Muscle | ACTION | ORIGIN | INSERTION |
Sternocleidomastoid | ACTION:
Flexion of neck.
Lateral flexion and turning of the head. | ORIGIN:
Manubrium of sternum; sternal third of clavicle. | INSERTION:
Mastoid process; lateral half of superior nuchal line. |
Diaphragm | ACTION: | ORIGIN: | INSERTION: |
External Intercostals | ACTION:
Elevates rib cage. | ORIGIN:
Inferior border of the ribs. | INSERTION:
Superior border of ribs. |
Internal Intercostals | ACTION:
Depresses rib cage. | ORIGIN:
Superior border of ribs. | INSERTION:
Inferior border of ribs. |
External Abdominal Oblique | ACTION:
Flexes vertebral column.
Compresses abdominal wall. | ORIGIN:
Ribs 5-12 | INSERTION:
Linea alba.
Pubic crest.
Pubic tubercle.
Iliac crest. |
Internal Abdominal Oblique | ACTION:
Flexes vertebral column.
Compresses abdominal wall. | ORIGIN:
Lumbar fascia.
Iliac crest.
Inguinal ligament. | INSERTION:
Linea alba.
Pubic crest. |
Transverse Abdominis | ACTION:
Compresses abdominal contents. | ORIGIN:
Inguinal ligament.
Lumbar fascia.
Cartilages of the last 6 ribs.
Iliac crest. | INSERTION:
Linea alba.
Pubic crest. |
Rectus Abdominis | ACTION:
Flexes lumbar region of vertebral column.
Rotates lumbar region of vertebral column. | ORIGIN:
Pubic crest.
Pubic symphysis. | INSERTION:
Xiphoid process.
Ribs 5-7. |
Erector Spinae (Iliocostalis) | ACTION:
Extend vertebral column, maintain posture.
Lateral flexion when acting on one side. | ORIGIN:
Iliac crests (lumborum).
Inferior 6 ribs (thoracis)
Ribs 3-6 (cervicis) | INSERTION:
Angle of ribs (lumborum & thoracis).
Cervical vertebrae C6-C4 (cervicis) |
Erector Spinae (Longissimus) | ACTION: | ORIGIN: | INSERTION: |
Erector Spinae (Spinalis) | ACTION: | ORIGIN: | INSERTION: |
Quadratus Lumborum | ACTION:
Flexes vertebral column laterally when alone.
When together, extends lumbar spine and fixes 12th rib.
Maintains upright posture.
Assists in forced breathing. | ORIGIN:
Iliac crest and lumbar fascia. | INSERTION:
Transverse process of upper lumbar vertebrae and lower margin of 12th rib. |
Multifidus | ACTION: | ORIGIN: | INSERTION: |
Transversus Thoracis | ACTION: | ORIGIN: | INSERTION: |
Pectoralis Minor | ACTION: | ORIGIN: | INSERTION: |
Pectoralis Major | ACTION: | ORIGIN: | INSERTION: |
Serratus Anterior | ACTION:
Rotates inferior angle of scapula laterally. | ORIGIN:
Ribs 1-8 | INSERTION:
Vertebral border of the scapula. |
Latissimus Dorsi | ACTION: | ORIGIN: | INSERTION: |
Scalenes | ACTION:
Elevates ribs.
Flexion of the neck. | ORIGIN:
Transverse processes of cervical vertebrae (C1 - C7) | INSERTION:
Ribs 1-2 |
Trapezius | ACTION:
Elevates, depresses, rotates and adducts scapula. | ORIGIN:
Occipital bone.
Spinous processes of C7-T12. | INSERTION:
Lateral third of the clavicle.
Spine of scapula.
Acromion process of scapula. |