Anatomy Head and Neck Imaging Overview 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)
Fat
Soft Tissue (Water)
Bone
Metal Basic Osteology Overview Skull Base Osteology
* Coronal Suture
Dorsum sellae Anterior clinoid Sella Turcica Palatine process Mastoid of maxilla air cells
Hyoid * * * Sag. suture
Crista galli Frontal sinus
Lesser wing
Greater wing Ethmoid air cells
Mastoid Inf. Turbinate
Dens
Mandible
____
______
_
_
_
__
______N = nasal V = vomer Frontal M= mandible bone S = sphenoid Frontal P = parietal sinus P T = temporal S
T
N
Z
V Maxilla M
Sphenoid sinus
Maxillary sinuses
*
Lesser wing
Greater Frontal process of wing zygo. bone
Maxillary sinus Zygomatic arch
L. Mastoid *
L. Coronoid process R. Condyle of mandible
R. Angle of mandible Dens *
* Mandible Nasopharynx Dens
Oropharynx Axis Tongue
C VI *
*
Intervert. foramen
Trans. Process of C IV
Spinous process
Pedicle * * *
Vestibular fold Laryngeal ventricle
Vocal fold
Trachea
______
____ Optic canal
Sphenoid sinus Rotundum
Ovale Clivus Spinosum Lacerum IAM Occipital condyle Jugular foramen
Lamdoidal suture Computed Tomography (CT) H&N CT
• Utilizes ionizing Anterior radiation to produce cross- sectional images • Digital “windowing” can highlight Right Left specific tissues • Note the patient orientation shown to the left Posterior Muscles of the Head Muscles of the Neck First Cervical Vertebrae – Atlas Second Cervical Vertebrae - Axis Seventh Cervical Vertebrae CT Axial Series
*
Use airway, apices of lung, and scapula to estimate level on body. * IJV CC Sternohyoid SCM Vertebral
Trapezius
*
Visceral compartment
* Sternohyoid CC Vascular IJV SCM compartment
Vertebral
Levator Scapulae
Trapezius
Vertebral Follow Vessels of neck superiorly in axial CT: compartment CCA, IJV, Vert. art; then follow SCM, then trapezius Semispinalis
*
* Sternohyoid Common Facial Common Carotid
EJV Vertebral SCM Levator Scapulae IJV
Trapezius
Semispinalis
* Vertebral level:___ @C3/C4 * Hyoid
External Carotid
Internal Carotid
EJV
Vertebral SCM
IJV
Levator Scapulae
Trapezius
Semispinalis
*
* L. Masseter
L. Parotid Post. Belly of gland Digastric m.
L. Medial pterygoid Dens SCM
Splenius
*
* L. Masseter
L. Medial pterygoid Post. Belly of Digastric m.
Splenius
*
* L. Temporalis
L. Masseter
L. Lateral Maxillary A. pterygoid Stylomastoid foramen L. Medial pterygoid
*
* L. Temporalis
Coronoid process L. Masseter
Pterygoid fovea L. Lateral pterygoid
* * * L. Temporalis
Coronoid process L. Masseter
Foramen ovale
TMJ
L. Mastoid Air Cells * *
____ *
Internal Carotid
Eustachian tube EAC
Cochlea
Malleus IAC
Vestibule
Horizontal (post.) Auricle Semicircular c.
*
* Inferior rectus Temporalis
*
Medial and lateral check ligaments * Lateral rectus
Optic nerve Temporalis
*
* Medial rectus Lens
Ophthalmic artery
Temporalis
*
* Superior oblique Superior rectus
Temporalis
CT Coronal Series *
Utilize the spine, TMJ, bones of the face, and clavicles to assess depth of coronal image * * TMJ * * * Lateral pterygoid Nasopharynx Medial pterygoid *
* R. Temporalis
Pterygoid fossa R. Masseter
SCM *
Lesser wing Greater wing *Sphenoidal sinus Medial pterygoid attachment Ramus of mandible
Pterygoid hamulus
SCM * * * Ethmoidal air cells
Inf. Orb. Mid. Turbinate fissure
Inf. Turbinate *
Medial rectus Superior rectus *Lateral rectus Optic nerve L. Temporalis Inferior rectus
L. Masseter
* 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 * * L. Maxillary sinus Inf. concha
Septum
Nasopharynx
R. Medial pterygoid m.
Tens. Veli palatini m.
L.Vertebral a.
L. Masseter m.
* * *
Cochlea
Vestibule
Vestibulocochlear and Facial nerves
Semi-circular canals * * Medial rectus * Lens Lat. rectus R. Optic nerve
R. Internal carotid a.
Basilar a.
MRA and Angiography Vasculature of the Neck *
* R. ICA
R. ECA R. ICA
R. CCA
R. sup. Cerv. A.
R. Vertebral A. Circle of Willis * * * Ant. Comm. A. Ant. Cer. A. Middle Cerebral a.
Int. Carotid a.
Basilar a. Vertebral a. *
* Ant. Cer. A.
Ant. Comm. A.
Mid. Cer. A.
Int. Car. A. Post. Comm. A.
Basilar a. Post. Cer. A. Vertebral a. Arteries of the Face * * Superficial Temporal a.
* Maxillary a. Mid. Meningeal a. Infraorbital a. Post. Auricular a.
Occipital a.
Asc. Facial a. Pharyngeal a.
External Carotid a.
Internal Lingual a. Carotid a.
Superior Thyroid. a. * * * Superficial Temporal Middle Meningeal
Occipital Maxillary Artery
Facial Artery Internal Carotid
Lingual Superior Thyroid * * Superficial Post. Auricular a. *Temporal a.
Maxillary a. Occipital a.
Internal Carotid a. Facial a.
Lingual a.
Superior Thyroid a. * * Superior sagittal * sinus
Straight sinus
Transverse sinus
Sigmoid sinus
IJV * * Superior sagittal sinus
Great cerebral vein
Straight sinus
Trans. sinus
Sigmoid sinus
IJV’s END