Muscle Anatomy: Origins, Insertions, and Actions

Comprehensive practice flashcards covering origins, insertions, and bolded/unbolded actions of abdominal, thoracic, and erector spinae muscles.

What is the origin of the Rectus abdominis muscle?

pubic symphysis

What is the insertion of the Rectus abdominis muscle?

xiphoid process & costal cartilages

What are the primary (bolded) actions of the Rectus abdominis muscle?

Compresses abdomen; flexes vertebral column

What is the origin of the External oblique muscle?

outer surfaces of lower 8 ribs

What is the insertion of the External oblique muscle?

linea alba

What are the primary (bolded) actions of the External oblique muscle?

Compresses abdomen; flexes vertebral column laterally.

What is the origin of the Internal oblique muscle?

iliac crest

What is the insertion of the Internal oblique muscle?

linea alba

What are the primary (bolded) actions of the Internal oblique muscle?

Compresses abdomen; flexes vertebral column laterally.

What is the origin of the Diaphragm?

bottom of rib cage, sternum, and lumbar vertebrae

What is the insertion of the Diaphragm?

central tendon

What is the primary (bolded) action of the Diaphragm?

Prime mover for inspiration (inhalation).

How does the shape of the Diaphragm change during contraction and relaxation?

The diaphragm flattens when it contracts and becomes dome-shaped when it relaxes.

What is the origin of the External intercostals?

inferior border of rib above

What is the insertion of the External intercostals?

superior border of rib below

What is the primary (bolded) action of the External intercostals?

Elevates the ribs for inspiration.

What is the origin of the Internal intercostals?

superior border of rib below

What is the insertion of the Internal intercostals?

inferior border of rib above

What is the primary (bolded) action of the Internal intercostals?

Depresses the ribs for forced expiration.

What is the primary (bolded) action common to all muscles in the Erector spinae group?

extend the vertebral column

What is the origin of the Iliocostalis muscle?

iliac crest

What is the insertion of the Iliocostalis muscle?

ribs

What is the origin of the Longissimus muscle?

transverse processes of lumbar vertebrae

What is the insertion of the Longissimus muscle?

transverse processes of thoracic vertebrae

What is the origin of the Spinalis muscle?

spinous processes of upper lumbar and lower thoracic vertebrae

What is the insertion of the Spinalis muscle?

spinous processes of upper thoracic vertebrae