Back: Nerves 229

1 Greater occipital nerve (C2)

2 Suboccipital nerve (C1)

3 Medial branches of dorsal rami of spinal nerves

4 Lateral branches of dorsal rami of spinal nerves

5 Superior cluneal nerves (L1–L3)

6 Middle cluneal nerves (S1–S3)

7 Inferior cluneal nerves (derived from branches

of the sacral plexus, ventral rami)

8 Lesser occipital nerve

9 Great auricular nerve

10 Trapezius muscle

11 Deltoid muscle

12 Latissimus dorsi muscle

13 Gluteus maximus muscle

14 External intercostal muscle

15 Internal intercostal muscle

16 Innermost intercostal muscle

17 Dorsal ramus of spinal nerve

18 Spinal nerve and spinal ganglion

19 Sympathetic trunk with ganglion

20 Intercostal nerve

21 Lateral cutaneous branch of intercostal nerve 22 Anterior cutaneous branch

23 Longissimus thoracis muscle

24 Spinal cord

25 Aorta

26 Esophagus

27 Body of rib

28 Thoracic rib

29 Thoracic duct

30 Azygos vein

General characteristics of the innervation of the back.

Distribution of dorsal branches of spinal nerves. Note the

segmental arrangement of the innervation of the dorsal part

of the trunk (schematic drawing).

Position and branches of spinal nerves in one segment of

thoracic wall (schematic drawing).

Posterior part of the thoracic wall (MRI scan, coronal section;

from Heuck et al., MRT-Atlas, 2009).

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Vertebral Canal and Spinal Cord

Lumbar portion of spinal cord. Note the relation between the

nervous and muscular segments.

Terminal part of spinal cord. Dura removed.

Innervation of the back. Spinal cord in the vertebral

canal (opened). Longissimus dorsi and iliocostal muscles

have been removed.

1 Cerebellomedullary

cistern

2 Medulla oblongata

3 Third cervical nerve (C3)

4 Greater occipital nerve (C2)

5 Dorsal primary ramus

6 Dorsal roots

7 Spinal ganglion

8 Spinal dura mater

9 Spinal arachnoid mater

10 Filum terminale

11 Conus medullaris

12 Cauda equina

13 Lateral branches of dorsal

rami of spinal nerves

14 Ventral ramus of spinal

nerve (intercostal nerve)

15 Iliocostalis muscle

Vertebral Canal and Spinal Cord 231

1 Arch of vertebra (divided)

2 Spinal nerve with meningeal coverings

3 Dorsal roots of thoracic spinal nerves

4 Spinal cord (thoracic portion)

5 Spinal ganglia with meningeal coverings

6 Pia mater with blood vessels

7 Dura mater (opened)

8 Denticulate ligament

9 Lateral branch of dorsal ramus

10 Dorsal ramus of spinal nerve

(dividing into a medial and lateral branch)

11 Medial branch of dorsal ramus

of spinal nerve

12 Spinal dura mater

13 Spinal nerves of sacral segments

14 Filum terminale

Thoracic portion of spinal cord (dorsal aspect). Vertebral canal and dura mater

opened.

Terminal part of spinal cord with dura

mater (dorsal aspect). Dorsal part of sacrum

removed.

232 Vertebral Canal and Spinal Cord

Horizontal section of the neck. Dissection of the second

cervical spinal nerve. Posterior surface at top of figure.

Meningeal coverings of the spinal cord (anterior aspect).

(Schematic drawing.)

Sagittal section through the vertebral canal, T9–L2.

(MRI scan.)

Sagittal section through the vertebral canal,

T12–L2. Notice red bone marrow (unfixed).

1 Trapezius muscle

2 Semispinalis capitis muscle

3 Dorsal ramus of spinal

nerve

4 Sternocleidomastoid muscle

5 Platysma muscle

6 Dorsal and ventral roots

of spinal nerves

7 Spinal ganglion

8 Posterior belly of digastric

muscle

9 Ventral ramus of spinal

nerve

10 Vertebral artery

11 Great auricular nerve

12 Superficial temporal artery

13 Styloid process

14 Internal jugular vein and

internal carotid artery

15 Rectus capitis posterior

major muscle

16 Dura mater and

subarachnoid space

17 Denticulate ligament

18 Vertebral artery

19 Parotid gland

20 Dens of axis (divided) and

inferior articular facet of

atlas

21 Longus capitis muscle

22 Pharyngeal cavity

23 Medial pterygoid muscle

24 Periosteum of vertebral

canal

25 Posterior spinal arteries

26 Anterior spinal artery

Meningeal coverings

27 Dura mater

28 Subdural space

29 Extradural or epidural

space with venous plexus

and fatty tissue

30 Arachnoid (green)

31 Subarachnoid space

32 Pia mater (pink)

33 Nucleus pulposus

34 Crus of diaphragm

35 Intervertebral disc

36 Body of first lumbar

vertebra

37 Spinal cord

38 Conus medullaris

39 Cauda equina

40 Filum terminale

41 Spinous process

Vertebral Canal and Spinal Cord 233

Median section of the head and trunk in the neonate.

Note that in the neonate the conus medullaris of the spinal cord

extends far more caudally than in the adult.

1 Cerebrum

2 Corpus callosum

3 Pons

4 Larynx

5 Trachea

6 Left atrium

7 Right ventricle

8 Esophagus

9 Liver

10 Stomach

11 Pancreas

12 Transverse colon

13 Umbilicus

14 Small intestine

15 Uterus

16 Urinary bladder

17 Pubic symphysis

18 Cerebellum

19 Medulla oblongata

20 Spinal cord

21 Conus medullaris

22 Cauda equina

23 Rectum

24 Vagina

25 Anus

26 Inferior vena cava

27 Aorta

28 Umbilical cord

29 Thymus

Median section of the head and trunk in

the adult (female). The conus medullaris of the

spinal cord is located at the level of L1.

Nuchal Region

Dorsal aspect of the neck (superficial layer). Nuchal region and shoulder.

1 Sternocleidomastoid muscle

2 Lesser occipital nerve

3 Descending fibers of trapezius muscle

4 Spine of scapula

5 Medial cutaneous branches of dorsal rami of spinal nerves

6 Medial margin of scapula

7 Rhomboid major muscle

8 Latissimus dorsi muscle

9 Galea aponeurotica

10 Occipital belly of occipitofrontalis muscle

11 Greater occipital nerve

12 Third occipital nerve

13 Splenius capitis muscle

14 Great auricular nerve

15 Cutaneous nerves of cervical plexus

16 Transverse fibers of trapezius muscle

17 Ascending fibers of trapezius muscle

18 Teres major muscle

234

Nuchal Region 235

Dorsal aspect of the neck (deeper layer). The left trapezius muscle has been divided and reflected. On the right, trapezius, rhomboid,

and splenius muscles have been divided. Right levator scapulae muscle has been slightly reflected.

1 Galea aponeurotica

2 Occipital belly of occipitofrontalis muscle

3 Occipital artery

4 Greater occipital nerve (C2)

5 Semispinalis capitis muscle

6 Sternocleidomastoid muscle

7 Lesser occipital nerve

8 Left splenius capitis muscle

9 Third occipital nerve (C3)

10 Spinous process of vertebra

prominens (C7)

11 Left trapezius muscle and accessory nerve

12 Levator scapulae muscle

13 Superficial branch of transverse cervical

artery

14 Rhomboid minor muscle

15 Rhomboid major muscle

16 Medial margin of scapula

17 Medial branches of dorsal rami of spinal

nerves

18 Ligamentum nuchae

19 Splenius capitis muscle (divided)

20 Splenius cervicis muscle

21 Right accessory nerve and superficial

branch of transverse cervical artery

22 Right levator scapulae muscle

23 Dorsal scapular nerve and deep branch

of transverse cervical artery

24 Serratus posterior superior muscle

25 Right trapezius muscle (divided and

reflected)

26 Right rhomboid major muscle

(divided and reflected)

236 Nuchal Region

Dorsal aspect of the neck (deepest layer). Trapezius, splenius capitis, and cervicis muscles have been divided and partly

removed or reflected.

1 Skin of scalp

2 Galea aponeurotica

3 Occipital belly of occipitofrontalis

muscle

4 Occipital artery

5 Greater occipital nerve

6 Third occipital nerve

7 Semispinalis capitis muscle

8 Levator scapulae muscle

9 Accessory nerve (n. XI)

10 Superficial cervical artery

11 Trapezius muscle (reflected)

12 Longissimus cervicis muscle

13 Medial cutaneous branches of

dorsal rami of spinal nerves

14 Medial margin of scapula

15 Splenius capitis muscle (divided)

16 Sternocleidomastoid muscle

17 Lesser occipital nerve

18 Great auricular nerve

19 Splenius cervicis muscle

20 Longissimus cervicis muscle

21 Spinous process of seventh cervical

vertebra (vertebra prominens)

22 Rhomboid muscles (divided)

23 Iliocostalis thoracis muscle

24 Longissimus thoracis muscle

Nuchal Region 237

1 Semispinalis capitis muscle

(divided)

2 External occipital

protuberance

3 Obliquus capitis superior

muscle

4 Rectus capitis posterior

minor muscle

5 Rectus capitis posterior

major muscle

6 Vertebral artery

7 Obliquus capitis inferior

muscle

8 Spinous process of axis

9 Third cervical vertebra

10 Occipital belly of

occipitofrontalis muscle

11 Greater occipital nerve

12 Suboccipital nerve (C1)

13 Lesser occipital nerve

14 Third occipital nerve (C3)

15 Mastoid process and

splenius capitis muscle

16 Atlas

17 Axis

18 Spinous process of third

cervical vertebra

19 Right semispinalis cervicis

muscle

20 Deep cervical artery

21 Left splenius capitis muscle

(divided)

22 Left sternocleidomastoid

muscle

23 Great auricular nerve

24 Left semispinalis capitis

muscle

25 Left longissimus cervicis

muscle

26 Levator scapulae muscle

27 Muscular branch of

vertebral artery

28 Left semispinalis cervicis

muscle (divided)

29 Medial branches of dorsal

rami of spinal nerves

30 Occipital artery

31 Dorsal scapular nerve

Suboccipital triangle and position of the vertebral artery

(schematic drawing).

Dorsal aspect of the neck (deepest layer). Suboccipital triangle. Right semispinalis capitis muscle

divided and reflected.

238 Nuchal Region

Dorsal aspect of the neck (deepest layer). Dissection of suboccipital triangle on both sides.

1 Occipital belly of occipitofrontalis muscle

2 Occipital artery

3 Insertion of semispinalis capitis muscle (divided)

4 Lesser occipital nerve (from cervical

plexus)

5 Suboccipital nerve (C1)

6 Greater occipital nerve (C2)

7 Splenius capitis muscle (reflected)

8 Splenius cervicis muscle

9 Levator scapulae muscle

10 Accessory nerve (n. XI), trapezius muscle

11 Longissimus cervicis muscle

12 Iliocostalis cervicis muscle

13 Medial cutaneus branches of dorsal rami

of spinal nerves (C7, C8)

14 Longissimus thoracis muscle

15 Medial margin of scapula

16 Rectus capitis posterior minor muscle

17 Obliquus capitis superior muscle

18 Rectus capitis posterior major muscle

19 Obliquus capitis inferior muscle

20 Spinous process of axis

21 Semispinalis cervicis muscle

22 Semispinalis capitis muscle

(divided and reflected)

23 Transverse cervical artery

(superficial branch)

24 Serratus posterior superior muscle

(divided and reflected)

25 Rhomboid minor muscle

(divided and reflected)

26 Rhomboid major muscle

(divided and reflected)

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