Anatomy & Physiology of Posture Flashcards

The quadratus lumborum muscle originates on the iliac crest and inserts primarily on which structure?

Answer: 12th rib and lumbar transverse processes

The quadratus lumborum attaches to the 12th rib and the transverse processes of L1–L4, enabling lateral flexion, hip hiking, and spinal stabilization.

Which type of muscle fiber is primarily responsible for maintaining static postural tone?

Answer: Type I (slow-twitch oxidative)

Type I slow-twitch fibers are highly fatigue-resistant and oxidative, making them ideal for sustained postural stabilization.

Overpronation of the foot most commonly leads to which compensatory postural change at the knee?

Answer: Knee valgus (inward collapse)

Excessive pronation causes medial tibial rotation which drives the knee into a valgus position, disrupting alignment from the foot to the hip.

The thoracolumbar fascia is important for postural stability because it:

Answer: Transfers force between the lower extremities, spine, and upper extremities

The thoracolumbar fascia acts as a key force-transfer structure connecting the gluteus maximus, latissimus dorsi, and spinal extensors, integrating trunk and limb movement.

Which postural pattern is characterized by a forward-shifted thorax over a posteriorly tilted pelvis?

Answer: Sway-back posture

Sway-back posture involves anterior displacement of the thorax and hips forward, with the pelvis posteriorly tilted and knees hyperextended.

Which plane of the body divides it into anterior and posterior halves?

Answer: Frontal (coronal) plane

The frontal (coronal) plane divides the body into anterior and posterior sections and is used to assess lateral deviations such as scoliosis.

The gastrocnemius muscle crosses how many joints, and what postural impact does its tightness have?

Answer: Two joints; limits dorsiflexion and may promote knee flexion

The gastrocnemius crosses both the ankle and knee; tightness restricts ankle dorsiflexion and can contribute to compensatory pronation or knee flexion.