Download Neck Geometry

Anterior Triangle
Superior
Inferior border of mandible
Lateral
Medial
Triangles
Anterior border of sternocleidomastoid
Medial plane
Carotid
Submandibular
Muscular
Submental
Superior:
Inf. Border of Mandible
Ant. Border
Contents:
Arteries

Common Carotid artery
o Carotid sinus
o Carotid body

External Carotid artery (ExC-SALFOP)
o Superior thyroid artery
o Ascending pharyngeal artery
o Lingual artery
o Facial artery
o Occipital artery
o Posterior auricular

Internal Carotid artery (IC-AM)
o Anterior cerebral artery
o Middle cerebral artery
Veins

Internal Jugular vein
Nerves

Vagus nerve (CN X)
o Superior laryngeal nerve
o Recurrent laryngeal nerve

Hypoglossal nerve (CN XII)

Sinus nerve (branch of glossopharyngeal, CN IX)
Cartilage

Thyroid

Cricoid

Tracheal
Other

Submandibular gland
Lateral:
Sternocleidomastoid
Ant. Border
Superficial (Roof):
Deep Cervical Fascia Investing Layer
Not Shown
Ant. Border
Medial:
Median plane of neck
Clinical Aspects
Thyroid Gland
- Ectopic/Lingual Thyroid (failed descent of thyroglossal duct)
- Goiter (neoplastic enlargement – iodine deficiency)
- Hypo-/ Hyper-thyroidism
General

Endocrine gland secretes thyroxin
Thyroidectomy risks
o Stimulates catabolism of glucose, fats, & proteins
- Recurrent laryngeal nerve damage (hoarsness of voice)

Structure
- External laryngeal nerve damage (monotonous voice)
o True fibrous capsule (intimately attached to gland)
o False capsule (formed by pretrachial fascia)
o Suspensory ligaments anchor gland to thyroid & cricoid cartilages

Lobes
o 2 lobes joined by isthmus covers tracheal rings 2-4
o Each lobe extends from 6th tracheal ring to oblique line of thyroid cartilage
o (pyramidal lobe – small prominence on superior border of isthmus, usually on left side if present)
Relationships
Anterolaterally
Covered by strap muscles & SCM
Parathyroid Glands
Posteromedially
Esophagus & trachea
- Pea sized control Ca2+ metabolism
Recurrent laryngeal nerve & external laryngeal nerve
- Two pairs
Posterior aspect bears parathyroid glands
- Inferior thyroid artery (major blood supply)
Blood - Arterial
Superior thyroid artery
- Sympathetic vasomotor fibers (innervation)
Inferior thyroid artery
- Aberrant parathyroid (with thymus instead of thyroid)
Thyroidea ima artery (inconstant)
Blood - Venous
Superior thyroid vein
Middle thyroid vein
Inferior thyroid vein
Lymphatic drainage
Deep cervical nodes
Pre-laryngeal nodes
Pre-tracheal nodes
Nerves
Sympathetic fibers (vasomotor to blood vessels)
Carotid Triangle
Anterior
Posterior
Superior
Floor
Roof
superior belly of omohyoid
anterior border of sternocleidomastoid
posterior belly of diagastric & stylohyoid
posteriorly – inferior pharyngeal constrictor muscle
anteriorly – thyrohyoid muscle & hyoglossus
Investing layer of fascia, cutaneous nerves & platysma
Contents:
Arteries

Common Carotid artery
o Carotid body (on bifurcation)

External Carotid artery (ExC-SALFOP)
o Superior thyroid artery
o Ascending pharyngeal artery
o Lingual artery
o Facial artery
o Occipital artery
o Posterior auricular

Internal Carotid artery (IC-AM)
o Anterior cerebral artery
o Middle cerebral artery
o Carotid sinus
Veins

Internal Jugular vein
Nerves



Superior:
Digastric (Post. Belly)
Inferiolateral:
Sternocleidomastoid Ant. Border
Inferiomedial:
Omohyoid (Sup. belly)
Vagus nerve (CN X)
o Superior laryngeal nerve
o Recurrent laryngeal nerve
Hypoglossal nerve (CN XII)
Sinus nerve (branch of glossopharyngeal, CN IX)
Muscular Triangle
Superiorly
Superiolaterally
Inferiolaterally
Medially
Hyoid bone
Omohyoid (superior belly)
anterior border of sternocleidomastoid
Median plane of neck
Superior
ly:
Hyoid
Superiorlaterally
Bone
:
Medial:
Omohyoid (Sup.
Median
belly) plane of
inferiorlateral:
neck
Sternocleidomastoid Ant.
Border
Contents (Muscles related to thyroid gland):





Sternohyoid
Sternothyroid
Thyrohyoid
Omohyoid (superior belly)
Nerve to thyrohyoid (C1 traveling with CN XII)
Submental Triangle
Superiorly
Laterally
Inferiorly
Floor
Roof
Mandibular symphysis
Digastrics (anterior bellies)
Body of Hyoid bone
Mylohyoid
Deep Cervical Fascia (investing layer)
Contents:


Lymph nodes
Tributaries forming anterior jugular vein
Left & Right:
Bellies)
Inferior
Deep
(Floor):
Mylohyoid
Superficial (Roof):
Deep Cervical Fascia
Submandibular Triangle (aka digastric triangle)
Anterioinferior Digastric (Anterior Belly)
Posterioinferior Digastric (Posterior Belly)
Superior
Inferior border of Mandible
Contents:




Muscles
o Digastric (anterior belly) – mylohyoid n.
o Digastric (posterior belly) – CN VII
o Stylohyoid – CN VII
o Mylohyoid – mylohyoid n.
o Geniohyoid – C1
o Hyoglossus – CN XII
o Middle Constrictor – CN X
Nerves
o Fascial nerve (CN VII)
o Vagus (CN X)
o Hypoglossal nerve (CN XII)
o Cervical nerve (C1)
o Mylohyoid (C5)
o Lingual (V3)
 Submandibular ganglion (suspended from lingual nerve)
Blood Vessels
o Facial artery
o Facial vein
o Lingual artery
Glands
o Submandibular gland
o Sublingual gland
Anterioinferior:
Digastric (Ant. Belly)
Superior:
Inf. Border of Mandible
Posterioinferior:
Digastric (Post. Belly)
Deep (Floor):
Mylohyoid &
Hyoglossus
Superficial (Roof):
Deep Cervical Fascia Investing Layer
Not Shown
Posterior Triangle
Anterior
Posterior
Inferior
Superior
Roof
Floor
Posterior border of sternocleidomastoid (SMC)
Anterior border of trapezius
Middle 1/3 of clavicle
Angle where SMC & trapezius meet on the superior nuchal line
Investing layer of cervicle fascia
Platysma
External jugular vein
Levator scapulae
Scalene muscles (anterior, middle, & posterior)
Prevertebral fascia
Contents:
Nerves - Spinal accessory (CN XI)
Nerves – Cervical Plexus
 Cutaneous (sensory branches)
o Lesser occipital (C2, C3)
o Greater auricular (C2, C3)
o Transverse cervical (C2, C3)
o Supraclavicular (C3, C4)
 Motor
o To prevertebral muscles
Anterior/Lateral:
o To infrahyoid muscles via ansa cervicalis Sternocleidomastoid
Post. Border
o To diaphragm via phrenic nerve
 Ans Cervicalis
o Superior root (C1)
o Inferior root (C2, C3)
Deep (Floor):
Nerves – Brachial Plexus roots
Muscles of the neck
covered by prevertebral fascia
 Dorsal scapular
1/3
 Suprascapular
 Nerve to subclavius
 Long thoracic
 Phrenic nerve does not enter posterior Δ
Inferior:
Clavicle
Middle 1/3
Superior:
Intersection of
Trapezius Sup. Border & SCM
at superior nuchal line
Posterior:
Trapezius Sup.
Border
Subdivision:
Omohyoid
(occipital &
subclavian triangles)
Superficial (Roof):
Platysma
External Jugular Vein
Deep Cervical Fascia Investing Layer (Not Shown)
Arteries
 Subclavian artery (3rd part)
 Transverse cervical ( superficial cervical)
o From thyrocervical trunk
On left, all branches arise from 1st part of subclavian artery except for dorsal scapular
 Superficial cervical artery
On right, costocervical trunk arises from the second
o Branch of transverse cervical
part
 Suprascapular
o From thyrocervical trunk
 Occipital artery (from external carotid a.)
Subclavian Artery Branches (Rt.)
Subclavian Artery Branches (Lft.)
 ?- Dorsal scapular (from 2nd part or 3rd part of subclavian)
1st Part
1st Part
Veins

Vertebral Artery

Vertebral Artery
 External jugular vein & tributaries

Thyrocervical Trunk

Thyrocervical Trunk
o Formed by union of posterior auricular
o
Inferior thyroid
o
Inferior thyroid
o
Ascending cervical
o
Ascending cervical
& a branch of the retromandibular
o
Transverse cervical
o
Transverse cervical
o Drains most tissues of posterior triangle

Superficial cervical

Superficial cervical
 Subclavian vein does not enter posterior Δ
o
Suprascapular
o
Suprascapular
Lymph nodes
2nd Part (usually)

Costocervical Trunk (usually)
o
Supreme intercostal
o
Deep cervical
3rd Part

Dorsal Scapular
(sometimes from 2nd part)

Items in highlight are in Posterior Δ
Items in highlight are in Posterior Δ
Costocervical Trunk
o
Supreme intercostal
o
Deep cervical
2nd Part or 3rd Part

Dorsal Scapular
(sometimes from 3rd part)
Anterior Triangle
Posterior Triangle (left side)
Superior:
Inf. Border of Mandible
Ant. Border
Deep (Floor):
Larynx & Pharynx
Superior:
Intersection of
Trapezius Sup. Border & SCM
at superior nuchal line
Anterior/Lateral:
Sternocleidomastoid
Post. Border
Lateral:
Sternocleidomastoid
Ant. Border
Superficial (Roof):
Deep Cervical Fascia Investing Layer
Not Shown
Ant. Border
Deep (Floor):
Muscles of the neck
covered by prevertebral fascia
1/3
Medial:
Median plane of neck
Contents (generally to thorax):
Nerves



Arteries



Veins

Other

Vagus nerve
o
Superior laryngeal nerve
o
Recurrent laryngeal nerve
Hypoglossal nerve
Sinus nerve
Common Carotid artery
o
Carotid sinus
o
Carotid body
External Carotid artery
o
Superior thyroid artery
o
Ascending pharyngeal artery
o
Lingual artery
o
Facial artery
o
Occipital artery
o
Posterior auricular
Internal Carotid artery
Internal Jugular vein
Submandibular gland
Posterior:
Trapezius Sup.
Border
Inferior:
Clavicle
M
iddle 1/3
Subdivision:
Omohyoid
(occipital &
subclavian triangles)
Superficial (Roof):
Platysma
External Jugular Vein
Deep Cervical Fascia Investing Layer (Not Shown)
Contents (generally to upper limb:
Nerves



Cervical plexus
Brachial plexus (roots)
Spinal accessory (CN XI)
Cutaneous (sensory branches)

Lesser occipital (C2, C3)

Greater auricular (C2, C3)

Transverse cervical (C2, C3)

Supraclavicular (C3, C4)
Arteries




Veins

Motor




Subclavian artery (3rd part)
o
Vertebral
o
Internal thoracic
o
Thyrocervical
o
Costocervical
o
Dorsal scapular
Superficial cervical artery
Suprascapular
Occipital artery (from external carotid a.)
External jugular vein & tributaries
To prevertebral muscles
To infrahyoid muscles via ansa cervicalis
To diaphragm via phrenic nerve
Ans Cervicalis
o
Superior root (C1)
o
Inferior root (C2, C3)
Anterior Triangle Subdivisions
Muscular Triangle
Submandibular Triangle (left side)
Superiorly:
Hyoid Bone
Anterioinferior:
Digastric (Ant. Belly)
Superior:
Inf. Border of Mandible
Posterioinferior:
Digastric (Post. Belly)
Superiorlaterally:
Omohyoid (Sup. belly)
Medial:
Median plane of neck
inferiorlateral:
Sternocleidomastoid Ant. Border
Deep (Floor):
Mylohyoid &
Hyoglossus
Superficial (Roof):
Deep Cervical Fascia Investing Layer
Not Shown
Submental Triangle
Carotid Triangle (left side)
Left & Right:
Digastrics (Ant. Bellies)
Superior:
Digastric (Post. Belly)
Inferior:
Hyoid Bone
Deep (Floor):
Mylohyoid
Inferiolateral:
Sternocleidomastoid Ant. Border
Superficial (Roof):
Deep Cervical Fascia Investing Layer
Not Shown
Inferiomedial:
Omohyoid (Sup. belly)