The Neck

BY: Lina Abdullah & Rahaf Jreisat

Boundaries of the Neck: generally from base of the skull to root of the neck

From superior nuchal line of occipital bone up to mastoid process down to margin of the mandible : Superior

margin

inferior margin: inlet of thoracic cavity , the clavicle and root of the neck

cervical vertebral muscles

subocciptal(part of deep muscles posteriorly and they form

triangular-like space ) and deep neck muscles

mainly extends head and neck

-rectus capitis posterior major m

-rectus capitis posterior minor m

-oblique capitis inferior m

-oblique capitis superior m

Action of these muscles is extension the head -

Recti muscles insert in inferior nuchal line of the occipital bones -

Anterior vertebral muscles

flexes head and

neck

•Longus coli m.

Capitis mean occipital bone so it attach from occipital to transverse processes of cervical vertebra: Longus capitis m.

Rectus capitis anterior m :anteriorly to cranium and vertebra of cervical

Remember that superior nuchal line

lines posterior of the occipital bone

from transverse

processes o middle cerviacal vertebrae to first rib and anteriorly to groove for subclavian artery: Anterior scalene m.

:Lateral vertebral muscles

laterally flex head

and neck

anterolateral to occipital condyle: Rectus capitis lateralis m.

•Splenius capitis m.

Lateral flexion of the head on one side of scapula up to cervical: Levator scapulae m.

: sup. attachment of transverse processes to first rib and posteriorly to groove for subclavian artery Middle scalene

m.

: also sup. Attachment of transverse processes of cervical vertebra to second rib Posterior scalene m.

So anterior to groove for subclavicn artery is anterior scalene

But posteriorly to this groove is middle scalene and between middle and anterior scalene is brachial plexus

all of lateral and anterior vertebra muscles are innervated by cervical nerves directly except levator scapulae ,which

is innervated by cervical nerves and brachial plexus

Superficial fascia: (externally) is layer of connective tissue that lies deeper to skin and part of hypodermis, it

contains the platysma

Deep fascia 3layers

The most superifical layer envelopes the trapezius and sternocleidomastoid muscles: Investing layer*

The middle layer has 2 parts: : Pretracheal layer**

Visceral part: it surrounds the thyroid , trachea ,parathyroid ,pharynx ,larynx and esophagus 1-

the fascia surrounds the pharynx and down to esophagus ( in some references) known as buccopharyngeal fascia ‐

2- muscular part :it surrounds the all anterior muscles of the neck (infrahyoid and suprahyoid muscles)

Prevertebral layer: the deepest one ,it surrounds all vertebral muscles and vertebrae***.

Posterior to pharynx(posterior to pretracheal layer)

Continue as axillary sheath

Carotid sheath

,it is surrounded by all layers of deep fascia Thickening of the other layers

: contents

Common & internal carotid

aa.

Intrnal jugular v.

Vagus n.

Deep cervical lymph nodes

Cervical Fascia extensions

Alar fascia:

Division from prevertebral fascia-

From skull to T2 that means in superior mediastinum region (merge with-

buccopharyngeal fascia anteriorly))

: Buccopharyngeal fascia

That surrounds the pharynx and esophagus Superior & posterior continuation of the pretracheal fascia

The Merging between alar fascia and buccopharyngeal fascia forms space in sup.mediastinum known as real

retropharyngeal space

Cervical Fascia: Spaces

: Retropharyngeal space

Prevertebral fascia Between buccopharyngeal fascia and

•Spread of infections

(Real) Retropharyngeal space:

ngealbuccophary Between the alar fascia and

Allow movement of pharynx, larynx, and trachea during swallowing-

Continuous with superior mediastinum toT2-

the spread of infection in real space stops at t2 where fusion of alar and buccopharyngeal

Prevertebral fascia posteriorly to alar Between the alar fascia and the

Continuous with mediastinum

The risk that an infection in this space can spread directly to the thorax ,because it continuous with mediastinum

Slide 12: (Bear with me)

Neck Triangles: Boundaries

• Anterior triangle: Anterior to SCM

• Carotid triangle • Digastric triangle • Submental triangle • Muscular triangle • Posterior triangle:

Posterior to SCM Anterior to trapezius

• Occipital triangle • Supraclavicular triangle

*Sternocleidomastoid (SCM)

seperates the neck into

anterior and posterior

triangles.

*Anterior triangle:

- Digastric (submandibular)

triangle: between the anterior

and posterior bellies of digastrics muscle, floor of digastrics: mylohyoid m.

The rest of the triangles are separated by hyoid bone and sup&inf bellies of

omohyoid m.

carotid triangle : anterior to SCM, posteriosuperior to sup belly of omohyoid, and

inferior to posterior belly of digastrics.

- Submental: superior to hyoid bone, between anterior bellies of digastrics.

Floor of submental triangle is made of mylohyoid muscles.

- Muscular triangle: inferior to hyoid bone and posterior to superior belly of

omohyoid.

*Posterior triangle:

Inferior belly of omohyoid divides it into two subtriangles

- Occipital triangle: superficial, superior to inf. belly of omohyoid, its floor is made

of muscles (scalenius medius, levator scapulae, splenius capitis)

- Supraclavicular triangle: superior to clavicle, inferior to inf. belly of omohyoid

and lateral to SCM.

Neck Triangles: Content

Anterior Triangle:

*Muscular triangle:

-Infrahyoid muscles (sternohyoid, sternothyoid, thyrohyoid, omohyoid)

-Viscera (thyroid cartilage, cricoid cartilage, trachea, thyroid gland isthmus

and connections btw these structures)

* Submental triangle:

-Lymph nodes in submental groove that can be felt is they swell.

* Digastric triangle:

- Submandibular lymph nodes: drain nasal&oral cavity, pharynx

- Submandibular salivary gland (superficial part)

- Facial artery: pass deep to submandibular gland then transverse the lower

edge of mandible (become superficial), you can feel it pulsing just inferior

to masseteric muscle.

Importance of this triangle:

1.injuries damage facial artery

2. Swelling of lymph nodes in common cold, sinusitis,…

*Carotid triangle:

-Carotid sheath and its contents

- Hypoglossal nerve before it goes deep to mylohyoid

- Cervical part of sympathetic trunk (posterior)

Posterior Triangle:

*Occipital triangle:

- accessory nerve which innervates SCM and trapezius

accessory nerve exits through jugular foramen(which is deep) then passes

deep towards SCM, it exits through posterior edge of SCM and transverses

occipital triangle where it becomes superficial (separated from skin by

investing deep fascia only) which makes it more susceptible to injury.

Any injury in this triangle can affect accessory nerve and leads to paralysis

in trapezius muscle – one can’t lift his shoulder.

*Supraclavicular triangle:

-External jugular vein

معلش

Sensory Innervations of the Neck

*cervical plexus:

-motor and sensory branches

sensory branches exit posterior to SCM muscle and spread all over cervical region.

-Deep: ansa cervicalis (part of carotid triangle) = hypoglossal nerve& C2& C3 –

innervate infrahyoid muscles.

*Well be taken in another lecture

Root of the Neck

*Boundries:

Ant: suprasternal angle

Lateral: first rib

Pos: body of T1

*Contents (from ant to pos):

Veins (Right and left brachiocephalic), vagus and phrenic nerves, arteries, trachea,

esophagus, thoracic duct & left lymphatic duct.

Arteries of the Head and Neck Branches of external carorid artery:

Superior thyroid artery

Ascending pharyngeal artery

Lingual artery (deep to mylohyoid m.)

Facial artery

occipital artery (hypoglossal nerve exit just

inferior to it)

Posterior auricular artery

Superficial temporal artery (pass

superficial to zygomatic arch anterior to

ear, you can feel its pulse)

Maxillary artery (Enter pteygopalatine fossa, pass with maxillary nerve)

Mneumonic:

Some American Ladies Find Our Pyramids Most Satisfactory

Veins of the Head and Neck

*Internal Jugular vein drain all cranial cavity and a lot of superficial veins (facial, retromandiular,

external jugular)

*Retromandibular vein = union of maxillary vein and superficial temporal veins

* External jugular can be drained in internal jugular or subclavian vein.

Principal groups of lymph nodes

Lymph drainage of Head and neck

• Regional lymph nodes: • Occipital

• Retroauricular • Parotid • Buccal • Submandibular • Submental • Anterior cervical • Laryngeal • Tracheal • Superficial cervical • Deep cervical: • Jugular trunk

*occipitaland & retroauricular are posterior.

*The fate of all lymph all over head and neck: Deep Cervical

*Deep cervical drain all superficial and ant group (pretracheal, paratracheal,

retrotracheal, retropharyngeal) and submandibular lymph nodes.

*Importance: knowing the sequence for tracing metastasis.

Occipital Triangle

• Above the inferior belly of omohyoid m. • Spinal accessory nerve (XI): -Junction of the superior & middle thirds of the posterior border of SCM → junction between middle & lower thirds of the anterior border of trapezius -Injury

Anterior Triangle

• Carotid triangle: -Carotid sheath: Between sternocalvicular joint and the mid point between mastoid and angle of mandible - Hypoglossal nerve - Cervical sympathetic trunk • Submandibular (digastric) triangle - Submandibular gland - Submandibular lymph nodes

Surface Anatomy of the Neck • Hyoid bone – C3:

- Posterior to the mandible • Laryngeal prominence (Adma’s apple)‐ tip (C4): - Vocal cords – at the middle • Cricoid cartilage – C6: - Cricothyroid ligament - Cricothyrotomy • First tracheal cartilage: - Tracheostomy • Thyroid gland: - Isthmus – 2nd – 4th tracheal Rings

Tracheostomy