Anatomy of neck spaces

ANATOMY OF NECK SPACES AND LEVELS OF CERVICAL LYMPH NODESBY DR. WALID REZK, M.D.LECTURER OF RADIODIAGNOSIS

INTR0DUCTION Basis for dividing neck into spaces and compartments : arrangement of superficial and deep layers of cervical fascia The importance of this spaces is that they may limit to some

degree the spread of most infections and some tumors A proper understanding of their anatomy will also aid in the

diagnosis of various conditions

CERVICAL FASCIAEFascia

Superficial

Deep

Superficial

Middle

Deep

Cervical fascial planes

NECK SPACESDescribed in relation to the hyoid bone. Suprahyoid Spaces. Infrahyoid Spaces. Spaces extending up to the entire length of the neck.

Spaces extending up to the entire length of the neck:

Carotid Space.

Retropharyngeal Space.

Danger space.

Peri-vertebral Space (prevertebral component & para-spinal component) .

SUPRAHYOID SPACES

Sublingual Space. Submandibular Space. Buccal Space. Masticator Space. Parotid Space. Pharyngeal mucosal Space. Parapharyngeal Space

INFRAHYOID SPACES Visceral Space. Anterior cervical

Space. Posterior cervical

Space.

Retropharyngeal Space 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 2.

Between middle layer deep layer of deep cervical fascia. 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.

pathway for spread of infections / tumors into the mediastinum from the neck.

http://radiopaedia.org/articles/retropharyngeal-space

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

Retropharyngeal space Lateral soft tissue X-ray (extension, inspiration) abnormal findings:

1. C2-post pharyngeal soft tissue >7mm2. C6–adults >22mm, peads >14mm3. STS of post pharyngeal region >50% width of vertebral body

DANGER SPACE Posterior to the RPS.

Bounded by the Alar fascia anteriorly and Prevertebral portion proper posteriorly.

Extends from the skull base up to the diaphragm.

Content : loose areolar tissue which provides easy pathway for the spread of

infections.

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.

PERIVERTEBRAL SPACE Posterior midline space of SHN

and IHN 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.

Extent : base of skull to level of coccyx

http://radiopaedia.org/articles/perivertebral-space

The deep cervical fascia sends a deep slip to the to the transverse process which subdivides the space into:• prevertebral portion: anteriorly located• paraspinal portion: posteriorly located

Contents:o prevertebral portion:

cervical vertebral body and disc prevertebral muscles: longus colli and capiti scalene msucles vertebral artery and vein phrenic nerve brachial plexus

o paraspinal portion: posterior elements of cervical vertebrae paraspinal muscles 

Boundaries: anterior: danger space and retropharyngeal space posterior: fascia attaches to spinous process and ligamentum

nuchae lateral: surrounded by posterior cervical space superior: base of skull inferior: the perivertebral space extends to the level of the

coccyx

CAROTID SPACE Paired tubular structure traversing

SHN and IHN Skull base to superior mediastinum Lateral to RPS Enveloped by carotid sheath : all 3

layers of DCf Contents : SHN – ICA IJV , CN9-12, :IHN - CCA, IJV , CN10 trunk ( vagus) The bifurcation of the common

carotid usually occurs at the boundary of the suprahyoid and infrahyoid spaces

http://radiopaedia.org/articles/carotid-space

CAROTID SPACE

CAROTID SPACE

IHN

SHN

CAROTID SPACE

MASTICATOR SPACE The masticator space are paired suprahyoid cervical spaces on

each side of the face. Each space is enveloped by the superficial (investing) layer of the deep cervical fascia.

The superficial layer of deep cervical fascia splits into two at the lower border of the mandible, the inner layer running deep to the medial pterygoid muscle and attaches to the skull base medial to foramen ovale and the outer layer covering masseter and temporalis muscles and attaches to the parietal cavarium superiorly.

Extends from skull base to the inferior edge of the mandible. Contents

• muscles of mastication• ramus and body of mandible • inferior alveolar nerve• inferior alveolar vein and artery• mandibular division of the trigeminal nerve (V3): enters the

masticator space via the foramen ovale Boundaries and relations

• anteriorly: buccal space • posterolaterally: parotid space • medially: parapharyngeal space

Communications• Masticator space malignancy can spread perineurally via the

mandibular division of the trigeminal nerve into the middle cranial fossa. 

MASTICATOR SPACE

MTL

PAROTID SPACE Boundary : Investing fascia(SLDCF) splitting at the angle of

mandible. Extends : Superiorly external acoustic meatus

Inferiorly up to the mandible. Contents: Parotid Gland, proximal part of the parotid duct,

intraparotid lymph nodes and vessels. Parotid gland is divided by facial nerve into superficial and deep. Division identified on imaging by retromandibular vein. http://radiopaedia.org/articles/parotid-space

Relations• lateral to the parapharyngeal space 1 • medial to superficial space and subcutaneous tissue• anterior to the carotid space • posterior to the masticator space

PAROTID SPACE

PAROTID SPACE

BUCCAL SPACE 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.

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 branch of the

mandibular division (CN Vc) http://radiopaedia.org/articles/buccal-space

Boundaries and relations• anterior: orbicular oris muscles and the angle of the mouth• posterior: masseter muscle, mandible, medial pterygoid and

lateral pterygoid muscles• superior: zygomatic process of the maxilla and zygomaticus

muscles • inferior: depressor anguli oris muscle and the deep fascia

attaching to the mandible• medial (deep): buccinator muscle• lateral (superficial): platysma muscle and subcutaneous

tissues with the skin

BUCCAL SPACE

SUBMANDIBULAR SPACE

Extend : Mylohoid superiorly & hyoid bone inferiorly.

Communicates freely with sublingual space.

Contents : superficial portions of the Submandibular gland, submental and submandibular LNs, facial artery and vein, fat and ant belly of digastric.

SUBMANDIBULAR SPACE

SUBLINGUAL SPACEExtent : Above the mylohyoid muscle

Contents : Sublingual gland and their ducts , LNs, hypoglossal muscle , lingual artery and vein , hypoglossal N and deeper portion of submandibular gland.

SUBLINGUAL SPACE

PHARYNGEAL MUCOSAL SPACE The pharyngeal mucosal space is the most internal compartment

(closest to the airway) of the seven 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.

http://radiopaedia.org/articles/pharyngeal-mucosal-space-1

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

PHARYNGEAL MUCOSAL SPACE

PARAPHARYNGEAL SPACE The parapharyngeal 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)• trigeminal nerve (CN V)• internal maxillary artery• ascending pharyngeal artery• pterygoid venous plexus only small

portion; mainly within masticator space

•  contains no lymph nodes or salivary glands

Relations• medial to the masticator space • lateral to the pharyngeal mucosal space • anterior to the prevertebral space • posterior to the medial pterygoid

http://radiopaedia.org/articles/paraphary

ngeal-space

PARAPHARYNGEAL SPACE

Visceral space 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. 

Extend from hyoid bone to superior mediastinum Contents

• thyroid gland• parathyroid gland• oesophagus• larynx• hypopharynx• trachea• recurrent laryngeal nerve• lymph nodes (level VI)

CERVICAL SPACESANTERIOR CERVICAL SPACE : Hyoid to clavicle

Anterior cervical space is continuous with the submandibular space and lateral to the visceral space. Content : Only fat

POSTERIOR CERVICAL SPACE : Extend from the skull base to the clavicles. Deep and posterior to sternocledomastoid

Content : fat, spinal accessory nerves and spinal accessory chain of deep cervical lymph nodes.

CERVICAL SPACES

CERVICAL SPACES

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Thyroid gland

57 The thyroid gland consists of two lateral lobes joined by a midline

isthmus, and lies anterior and lateral to the trachea. The lobes extend from the thyroid cartilage superiorly to the sixth

tracheal ring inferiorly Posterolaterally are the neck vessels, Behind these, on either side, are

the prevertebral muscles Anterior to the gland are the strap muscles of the neck and the

sternomastoid muscles

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Larynx

67 The larynx extends from the base of the tongue to the trachea, lying anterior to the third to sixth cervical vertebrae.

Its framework is composed of three single and three paired cartilages, which articulate with each other

the cricoid cartilage: shaped like a signet ring, with a flat, wide lamina posteriorly and an arch anteriorly.

It is joined to the thyroid cartilage above by the cricothyroid membrane,

The paired pyramidal arytenoid cartilages sit on the superolateral margin of the signet posteriorly.

These bear anteroinferior vocal processes, which give rise to the vocal ligaments of the true vocal cords.

The thyroid cartilage forms anterior and lateral boundary of the larynx.

It is formed by a pair of laminae, which are joined anteriorly forming an angle and are separated above to form the superior thyroid notch.

The posterior parts of the laminae have upper and lower projections known as the superior and inferior horns or cornua.

The inferior horns articulate with the signet of the cricoid cartilage.

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70 The epiglottis is a leaf-shaped cartilage whose

narrow base is attached to the inner surface of the thyroid cartilage

It projects up behind the base of the tongue and directs boluses laterally into the piriform fossae during deglutition, thus protecting the larynx.

Three mucosal folds, the glossoepiglottic folds - namely, a central and two lateral folds - pass from the anterior surface of the epiglottis to the base of the tongue. These form paired recesses between the base of the tongue and the epiglottis known as the valleculae.

A further pair of mucosal folds pass from the lateral margin of the epiglottis posteriorly to the arytenoid cartilages separating the larynx from the piriform fossae. These are the aryepiglottic folds which, together with the epiglottis, define the entrance to the larynx.

The cavity of the larynx is divided into three parts by upper and lower pairs of mucosal folds. The upper pair of folds are the false cords. The space between the laryngeal entrance and the false cords is known as the vestibule or the sinus of the larynx.

The lower pair of folds are the true cords and contain the vocal ligaments, which are responsible for voice production. The space between the false and true vocal cords is the laryngeal ventricle.

71Cross-sectional anatomy of the larynx

Supraglottic level The larynx is anterior to the

piriform sinuses, separated from them by the aryepiglottic folds.

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74Glottic level A complete ring of cartilage is seen at this level –thyroid cartilage

anteriorly & lamina of the cricoid &arytenoid cartilages posteriorly. The anterior fusion of the vocal cords is known as the anterior

commissure and is very thin when the cords are abducted. Similarly, the posterior commissure, which is seen between the arytenoids

The larynx is elliptical in shape at the level of the true cords and triangular at the level of the false cords, which are at a slightly higher level.

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76Infraglottic level Just below the cords the larynx is elliptical. The lamina of the

cricoid is posterior, with the cricothyroid membrane anterior. At a lower level the larynx is more circular and the cricoid forms a

complete ring. Part of the lobes of the thyroid gland may be seen laterally,

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79SG 1 (V)

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81SG2 (AEF)

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83SG3 (FVF)

84G

85IG1

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Cervical trachea and esophagus

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CT

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MRI

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LEVELS OF CERVICAL LYMPH NODES

Deep Lymph Nodes1. Submental2. Submandibular (Submaxillary)Anterior Cervical Lymph Nodes (Deep)3. Prelaryngeal4. Thyroid5. Pretracheal6. ParatrachealDeep Cervical Lymph Nodes7. Lateral jugular8. Anterior jugular9. JugulodigastricInferior Deep Cervical Lymph Nodes10. Juguloomohyoid11. Supraclavicular (scalene

Level I Submental and submandibular nodes

Level I A Submental nodes, between the medial margins of the anterior bellies of the digastric muscles.

Level I B Submandibular nodes, lateral to level I A nodes and anterior to the back of the submandibular salivary gland.

Level II Upper internal jugular nodes, posterior to the back of the submandibular salivary gland, anterior to the back of the sternocleidomastoid muscle and above the level of the bottom of the body of the hyoid bone.

Level III Middle jugular nodes, between the level of the bottom of the body of the hyoid bone and the level of the bottom of the cricoid arch, anterior to the back of the sternocleidomastoid muscle.

Level IV Low jugular nodes, between the level of the bottom of the cricoid arch and the level of the clavicle, anterior to a line connecting the back of the sternocleidomastoid muscle and the posterolateral margin of the anterior scalene muscles; they are lateral to the carotid arteries.

Level V Posterior triangle nodes, posterior to the back of the sternocleidomastoid muscle, and posterior to the line described in level IV. Level V A Above the level of the bottom of the cricoid arch. Level V B Between the level of the bottom of the cricoid arch and

the level of the clavicle

Level VI Upper visceral nodes, between the carotid arteries from the level of the bottom of the body of the hyoid bone to the level of the top of manubrium.

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