2. Muscles of back
• Introduction
• Cutaneous nerve supply
• Development of muscles
• Muscles of back
Introduction
Classification
• Nerve supply of muscles of back
• Action of muscles of back

3. Cutaneous Nerves
• Dorsal primary rami of
spinal nerves.
• Each dorsal primary ramus
divides into medial and
lateral branches.

4. Muscles of back
 Development:
• Epaxial muscles: Extensors
of the neck and vertebral
column
• Hypaxial muscles: Thoracic
myotome form lateral and
ventral flexor muscles of
the vertabral
column,lumbar myotome
form quadratus lumborum.

5. Arrangement of Back Muscles
• Three groups:
Superficial:
Extrinsic.
Intermediate:
Extrinsic.
Deep:
Intrinsic.

6. Ligamentum nuchae
•Consist of dorsal
raphae and medial
fascial septum
•Attachment
•extension

7. Thoracolumbar Fascia
• Deep fascia on the back of
trunk.
• It binds long exetonsors of
vertabral column to
posterolateral surfaces of
vertabral bodies.
• Two parts :Lumbar
Thoracic

8. Thoracolumbar Fascia Laminae
• Posterior lamina to lumbar
spinous processes.
• Middle lamina to lumbar
transverse processes.
• Anterior lamina (deepest) to
lumbar transverse processes.

9. Superficial Extrinsic Muscles
• Connect limb to axial skeleton.
• Innervated by ventral rami or CN XI.
• Include:
Trapezius.
Latissimus dorsi.
Levator scapulae.
Rhomboideus major.
Rhomboideus minor.

10. Trapezius:
• Diamond shaped
• Origin:
• Insertion:
• Innervation:
• Action:

11. Lattissimus dorsi:
• Origin:
• Insertion:
• Innervation:
• Action:

12. Levator scapulae:
• Origin :
• Insertion:
• Innervation :
• Action:

13. Rhomboid major:
• Origin:
• Insertion:
Rhomboid minor:
• Origin:
• Insertion:
• Innervation:
• Action:

14. Intermediate Extrinsic Muscles
• Serratus posterior group:
Serratus posterior superior.
Serratus posterior inferior
• Innervated by ventral rami of
spinal nerves.

15. Intrinsic Back Muscles
• True intrinsic muscles of the back are innervated by dorsal
(posterior) rami.
• Three groups:
Superficial
Intermediate
Deep.

16. INTRINSIC (DEEP) BACK MUSCLES
• Superficial :Splenius ,
Erector spinae
• Deeper layer :
Spinotransverse
group,
Suboccipitals
• Deepest layer:
Interspinous,
Intertranseverse
.

17. Superficial muscles
• Consists of the Splenius group:
• Long muscles.
• Originate from ligamentum nuchae and spinous processes.
• Cover neck and upper part of thorax.
• Two parts: Splenius capitis
Splenius cervicis

18. Splenius capitis:
• Attachments:
• Relations:
• Innervation:
• Action:
Splenius cervicis:
• Attachments:
• Relations:
• Innervation:
• Action:

19. Superficial Intrinsic
Erector spinae: Three muscles
each with three regional
parts.
1.Spinalis:Spinalis thoracis
Spinalis cervicis
Spinalis capitis
2.Longissimus:Longi capitis
Longi cervicis
Longi thoracis
3.Iliocostalis:Iliocost cervicis
Iliocost thoracis
Iliocost capitis

20. Spinalis:
Components:
 Thoracis:
Attachments:
 Cervicis:
Attachments:
poorely developed
 Capitis:
Attachments:

21. Intermediate Intrinsic
• Longissimus:Central
component of erector
spinae
 Longissimus capitis:
Attachments
 Longissimus cervicis:
Attachments:
 Longissimus
thoracis:Largest component
Has lumbar and
thoracic part.
Attachments:
.

22. • Iliocostalis:most lateral
component of erector
spinae
Components:
 Iliocostalis cervicis:
Attachments
 Iliocostalis thoracis:
Attachment
 Iliocostalis lumborum:
Attachments
Has lumbar and
thoracic part

23. Erector spinae aponeurosis:
• Formation:
• Attachments:
• Relations:
• Innervation:
• Action:

24. Deep Intrinsic Muscles
• Spinotransverse group:
Present between
spinous process and
transverse elements of
vertebrae.
Components:
 Rotators: Rotators thoracis
Rotators cervicis
Rotators capitis
 Multifidus
 Semispinalis: Semi cervicis
Semi thoracis
Semi capitis
 Suboccipital muscle

25. Rotatores
• Deepest and shortest muscle
• 11 pairs of small
quadrilateral muscle
• Attachments:
• Components:
 Rotator brevis:
Attachments
 Rotator longus:
Attachments

26. Multifidus
• Thick muscle mass.
• Present at
cervical,thoracic,upper
lumbar levels lies lateral
to spinous process and
also expands to cover
posterior surface of
sacrum.
• Multifidus arises from
lateral surface and tip of
trnsverse process and
insert into transverse
elements of vertebrae.

27. Semispinalis
• Longest fibres of
spinotransverse group
• Components:
 Cervicis:
Attachments
 Thoracis:
Attachments
 Capitis:
Attachments
• Relations:
• Innervation:
• Action:

28. Suboccipital muscle:
• 4 small muscles that connect
occipital bone,atlas and axis.
• Suboccipital triangle
• Components:
 Rectus capitis posterior major:
Attachments
 Rectus capitis posterior minor:
Attachments
 Obliquus capitis inferior:
 Obliquus capitis superior:
• Innervation:
• Actions:

29. Intrinsic Segmental Muscles
• Interspinales:
Attachments.
• Intertransversarii
Attachments.

30. Applied:

31. • Low bachache:
Lumbar strain
Lumbar radiculopathy
• Lumbar triangle:
– Superior(Grynfeltt)
– Inferior(Petit)
• Renal angle