Muscle Actions Flashcards
Trapezius
Elevate, depress, retract, and rotate scapula superiorly (depending on fibers - upper/mid/lower)
Latissimus Dorsi
Extension and medial rotation of arm
Levator Scapulae
Scapular elevation
Rhomboid major and minor
Scapular retraction, elevation, rotate inferiorly
Serratus posterior superior
Elevate ribs
Serratus posterior inferior
Depress ribs
Splenus capitus and cervicus
Bilaterally extend C-Spine
Unilaterally flex and rotate head to same side
Erector spinae - Iliocostalis
Bilaterally extend spine
Unilaterally side bend
Erecrtor spinae - longissimus
Bilaterally extend head/spine
Unilaterally side bend
Etector spinae - Spinalis
Bilateraaly extend C+T spine
Unilaterally side bend
Semispinalis capitis and cervicis
Bilaterally extend C+T spine, stabilize craniovertebral joints
Unilaterally bend C+T spine to same side and rotate to opposite side
Rotators (longus and brevis)
Bilaterally extend T spine
Unilaterally rotate spine to opposite side
Levatores costarum (longus and brevis)
Bilaterally extend T spine
Unilaterally bend T spine to same side and rotate to opposite side
Multifidus
Bilaterally extend spine
Unilaterally bend to same side, rotate to opposite side
Suboccipital triangle - obliquus capitus inferior
Bilaterally extend head
Unilaterally rotate head to same side
Suboccipital triangle - obliquus capitis superior
Bilaterally extend head and tilt to same side
Unilaterally rotate head to opposite side
Suboccipital triangle - rectus capitus posterior major and minor
Bilaterally extend head
Unilaterally rotate head to same side
External intercostals
Raise ribs in inspiration, support intercostal spaces, stabilize chest wall
Internal intercostals and innermost intercostals
Lower ribs in expiration, support intercostal spaces, stabilize chest wall
Transversus thoracis
Weakly lower ribs during expiration
External abdominal oblique
Bilaterally flex trunk
Unilaterally side bend to same side and rotate to opposite side
Internal abdominal oblique
Bilaterally flex trunk
Unilaterally side bend and rotate to same side
Transversus abdominis
Bilaterally compress abdomen
Unilaterally rotate trunk to same side
Rectus abdominis
Flex trunk
Psoas major
Hip - flex
Lumbar spine - externally rotate
Unilaterally side bend
Bilaterally raise trunk from supine
Psoas minor
Weak trunk flexor
Quadratus lumborum
Bilateral bear down in expiration, stabilize 12th rib
Unilaterally side bend
Iliacus
Flex thigh (flex pelvis if thigh is fixed)
Deltoid (anterior / clavicular)
Flex, internally rotate, adduct arm
Deltoid (lateral, acromial)
Abduct arm
Deltoid (posterior, spinal)
Extend, externally rotate, adduct arm
Pectoralis major
Adduct and internally rotate arm
Clavicular and sternocostal parts flex arm and assist with respiration
Pectoralis minor
Depress scapula medially, rotate glenoid inferiorly, assist in respiration
Latissimus dorsi
Internally rotate, adduct, and extend arm
Teres major
Internally rotate, adduct, and extend arm
Subscapularis
Internally rotate arm
Serratus anterior
Lower arm, rotate scapula laterally, elevate ribs
Teres minor
Externally rotate shoulder, weakly adduct
Triceps brachii
Extend elbow Adduct shoulder (long and medial heads also extend shoulder)
Anconeus
Extend and stabilize elbow
Supraspinatus
Abduct shoulder
Infraspinatus
Externally rotate shoulder
Biceps brachii
Flex elbow
Supinate forearm
Flex, abduct, internally rotate shoulder
Coracobrachialis
Flex, adduct, internally rotate shoulder
Brachialis
Flex elbow
Brachioradialis
Weak elbow flexor (most effective w/forearm neutral)
Pronator teres
Pronate forearm, weakly flex elbow