L4 - MSK Back Myology Flashcards
Muscle:
Layer #:
Layer Classification:
Trapezius M.
Layer 1
Superficial/Extrinsic
Trapezius M.
Origin:
Spinous processes of C7-T12,
Ligamentum Nuchae,
External Occipital Protuberance,
Medial 1/3 of Superior Nuchal Line of Occipital B.
Trapezius M.
Insertion:
Lateral 1/3 of the Clavicle, Acromion and Scapular Spine
Trapezius M.
Action:
Whole muscle: Rotate point of the Glenoid Cavity superiorly / Retract the Scapula
Upper fibers: Elevate Scapula
Lower fibers: Depress Scapula
Upper fibers, with the Scapula fixed:
Extend the Neck working bilaterally
Laterally Flex the Neck & Rotate the Face away when working unilaterally
Trapezius M.
Innervation:
Motor: Spinal Accessory N. (CN XI/11)
Sensory: C3, 4
Muscle:
Layer #:
Layer Classification:
Latissimus Dorsi M.
Layer 1
Superficial/Extrinsic
Latissimus Dorsi M.
Origin:
Spinous processes of T6-T12
Ribs 9-12
Iliac Crest and Spinous Processes of L1-5
Median Sacral Crest via Thoracolumbar Fascia
Latissimus Dorsi M.
Insertion:
Floor of the Humeral Intertubercular Groove
Latissimus Dorsi M.
Action:
Extend, ADduct and Medially Rotate the Humerus
Rotate the Glenoid Cavity inferiorly
Latissimus Dorsi M.
Innervation:
Thoracodorsal N. (C6-8)
Layer 2 muscles
- Rhomboid Major M.
- Rhomboid Minor M.
- Levator Scapulae M.
Rhomboid Major M.
Origin:
Spinous processes of T2-T5
Rhomboid Major M.
Insertion:
Medial border of scapula (Inferior to scapular spine)
Rhomboid Major M.
Action:
Retract and Elevate scapula
Rotate Glenoid Cavity inferiorly
Rhomboid Major M.
Innervation:
Dorsal Scapular N. (C4, 5)
Rhomboid Minor M.
Origin:
Spinous processes of C7-T1
Lower part of the Ligamentum Nuchae
Rhomboid Minor M.
Insertion:
Medial border of scapula (at scapular spine)
Rhomboid Minor M.
Action:
Retract and Elevate scapula
Rotate the Glenoid Cavity inferiorly
Rhomboid Minor M.
Innervation:
Dorsal Scapular N. (C4, 5)
Levator Scapulae M.
Origin:
O: Posterior Tubercles of Transverse processes C1-4
Levator Scapulae M.
Insertion:
I: Medial border of scapula (superior to scapular spine)
Levator Scapulae M.
Action:
Elevate scapula
Rotate the Glenoid Cavity inferiorly
When the Scapula is fixed: Extend and Laterally Flex the Neck
Levator Scapulae M.
Innervation:
N: C3, 4, Dorsal Scapular N. (C5)
Layer 3 Muscles
1.
2.
- Serratus Posterior Superior M.
- Serratus Posterior Inferior M.
Serratus Posterior Superior M.
Origin:
Nuchal L. and Spinous Processes C7-T3
Serratus Posterior Superior M.
Insertion:
I: Superior surfaces of Ribs 2-4
Serratus Posterior Superior M.
Action:
Elevate Ribs with forced inspiration (primarily proprioceptive)
Serratus Posterior Superior M.
Innervation:
N: Intercostal N. (2-5)
Serratus Posterior Inferior M.
O:
O: Spinous Processes T11-L2
Serratus Posterior Inferior M.
Insertion:
I: Inferior surface of Ribs 8-12
Serratus Posterior Inferior M.
Action:
Depress Ribs with forced expiration (primarily proprioceptive)
Layer 4 Muscles
Classification:
Names:
1.
2.
Intrinsic
- Splenius Capitis M.
- Splenius Cervicis M.
Splenius Capitis M.
O:
O: Lower 1/2 Nuchal L., Spinous Process C7-T3(4)
Splenius Capitis M.
Insertion:
Mastoid process of Temporal B.
Lateral 1/3 Superior Nuchal Line of the Occipital B.
Splenius Capitis M.
Action:
Extend the Neck when working bilaterally
Laterally Flex the Neck and Rotate Face toward when working unilaterally
Splenius Cervicis M.
O:
O: Spinous processes T3-6
Splenius Cervicis M.
Insertion:
I: Transverse processes C1-3(4)
Splenius Cervicis M.
Action:
A: Extend the Neck when working bilaterally
Laterally Flex the Neck and Rotate Face toward when working unilaterally
Layer 5
Name:
Classification:
Muscles groups:
1.
2.
3.
Erector Spinae Group
Instrinsic, largest layer
- Iliocostalis (Lateral Group)
- Longissimus (Intermediate Group)
- Spinalis (Medial Group)
Iliocostalis (lateral group)
Submuscles:
1.
2.
3.
- Iliocostalis Lumborum M.
- Iliocostalis Thoracis M.
- Iliocostalis Cervicis M.
Iliocostalis Lumborum M.
Origin:
Posteromedial Iliac Crest
Spinous Processes T11-L5
Median Sacral Crest
Lateral Sacral Crest
Sacrotuberous L. and Long Posterior Sacroiliac L.
Iliocostalis Lumborum M.
Insertion:
I: Costal Angles of Ribs 6-12
Iliocostalis Thoracis M.
Origin:
Insertion:
O: Costal Angles of Ribs 6-12
I: Costal Angles of Ribs 1-6 and Transverse Process C7
Iliocostalis Cervicis M.
Origin:
Insertion:
O: Costal Angles of Ribs 3-6
I: Posterior Tubercles of Transverse Processes C4-6
Longissimus Thoracis M.
O:
I:
O: Common Origin with Iliocostalis Lumborum, Transverse and Accessory processes L1-5
I: Transverse Processes T1-L2, Ribs 3-12 between the Costal Tubercle and Costal Angle
Longissimus Cervicis M.
O:
I:
O: Transverse processes T1-5
I: Posterior Tubercles of Transverse processes and Articular Processes of C2-6
Longissimus Capitis M.
O:
I:
A:
O: Transverse Processes T1-5, articular processes C4-7
I: Mastoid Process of the Temporal B.
A: Extend neck working bilaterally, laterally flex the Neck and rotate Face toward working unilaterally
Spinalis (medial group)
Subgroups:
1.
2.
3.
- Spinalis Thoracis M.
- Spinalis Cervicis M.
- Spinalis Capitis M.
Spinalis Thoracis M.
O:
I:
* often blends with Longissimus Thoracis M.
O: Spinous Processes T11- L2
I: Spinous Processes T1-4
Spinalis Cervicis M.
O:
I:
* usually absent
O: Spinous Processes T1- 6
I: Spinous Processes C2 (3,4)
Spinalis Capitis M.
* usually absent or blended with Semispinalis Capitis M.
CN: Back Sprain vs. Back Strain
CN:
Sprain: Ligamentous
Strain: Muscular
–> A Back Sprain is an injury to the ligamentous attachments between bone, usually the result of inadequate stretching before activity.
–> A back Strain involves excessive stretching and sometimes tearing of muscle fibers produced by an overly strong muscular contraction.
Muscle tissue will spasm, or involuntarily contract in response to injury and inflammation as a protective measure.
Layer 6 (Intrinsic) Transversospinalis Group
1.
a, b, c
2.
3.
4.
- Semispinalis Group (extending 5 or more spinal segments)
a. Semispinalis Thoracis M. (thin muscular fasciculi)
b. Semispinalis Cervicis M.
c. Semispinalis Capitis M. (best developed Semispinalis) - Multifidus M. (extending 3 or 4 Spinal segments; best developed in Lumbar region)
- Rotatores Longus M. (extending 2 spinal segments)
- Rotatores Brevis M. (extending to adjacent spinal segment)
Semispinalis Thoracis M.
O:
I:
A:
N:
*thin muscular fasciculi
O: Transverse processes T6-12
I: Spinous processes C6-T4
A: Extend Spine and Rotate Spine away
N: Posterior Rami
Semispinalis Cervicis M.
O:
I:
A:
N:
O: Transverse processes T1-6
I: Spinous processes C2-5
A: Extend Spine and Rotate Spine away
N: Posterior Rami
Semispinalis Capitis M.
O:
I:
A:
N:
*best developed Semispinalis
O: Transverse processes C7-T6, articular processes C4-6
I: Between Superior and Inferior Nuchal Lines of the Occipital B.
A: Extent Head, Rotate Face away
N: Posterior Rami
Multifidus M.
O:
I:
A:
N:
*extending 3 or 4 Spinal segments; best developed in Lumbar region
O: Mamillary processes of Lumbar Vertebrae, Transverse Processes of Thoracic Vertebrae and Articular Processes of C4-7
I: Spinous processes three numeric segments superior, does not insert onto the Atlas
A: Extend Spine, Rotate the Spine away
N: Posterior Rami
Rotatores Longus M.
O:
I:
A:
N:
*extending 2 spinal segments
O: Transverse processes
I: Roots of Spinous processes 2 numeric segments superior
A: Extend Spine, Rotate the Spine away (primarily proprioceptive)
N: Posterior Rami
Rotatores Brevis M.
O:
I:
A:
N:
*extending to adjacent spinal segment
O: Transverse processes
I: Roots of Spinous processes 1 numeric segments superior
A: Extend Spine, Rotate the Spine away (primarily proprioceptive)
N: Posterior Rami
Interspinalis M.
O:
I:
A:
N:
*Deep Muscle
*best developed in Cervical and Lumbar regions
O: Spinous process
I: Adjacent Spinous process
A: Extend Spine
N: Posterior Rami
Intertransversarii M.
O:
I:
A:
N:
*best developed in Cervical and Lumbar regions
O: Transverse process
I: Adjacent transverse process
A: Laterally Flex spine
N: Posterior portion (Posterior Rami), Anterior portion (Anterior Rami)
Levator Costarum Longus M.
O:
I:
A:
N:
O: Transverse Processes C7-T11I: 2nd rib inferior to origin
A: Elevate ribs
N: Posterior Rami
Levator Costarum Brevis M.
O:
I:
A:
N:
O: Transverse Processes C7-T11
I: Adjacent rib inferior to origin
A: Elevate ribs
N: Posterior Rami
Rectus Capitis Posterior Major M.
*medial border Suboccipital Triangle
O: Spinous Process C2
I: Lateral portion Inferior Nuchal Line
A: Extend Head, Rotate Face toward
N: Suboccipital N.
- Semispinalis Capitis M.
- Rectus Capitis Posterior Minor M.
- Rectus Capitis Posterior Major M.
- Oblique Capitis Superior M.
- Oblique Capitis Inferior M. (doesn’t actually connect to skull, shouldn’t be called capitis)
- Semispinalis Cervices M.
Rectus Capitis Posterior Minor M.
O:
I:
A:
N:
O: Posterior tubercle C1
I: Below Inferior Nuchal Line
A: Extend Head
N: Suboccipital N.
Obliquus Capitis Inferior M.
O:
I:
A:
N:
*inferior border Suboccipital Triangle
O: Spinous Process C2
I: Transverse process C1
A: Rotate the Face toward
N: Suboccipital N.
Obliquus Capitis Superior M.
O:
I:
A:
N:
*lateral border Suboccipital Triangle
O: Transverse process C1
I: Between Superior and Inferior Nuchal Lines
A: Extend and Laterally Flex Head
N: Suboccipital N.
Suboccipital Triangle
Boundaries:
Contents:
HN:
The boundaries of the Suboccipital Triangle:
1 - Rectus Capitis Posterior Major M. (medial border)
2 - Obliquus Capitis Inferior M. (inferior border)
3 - Obliquus Captits Superior M. (lateral border)
The contents of the Suboccipital Triangle:
- Vertebral A. traveling though the floor of the triangle
- Suboccipital N.
- > is the posterior ramus of the 1st Cervical Spinal N.
- > Innervates the musculature of the Suboccipital Region.
