Spinal Extensors

Question 1

Erector Spinae

Answer 1

Origin: Along length of vertebral column, ribs, pelvis
Insertion: Vertebral column, ribs
Action: Ext. of spine and maintenance of upright posture. Also lifts pelvis anteriorly

Question 2

Multifidus

Answer 2

Origin: Sacrum, lumbar vertebrae
Insertion: Every second vertebra until C2
Action: Ext. of spine. Also assists in spinal rotation

Question 3

Quadratus Lumborum

Answer 3

Origin: Iliac crest
Insertion: 12th rib, L1 to L4
Action: Bilaterally, spinal ext. Unilaterally, lat. flex. of spine. Also works with diaphragm to depress last rib during forced expiration