Soft Tissue of the Back

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 • 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 • 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 • Dorsal ramus of suboccipital nerve

28. Sub-Occ. Triangle • Obliqus Capitis Superior • 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

47. Phrenic Nerve in Thorax

48. Cervical Plexus

49. Suprahyoids

50. Infrahyoids