Anatomy & Physiology of Posture Flashcards

The 'deep longitudinal subsystem' for force transmission through the posterior chain includes which key structure?

Answer: Erector spinae, thoracolumbar fascia, sacrotuberous ligament, and biceps femoris

The deep longitudinal subsystem transmits forces from the erector spinae through the thoracolumbar fascia and sacrotuberous ligament into the biceps femoris, creating a posterior force couple.

Which vertebral region has the least mobility due to its articulation with the rib cage?

Answer: Thoracic

The thoracic spine is the least mobile region because each vertebra articulates with a pair of ribs, dramatically restricting range of motion especially in flexion and extension.

In assessing genu recurvatum (knee hyperextension), which postural finding at the pelvis is commonly associated?

Answer: Posterior pelvic tilt

Posterior pelvic tilt is commonly associated with knee hyperextension as the body shifts its center of mass anteriorly, requiring the knees to lock back for stability.

Which nerve innervates the diaphragm, and why is diaphragm function relevant to postural alignment?

Answer: Phrenic nerve; the diaphragm is part of the intra-abdominal pressure system that stabilizes the spine

The phrenic nerve (C3–C5) innervates the diaphragm, which contributes to intra-abdominal pressure production critical for spinal stabilization during loading.

What does 'upper crossed syndrome' describe in terms of postural muscle imbalances?

Answer: Overactive upper trapezius/levator scapulae crossing with underactive deep neck flexors and lower trapezius

Upper crossed syndrome (Janda) describes an X-pattern of overactive upper trapezius, levator scapulae, and pectorals opposing underactive deep neck flexors, rhomboids, and lower trapezius.

The center of mass in a standing adult is located approximately at which spinal level?

Answer: S2

The body's center of mass is located approximately at the level of S2, just anterior to the sacrum, in a normally proportioned standing adult.

Which postural assessment finding would most suggest overactivity of the tensor fasciae latae (TFL)?

Answer: Knee valgus with contralateral hip drop during single-leg stance

An overactive TFL contributes to IT band tightness, medial knee pull, and ipsilateral hip abduction dominance, often presenting as contralateral hip drop (Trendelenburg pattern) during single-leg loading.