The document discusses the muscles of the back, describing their arrangement in three groups - superficial, intermediate, and deep intrinsic muscles. The deep intrinsic muscles comprise several subgroups including the spinotransverse group, rotatores, multifidus, semispinalis, and suboccipital muscles. Each muscle is described in terms of its origin, insertion, innervation, and action. Clinical correlations are also made regarding low back pain and the lumbar triangle.

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