1. Cover slide

2. Spinal Muscles Professor Emeritus Moira O’Brien
MOB TCD
Spinal Muscles
Professor Emeritus Moira O’Brien
FRCPI, FFSEM, FFSEM (UK), FTCD
Trinity College
Dublin

3. Thoracolumbar Fascia
MOB TCD
Three layers of fascia enclosing the muscles of the posterior abdominal wall
Laterally fascia is fused and is continuous with internal oblique and transversus abdominis

4. Thoracolumbar Fascia Posterior layer
MOB TCD
Covers the erector spinae is very strong three layers
It is reinforced by the aponeurosis of latissimus dorsi
Medially it is attached to lumbar and sacral spinous processes
Superiorly it extends over the back muscles to be continuous with the deep fascia of the neck

5. Thoracolumbar Fascia Partial origin to internal oblique
MOB TCD
Partial origin to internal oblique
Transversus abdominus
Latissimus dorsi
Tensile strength of 2000 psi
Most important non-contractile structure

6. Thoraco-Lumbar Fascia
MOB TCD
Anterior layer
Covering quadratus lumborum muscle, separating it from the psoas major
Attaches in front of lumbar transverse processes and from iliac crest to12th rib

7. Thoraco-Lumbar Fascia
MOB TCD
Middle layer
Between erector spinae and quadratus lumborum
Attached to tips of transverse processes of lumbar vertebrae
Extending in a vertical plane between the iliac crest and the 12th rib
Posterior layer attached to spinous process covers sacrospinalis

8. Superficial Muscles Superficial layer Trapezius Latissimus dorsi
MOB TCD
Superficial layer
Trapezius
Latissimus dorsi
Levator scapulae
Rhomboid minor and major
Connect upper limb to trunk

9. Trapezius
MOB TCD
The trapezius is a large, flat, triangular muscle, covering the posterior aspect of the neck and superior half of the trunk.
It attaches the pectoral girdle to the skull and the vertebral column.
It also helps in suspending the shoulder girdle and rotates the scapula.
The trapezius is supplied by the spinal part of the accessory, the eleventh cranial nerve.

10. Trapezius Origin Medial third superior nuchal line
MOB TCD
Origin
Medial third superior nuchal line
Ligamentum nuchae and spines and inter spinous ligaments of all thoracic vertebrae
Insertion
Upper third to lateral third of posterior border of clavicle
Middle third to medial border of acromion and the superior lip of the crest of the spine of the scapula

11. Trapezius
MOB TCD
Lower third fibres insert into the medial end of spine of scapula
Nerve supply: spinal accessory nerve (C1 - 5)
Proprioceptive fibres from the C3 - 4 cervical plexus.
Actions: upper fibres elevate and extension of the neck
Middle fibres retract scapula
Upper and lower fibres rotation of scapula

12. Trapezius The upper fibres elevate the scapula, shrug shoulders.
MOB TCD
The upper fibres elevate the scapula, shrug shoulders.
The intermediate fibres draw the medial border of the scapula near to the midline and press against the chest wall.
The lower fibres pull the scapula downward and depress the tip of the shoulder.
The three parts of the trapezius, acting together, draw the scapula medially and rotate the glenoid fossa superiorly in abduction of the shoulder.

13. Trapezius The trapezius muscle is involved in throwing events
MOB TCD
The trapezius muscle is involved in throwing events
In racquet sports and in overhead movements
Middle fibres help to stabilise the scapula in rowing and swimming
It prevents the glenoid fossa being pulled down when lifting heavy objects with your arms
It also helps when you are holding an object overhead

14. Latissimus Dorsi
MOB TCD
The latissimus dorsi is a large, wide fan-shaped muscle covering the inferior part of the back
It arises from the spines of the lower six thoracic vertebrae
The lumbar fascia
The posterior third of the outer lip of the iliac crest
The lower three ribs and the inferior angle of the scapula

15. Latissimus Dorsi It spirals around the teres major
MOB TCD
It spirals around the teres major
Forms medial part of the posterior fold of the axilla
It is inserted by a flat white bilaminated tendon into the floor of the bicipital groove
Nerve supply: thoracodorsal nerve C6,7,8

16. Latissimus Dorsi Extends the shoulder
MOB TCD
Extends the shoulder
Powerful adductor of the arm (climbing muscle)
Rotates the humerus medially at the shoulder joint
The latissimus dorsi is an accessory muscle of respiration if humerus is fixed
It is supplied by the thoracodorsal nerve C6,7,8
It is involved in activities such as paddling a canoe, climbing and swimming

17. Latissimus Dorsi
MOB TCD
In freestyle swimming, the latissimus dorsi is a prime mover in the down stroke of the arm, mainly an extension movement and some medial rotation
In canoeing, the muscle is a prime mover in the down stroke of the paddle, a movement of extension, adduction and medial rotation

18. Superficial Muscles Deep to trapezius Levator scapulae
MOB TCD
Deep to trapezius
Levator scapulae
Rhomboid minor and major
They connect upper limb to trunk

19. Levator Scapulae The levator scapulae muscle lies under the trapezius
MOB TCD
The levator scapulae muscle lies under the trapezius
It has its origin from the transverse processes of the upper four cervical vertebrae (C1 to C4)
Inserted into the superior part of the medial border of the scapula

20. Levator Scapulae
MOB TCD
The action of the levator scapulae is to raise the medial margin of the scapula and in doing so rotate it so as to produce downward rotation of the glenoid cavity
The nerve supply is C5 via the nerve to the rhomboids from the roots of the brachial plexus

21. Rhomboid Major and Minor
MOB TCD
The rhomboid major and minor muscles lie deep to the trapezius and are not always distinct from each other
Rhomboid minor arises from C7 and T1 vertebrae
The major is about twice as wide as the minor
Arises from T2-5
Appearing as parallel bands, they both pass inferiolaterally from the vertebrae .

22. Rhomboid Major and Minor
MOB TCD
The rhomboid major and minor muscles work together
Retract the scapula and rotate it to depress the glenoid cavity
Help the serratus anterior muscle to hold the scapula against the thoracic wall
Fix the scapula during movements of the upper limb
The nerve supply is C5 via the nerve to the rhomboids from the roots of the brachial plexus

23. Intermediate Serratus posterior is an accessory muscle of respiration
MOB TCD
Serratus posterior is an accessory muscle of respiration

24. Superficial Layer: Splenius Capitis and Cervicis
MOB TCD
Inferior half of ligamentum nuchae and all the spinous processes of T1-T6
Insertion: lateral aspect of mastoid process
Lateral third of superior nuchal line of occipital bone deep to sternocleidomastoid
Splenius cervicis
Posterior tubercles of transverse processes C1-C4 posterior to levator scapulae

25. Splenius Capitis and Cervicis
MOB TCD
Acting alone
Lateral flexion
Rotation of head and neck to same side
Acting together
Extension of neck and head
Nerve supply: dorsal rami inferior cervical nerves.

26. Intrinsic Muscles of Back
MOB TCD
Deep layer of postural muscles attached to vertebral column and the back of head
Anatomically in three layers: superficial, intermediate and deep
Deep layer of muscles is responsible for movement of vertebral column
Represents the intrinsic group of back muscles

27. Intermediate Layer: Erector Spinae
MOB TCD
Lies between anterior and posterior layers of thoraco-lumbar fascia
Three vertical columns:
medial = spinalis
intermediate = longissimus
lateral = iliocostalis
Origin: a common broad band from posterior aspect of iliac crest
Sacrum
Sacroiliac ligaments
Sacral and inferior lumbar spines

28. Erector Spinae: Iliocostalis and Longissimus
MOB TCD
Iliocostalis
Forms lateral column of erector spinae
Inserts into angles of the ribs
Longissimus
Forms the intermediate column of erector spinae
Attached to transverse processes of thoracic and cervical vertebrae
Mastoid process of temporal bone (muscle has a herring bone appearance)

29. Erector Spinae: Spinalis
MOB TCD
Narrow medial column of erector spinae (relatively insignificant)
Extending to spinous processes of superior lumbar and inferior thoracic region

30. Deep Layer: Transversospinal
MOB TCD
In the groove between transverse processes and spines of vertebrae
Collectively termed the transversospinal muscles
Consists of several short muscles
Semispinalis
Acting bilaterally: extend and stabilise spine
Acting unilaterally: rotate spine to opposite side and laterally flex

31. Semispinalis Three part muscle Thoracis Cervicis Capitis
MOB TCD
Three part muscle
Thoracis
Cervicis
Capitis
Acting bilaterally it will extend head, neck and thoracic spine
Acting unilaterally it rotates head and neck to the opposite side

32. Rotatores Short muscle
MOB TCD
Short muscle
Attached from transverse processes of one vertebra
To the base of the spinous process of the vertebra superiorly
Action: rotates the spine to opposite side
Mainly in thoracic region

33. Multifidus
MOB TCD

34. “BMJ Publishing Group Limited (“BMJ Group”) 2012. All rights reserved
Copyright slide