Radiology Pt 1 Anatomy - Head And Neck

Front 1

Superior oblique

Back 1

a

Front 2

Inferior oblique

Back 2

a

Front 3

Lateral rectus

Back 3

a

Front 4

Medial rectus

Back 4

a

Front 5

Superior rectus

Back 5

a

Front 6

Inferior rectus

Back 6

a

Front 7

Levator palpabrae

Back 7

a

Front 8

Osteomeatal unit

Back 8

a

Front 9

Pterygopalatine fossa

Back 9

a

Front 10

MAxillary sinus

Back 10

a

Front 11

Ethmoid air cells

Back 11

a

Front 12

Frontal sinus

Back 12

a

Front 13

Sphenoid sinus

Back 13

a

Front 14

Parapharyngeal space

Back 14

a

Front 15

Masticator space

Back 15

a

Front 16

Infratemporal fossa

Back 16

a

Front 17

Base of the skull openings

Back 17

a

Front 18

Orbit walls

Back 18

Superior - frontal bone
Lateral - zygomatic bone
Inferior - Maxillary bone
Medial - ethmoid and lacrimal
Posterior - sphenoid bone

Front 19

Orbit contents cross section

Back 19

Central - opic nerve containing the central retinal artery and vein
surrounded by fat

Inferior is inferior rectus and inferior opthalmic vein lateral to this

Medial is medial rectus, and superior oblique above this

Superior is the superior opthalmic vein, then the superior rectus, then levator palpebrae superioris, finally the supraorbital nerve (trigeminal 1st div)

Lateral is lateral rectus

The inferior oblique arises at the globe, so does not appear in the plane of the optic sheath.

Front 20

Sinus drainage pathways

Back 20

Sphenoid - via sphenoid ostia and sphenoethmoid recess into superior meatus

Ethmoid - posterior cells via sphenoethmoid recess to superior meatus
anterior cells via ethmoid bulla and hiatus semilunaris to middle meatus

Maxillary - via maxillary ostium to infundibulum to hiatus semilunaris to middle meatus

Frontal sinus - via frontal recess to hiatus semilunaris to middle meatus

Lacrimal gland - not a sinus, but drains via lacrimal duct to inferior meatus

Front 21

Spaces of the suprahyoid neck

Back 21

Spaces are seperated by 3 layers of fascia (deep, middle and superficial layers of the 'deep cervical fascia')

The deep layer is just anterior to the vertebrae/BoS and forms the base of the retropharyngeal space and the carotid space laterally.

The middle layer is anterior and midline, and encloses the pharyngeal mucosal space. It contributes to the carotid sheath laterally.

The superficial fascia encloses the superficial spaces - the masticator space, the parotid space, the submandibular space and follows the muscles down the neck

SPACES:

Pharyngeal mucosal space -
Contains the mucosal surfaces, lymphatics and constrictor muscles. The mucosal structures and muscles (tonsils, torus tubarius, palate, levator palatini etc) are within this space.

Parapharyngeal space: Lateral to the mucosal space, more in the posterior region is the parapharyngeal. Contains mainly fat (some veins). Seperates mucosal space from carotid and masticator spaces.
It is a potential space that can be filled by pathology.

Retropharyngeal space - Posterior to mucosal space, anterior to foramen magnum at level of pharynx, runs posterolaterally to the carotid space.
Contains fat and some lymph nodes. Continuous with danger space/perivertebral space and thus communicates with mediastinum.
Posterior to pharynx/oesophagus/trachea

Masticator space -
Anterolateral to mucosal and parapharyngeal spaces, from pterygoids to zygomatic arch. Posterior extent to around styloid process.
Contains the ramus and condyle of mandible, pterygoid and temporalis muscles, masseter muscles and third division of trigeminal nerve, along with maxillary artery. Superior extent is under sygomatic arch to temple (around temporalis muscle).

Parotid space -
Around the parotid. From SM foramen around gland. Contains parotid, facial nerve and ECA.

Carotid space -
Between parotid and parapharyngeal spaces, contains the internal carotid arteries, IJVs and CN9-12. Continues down the neck as carotid sheath.

Front 22

Spaces of the infrahyoid neck

Back 22

3 main spaces -
Anteriorly the visceral space
Middle (slightly lateral) is the carotid space
Posteriorly is the perivertebral space, made up of prevertebral and paraspinal components, as well as the danger space.


The visceral space -
contains the Oesophagus, trachea, recurrent laryngeal nerve, thyroid and parathyroids. Continues with mediastinum.

The carotid space -
Carotid, IJVs and CN 9-12

Prevertebral space -
from base of skull to clavicles. Contains vertebral bodies, veins and arteries, scalene muscles, brachial plexus and the phrenic nerve

Paraspinal -
posterior spinal elements, levator scapulae and paraspinal muscles

Posterior cervical space -
between the perivertebral space and the superficial muscles circumferentially.
Contains fat and nodes.

Front 23

Lymphatic ring of mucosal pharyngeal space

Back 23

Waldeyer's ring

Adenoids in nasopharynx
Palatine tonsils in lateral oropharynx
Lingual tonsils in lower oropharynx (base of tongue)

Front 24

Masticator space

Back 24

Contains muscles of mastication, mandibular division of trigeminal, and the branches of the 2nd portion of the maxillary artery.

The path of CNV3 is from the foramen ovale after Meckel's cave, and between the two pterygoid muscles down and lateral to the mandibular ramus. It supplies all the muscles of the masticator space, the ant digastric and mylohyoid, and senation to oral structures, including sensation to tongue via lingual nerve (which is joined in the region by chorda tympani)

MUSCLES:
medial and lateral pterygoids
masseter
temporalis

Front 25

Parotid space

Back 25

Contains superficial lobe of parotid (deep is in parapharyngeal space)

Facial nerve (extracranial portion)

External carotid artery medial to retromandibular vein behind ramus of jaw

Retromandibular vein lateral to ECA. Medial to facial nerve in parotid. Joins external jugular

Lymph nodes in parotid

Parotid duct which passes anterior from gland and along masseter muscle. Arches through buccal space to enter mouth at 2nd upper molar

Front 26

Carotid space

Back 26

runs from base of skull to aortic arch

Upper -
Sheath contains ICA anteromedially.
In this sheath, relative to the ICA is
medial: CN12
posterior: CN10 medial, CN11 lateral
lateral: CN9
deep posterolateral: IJV

below oropharynx
medial: ICA
lateral: IJV
posterior: CN10

Front 27

Retropharyngeal space

Back 27

Only fat and nodes.

Nodes only above the hyoid. Medial and lateral groups bilaterally

Front 28

Temperomandibular joint

Back 28

Complex diarthrodial joint, involved in both rotatory and sliding movements.

PARTS:
Articular surface -
Mandibular fossa and articular eminence (anterior prominence bordering the mandibular fossa) on the zygomatic portion of the squamous temporal bone. Located anterior to IAM

Mandibular condyle - Posterior protrusion/head of mandible.

Articular disk -
Made up of anterior and posterior bands. The posterior band sits in the mandibular fossa, above the condyle. It is fixed posteriorly to the mandibular fossa, restricting it's forward movement during jaw opening. A inferior posterior band of fibrous tissue attaches to the condyle.

The smaller anterior band rests in front to the peak of the articular eminence. Here it is integrated into the superior portion of the lateral pterygoid muscle.

TMJ compartments -
Superior compartment above disc, below mandibular fossa
Inferior compartment below disc and condyle, with an anterior and posterior recess adjacent to condyle.

Capsule and ligaments -
The capsule runs from the articular eminence and mandibular fossa around the condyle and to the condylar neck.

ACTION:
on mouth opening the joint initially rotates, but then slips forward over the articular eminence. The disc moves with it, and the forward motion is restricted by the posterior band between the mandibular fossa and condylar head.

The other mandibular process - the coronoid - is a site of muscle insertion.

Front 29

Head and neck veins

Back 29

There are 3 main drainage trunks externally

The common facial vein anteriorly from the face

The retromandibular vein from the scalp

The occipital vein from the occiput.

Additionally, the anterior neck is drained by the anterior jugular vein.

FACIAL:
Courses from the angular vein along the lateral border of the nostril, down inder the zygoma, over the muscles of mastication and under the angle of the jaw to drain to the IJV.

RETROMANDIBULAR:
The superficial temporal vein, maxillary and posterior auricular vein join together, passing behind the mandibular ramus to drain to the IJV and EJV.

These 2 veins (facial and retromandibular) both drain the pterygoid plexus veins

OCCIPITAL:
The occipital vein drains the scalp over the occiput, and runs into the EJV.

Finally the anterior neck is drained by the anterior jugular vein.

Front 30

Cartilages of the throat

Back 30

MAIN RINGS:
Hyoid bone - anterior wishbone only
Thyroid cartilage - Anterior batwing shaped. Has a superior central notch seperating 2 laminae. These laminae have superior and inferior horns.

Cricoid cartilage - Circumferential, only complete ring

MNEMONIC - HTC

Additional cartilages - the aretynoids run upwards from the posterior cricoid cartilage. These are topped by the small corniculate cartilages.
The true vocal cords attach to the aretynoid cartilages.

EPIGLOTTIS:
A leaf shaped cartilage that acts as the lid to the larynx. It is attached inferiorly to the hyoid (midline hyoepiglottic ligament), the thyroid cartilage (thyroepiglottic ligament) and more superiorly the opening of the vallecula are bounded by the pharyngoepiglottic fold laterally and the glossoepiglottic fold in the midline.

Anteriorly from the epiglottis is the preglottic space, and laterally is the paraglottic space.

Front 31

Vocal cords

Back 31

True vocal cords run between vocal process of aretynoid and the thyroid cartilage.
The bulk of the cord is made up of the thyroaretynoid muscle. The medial 'cord' is called the vocal ligament.

Neuro - the recurrent laryngeal nerve controls the muscles. It runs up the neck from the turning point at the great vessels. In the most superior part it sits between the inferior cornu of the thyroid cartilage posteriorly, and the cricoid ring.

The mucous membranes of the paraglottic space become the false cords, seperated from the true cords by the laryngeal ventricle.

Front 32

Hypopharynx/larynx

Back 32

Supraglottic and Glottic/subglottic divisions (develop seperately).

SUPRAGLOTTIC REGION:

GLOTTIC REGION:
True vocal cords, between thyroid and aretynoid cartilages.

SUBGLOTTIC REGION:
from true vocal cords to inferior surface of cricoid cartilage. Minimal nodes (Cancer here far less likely to metastasise to nodes).

Front 33

Thyroid

Back 33

Lies anterior and lateral to trachea in the visceral space of the infrahyoid neck

PARTS:
Lateral lobes, with upper and lower poles. Commonly asymmetric.
Isthmus between lobes
Parathyroids (usually 4) near the deep surface of the gland in each pole.

Blood supply -
Superior thyroid artery from external carotid
Inferior thyroid artery from thyrocervical trunk (of subclavian)

Variant: Thyroidea ima, a single vessel from the aortic arch or brachiocephalic in 3%

VENOUS:
Superior and middle veins to IJV
Inferior vein to left brachiocephalic

Front 34

Trachea

Back 34

10-13cm tube from larynx (C6) to carina (T5)

PARTS:
Cartilage rings - enclose anterior 2/3rds of trachea, with flat fibromuscular membrane closing posterior portion

Blood supply:
Inferior thyroid arteries and veins

Front 35

Oesophagus

Back 35

25cm tube from C6 behind hypopharynx to T11 at hiatus.

Cervical oesophagus is supplied blood by inferior thyroid arteries and veins