Table 15.1: Muscles of the Torso

Vocabulary flashcards detailing the origin, insertion, and action of the muscles of the torso from Table 15.1.

External abdominal oblique

• A: Compresses abdominal wall, laterally rotates trunk
• O: Ribs 5–12
• I: Inguinal ligament, iliac crest, rectus sheath

Internal abdominal oblique

• A: Compresses abdominal wall, laterally rotates trunk
• O: Inguinal ligament, iliac crest, lumbar fascia
• I: Linea alba, ribs 10–12, rectus sheath

Transversus abdominis

• A: Compresses abdominal wall, laterally rotates trunk
• O: Inguinal ligament, iliac crest, ribs 7–12
• I: Xiphoid process, linea alba, crest of pubis

Rectus abdominis

• A: Flexes vertebral column, compresses abdominal wall
• O: Pubic crest, symphysis pubis
• I: Inferior ribs, xiphoid process

Quadratus lumborum

• A: Laterally flexes vertebral column, depresses rib 12

• O: Posterior iliac crest, lower lumbar vertebrae

• I: T12, L1–4, rib 12

Erector Spinae (spinalis, longissimus, and iliocostalis)

• A: Extends and rotates vertebral column and head

• O: Vertebral column, ilium, ribs

• I: Ribs, vertebral column, occipital and temporal bones (Comprises Spinalis, Longissimus, and Iliocostalis)

Serratus anterior

• A: Abducts scapula
• O: Ribs 1–9
• I: Medial border of scapula

Diaphragm

• A: Inspiration
• O: Xiphoid process, lower ribs, upper lumbar vertebrae
• I: Central tendon

External intercostals

• A: Elevates ribs, inspiration
• O: Inferior margin of a rib
• I: Superior margin of rib below

Internal intercostals

• A: Depresses ribs, expiration
• O: Superior margin of a rib
• I: Inferior margin of rib above

Splenius

• A: Extends and rotates head
• O: C4–T6
• I: Occipital and temporal bone

Semispinalis

• A: Extends and rotates head
• O: C4–T6
• I: Occipital bone

Multifidus

• A: Extends and rotates vertebral column
• O: Vertebral column, ilium
• I: Vertebral column

Vertebral Column Abbreviations (C, T, L, S)

Standard anatomical designations:

• C: Cervical vertebrae
• T: Thoracic vertebrae
• L: Lumbar vertebrae
• S: Sacral vertebrae