Head and Neck Anatomy - ACR

Head and NeckImaging Overview

Anatomy

Before You Begin

This module, intended for pre-clinical medical students, is part of the core anatomy teaching series. There should be no prerequisite knowledge necessary for medical students to successfully review and understand this module.

Many of the additional module series in our website build off a strong understanding of human anatomy as it presents in imaging. Please refer back to these anatomy modules if you ever need to review.

If material is repeated from another module, it will be outlined as this text is so that you are aware

Introduction

• The Head and Neck includes:• Skull and Cranial Cavity• Face and Scalp• Eyes and Orbits• Ears• Nasal Cavity and Pterygopalatine Fossa• Oral Cavity and Pharynx• Larynx• Neck

• In this module, we will explore basic H&N anatomy identifiable with common imaging modalities

Plain Film Radiographs

Head and Neck Radiographs• Utilize ionizing radiation to

capture images

• Material density determines the degree of X-ray attenuation, and thus, appearance:

Gas (Air)

Soft Tissue (Water)

Metal

Fat

Bone

Basic Osteology Overview

Skull Base Osteology

*

Sella

Turcica

Hyoid

Dorsum

sellae Anterior

clinoid

Mastoid

air cells

Palatine

process

of maxilla

Coronal

Suture

*

*

*Sag. suture

Frontal sinus

Ethmoid air

cells

Crista galli

Dens

Lesser wing

Greater wing

Mandible

MastoidInf. Turbinate

_____

__

____

__

_

____

_

_

__

_

Frontal

sinus

V

Maxilla

Z

N

Frontal

bone

M

S

P

T

N = nasalV = vomerM= mandibleS = sphenoidP = parietalT = temporal

Sphenoid sinus

Maxillary

sinuses

*

Zygomatic arch

Frontal process of

zygo. bone

Maxillary

sinus

Lesser wing

Greater

wing

L. Mastoid

*

L. Maxillary

sinus

Dens

L. Coronoid

processR. Condyle of

mandible

R. Angle of

mandible

*

*Nasopharynx

Soft Palate

Tongue

Mandible

C VI

Atlas

Axis

Dens

Oropharynx

*

*

Trans. Process of C IV

Intervert. foramen

Spinous process

Pedicle

*

*

*

Vestibular fold

Vocal fold

Trachea

Laryngeal ventricle

____

________

Clivus

Occipital

condyle

Lamdoidal

suture

Spinosum

Ovale

Jugular foramen

Lacerum

Optic canal

Sphenoid sinus

IAM

Rotundum

Computed Tomography (CT)

H&N CT

• Utilizes ionizing radiation to produce cross-sectional images

• Digital “windowing” can highlight specific tissues

• Note the patient orientation shown to the left

Anterior

Posterior

Right Left

Muscles of the Head

Muscles of the Neck

First Cervical Vertebrae – Atlas

Second Cervical Vertebrae - Axis

Seventh Cervical Vertebrae

CT Axial Series

*

Vertebral

CC

IJV*

Trapezius

Sternohyoid

SCM

Use airway, apices of lung, and

scapula to estimate level on body.

*

Visceral

compartment

Vascular

compartment

Vertebral

compartment

*

Levator

Scapulae

Semispinalis

Vertebral

CCIJV

Trapezius

Sternohyoid

SCM

Follow Vessels of neck superiorly in axial CT:

CCA, IJV, Vert. art; then follow SCM, then

trapezius

*

*Common Facial

IJVLevator

Scapulae

Semispinalis

Vertebral

Common Carotid

Trapezius

Sternohyoid

SCM

EJV

*

Vertebral level:___

@C3/C4

* Hyoid

EJV

IJV

Levator

Scapulae

Semispinalis

Vertebral

External Carotid

SCM

Internal Carotid

Trapezius

*

*

L. Medial

pterygoid

L. Masseter

L. Parotid

glandPost. Belly of

Digastric m.

DensSCM

Splenius

*

*

L. Medial

pterygoid

L. Masseter

L. Parotid

gland

Splenius

Post. Belly of

Digastric m.

*

Stylomastoid

foramen

*L. Temporalis

L. Lateral

pterygoid

L. Masseter

L. Medial

pterygoid

Maxillary A.

*

Coronoid process

Pterygoid fovea

*L. Temporalis

L. Masseter

L. Lateral pterygoid

*

*

TMJ

Foramen ovale

*L. Temporalis

L. MasseterCoronoid process

L. Mastoid Air

Cells

*

*

____

*

IAC

Cochlea

Auricle

EAC

Horizontal (post.)

Semicircular c.

Internal Carotid

Eustachian tube

Vestibule

Malleus

*

Inferior rectus

*Temporalis

*

Optic nerve

Medial and lateral check ligaments

*Temporalis

Lateral rectus

*

Medial rectus Lens

Ophthalmic artery

*Temporalis

*

Superior rectus

*Temporalis

Superior oblique

CT Coronal Series

*

Utilize the spine,

TMJ, bones of the

face, and clavicles

to assess depth of

coronal image

*

TMJ*

*

*

Lateral pterygoid

Medial pterygoid

*Nasopharynx

*

R. Masseter

R. Temporalis*

SCM

Pterygoid fossa

*

*Lesser wing

Greater wing

Pterygoid hamulus

Ramus of

mandible

Sphenoidal sinus

Medial pterygoid

attachment

SCM

*

*

*

Inf. Orb.

fissure

Ethmoidal air

cells

Mid. Turbinate

Inf. Turbinate

*

L. Temporalis

L. Masseter

Superior rectusMedial rectus

Inferior rectus

Lateral rectus Optic nerve*

*

Magnetic Resonance Imaging (MRI)

MRI

• Utilizes powerful magnetic fields and radio-frequency pulses to excite (usually hydrogen) atoms within tissues• The energy released by atoms as they return to baseline can be

captured to produce an image

• By varying parameters such as pulse frequency, image qualities can be modulated (i.e. T1 vs T2 weighted)

• MRI can highlight structures that may not be apparent in CT imaging• MRIs are particularly apt when imaging soft tissues

• As they do not rely on X-rays, MRI studies do not expose patients to radiation

MRI – Axial Series

*

*

Inf. concha

Septum

L. Maxillary sinus

L.Vertebral a.

Nasopharynx

Tens. Veli palatini

m.

R. Medial

pterygoid m.

L. Masseter m.

*

*

*

Cochlea

Semi-circular

canals

Vestibule

Vestibulocochlear and

Facial nerves

*

*

*

R. Internal carotid a.

Basilar a.

R. Optic nerve

Lens

Medial rectus

Lat. rectus

MRA and Angiography

Vasculature of the Neck

*

*

R. Vertebral A.

R. ICA

R. ECA

R. ICA

R. CCA

R. sup. Cerv. A.

Circle of Willis

*

*

* Ant. Cer. A.Ant. Comm. A.

Middle Cerebral

a.

Int. Carotid a.

Basilar a. Vertebral a.

*

*Ant. Cer. A.

Ant. Comm. A.

Mid. Cer. A.

Int. Car. A.

Basilar a.

Vertebral a.

Post. Cer. A.

Post. Comm. A.

Arteries of the Face

*

*

*Superficial

Temporal a.

Infraorbital a.

Occipital a.

Asc.

Pharyngeal a.

Internal

Carotid a.

External Carotid

a.

Lingual a.

Facial a.

Superior Thyroid. a.

Post. Auricular a.

Maxillary a.

Mid. Meningeal a.

*

*

Superior Thyroid

Lingual

Facial Artery

Occipital

Internal Carotid

Maxillary Artery

Superficial Temporal

Middle Meningeal

*

*

*

Superior

Thyroid a.

Lingual a.

Facial a.

Occipital a.

Internal Carotid a.

Maxillary a.

Superficial

Temporal a.* Post. Auricular a.

*

*

Straight sinus

Transverse

sinus

Sigmoid

sinus

IJV

Superior sagittal

sinus*

*

*

IJV’s

Sigmoid sinus

Trans. sinus

Superior sagittal

sinus

Straight sinus

Great cerebral

vein

END