Posterior Muscles Of Back Flashcards
What are the general actions of the muscles of the back?
Extension and lateral flexion
Rotation from obliques
Are the muscles of the back primarily fast or slow twitch fibers?
Slow twitch - providing stability and endurance
True or false: Muscle atrophy follows an episode of back pain
True
What are three segmental muscle groups?
Interspinalis
Intertransversarii
Rotatores
What are the origins and insertions of the interspinalis muscle group?
Connects one spinous process to the next
What is the action of the interspinalis muscle group?
Intersegmental extension
At which segments is the interspinalis muscle missing?
C1/2
What are the origins and insertions of the intertransversarii muscle group?
Connects transverse processes to each other
What is the action of the intertransversarii muscle group?
Lateral flexion
Between which segments are the intertransversarii muscles?
C1-T1
T10-S1
What is the origins and insertions of the rotatores muscle group?
Transverse process to spinous process base of level above
What is the action of the rotatores muscles of the back?
Segmental rotation
What are the overall actions of the segmental muscles of the back?
Provide intersegmental stability - support posture
What are the two muscles of the transversospinalis muscles?
Semispinalis
Multifidus
What are the three muscles of the semispinalis muscle group?
Thoracics
Cervicis
Capitus
What is the origin and insertion of the semispinalis thoracics?
O: TPs of T7-T12
I: SPs of upper thoracic and lower cervical
Of semispinalis thoracics and semispinalis cervicis, which muscle is thicker?
Semispinalis cervicis
What is the origin and insertion of semispinalis cervicis?
O: TPs of T5-6
I: SPs C2-C5
What is the origin and insertion of semispinalis capitus?
O: T1-6 TPs
C4-7 articular pillars
I: btwn superior/inferior nuchal lines of occiput
What is the general action of semispinalis?
Extension
Lateral flexion
Contralateral rotation
Acts on trunk, neck, individual spinal joints
What is the origin and insertion of multifidus?
O: Posterior sacrum
PSIS
L5 maxillary - C4 TPs
I: SPs 2-4 segments above origins
What are the actions of multifidus?
Bilateral = extension Unilateral = rotation to opposite side
What are the three muscles of the erector spinae?
Iliocostalis
Longissimus
Spinalis
True or false: the erector spinae muscles are the largest muscle group of the back
True
True or false: the erector spinae have a vertical orientation
True
What are the actions of the erector spinae?
Bilateral = extension Unilateral = lateral flexion to ipsilateral side
What is the most lateral muscle of the erector spinae group?
Iliocostalis
What are the muscles of the iliocostalis muscle group?
Iliocostalis Lumborum
Iliocostalis thoracis
Iliocostalis cervicis
What is the origin and insertion of the iliocostalis lumborum?
O: Thoracolumbar aponeurosis
I: lower borders of ribs 6/7-12
What is the origin and insertion of the iliocostalis thoracis?
O: upper border/angels of ribs 7-12
I: lower borders/angles of ribs 1-6
TPs of C7
What is the origin and insertion of iliocostalis cervicis?
O: upper borders, angles of ribs 3-6
I: posterior tubercles of c4-6
What are the actions of the iliocostalis muscle group?
Bilateral: extension
Unilateral: lateral flexion
What are the muscles of the longissimus groups?
Longissimus thoracis
Longissimus cervicis
Longissimus capitus
What is the origin of the longissimus thoracis?
O: Thoracolumbar aponeurosis
I: ribs 3/4-12 and thoracic TPs
What is the origin of longissimus cervicis?
O: T1-4 TPs
I: C2-6 posterior tubercles