1. SUPERFICAL AND DEEP BACK
Human Gross Anatomy
Module 3
V1_053116
Ernest F. Talarico, Jr., Ph.D.
Associate Professor of Anatomy & Cell Biology
Associate Faculty, Radiologic Sciences
Indiana University School of Medicine - Northwest - Gary
Muscle Asylum ProjectTM Superstar, Joel Stubbs

2. OBJECTIVES
Define and demonstrate the anatomical planes (median, sagittal, coronal, and transverse), and anatomical terms of relationship and movement (See Module 1).
Compare and contrast (grossly) the layers of skin, superficial fascia, and deep fascia of the back.
Compare and contrast the bony attachments, function(s), and nerve and blood supply of the superficial, [intermediate], and deep muscles of the back.
Identify all structures in this region.ET
Understand anatomical relationships in this region.ET
To be able to comprehend and discuss the structure of the nervous system.ET
To apply this knowledge to clinical situations and radiography.ET

3. OVERVIEW Back comprises the posterior trunk Back includes
Inferior to the neck
Superior to the buttocks
Head, neck and extremities attach to this region
Back includes
Integument and subcutaneous tissue (fascia)
Muscles
Superficial
positioning and movement of upper extremities)
Deeper
true back muscles
moving or maintaining the position of the axial skeleton (i.e., posture)
Vertebral Column (Spinal Column) [To be covered in a separate module.]
vertebrae and intervertebral (IV) discs
associated ligaments
Ribs in the thoracic region
posterior aspects (medial to angle of rib)
Spinal cord and meninges [To be covered in a separate module.]
Various segmental nerves

4. VERTEBRAL COLUMN

5. FASCIA Superficial fascia
Thoracolumbar fascia (lumbodorsal fascia; thoracolumbar aponeurosis)
is a deep investing membrane which covers the deep muscles of the back
made up of three layers, anterior, middle, and posterior.
anterior layer is the thinnest
posterior layer is the thickest
Two spaces are formed between these three layers of the fascia
Between the anterior and middle layer lies the quadratus lumborum muscle.
The erector spinae muscle is enclosed between the middle and posterior layers.
Above, it passes in front of the serratus posterior superior and is continuous with a similar investing layer on the back of the neck—the nuchal fascia.
In the thoracic region the lumbodorsal fascia is a thin fibrous lamina which serves to bind down the Extensor muscles of the vertebral column and to separate them from the muscles connecting the vertebral column to the upper extremity.
It contains both longitudinal and transverse fibers, and is attached, medially, to the spinous processes of the thoracic vertebræ; laterally to the angles of the ribs

6. MUSCLES OF THE BACK
Most body weight lies anterior to the vertebral column
Strong muscles attach to the spinous and transverse processes of the vertebrae
Two major groups of back muscles
Extrinsic Back Muscles
Intrinsic Back Muscles
Superficial muscles
Control of upper extremity movements
Intermediate muscles
Control of respiratory movements
Deep muscles
Include muscles that act specifically on the vertebral column (extend from pelvis to cranium)
Movements of the vertebral column
Maintaining posture

7. EXTRINSIC BACK MUSCLES
SUPERFICIAL
INTERMEDIATE
Trapezius m.
Serratus posterior superior m.
Latissimus dorsi m.
Serratus posterior inferior m.
Rhomboideus major m.
Rhomboideus minor m.
Levator scapulae m.
Anchor the upper extremity to the axial skeleton
Function in respiration
Rohen Atlas, 3rd Ed., Wolters Kluwer (2016)

8. EXTRINSIC BACK MUSCLES
SUPERFICIAL
Origin
Insertion
Innervation
Action
Trapezius m.
Middle third of superior nuchal line; external occipital protuberance; nuchal ligament; spinous processes of C7-T12 Vertebrae
Lateral 3rd of the clavicle; acromion and spine of the scapula
CN XI – Spinal Accessory (motor)
C3, C4 spinal nerves (pain; proprioception)
Descending part elevates; ascending part depresses; and middle part ( or all parts together) retract the scapula; descending and ascending parts act together to rotate the glenoid cavity superiorly.
Latissimus dorsi m.
Spinous processes of inferior T7-T12 vertebrae; thoracolumbar fascia; iliac crest and inferior 3 or 4 ribs
Floor of the intertubecular sulcus of the humerus
Thoracodorsal Nerve (C6, C7, C8)
Extends, adducts and medially rotates the humerus; raises the body toward the arms during climbing.
Rhomboideus major m.
Spinous processes of T2-T5 vertebrae
Medial border of the scapula from level of spin to inferior angle
Dorsal Scapular Nerve (C4, C5)
Retract the scapula and rotate its glenoid cavity inferiorly; fix scapula to thoracic wall
Rhomboideus minor m.
Nuchal ligament; spinous processes of C7 and T1 vertebrae
Smooth triangular area at medial end of scapular spine
Levator scapulae m.
Posterior tubercles of transverse processes of C1-C4 vertebrae
Medial border of the scapula superior to the root of the scapular spine
Dorsal Scapular Nerve (C4, C5) and cervical (C3, C4) nerves
Elevates the scapula and rotates its glenoid cavity inferiorly by rotating scapula

9. EXTRINSIC BACK MUSCLES
SUPERFICIAL
INTERMEDIATE
Trapezius m.
Serratus posterior superior m.
Latissimus dorsi m.
Serratus posterior inferior m.
Rhomboideus major m.
Rhomboideus minor m.
Levator scapulae m.
Anchor the upper extremity to the axial skeleton
Function in respiration
Rohen Atlas, 3rd Ed., Wolters Kluwer (2016)

11. EXTRINSIC BACK MUSCLES
INTERMEDIATE
Origin
Insertion
Innervation
Action
Serratus posterior superior m.
Nuchal ligament, spinous processes of C& to T3 vertebrae
Superior border of 2nd to 4th ribs
2nd to 5th intercostal nerves
Proprioception (elevates the ribs)
Serratus posterior inferior m.
Spinous processes of T11 to L2 vertebrae
Inferior borders of 8th to 12th ribs near their angles
Anterior rami to T9; to T12 thoracic spinal nerves
Proprioception (depress the ribs)

12. EXTRINSIC BACK MUSCLES
SUPERFICIAL
INTERMEDIATE
Trapezius m.
Serratus posterior superior m.
Latissimus dorsi m.
Serratus posterior inferior m.
Rhomboideus major m.
Rhomboideus minor m.
Levator scapulae m.
Anchor the upper extremity to the axial skeleton
Function in respiration
Human Anatomy Slide Atlas, 2nd Ed., Gower Medical Publishing (1991)

13. INTRINSIC BACK MUSCLES
SUPERFICIAL
INTERMEDIATE
DEEP
Splenius Muscles
Erector Spinae Group
Transversospinalis Group
Splenius capitis
Iliocostalis m.
Semispinalis m.
Splenius cervicis
Longissimus m.
Multifidus m.
Spinalis m.
Rotatores (brevis and longus) mm.
Minor Deep Layer
Interspinales m.
Intertransversarii m.
Levatores costarum m.
Extend from the pelvis to the cranium; are enclosed in deep fascia that attached medically to the nuchal ligament, the tips of the spinous processes of the vertebrae, the supraspinous ligament, and the median sacral crest.
The fascia attaches laterally to the cervical and lumbar transverse processes and the angles of the ribs.
The thoracic and lumbar parts of the deep fasica constitute the thoracolumbar fascia.

14. INTRINSIC BACK MUSCLES
SUPERFICIAL
Origin
Insertion
Innervation
Action
Splenius Muscles
Splenius capitis m.
Nuchal ligament and spinous processes of C7-T6 vertebrae
Mastoid process of temporal bone; lateral third of superior nuchal line of occipital bone
Posterior rami of spinal nerves
Acting Alone: laterally flex neck and rotate head to side of active muscles
Acting Together: extend head and neck.
Splenius cervicis m.
Tubercles of transverse processes of C1-C3 or C4 vertebrae

15. INTRINSIC BACK MUSCLES
INTERMEDIATE
Origin
Insertion
Innervation
Action
Erector Spinae Group
Iliocostalis m.
Arise from a broad tendon from posterior part of the iliac crease, posterior surface of sacrum, sacro-iliac ligaments, sacral and inferior lumbar spinous processes and supraspinous ligament
Lumborum, thoracis and cervicis: fibers run from superiorly to angles of lower ribs and cervical transverse processes.
Posterior rami of spinal nerves
Acting Bilaterally: extend vertebral column and head; as back is flexed, control movement via eccentric contraction
Acting Unilaterally: laterally flex vertebral column
Longissimus m.
Thoracis, cervicis, capitis: fibers run superiorly to ribs between tubercles and angels to transverse processes in thoracic and cervical regions, and to mastoid process of temporal bone
Spinalis m.
Thoracis, cervicis, capitis: fibers run superiorly to spinous processes in the upper thoracic region and to cranium
“I Like Standing.” (lateral to medial)

16. INTRINSIC BACK MUSCLES
INTERMEDIATE
Origin
Insertion
Innervation
Action
Erector Spinae Group
Iliocostalis m.
Arise from a broad tendon from posterior part of the iliac crease, posterior surface of sacrum, sacro-iliac ligaments, sacral and inferior lumbar spinous processes and supraspinous ligament
Lumborum, thoracis and cervicis: fibers run from superiorly to angles of lower ribs and cervical transverse processes.
Posterior rami of spinal nerves
Acting Bilaterally: extend vertebral column and head; as back is flexed, control movement via eccentric contraction
Acting Unilaterally: laterally flex vertebral column
Longissimus m.
Thoracis, cervicis, capitis: fibers run superiorly to ribs between tubercles and angels to transverse processes in thoracic and cervical regions, and to mastoid process of temporal bone
Spinalis m.
Thoracis, cervicis, capitis: fibers run superiorly to spinous processes in the upper thoracic region and to cranium

17. INTRINSIC BACK MUSCLES
DEEP
Origin
Insertion
Innervation
Action
Transversospinalis Group
Transverse Processes
Spinous processes of more superior vertebrae
Extension
Semispinalis m.
Arises from transverse processes of C4-T12 vertebrae
Thoracis, cervicis, capitis fibers run superomedially to occipital bone and spinous processes in thoracic and cervical regions; spanning 4-6 segments
Posterior rami of spinal nerves
Extends head and thoracic and cervical regions of vertebral column and rotates them medially
Multifidus m.
Arises from the posterior sacrum; posterior superior iliac spine of the ilium; aponeurosis of the erector spinae, sacro-iliac ligaments; mammillary processes of lumbar vertebrae; transverse processes of T1-T3; articular processes of C4-C7
Thickest in lumbar region: fibers pass obliquely superomedially to entire length of spinous processes, located 2-4 segments superior to proximal attachment
Stabilizes vertebrae during local movements of vertebral column
Rotatores (brevis and longus) mm.
Arise from transverse processes of vertebrae; best developed in thoracic region.
Fiber pass superomedially to attach to junction of lamina and transverse process or spinous process of vertebra immediately (brevis) or 2 segments (longus) superior to vertebra of attachment
Stabilize vertebrae and assist with local extension and rotatory movements of the vertebral column; may function as organs of proprioception
Minor Deep Layer
Interspinales m.
Superior surfaces of spinous processes of cervical and lumbar vertebrae
Inferior surfaces of spinous processes of vertebra superior to vertebra of proximal attachment
Posterior rami of spinal nerves
Aid in extension and rotation of vertebral column
Intertransversarii m.
Transverse processes of cervical and lumbar vertebrae
Transverse processes of adjacent vertebrae
Posterior and anterior rami of spinal nerves
Aid in lateral flexion of vertebral column; acting bilaterally, stabilize vertebral column
Levatores costarum m.
Tips of transverse processes of C7 and T1-T11 vertebrae
Pass inferolaterally and insert on rib between tubercle and angle
Posterior rami of C8-T11 spinal nerves
Elevate ribs, assisting respiration; assist with lateral flexion of vertebral column

19. BLOOD SUPPLY Muscle Artery Trapezius muscle transverse cervical artery
Latissimus dorsi muscle
thoracodorsal artery
rhomboid major and minor mm.
dorsal scapular artery
levator scapulae m.
serratus posterior (superior and inferior)
Intersegmental artery
illiocostalis m.
dorsal rami of segmental artery
spinalis m.
splenius m.

20. Surface Anatomy of Back Muscles

21. YOU Are the Physician! Can You Answer the Question?
During a fight between rival gangs, “Big Bob (aka, “The Chief”) receives a stab wound around the superior angle of the scapula near the medial border. Neurological work-up in the trauma unit documents injuries to both the dorsal scapular nerve and CN XI. Examination revealed paralysis and/or weakness of which of the following muscles?
Rhomboid major and trapezius
Latissimus dorsi and rhomboid minor
Trapzius and serratus posterior
Levator scapulae and erector spinae
Splenius cervicis and sternocleidomastoid
(A) Rhomboid major and trapezius

22. Rhomboid major and trapezius Latissimus dorsi and rhomboid minor
During a fight between rival gangs, “Big Bob (aka, “The Chief”) receives a stab wound around the superior angle of the scapula near the medial border. Neurological work-up in the trauma unit documents injuries to both the dorsal scapular nerve and CN XI. Examination revealed paralysis and/or weakness of which of the following muscles?
Rhomboid major and trapezius
Latissimus dorsi and rhomboid minor
Trapzius and serratus posterior
Levator scapulae and erector spinae
Splenius cervicis and sternocleidomastoid
Explanation:
The serratus posterior muscle is innervated by ventral primary rami of the spinal nerves, whereas the splenius cervicis muscle and the erector spinae muscle group are innervated by dorsal primary rami of spinal nerves. The dorsal scapular nerve innervates the levator scapulae and rhomboid muscles. CN XI – Accessory (Spinal Accessory) nerve supplies the trapezius and sternocleidomastoid muscles.
(A) Rhomboid major and trapezius

23. SUBOCCIPITAL REGION
Is a muscle compartment deep to the superior part of the posterior cervical region
Underlies
Trapezius, sternocleidomastoid, splenius and semispinalis mm.
Pyramidal space inferior to the external occipital prominence
Includes the posterior aspects of cervical vertebrae C1 and C2
Often misrepresented as a surface region

24. Four Muscles Suboccipital Nerve
Lie deep (anterior) to the semispinalis capitus muscles
Rectus capitis posterior minor m.
Rectus capitis posterior major m.
Superior oblique m.
Inferior oblique m. (no attachments to the cranium)
Suboccipital Nerve
Posterior ramus of C1
Supplies all 4 muscles
Emerges between the occipital bone and atlas ; near the vertebral artery, but within the occipital triangle.

25. Reflect trapezius; splenius and semispinalis
Identify
Rectus capitis minor m. (16)
Rectus capitis major m. (18)
Superior oblique m. (17)
Inferior oblique m. (19)
Greater occipital n. (C2; 6)
Suboccipital n. (C1; 5)
Occipital artery (2)
Vertebral artery

26. Nerves and Vessels of the Posterior Cervical Region

28. CLINICAL CORRELATIONS
Primarily sprains, strains and spasms
SPRAIN
STRAIN
SPASM
A stretching or tearing of ligaments (ankle is most common location)
a stretching or tearing of muscle or tendon (common sports injury)
a sudden involuntary muscular contraction or convulsive movement (can be a protective mechanism following a strain)
Only ligamentous tissues
Tendon or muscle (or tendon)
Muscles
No fracture or dislocation
Results from excessively strong contractions relate to movement of the vertebral column (i.e., excessive extension or rotation)
Results from overly strong muscular contraction (usually those muscles of the lumbar IV joints – erector spinae mm.)
Results from injury or inflammation

29. Reduced blood supply to brainstem
Vertebral arteries are major arteries of the neck.
branch from the subclavian arteries
course through transverse vertebral foramina
pass through the suboccipital triangles
enter the base of the skull through the foramen magnum
merge to form the single midline basilar artery in a complex called the vertebrobasilar system, which supplies blood to the posterior part of the circle of Willis and thus significant portions of the brain.

30. mechanism Arteriosclerosis
Prolonged turning of the head (i.e., when backing up a vehicle) may cause light-headedness, dizziness and other symptoms

31. TRIANLE of Auscultation
The triangle of auscultation of the lungs is a relative thinning of the musculature of the back, situated along the medial border of the scapula.
Boundaries
Trapezius m.
Latissimus dorsi m.
Scapula
Physical Examination
Due to the relative thinning of the musculature of the back in the triangle, the posterior thoracic wall is closer to the skin surface, making respiratory sounds able to be heard more clearly with a stethoscope.
To better expose the floor of the triangle up of the posterior thoracic wall in the 6th and 7th intercostal space, a patient is asked to fold their arms across their chest, laterally rotating the scapulae, while bending forward at the trunk.

34. MEDICAL IMAGING
In Duchenne muscular dystrophy (DMD), the muscular degeneration often leads to the development of scoliosis.
T-1 AX MR images obtained at L2 level for the pre-scoliotic (PS) patient P6 (left column) and for the scoliotic (S) patient P7 (right column). A: original images; B: manually obtained contours of the erector spinae (ES); C: manually obtained contours of the spinalis (SP), longissimus (LO), and iliocostalis (IL)
Zoabli. G. , et al. (2008), Scoliosis 3(21):1-11

35. What is the radiographic modality used?
What is the plane of slice?
Can you identify the following muscles?
Trapizeus m. (T)
Spinalis m. (S)
Levator scapulae m. (LS)

36. COR MRI T-2 Weighted
What is the radiographic modality used?
MRI T-2 Weighted (CSF is light)
What is the plane of slice?
Coronal (Frontal) = COR
Can you identify the following muscles?
Trapizeus m. (T)
Spinalis m. (S)
Levator scapulae m. (LS)
CSF LS T S

37. LABORTORY OBJECTIVES
Distinguish epidermis, dermis, superficial fascia, deep fascia, cutaneous nerves and superficial blood vessels grossly.
Identify the muscles associated with the superficial, [intermediate], and deep layers of the back, their attachments, and nerve and blood supplies.
Demonstrate professionalism by working cooperatively in a small group setting.
Identify the muscles, nerves and vessels associated with the suboccipital region.ET