Trunk Muscles Flashcards
What are the rough origins and insertions of the four muscles of the abdominal wall? Actions?
External Oblique - Origin @ the external/inferior surfaces of the 5th-12th ribs and inserts @ the ASIS, anterior half of the iliac crest, pubic crest, pubic tubercle and the linea alba
Action: Flexes lumbar, laterally flexes trunk, and contralaterally rotates
Internal Obliques - Origin @ the iliac crest and anteriorly at the thoracolumbar fascia. It inserts @ the inferior margins of the 10th-12th ribs, linea alba, and pectin pubis
Action: Flexes lumbar, laterally flexes trunk, and ipsilaterally rotates
Rectus Abdominis - Origin @ the pubic crest and inserts @ the xiphoid process and costal cartilages of the 5th-7th ribs
Action: Trunk flexion
Transverse Abdominis - Origin @ the costal cartilages of the 7th-12th ribs, thorcolumbar fascia, iliac crest and inguinal ligament. It inserts @ the middle of the thoracolumbar region (linea alba, pubic crest, and pecten pubis)
Action: Compresses and provides structural support to adjacent abdominal structures
What are the two most superficial global back movers? What are their actions?
Trapezius and Lattissmus Dorsi
- Both generate large range of movement
Traps: COntralateral rotation, lateral flexion, extension
Lats: Adducts, medially rotates, and extends the arm @ the glenohumeral joint
What are the two deep muscles along the spine? O’s, I’s, actions?
Erectus Spinae - Consists of three muscles vertically orientated that lie parallel to the vertebral column. Medial to lateral: Spinalis, Longissimus, Iliocostalis
Action: Extends and laterally flexes the trunk - MAIN TRUNK EXTENSOR
Multifidus muscles - Origin @ the PSIS, sacrum, mamillary processes of lumbar vertebrae, transverse processes of the thoracic vertebrae, articular processes of C4-C7 vertebrae. Inserts @ spinous processes of lumbar, thoracic and cervical vertebrae
Action: Extends neck and trunk; stabilizes vertebral column
Quadratus Lumborum - origin @ the posterior half of the iliac crest and inserts @ the inferior border of the 12th rib and transverse processes of L1-L4 (behind psoas)
Action: Extends and laterally flexes trunk; stabilizes 12th rib during inspiration
