The cervical plexus is formed by the anterior rami of cervical nerves C1-C4. It is located in the neck beneath the prevertebral fascia and supplies skin and muscles of the neck. The phrenic nerve originates from C3-C5 and innervates the diaphragm. The cervical sympathetic trunk contains three ganglia - superior, middle, and inferior. The ganglia receive preganglionic fibers and provide postganglionic fibers to cervical nerves and structures in the head and neck via branches.

1. CERVICAL PLEXUS
DR. SUNDIP CHARMODE
ASSOCIATE PROFESSOR
DEPARTMENT OF ANATOMY
AIIMS RAJKOT

2. OBJECTIVES
1. Formation and branches of Cervical Plexus
2. Origin, course and branches of Phrenic Nerve
3. Structure and branches of Sympathetic Ganglion
4. Clinical Correlates

3. FORMATION
• Formed by the Anterior rami of Cervical nerves C1 to C4
• The cervical plexus is situated in the substance of the muscles forming
the floor of the posterior triangle within/beneath the pre-vertebral layer
of cervical fascia.
• Supplies skin and muscles of neck and the diaphragm.

5. SITUATION
• It is a plexus of loops and lies in
series with brachial plexus.
• On scalenus medius and levator
scapulae and under cover of
Sternocleidomastoid

6. CERVICAL LOOPS - FORMATION
• Each formative ramus divides into upper and lower branches, except
first cervical nerve.
• A slender branch of C1 runs along with Hypoglossal Nerve (XII).
• C1 trunk joins with upper branch of C2.
• Adjoining upper and lower branch fuse with one another.
• Lower branch of C4 nerve joins with C5 of brachial plexus.

7. CERVICAL LOOPS - SITUATION
• Three loops are formed
• First loop - directed forward in front of transverse process of atlas
• Remaining two loops – directed backwards
• Branches are arranged in:
• Superficial group
• Deep group

8. SUPERFICIAL BRANCHES
• These form four cutaneous branches - visible in the posterior triangle, pass
outward from middle of posterior border of the SCM.
• Ascending branches:
• Lesser occipital (C2)
• Great auricular (C2, C3)
• Transverse cervical (C2, C3)
• Descending branch:
• Supra clavicular nerve (C3, C4)

9. DEEP BRANCHES
• Muscular and divide into medial and
lateral series
• Medial series:
1. Rectus capitis lateralis – C1
2. Rectus capitis anterior – C1, C2
3. Longus capitis – C1, C4
4. Longus colli – C2, C4
5. Inferior root of Ansa cervicalis C2, C3
6. Phrenic nerve – C3, C4, C5
• Lateral series:
1. Sternomastoid – C2
2. Trapezius – C3, C4
3. Levator scapulae – C3, C4
4. Scalenus medius – C3, C4

10. COMMUNICATING BRANCHES
• With sympathetic: Each of the four formative rami receive grey rami
communicates from superior cervical ganglion of sympathetic trunk.

11. COMMUNICATING BRANCHES
• With hypoglossal nerve:

14. CLINICAL CORRELATES
1. Enlargement of inferior group of deep cervical lymph nodes
(Virchow’s nodes)
2. Injury to Spinal accessory nerve.

15. PHRENIC NERVE

16. FORMATION
• They are a pair of mixed peripheral
nerves, originates in neck, descends
through thorax to reach the diaphragm.
• Formed by ventral rami of C3, C4 and
C5
• Sometimes, C5 forms accessory phrenic
nerve.

17. COURSE – NECK
• Each nerve begins in the neck in the upper
part of lateral border of scalenus anterior
• Pass vertically down, beneath prevertebral
fascia, over anterior surface of scalenus
anterior
• Intervenes between the subclavian artery
(behind) and subclavian vein (front)
• The nerve enters thorax after crossing
internal thoracic artery from lateral to medial
side

20. RELATIONS - NECK
• In front: (from before backwards)
• Skin, superficial fascia, platysma, deep cervical fascia
• Clavicular part of SCM
• Inferior belly of omohyoid and omohyoid fascia
• Internal Jugular vein, termination of subclavian veins, commencement of
brachio-cephalic vein
• Thoracic duct on left side, on right side – right lymphatic duct
• Branches of thyrocervical trunk
• Pre-vertebral fascia

21. RELATIONS - NECK
• Behind:
• Scalenus anterior
• Subclavian artery (first part of left side, second part on right side)
• Internal thoracic artery

22. COURSE -THORAX
• Pass through superior and middle mediastinum.
• Middle mediastinum- lies in front of respective lung root
• Intervenes between fibrous pericardium and mediastinal pleura
• In thorax, it is accompanied by peri-cardio-phrenic vessels.

25. After passing through
venacaval opening, right
phrenic nerve joins with right
phrenic sympathetic plexus and
forms a phrenic ganglion.

26. LEFT PHRENIC NERVE
• The nerve crosses first part of left subclavian artery and is crossed by
thoracic duct.
• Pass downwards, along the left side of arterial system

28. LEFT PHRENIC NERVE
• After piercing left cupola, it joins left phrenic sympathetic plexus
without forming a ganglion.

29. TERMINATION
• Beneath the diaphragm or sometimes within it, each phrenic nerve
ramifies on abdominal surface and supplies the muscle.
• It divides into 4 sets of branches.
1. Antero-medial (sternal)
2. Antero-lateral
3. Postero-medial (crural)
4. Postero-lateral

30. INNERVATION
 Right phrenic nerve: Supplies right part of diaphragm up to the right
margin of esophageal opening, including the right crus.
 Left phrenic nerve: Supplies left part of diaphragm up to the left
margin of esophageal opening.
 Right crus is supplied by both the right and left phrenic nerves
 Left crus is supplied by only left phrenic nerve

32. TERMINAL BRANCHES
RIGHT PHRENIC GANGLION
• Twigs to right suprarenal gland
• Inferior vena cava
• Falciform and coronary
ligaments
• Sometime gall bladder
LEFT PHRENIC PLEXUS
• Twigs to left supra renal gland
only

33. ACCESSORY PHRENIC NERVE
• Accessory phrenic nerve is present in up to 75%. (cadaveric study).
• If present, it is the continuation of C5 and joins with the trunk of
phrenic nerve via nerve to subclavius.
• The joining of accessory phrenic nerve and trunk of phrenic nerve
occurs in front of subclavian vein.

35. DISTRIBUTION
• Motor fibers - entire diaphragm
• Sensory fibers –
• carry proprioceptive fibers from stretch receptors of diaphragm
• convey pain sensations from pericardium, mediastinal and
diaphragmatic pleurae and peritoneum on undersurface of diaphragm
• Sympathetic fibers- they are postganglionic and vasomotor in function

36. CLINICAL CORRELATION

37. CLINICAL CORRELATION

38. CLINICAL CORRELATION
• Referred pain: Irritation of central part of diaphragm due to
inflammation of diaphragmatic pleura or peritoneum may be referred
to tip of shoulder and lower part of neck via supraclavicular nerves
(C3,C4).
• Avulsion of phrenic nerve: During such procedure, sometimes, if
accessory phrenic nerve is present, then there is chance for tear of
subclavian vein and hemorrhage.

39. SYMPATHETIC
TRUNK:
CERVICAL PART

40. INTRODUCTION
• Also called as Autonomic ganglion.
• They are the ganglia of sympathetic nervous
system.
• All the ganglia are arranged vertically,
connected to each other in the form of
‘sympathetic chain’
• Each ganglionic sympathetic chain/trunk is
bilateral and paravertebral in position.

41. EXTENT
• Each ganglionic sympathetic chain/trunk is
extending from the base of skull to first
coccygeal vertebra.
• It consists of ganglia as follows:
1. Cervical part – three
2. Thoracic part – eleven
3. Lumbar – four
4. Sacral – four
• In front of coccyx two trunks unite and form
unpaired ‘Ganglion Impar’

43. STRUCTURE
• Initially, the number of sympathetic ganglia corresponded with spinal
nerves
• Later,
• Upper four cervical ganglia fused to form superior cervical ganglion
• 5th and 6th cervical ganglia fused to form middle cervical ganglion
• 7th and 8th cervical ganglia fused to form inferior cervical ganglion

45. STRUCTURE
• Sometimes,
• Inferior cervical ganglion and first thoracic fuse to form Cervico-
thoracic/Stellate ganglion.

46. STRUCTURE
• Each ganglion contains a collection of multipolar post-ganglionic
neurons and a few interneurons including chromaffin cells of para-
ganglia.
• Cells of para-ganglia (SIF cells) modulate the activities of post-
ganglionic neurons by liberating dopamine.
• The sympathetic trunk between the ganglia conveys pre- and post-
ganglionic motor fibers and sensory sympathetic fibers.

48. SYMPATHETIC TRUNK –
CERVICAL PART -
RELATIONS
• Anteriorly- Carotid Sheath
• Posteriorly –Longus Colli and
Longus Capitis

50. PRE-GANGLIONIC FIBERS

51. PRE-GANGLIONIC FIBERS

52. PRE-GANGLIONIC FIBERS

53. CERVICAL PART OF SYM. TRUNK -
CONNECTIONS
• Pre-ganglionic fibers for cervical part comes from lateral horn cells of
T1 – T5 spinal segments, ascend through the trunk, relay into the
three cervical ganglia.
• Postganglionic fibers pass via grey rami communicantes to each of
the eight cervical nerves.
• Do not receive white rami communicantes from cervical spinal
segments.

54. CERVICAL PART OF SYM. TRUNK -
CONNECTIONS
• The post ganglionic fibers supplies the skin, smooth muscles, arrector
pili muscles, sweat glands, blood vessels of body wall and limb.

55. SUPERIOR CERVICAL GANGLION
• Largest ganglion, fusiform in shape, 2.5 cm length.
• Fused upper four cervical ganglia.
• Site: Opposite transverse processes of C2 and C3 vertebrae, behind
Internal Carotid Artery and in front of Longus capitis.
• Pre-ganglionic fibers received from mostly upper three thoracic
segments.
• Post-ganglionic fibers pass through the branches and some sensory
fibers.

57. SUPERIOR CERVICAL GANGLION -BRANCHES
• Branches – Lateral, Medial , Anterior and Ascending groups
• Lateral – Send Grey Rami Communicans to upper 4 cervical nerves
and last four cranial nerves or its branches.
• Medial:
1. Laryngo-pharyngeal branches supply carotid body & form
pharyngeal plexus with vagus and glossopharyngeal nerve.
2. Cardiac branch conveys postganglionic efferent fibers only
• Right cardiac branch joins deep cardiac plexus
• Left cardiac branch joins superficial cardiac plexus

59. SUPERIOR CERVICAL GANGLION -
BRANCHES
• Anterior: They ramify around CCA, ECA and its branches forming
delicate plexuses.
• Plexus around facial artery – filament to submandibular ganglion
• Plexus around middle meningeal artery – filament to otic ganglion
• Another filament is given to geniculate ganglion of facial nerve as the external
petrosal nerve.

61. SUPERIOR CERVICAL GANGLION -
BRANCHES
• Ascending: They form Internal Carotid Nerve which accompanies the
ICA as a plexus. From the carotid plexus following branches are given
off:
• Carotido-tympanic nerves
• Deep petrosal nerve
• Communicating branches to trigeminal ganglion, 3rd, 4th, 5th and 6th cranial
nerves in cavernous sinus. The branches which accompany the nasociliary
nerve pass through ciliary ganglion without interruption – supply dilator
pupillae and vessels of eye ball.

62. SUPERIOR CERVICAL GANGLION -
BRANCHES
• Ascending:
• Some branches called Nervus Conarii, pass through tentorium
cerebelli and supply the parenchymal cells of the pineal gland.
• Terminal branches accompany the anterior cerebral, middle cerebral
and ophthalmic arteries and supply cerebral pia mater and the tarsal
muscles.

65. MIDDLE CERVICAL GANGLION
• Formed by C5 and C6 ganglia
• Site: Opposite C6 vertebra, between CCA in front and the loop of inferior
thyroid artery behind.
• Communications: Connected to Inferior Cervical Ganglion with two cords.
• Posterior cord – It splits to enclose vertebral artery.
• Anterior cord - Forms Ansa cervicalis which loops in front and below and
behind the first part of subclavian artery.

67. MIDDLE CERVICAL GANGLION - BRANCHES
• Lateral branches: Send grey rami communicans to C5 and C6 spinal
nerves.
• Medial Branches:
1. Thyroid branches - accompany the Inferior thyroid artery and
supply the gland.
2. Cardiac branches - join to form deep cardiac plexus.

69. INFERIOR CERVICAL GANGLION
• Formed by joining of two ganglia corresponding with C7 and C8
nerves.
• Sometimes, inferior ganglion joins with first Thoracic ganglion to
form Cervico- Thoracic or Stellate ganglion.
• Situation: Between Transverse process of C7 vertebra and the Neck
of first rib.

71. INFERIOR CERVICAL GANGLION -
RELATIONS
• In front:
1. First Part of Vertebral Artery and corresponding Vein
2. Thoracic duct (Lt) or Rt Lymphatic duct
3. Carotid sheath
4. Cervical pleura covered by Supra-pleural Membrane
• Behind: C8 nerve
• Medially: Longus Coli Muscle
• Laterally: Costo-cervical Trunk

72. INFERIOR CERVICAL GANGLION -BRANCHES
1. Send grey rami communicantes to C7 & C8 nerves: They convey
post-ganglionic vasoconstrictor fibers to arteries of upper limb.
2. Cardiac branches: convey postganglionic fibers which reach the
heart via deep cardiac plexus.
3. Vascular branches to subclavian artery.
4. Vertebral branch : forms a plexus around vertebral artery.

73. CLINICAL CORRELATION
1. Horner’s syndrome – lesion
affecting preganglionic fibers from
T1 and T2 cord segments at the
inferior cervical ganglion
1. Miosis
2. Ptosis
3. Enophthalmos
4. Anhidrosis

74. CLINICAL CORRELATION
2. Raynaud’s disease- In this condition of vasospasm of upper limb,
surgical section of sympathetic trunk below the T3 ganglion and
cutting of the rami communicans connecting T2 and T3 brings relief.

75. THANK YOU