1. Soft Tissue of the Back

2. Innervation
As a general rule, muscles associated with the back are innervated by the dorsal rami of the spinal nerves
They are innervated segmentally and near their origin
Only a couple of exceptions

3. Innervation

4. Innervation

5. The Exceptions Serratus Posterior Superior Serratus Posterior Inferior
Lig. Nuchae and spinous processes of C7-T3 to 2nd to 5th ribs
Serratus Posterior Inferior
Spinous Proceses of T11-L2 to inferior borders of last 4 ribs
Elevate or depress ribs (accessory respiratory muscles)
Innervated by ventral rami

6. Serratus Post.

7. Major Groups of Back Muscles
Those that arise from the mid-line and run superiorly and laterally – The Splenius Muscles (Bandage)
Those that arise from near the mid-line or slightly laterally and run almost longitudinally with no marked inward or outward slant – called the Erector Spinae

8. Major Groups
The third group are those that arise laterally and run towards the mid-line as they travel up
Called the Transversospinalis group
Last – small muscles that run from one spinous process to another or one transverse process to another (interspinales and intertransvesus)

9. Splenius Muscles Splenius Capitis Splenius Cervicis
Lig. Nuchae and Spinous Process of C7-T4 to sup. Nuchal line and mastoid process
Splenius Cervicis
Spinous processes of T3-T6 to Transvers process of C2-C4
Both extend head and neck and can laterally flex (side bend) the head; Also support and can contribute to rotation of cervical spine and, thus, the head
Dorsal rami of spinal nerves nearest their respective origins

10. Splenius

11. Erector Spinae Long Muscles with multiple, overlapping, origins
Three sub groups; iliocostalis, longissimus, spinalis
Common “origin” of the entire group is a muscle mass located on the posterior sacrum, iliac crest, and spinous process of lumbar vertebrae
Beyond that, specific muscles have various attachments

12. Erector Spinae

13. E. Spinae

14. E. Spinae
The three groups are broken down into sub -subgroups based upon where they are located
E.G., in the lumbar region called lumborum, in thoracic region called thoracis, in cervical region called cervicis and, if they reach anywhere on the skull, they are called capitis.
E.G., Iliocostalis lumborum

15. E. Spinae Overlap or multiple attachments
Despite the common “origin” of the group, most muscles have various and multiple origins and insertions
These tend to overlap so that the group can traverse a large length of the back
Some components will attach as an insertion while new fibers will originate from the same region

16. E. Spinae
For example, the iliocostalis lumborum muscles will attach to the lower six ribs while the iliocostalis thoracis will originate from the lower six ribs and insert on the upper six ribs
Likewise the iliocostalis cervicis will originate from the upper six ribs and insert on the transverse process of C4 thru C6
All are innervated by the dorsal rami of the nerves nearest their origin – e.g., iliocostalis thoracis will be innervated by the lower thoracic nerves (T6-T12)

17. Longissimus
Generally, run from the transverse processes of one level of v. column up several levels to attach to another transverse process
The longissimus capitis originates on t. processes of T1-T4 and attach to the skull at the mastoid process, hence the name capitis
Is the only E.Spinae to attach to skull

18. Spinalis E. Spinae nearest the mid-line, hence, the name spinalis
The spinalis group run from spines of one group of vetebrae to spines of v. several segments up
Most prominent in thoracic spine but also located in cervical and lumbar spine

19. General, Collective, Function of E. Spinae
To support spine (anti-gravity)
To extend spine
To laterally flex spine (side bend)
To rotate the spine
They work together

20. Transversospinalis Group
Arise laterally and run, more or less, to the mid-line
Semispinalis Capitis
Transverse Process C7-T6 to Occipital bone, near mid-line, Extend head, rotate to same side
Semispinalis Cervicis
Transverse process T1-T6 to Spines of C2-C6, Extend head (Cervical Spine) and side bend

21. Semispinalis

22. Semispinalis

23. Transversospinalis Group
Multifidi
From the sacrum, and transverse process of L., T. and lower C vertebrae to Spinous Process of Lumbar, thoracic and cervical vetebrae 2 or 3 levels up
Very large and obvious in lumbar region
Support V. column. May contribute to minor motions (lat. flex., rot., ext.)

24. Rotatores
Transverse processes of 2nd cervical to sacrum to lamina on vertebrae above origin (one segment)
Same function as multifidi

25. Interspinous and Intertransversus
Run between spinous processes or transverse processes
Blend with ligaments of same name
Perform same function (Stability)

26. Small Muscles

27. Muscles mostly associated with the head
Sub-Occipital (Posterior) Triangle very small, support head on v. column, minor motions
Rectus Capitis Post. Major
Spinous process of C2 to Lateral aspect of nuchal line
Dorsal ramus of suboccipital nerve
Rectus capitis Post. Minor
Post. Arch of atlas (C1) to med. aspect of inferior nuchal line

28. Sub-Occ. Triangle Obliqus Capitis Superior Obliqus Capitis Inferior
Transverse process Atlas to a point between sup. and inf. Nuchal line
Obliqus Capitis Inferior
Spinous Process Axis to transverse process atlas

29. Suboccipital Triangle

30. Anterior Muscles – all innervated by Ventral Rami
Sterno-Cleido-Mastoid
Manubrium (S) and Medial ½ clavicle to mastoid process
Together – head flexion, unilaterally, side bending (same side) rotation (opposite side)
CN XI and ventral rami of C2, C3

31. SCM

32. SCM - Anterior

33. Scaleni-AKA Pre-Vertebral
Scalaneus Anterior
Ant tubercle of transverse process of C2-C6
Scalene tubercle of anterior surface of 1st rib
Flex and rotate spine
Reverse action = accessory respiratory muscle by raising 1st rib.
ventral rami C2-C6

34. Pre-Vertebrals

35. Scaleni
Scaleneus Medius from post. tubercle of transverse processes C2-C7 to sup. surface of 1st rib behind subclavian groove
Scaleneus Posterior from post. tubercles of transverse processes C4-C6 to lateral superior surface of 2nd rib
Flex, rotate elevate rib

36. Pre-Vertebral

37. Longus Coli Bodies of C5-T3 to bodies of C2-C4
Bilaterally flexes cervical v., unilaterally rotates rotate and side bend
C2-C8 innervation

38. Longus Capitis Ant. Tubercles of transverse processes of C3-C6
To inferior surface of basilar portion of occipital bone
Flex, c. v. and head rotate and flex c. v.

39. Anterior Small Muscles
Rectus Capitis Anterior
Ant. Surface of lateral mass of the atlas to inf. Surface of occipital bone anterior to foramen magnum
C1 – C2
Rectus Capitis Lateralis
Sup surface of transverse process of atlas to inferior surface of jugular process, occipital bone
C1-C2
Both support skull

40. Anterior Sub Occipital Muscles

41. Cervical Plexus
A small plexus originating from the ventral rami of C1-C4 with some contribution from C5
Mostly cutaneous type nerves
One notable somatic motor nerve = the Phrenic nerve to the diaphragm muscle
The other motor nerves work with cranial nerves to innervate hyoid type muscles

42. Cervical Plexus

43. Cervical Plexus

44. Cervical Plexus

45. Cervical Plexus

46. Phrenic Nerve in Thorax

47. Phrenic Nerve

48. Cervical Plexus

49. Suprahyoids

50. Infrahyoids

51. Comparison