Back Musculature

Question 1

Superficial Erector Spinae: Iliocostalis, longissimus, and spinalis

Answer 1

★ Insertion
Iliocostalis
Lumborum: Inferior border of ribs 7 - 12
Thoracis: Superior border of ribs 1 - 6
Cerevicis: 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: Spinus process of C3 - C2
Capitis: between the superior and inferior nuchal lines on occipital bone of the skull
★ Isolated function
Concentrically accelerates spinal extension, rotation, ad 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

★ Insertion
12th rib
Transverse process L2 - L5
★ Isolated function
Spinal lateral flexion
★ Integrated function
Eccentrically decelerates contralateral lateral spinal flexion
Isometrically stabilizes the LPHC

Question 3

Multifidus

Answer 3

★ Insertion
Spinous processes 1 to 4 segments above the origin(pg 635)
★ Isolated function
Concentrically accelerates spinal extension and contralateral rotation
★ Integrated function
Eccentrically decelerates spinal flexion and rotation
Isometrically stabilizes the spine

Question 4

Latissimus Dorsi

Answer 4

★ 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 rotation
Eccentrically decelerates spinal flexion
Isometrically stabilizes the LPHC and shoulder