AIC: Anterior Inferior Chain
There is a polyarticular muscular chain from rib seven to the lower extremity. This is called Anterior Inferior Chain (AIC). These polyarticular muscles influence on respiration and three-dimensional movement of the trunk, pelvis, and lower extremities.
Muscles: Diaphragm, Iliacus, Psoas, TFL, Vastus Lateralis, Biceps Femoris
Left AIC pattern
The Left AIC pattern is the dominant pattern in human beings because of the asymmetrically designed body (the heart on the left, the liver on the right, the longer vagus nerve on the right, the bigger diaphragm on the right, and so on). Because of dominated left AIC pattern, we often see;
- a left hemipelvis (left innominate) rotates forward and creates a ‘right-on-right’ (aka R/R torsion) pattern
- the lumbar spine is rotated to the right
- the right hip is adducted
- the left hip is abducted
Overactive muscles: R Diaphragm, Iliacus, L Psoas, L TFL, R Vastus Lateralis, R Biceps Femoris
Symptoms often associated with Left AIC are:
- Repeated ankle sprains
- Hamstring strain
- Planter fascitis
- Hip flexor strain
- Hip impingement
- Shin splint
- Bunions
- Sacroiliac (SI) joint pain
- Sciatica
- Lower back pain (L4, L5, S1 instability)
