Back Musculature

Question 1

Superficial erector spinae: iliocostalis, longissimus, and spinalis

Answer 1

division in the group -

• • lumborum /lumbar
• • thoracis/ thoracic
• • cervicis/cervical

common origin -

• • iliac crest of the pelvis
• • sarcrum
• • spinous and transverse process of t11-15

intertion
>> Iliocostalis 
- lumborum - inferior border of ribs 7-12
- thoracis - superior border of ribs 1-6
- cervicis - transverse process of c4-c6

> > longissimus

• thoracis - transverse process t1-t12, ribs 2-12
• cervicis - transverse process of c6-c2
• capitis - mastoid process of the skull

> > spinalis

• thoracis - spinous process of t7-t4
• cervicis - spinous process of c3-c2
• capitis - bretween the superior and inferior nuchal lines on occipital bone of the skull

isolated function - concentrically accelerates spinal extension, rotation, and lateral flexion

integrated function -

• • eccentrically decelerates spinal flexion, rotation, and lateral flexion
• • dynamically stabilizes the spine during functional movements

Question 2

Quadratus Lumborum

Answer 2

origin - iliac crest of the pelvis

insertion -

• • 12th rib
• • transverse process 12-15

isolated function - spinal lateral flexion

integrated function -

• • ecccentrically decelerates contralateral lateral spinal flexion
• • isometrically stabilizes the lumbo-pelvic-hip complex

Question 3

Multifidus

Answer 3

origin -

• • posterior aspect of the sacrum
• • process of the lumbar, thoracic of the cervical spine

insertion - spinous processes one to four segments above the origin

isolated function - concentrically accelerates spinal extension and contralateral rotation

integrated function -

• • eccentrically decelerates spinal flexion and roation
• • isometrically stabilizes the spine

Question 4

Latissimus Dorsi

Answer 4

origin -

• • spinous processes of t7-t12
• • iliac crest of the pelvis
• • thoracolumbar fascia
• • ribs 9-12

insertion -

• • inferior angle of the scapula
• • intertubercular groove of the humerus

isolated function - concentrically accelerates shoulder extension, adduction, and internal rotation

integrated function -

• • eccentrically decelerates shoulder flexion, abduction, and external roration
• • eccentrically decelerates spinal flexion
• • isometrically stabilizes the lumbo-pelvic-hip complex and shoulder