rectus femoris, sartorius, tensor fasciae latae, and pectineus
Anatomy of Psoas Major Muscle: Originates from transverse processes of all lumbar vertebrae (L1-L5), and bodies of T12-L5 and intervertebral discs. Inserts into the middle surface of the lesser trochanter of the femur. Innervated by anterior primary rami of L1, L2, and L3.
Anatomy of Iliacus Muscle: Originates from the iliac fossa within the abdomen. Inserts onto the lowermost surface of the lesser trochanter of the femur. Innervated by the femoral nerve.

Hip Extension Motion

Primary Muscles: Gluteus maximus, biceps femoris, semimembranosus, and semitendinosus
Range of Motion: Hip extension ranges from 115-125 degrees to 0 degrees, and beyond midline, ranging from 0 to 10-15 degrees.
Factors Limiting Factors of Range of Motion: Tension of iliofemoral ligament and tension of hip flexor muscles.
Anatomy of Gluteus Maximus: Originates from the outer surface of the ilium behind the posterior gluteal line, the posterior third of the iliac crest, lumbar fascia, lateral portion of the sacrum, and sacrotuberous ligaments and coccyx. Inserts into the gluteal tuberosity of the femur (with 3/4 inserting into the iliotibial tract). Innervated by the inferior gluteal nerve.
Anatomy of Biceps Femoris (Lateral Hamstring): Originates from the upper inner quadrant of the posterior surface of the ischial tuberosity(long head) and the middle third of Linea aspera, lateral supracondylar ridge of the femur (short head). Inserts into the styloid process of the fibula. The long head is innervated by the tibial portion of the sciatic nerve, and the short head is innervated by the common peroneal portion of the sciatic nerve.
Anatomy of Semimembranosus: Originates from the upper outer quadrant of the posterior surface of the ischial tuberosity. Inserts into the medial condyle of the tibia below the articular margin, over the popliteus and oblique popliteal ligaments. Innervated by the tibial portion of the sciatic nerve.
Anatomy of Semitendinosus: Originates from the upper inner quadrant of posterior surface of ischial tuberosity. Inserts into upper medial shaft of tibia below Gracilis. Innervated by the tibial portion of the sciatic nerve.

Effects of Weakness

Hip Flexor Weakness: Weakness in hip flexors results in difficulties with activities like stair climbing, walking inclines, and getting up from a reclined position.
Hip Extensor Weakness: Weakness in hip extensors can make walking extremely difficult, and crutches may be needed.