1. NECK SPACES AND ANATOMY
DR ANURAG BIJPURIYA
JUNIOR RESIDENT III
GUIDE DR TEJAS MANKESHWAR
ASSISTANT PROFESSOR
DEPT OF RADIODIAGNOSIS
BJMC & SGH PUNE

2. The deep spaces of neck is separated by fascial planes and also by the hyoid bone into supra and infra-hyoid neck. 
There is continuation of some suprahyoid neck spaces into the infrahyoid neck spaces, and continuation of some infrahyoid neck spaces into the superior mediastinum.
Suprahyoid Neck: Encompasses the deep spaces between the base of the skull and hyoid bone.
Infrahyoid Neck: Lies inferiorly between the hyoid bone and clavicles.

3. Three layers of deep cervical fascia form the boundaries of the deep spaces in the neck.
The investing fascia completely surrounds the neck and split to enclose the sternocleidomastoid and trapezius muscles.
The pretracheal fascia encloses the content of the visceral space.
The paravertebral fascia encloses the paraspinous and prevertebral muscles to form the prevertebral space.
The carotid sheath is a dense framework of areolar tissue that surrounds the carotid arteries, internal jugular vein and vagus nerve and receives contributions from all three layers of deep cervical fascia. 

4. DEEP CERVICAL FASCIA

5. DEEP NECK SPACES

6. SUPRAHYOID NECK
INFRAHYOID NECK
SUPRA- AND INFRAHYOID NECK
PARAPHARYNGEAL SPACE
ANTERIOR CERVICAL SPACE
CAROTID SPACE
PAROTID SPACE
POSTERIOR CERVICAL SPACE
RETROPHARYNGEAL SPACE
PHARYNGEAL MUCOSAL SPACE
VISCERAL SPACE
PERIVERTEBRAL SPACE
MASTICATOR SPACE
DANGER SPACE
BUCCAL SPACE

7. PARAPHARYNGEAL SPACE

8. Internal Maxillary Artery Ascending Pharyngeal Artery
The para-pharyngeal space is shaped like a pyramid, inverted with its base at the skull base, with its apex inferiorly pointing to the greater cornu of the hyoid bone.
CONTENTS
Fat (Main Component)
Internal Maxillary Artery
Ascending Pharyngeal Artery
Pterygoid Venous Plexus 
Lymph Nodes

10. Relations
Medial to the masticator space.
Lateral to the pharyngeal mucosal space.
Anterior to the prevertebral space.
Posterior to the medial pterygoid.
Divisions
Prestyloid compartment
Poststyloid compartment

11. Parotid space displaces the parapharyngeal fat anteromedially
Masticator space displaces the parapharyngeal fat posteromedially
Carotid space displaces the parapharyngeal fat anteriorly
Pharyngeal mucosal space displaces the parapharyngeal fat posterolaterally
Retropharyngeal space and danger space displace the parapharyngeal fat anterolaterally

12. Related pathology
A lesion arising in the parapharyngeal space will displace the carotid space posteriorly and/or is completely surrounded by parapharyngeal space fat. Lesions include:
Salivary gland tumours (most common)
Lipoma
Parapharyngeal cellulitis / parapharyngeal abscess
Trigeminal schwannoma

14. PARAPHARYNGEAL ABSCESS

15. LIPOMA

16. PLEOMORPHIC ADENOMA
Pleomorphic adenoma: Post contrast axial CT image shows a homogeneously enhancing mass in the deep lobe of right parotid gland. Note its smooth non-invasive margins and displacement of the parapharyngeal space medially (red arrow), the masticator space anteriorly (yellow arrow) and widening of stylomandibular tunnel (yellow arrowhead). Normal left stylomandibular tunnel (red arrowhead). 

17. PARAPHARYNGEAL SPACE SCHWANNOMA

19. PHARYNGEAL MUCOSAL SPACE

20. It extends from the base of the skull to the cricoid cartilage
The pharyngeal mucosal space is the most internal compartment (closest to the airway) of the deep compartments of the head and neck, delineated by the middle (pretracheal) layer of deep cervical fascia.
It extends from the base of the skull to the cricoid cartilage
Contrast enhanced CT 1 Parapharyngeal space. 2 Masticator space. 3 Carotid space. 4 Parotid space. 5 Mucosal space. 6 Perivertebral space (anterior portion). 7 Retropharyngeal space

21. Contents
Squamous mucosa
Lymphoid tissue belonging to the pharyngeal lymphoid ring (waldeyer's ring)
Minor salivary glands.
Cartilaginous portion of the eustachean tube.
Superior pharyngeal constrictor.
Middle pharyngeal constrictor.
Levator palatini.
Relations
Medial to the parapharyngeal space 
Anterior to the retropharyngeal space 

22. Related pathology
Tornwaldt cyst
Benign minor salivary gland pathology
Nasopharyngeal carcinoma
Squamous cell carcinoma
Adenoid cystic carcinoma
Lymphoma
Minor salivary gland tumours
Juvenile angiofibroma
Tonsillitis
Peritonsillar abscess

26. THRONWALDT CYST

28. ABSCESS IN PHARYNGEAL MUCOSAL SPACE

29. CARCINOMA OF NASOPHARYNX

30. Parotid space

31. The parotid space is a roughly pyramidal space, the broad elongated base facing laterally, formed by the superficial layer of the deep cervical fascia overlying the superficial lobe of the parotid gland, and its apex pointing medially.
It is traversed by the external carotid artery (ECA), retromandibular vein and facial nerve. 

32. Contents 
Parotid glands
Intraparotid lymph nodes
Intraparotid facial nerve (CN VII)
External carotid artery (ECA)
Retromandibular vein

33. Salivary gland tumours
Related pathology
Congenital 
Agenesis
First branchial cleft cyst
Hemangioma
Cystic hygroma/lymphangioma
 Salivary gland tumours
Benign tumour
Primary malignant tumour
Metastatic malignant tumour
Metastatic adenopathy
Lymphoma
Parotid cysts
Inflammatory
Sialadenitis
Chronic granulomatous parotitis
Abscess/cellulitis
Sjogren's syndrome/autoimmune
Benign lymphoepithelial cysts (AIDS)
Nodular fascitis
Reactive adenopathy

34. CYSTIC LYMPHANGIOMA

35. CYSTIC HYGROMA

36. PAROTID ABSCESS

40. Masticator space

41. Contents
Muscles of mastication.
Ramus and body of mandible.
Mandibular division of the trigeminal nerve. 
​Inferior alveolar nerve.
Inferior alveolar artery and vein.

42. Boundaries and relations
Anteriorly: Buccal space.
Posterolaterally: Parotid space.
Medially: Parapharyngeal space.

43. Related pathology
Odontogenic abscess
Osteomyelitis
Direct spread of squamous cell carcinoma
Lymphoma
Minor salivary gland tumours
Muscle sarcoma
Bone sarcoma
Osteoradionecrosis
Schwannoma
Neurofibroma
Benign masseteric hypertrophy
Accessory parotid tissue

44. ABSCESS IN MASTICATOR SPACE

45. CHRONIC OSTEOMYELITIS MANDIBLE

46. CARCINOMA MANDIBLE

47. RETROPHARYNGEAL SPACE

48. The retropharyngeal space (also known as the true retropharyngeal space to distinguish it from the danger space, which is sometimes referred to as part of the retropharyngeal space) is one of the seven deep compartments of the head and neck.
It is a midline space that consists largely of fatty areolar tissue and contains lymph nodes that drain the pharynx, nose and middle ear.

49. The retropharyngeal space is posterior to the pharynx and oesophagus, and extends from the base of the skull to a variable level between the T1 and T6 vertebral bodies. The main component of the retropharyngeal space is areolar fat.
Lymph nodes are found in the portion of the retropharyngeal space above the hyoid bone, and these lymph nodes drain the pharynx, nasal cavity, paranasal sinuses and middle ears. These lymph nodes are prominent in children, and atrophy with age 

50. Contents
Areolar fat
Lymph nodes (lateral and medial retropharyngeal) only above hyoid 
Small vessels
Relations
The retropharyngeal space is:
Anterior to the danger space
Posterior to the pharyngeal mucosal space
Anteromedial to the carotid space
Posteromedial to the parapharyngeal space

51. Related pathology
Retropharyngeal abscess
Metastatic adenopathy
Lymphoma

52. RETROPHARYNGEAL ABSCESS

54. DANGER SPACE

55. The danger space is a potential space located behind the true retropharyngeal space, which connects the deep cervical spaces to the mediastinum. 
In healthy patients, it is indistinguishable from the retropharyngeal space. It is only visible when distended by fluid or pus, below the level of T1-T6, since the retropharyngeal space variably ends at this level.

56. Boundaries
Anteriorly: Alar fascia
Posteriorly: Prevertebral layer of the deep cervical fascia
Superiorly: Clivus
Inferiorly: posterior mediastinum at the level of the diaphragm
Related pathology
It is a potential path for spread of infections e. g. Retro pharyngeal abscess from the pharynx to the mediastinum.

58. CAROTID SPACE

59. The carotid space is roughly cylindrical space that extends from the skull base through to the aortic arch.  
It is circumscribed by all three layers of the deep cervical fascia, forming the carotid sheath.
The bifurcation of the common carotid usually occurs at the boundary of the suprahyoid and infrahyoid spaces

60. Contents
Common carotid artery  inferiorly and internal carotid artery superiorly
Internal jugular vein
Glossopharyngeal nerve (CN IX): anterior to vessels
Vagus nerve (CN X): posterior to vessels in posterior notch; extends below hyoid to mediastinum within the carotid sheath 
Accessory nerve (CN XI)
Hypoglossal nerve (CN XII)
Sympathetic nerves: medial to vessels lateral to retropharyngeal space
Deep cervical lymph node chain

61. Suprahyoid carotid space:
Relations
Suprahyoid carotid space:
Anteriorly: Masticator space; parapharyngeal space
Laterally: Parotid space
Posteriorly: Perivertebral space
The suprahyoid portion of the carotid space is often synonymous with the post-styloid compartment of the Parapharyngeal space
Contrast enhanced CT
1 Parapharyngeal space. 2 Masticator space. 3 Carotid space. 4 Parotid space. 5 Mucosal space. 6 Perivertebral space (anterior portion). 7 Retropharyngeal space

62. Vascular pseudotumours
Related pathology
A mass originating from the carotid space will cause anterior displacement of the parapharyngeal space. Lesions can include:
Vascular pseudotumours
Ectatic carotid artery
Asymmetrically enlarged internal jugular vein
Vascular lesions
Arterial or venous thrombosis
Internal jugular vein thrombophlebitis
Carotid artery dissection
Carotid artery aneurysms
Cellulitis/abscess
Benign tumour
Schwannoma
Neurofibroma
Paraganglioma
Meningioma
Lymphoma
Metastatic or reactive lymphadenopathy

64. CAROTID BODY TUMOR

65. Peripheral nerve sheath tumor of cervical vagus nerve

66. EXTRAMEDULLARY PLASMACYTOMA
 Axial section contrast-enhanced CT shows a very well-defined non-infiltrating mass in the carotid space displacing the carotid sheath anteriorly

67. THE BUCCAL SPACE OR BUCCINATOR SPACE

68. The buccal spaces are paired fat contained spaces on each side of the face forming cheeks. Each space is enveloped by the superficial (investing) layer of the deep cervical fascia.
It is located between the buccinator and platysma muscles, therefore only a small potential space with limited contents.

69. Contents
Fat: cheek padding
Parotid duct
Accessory parotid gland in 20% of people which can cause facial asymmetry; readily seen on MRI 
Facial and buccal arteries and corresponding veins
Facial nerve (CN VII): buccal branch
Trigeminal nerve (CN V): buccal nerve of the mandibular division (CN vc)

70. Communications
Buccal space infection can spread to or from the teeth. There is no real boundary between the buccal space and the submandibular space inferiorly.
There is also potential communication with the pterygomandibular region , infratemporal space and to the parapharyngeal space posteriorly.
Related pathology
Parotid duct calculi
Odontogenic infection
Tumours: Minor salivary gland tumours, vascular lesions (eg haemangiomas)

71. Axial CT, in a different patient, shows an abscess (arrow) in the left buccal space. Note overlying stranding of fat due to inflammation.

72. CARCINOMA OF BUCCAL MUCOSA

73. ANTERIOR CERVICAL SPACE

75. Contents
Areolar fat
Relations
Posterior: Carotid space
Medial: Visceral space
Superior: Submandibular space
Related pathology
Lipoma (most common).
Second branchial cleft cysts.

76. POSTERIOR CERVICAL SPACE

77. Posterolateral part of the neck extending from the mastoid tip and base of skull to the clavicles.

78. Spinal accessory nerve (cranial nerve XI) Preaxillary brachial plexus
Contents
Spinal accessory nerve (cranial nerve XI)
Preaxillary brachial plexus
​Dorsal scapular nerve
Spinal accessory lymph nodes
Fat
Relations
Superficial: Sternocleidomastoid and trapezius muscles
Deep: Prevertebral space
Anterior: Carotid space

79. Reactive lymph node along spinal accessory nerve

80. SPINAL ACCESSORY NERVE SCHWANNOMA

81. PERIVERTEBRAL SPACE

82. The perivertebral space is a cylinder of soft tissue lying posterior to the retropharyngeal space and danger space surrounded by the prevertebral layer of the deep cervical fascia and extends from the skull base to the upper mediastinum.
The deep cervical fascia sends a deep slip to the transverse process which subdivides the space into:
Prevertebral portion: 
Anteriorly located
Paraspinal portion: 
Posteriorly located

83. Contents Prevertebral portion. Paraspinal portion
Cervical vertebral body and disc
Prevertebral muscles: longus colli and capiti
Scalene muscles
Vertebral artery and vein
Phrenic nerve
Brachial plexus
Paraspinal portion
Posterior elements of cervical vertebrae
Paraspinal muscles 

84. Retropharyngeal abscess Osseous metastases Chordoma Osteomyelitis
Related pathology
Retropharyngeal abscess
Osseous metastases
Chordoma
Osteomyelitis
Schwannoma
Chondromas
Direct invasion by squamous cell carcinoma
Pseudotumours
Anterior herniated disc
Vertebral osteophytes
Longus colli tendon calcification
Lymphoma

85. PREVERTEBRAL SPACE ABSCESS

87. VERTEBRAL ARTERY ANEURYSM

88. VISCERAL SPACE

89. The visceral space extends from the hyoid bone to the superior mediastinum (level of aortic arch / T4), and is surrounded by the middle layers of the deep cervical fascia. 

90. Contents
Thyroid gland
Parathyroid gland
Oesophagus
Larynx
Hypopharynx
Trachea
Recurrent laryngeal nerve
Lymph nodes (level VI)

91. LARYNGOCELE

92. COLLOID CYST OF THYROID

93. CARCINOMA OF LARYNX
Axial CT image through the subglottis shows a circumferential subglottic mass with destruction of the cricoid and the thyroid cartilages .

94. CYSTIC PARATHYROID ADENOMA

95. SUMMARY
The deep spaces of the neck present a variety of unique oncologic, infectious, congenital, and vascular lesions.
An understanding of the anatomy, imaging characteristics and differentials of each particular region are vital in making an accurate diagnosis.
The radiologist's role in accurate diagnosis of these lesions and understanding of their manifestation plays a crucial role in patient care and management.

96. THANK YOU