Intrinsic Back Muscles

Question 1

Splenius Capitis

Answer 1

SUPERFICIAL LAYER
Attachments:

Superior/Proximal: Nuchal Ligament & Spinous Process C7-T6
Inferior/Distal: Mastoid Process

Action:

Acting Alone: Laterally Flex Neck & Rotate Head to the Side
Acting with Splenius Cervicis: Extend Head & Neck

Question 2

Splenius Cervicis

Answer 2

SUPERFICIAL LAYER
Attachments:

Superior/Proximal: Nuchal Ligament & Spinous Process C7-T6
Inferior/Distal: Tubercles of Transverse Process C1-C3

Action:

Acting Alone: Laterally Flex Neck & Rotate Head to the Side
Acting with Splenius Capitis: Extend Head & Neck

Question 3

Iliocostalis (Erector Spinae)

Answer 3

INTERMEDIATE LAYER
Attachments:

Superior/Proximal: Arises by tendon from the Posterior Iliac Crest, Sacrum, Sacral, & Lumbar Spinous Processes
Inferior/Distal: Lumborum & Thoracis (angle of Ribs), Cervicis (Transverse Processes)

Action:

Acting Bilaterally: Extend Vertebral Column & Head. Control Flexion Eccentrically
Acting Unilaterally: Laterally Flex Vertebral Column.

Question 4

Longissimus (Erector Spinae)

Answer 4

INTERMEDIATE LAYER
Attachments:

Superior/Proximal: Arises by tendon from the Posterior Iliac Crest, Sacrum, Sacral, & Lumbar Spinous Processes
Inferior/Distal: Thoracis (Ribs), Cervicis (Transverse Processes), & Capitis (Mastoid Process)

Action:

Acting Bilaterally: Extend Vertebral Column & Head. Control Flexion Eccentrically
Acting Unilaterally: Laterally Flex Vertebral Column.

Question 5

Spinalis (Erector Spinae)

Answer 5

INTERMEDIATE LAYER
Attachments:

Superior/Proximal: Arises by tendon from the Posterior Iliac Crest, Sacrum, Sacral, & Lumbar Spinous Processes

Inferior/Distal:, to spinous processes of vertebra in upper thoracic region and cervicis (nuchal ligament) and mastoid process

Action:

Acting Bilaterally: Extend Vertebral Column; Head. Control Flexion Eccentrically
Acting Unilaterally: Laterally Flex Vertebral Column.

Question 6

Semispinalis (Transversospinalis)

Answer 6

DEEP LAYER
Attachments:

Superior/Proximal: Transverse Process & C4-T12
Inferior/Distal: Spinous Processes of Superior Vertebrae & Thoracis, Cervicis, Capitis (Occipital Bone)

Action:

Extension: Head & Thoracic & Cervical Region of Vertebral Column and rotates them contralaterally

Question 7

Multifidus (Transversospinalis)

Answer 7

DEEP LAYER
Attachments:

Superior/Proximal: Posterior Sacrum & PSIS, ancillary process of lumbar, transverse processes T1-T3, articular processes C4-C7

Inferior/Distal: Spinous Processes of Superior Vertebrae 2-4 segments superior. Thickest in Lumbar Region

Action:

Extension & Stabilises Vertebrae during local movement of the column

Question 8

Rotatores (Transversospinalis)

Answer 8

DEEP LAYER
Attachments:

Superior/Proximal: Transverse Process & Most developed in thorax
Inferior/Distal: Spinous Processes of Superior Vertebrae & Junction of Lamina and Transverse Processes

Action:

Extension & Stabilises Vertebrae & Assists with local Extension and Rotation

Question 9

Levator Costarum

Answer 9

MINOR DEEP LAYER
Attachments:

Superior/Proximal: Transverse Processes T7-T11
Inferior/Distal: Adjacent Ribs

Action:

Elevate Ribs

Question 10

Interspinales

Answer 10

MINOR DEEP LAYER
Attachments:

Superior/Proximal: Superior surfaces of Spinous Processes (Cervical & Lumbar)
Inferior/Distal: Inferior surfaces of Spinous Processes Superior

Action:

Aid in Extension and Rotation of Vertebral Column

Question 11

Intertransversarii

Answer 11

MINOR DEEP LAYER
Attachments:

Superior/Proximal: Transverse Processes (Cervical & Lumbar)
Inferior/Distal: Transverse Processes of Adjacent Vertebrae

Action:

Aid in Lateral Flexion & Stabilise the Column when acting Bilaterally