Head and Neck Flashcards
Where does sternocleidomastoid attach?
From lateral mastoid process to anterior manubrium of sternum and to superior aspect of medial clavicle
What nerve innervates sternocleidomastoid and trapezius?
Spinal accessory nerve CN XI
What are the borders of the posterior triangle?
Anterior - Posterior border of sternocleidomastoid Posterior - Anterior border of trapezius Inferior - medial third of the clavicle Floor - paravertebral fascia Roof - investing fascia
What are the main contents of the posterior triangle?
Accessory nerve
External jugular vein
Subclavian artery and vein
Transverse cervical artery and vein
What are the subdivisions of the posterior triangle?
Inferior head of omohyoid muscle splits it into Occipital triangle superiorly and subclavian triangle inferiorly
What are the borders of the anterior triangle?
Superior - inferior border of madible
Lateral - Medial border of SCM
Medial - midline of neck
What are the different subdivisions of the anterior triangle?
Carotid, submandibular, submental, muscular
What are the borders of the carotid triangle?
Superior - Posterior belly of digastric muscle
Inferior- Superior belly of omohyoid muscle
Lateral - Medial border of SCM
What are the borders of the submental triangle?
Floor - Mylohyoid bone
Lateral - Anterior belly of digastric muscle
Medial - midline of neck
Inferior - hyoid bone
What are the borders of the submandibular triangle?
Anterior - anterior belly of digastric muscle
Posteriorly - Posterior belly of digastric muscle
Superior - body of mandible
What are the borders of the muscular triangle?
Superolateral - Superior belly of omohyoid muslce
Inferolateral - Medial SCM
Superior - Hyoid bone
Medial - midline of neck
What are the different divisions of the deep fascia of the neck?
Prevertebral, pretracheal and investing
What is contained in the carotid sheath?
Internal jugular vein Common carotid then internal carotid artery Vagus nerve Deep cervical lymph nodes Carotid sinus nerve Sympathetic nerve fibres
If there’s infection in the retropharyngeal space, where can it spread to?
Down into thorax and mediastinum
At what vertebral level does the common carotid artery bifurcate?
C4
What are the names of the 4 suprahyoid muscles and what are their actions?
Digastric - (facial) elevates and steadies the hyoid
Stylohyoid (facial) elevates and retracts hyoid
Geniohyoid (hypoglossal) Widens pharynx. pulls hyoid anterosuperiorly
Mylohyoid (nerve to) Elevates hyoid, tongue and floor of mouth
What are the 4 infrahyoid muscles and what are their actions?
Omohyoid (C1-C3) Depresses, retracts and steadies hyoid
Sternohyoid (C1-C3) Depresses hyoid after elevation
Thyrohyoid (hypoglossal) depresses hyoid and raises larynx
Sternothyroid (C2, C3) Depresses hyoid and larynx
What are the four main layers of the neck?
Skin
Superficial fascia
Platysma muscle (anteriorly)
Deep cervical fascia
What is contained in the superficial fascia?
Fatty connective tissue Cutaneous nerves Vasculature Lymphatic vessels Platysma
What are the three layers of the deep cervical fascia?
Investing
Pre tracheal
Pre vertebral
What does the investing layer of fascia in the neck contain?
Encloses sternocleidomastoid and trapezius muscles.
Contains parotid and submandibular salivary glands
What are the attachments of the investing layer of fascia in the neck?
Ligamentum nuchae Mastoid process Zygomatic arches Inferior mandible Hyoid bone Spinous process of C7 vertebrae
Where is the investing layer of fascia, in relation to the platysma muscle?
Posterior
Where does the pretracheal layer of fascia in the neck run from and to?
From inferior hyoid bone to the superior thorax where it fuses with the pericardium
What does the pretracheal layer of fascia in the neck contain?
Visceral part contains the trachea, thyroid gland and oesophagus.
Muscular part encloses the infrahyoid muscles
What’s the purpose of the thickenings of the pretracheal fascial layer in the neck?
Thickens to form a trochlea through which the intermediate tendon of the digastric muscle can pass and suspend the hyoid bone.
Tethers the omohyoid muscle
Where does the prevertebral fascial layer in the neck run from and to?
From the cranial base and then down to where it fuses with the endothoracic fascia peripherally and with the anterior longitudinal ligament at the level of T3, centrally
What does the prevertebral fascial layer extend laterally to form?
Axillary sheath, containing axillary vessels and the brachial plexus.
Where does the carotid sheath fuse with other fascial layers?
Anteriorly with the investing and pretracheal fascial layers and posteriorly with the prevertebral layer
What structures does the carotid sheath communicate with, inferiorly and superiorly?
Along with the pretracheal fascia, communicates superiorly with the cranial cavity and inferiorly with the mediastinum. This is important in the spread of infections and blood.
What is the retropharyngeal space?
Potential space between the prevertebral and visceral pretracheal fascial layers in the neck.
What is the alar fascia?
A subdivision of the retropharyngeal space. Runs from the cranium to C7 and extends laterally to the carotid sheath.
What is the purpose of the retropharyngeal fascia?
To allow movement of viscera, relative to the vertebral column on swallowing.
Where does the retropharyngeal space open?
Into the superior mediastinum
From where do most infections in the retropharyngeal space originate?
Nasopharyngeal lymph nodes, especially in children
Where is the parapharyngeal space?
Lateral to the pharynx, anterior to the carotid sheath and medial to the parotid gland
From where do infections in the parapharyngeal space most often originate?
The teeth or parotid gland. Spread to the mediastinum
From where does the right common carotid artery originate?
From the right brachiocephalic trunk
Where do the common carotids bifurcate?
At superior border of the thyroid cartilage, roughly level with C4
Where does the internal carotid artery enter the cranium?
At the carotid canal, anterior to the jugular foramen
Where is the thyrocervical trunk?
Arises from the subclavian artery, distal to the vertebral artery. Arises near the anterior border of the anterior scalene muscle
What are the four branches of the thyrocervical trunk?
Inferior thyroid
Ascending cervical
Transverse cervical
Suprascapular
What does the inferior thyroid artery innervate?
Larynx, trachea, oesophagus, thyroid, parathyroids, and their accompanying muscles.
What does the suprascapular artery supply?
Minor supply to sternocleidomastoid
Subclavius muscle
What’s an anatomical variant of place of origin of the suprascapular artery?
From thyrocervical trunk or direct from the subclavian artery
What does the transverse cervical artery supply?
Sternocleidomastoid
Trapezius
Vasovasorum of brachial plexus nerves after branching into superficial cervical artery and dorsal scapular artery
What does the ascending cervical artery supply?
Upper lateral muscles of the neck
SOme branches to intervertebral foramina
Where do the vertebral arteries originate?
From subclavian artery, medial to anterior scalene muscle.
Where do the vertebral arteries travel from their origin?
Up the back of the neck, through the transverse foramina of C6-C1 and then enter the cranial cavity through the foramen magnum. They then merge to form the basilar artery
What are the main branches of the external carotid artery?
Superior thyroid Occipital Maxillary Facial Lingual Ascending pharyngeal SUperficial temporal Posterior auricular
What happens if there’s a rupture of the middle meningeal artery due to a pterion fracture?
Can cause an extradural haemorrhage
What’s the embryological origin of muscles of facial expression?
Second pharyngeal arch
What cranial nerve supplies the muscles of facial expression?
Facial - CN VII and its branches: temporal, zygomatic, buccal, marginal mandibular and cervical
What’s the only muscle in the epicranial group of muscles of facial expression?
Occipitofrontalis. Flat digastric muscle with two bellies joined by epicranial aponeurosis
What’s the action of occipitofrontalis?
Raises eyebrows and wrinkles forehead
What are the muscles in the orbital group of muscles of facial expression?
Orbicularis oculi
Corrugator supercilii
What are the divisions of orbicularis oculi?
Orbital group more peripheral and thicker. Closes eyelids firmly and is under voluntary control
Palpebral portion is more central and thinner. Closes eyelids gently and isn’t under voluntary control
Lacrimal portion compresses lacrimal sac to aid the passing of tears
What’s the function of corrugator supercilii?
Draws eyebrows infermedially
What are the main nasal muscles of facial expression?
Nasalis
Procerus
Levator labii superioris alaeque nasi
What’s the main function of the nasal muscles of facial expression?
Flare nostrils.
Procerus also lowers eyebrows
What muscles are in the oral group of muscles of facial expression?
Buccinator Obicularis oris Mentalis Zygomaticus major and minor Risorius Depressor anguli oris Platysma
What’s the action of the buccinator muscle?
Presses cheeks against molar teeth and resists distension when blowing.
What’s the action of obicularis oris?
Oral sphincter. Purses lips and provides attachment for various muscles.
What’s the action of zygomaticus major and minor?
Dilators of the mouth that elevate the lip. If bilateral, helps produce a smile. If unilateral, produces a sneer
What’s the purpose of risorius?
Retracts the angle of the mouth to help with smiling.
Where does the risorius muscle arise?
From fascia covering the parotid gland
What’s the action of depressor anguli oris?
Dilator of the mouth that pulls the corners of the lips down
What’s the action of the mentalis muscle?
Protrudes the lower lip. Also wrinkles chin skin.
What’s the action of platysma?
Depresses and tenses the skin of the lower face and mouth. Aids in depression of the mandible.
Which muscles lie under the prevertebral fascia to form the floor of the posterior triangle of the neck?
Anterior, middle and inferior scalene muscles
Splenius capitis
Levator scapulae
Which vessels form the external jugular vein?
Retromandibular and posterior auricular veins
Where in the posterior triangle do the suprascapular and transverse cervical arteries run?
Along the base of the triangle
What happens if the external jugular vein is ligated?
Its lumen is kept patent by the thick, tough layer of investing fascia. Air is drawn into the vein so this can form a froth and therefore cause central cyanosis. To prevent this, pressure must be applied to the vein.
Where does the accessory nerve lie in the posterior triangle?
After innervating sternocleidomastoid, it crosses the traingle in an oblique, inferoposterior direction, within the investing layer of fascia. Therefore it is relatively superficial and prone to injury.
Where in the neck does the phrenic nerve pass?
Part of the cervical plexus which forms within the muscles of the floor of the posterior triangle. Arises from C3-C5 and then travels down the neck, within the prevertebral fascia, to innervate the diaphragm.
How is a cervical plexus nerve block performed?
Performed to numb the neck. Anaesthesia is injected along the posterior border of sternocleidomastoid, at the junction between it’s superior and middle thirds, as this is where the cutaneous branches of the cervical plexus emerge. (nerve point)
In what group of people should a cervical plexus nerve block not be performed?
In patients with cardiac or pulmonary problems as the block damages the phrenic nerve
What are the contents of the anterior triangle?
Infrahyoid muscles Supra hyoid muscles Common carotid artery and bifurcation into external and internal carotids Internal jugular vein Facial nerve (VII) Glossopharyngeal nerve (IX) Vagus nerve (X) Accessory nerve (XI) Hypoglossal nerve (XII)
What are the main contents of the carotid triangle?
Common carotid artery and bifurcation into internal and external carotids Internal jugular vein Vagus nerve (X) Hypoglossal nerve (XII)
What forms the base of the submental triangle?
Mylohyoid muscle. Runs from hyoid bone to body of mandible
What are the contents of the submandibular triangle?
Submandibular salivary gland
Submandibular lymph nodes
Facial artery
Facial vein
What are the contents of the muscular triangle?
Infrahyoid muscles
Pharynx
Thyroid gland
Parathyroid glands
What kind of connective tissue are deep and superficial fascia?
Superficial is loose connective tissue
Deep fascia is dense irregular connective tissue
What are the purposes of fascial planes?
Division into compartments
Ease of movement against other structures eg in swallowing
Forms natural planes
Determines spread of infection
Where do the heads of the platysma muscle originate?
Pectoralis major and deltoid muscle. Meet in midline and fuse with facial muscles
What are the attachments of the investing layer of fascia?
Superior - External occipital protuberance, superior nuchal line
Inferior - Spine of scapular, acromion, manubrium, clavicle
Lateral - Mastoid process, zygomatic arch
What other fascial layer helps to contribute to the posterior portion of the muscular pretracheal fascia layer?
Buccopharyngeal fascia
What are the attachments of the prevertebral layer of fascia?
Anteriorly attaches to vertebral bodies and transverse processes of cervical vertebrae
Posteriorly, attaches along the ligamentum nuchae
What stops a superficial skin abscess of the neck spreading further into the neck?
The investing layer of fascia
What are the two main locations, deep to investing fascia where an infection could be particularly problematic?
Posterior to the prevertebral fascia.This can errode through the prevertebral fascia, into the retropharyngeal space. This extends into the thorax so the drainage of pus can lead to infection of mediastinal contents.
Between investing fascia and visceral pretracheal. Infections can spread into the chest, causing infection anterior to the pericardium
What are the four suprahyoid muscles?
Mylohyoid
Geniohyoid
Digastric
Stylohyoid
What are the attachments of stylohyoid?
From styloid process of temporal bone to lateral side of hyoid bone
What innervates stylohyoid?
Facial nerve (CN VII)
What are the actions of stylohyoid?
Initiates swallowing by pulling the hyoid posteriorly and superiorly
What are the attachements of digastric?
Anterior belly originates from the digastric fossa of the mandible
Posterior belly originates from mastoid process. Both are joined by a tendon that’s attached to the hyoid bone
What innervates diagastric?
Anterior belly innervated by trigeminal nerve (CN V)
Posterior belly innervated by facial nerve
What are the actions of digastric?
Depresses mandible and elevates hyoid
What are attachments of mylohyoid?
Mylohyoid line of mandible to hyoid bone
What is mylohyoid innervated by?
Trigeminal nerve
What are the actions of mylohyoid?
Elevates the floor of the mouth and the hyoid bone
What are the attachments of geniohyoid?
Inferior mental spine of mandible to the hyoid.
What is geniohyoid innervated by?
C1 roots that run with the hypoglossal nerve
What are the actions of geniohyoid?
Depresses mandible and elevates hyoid
What are the four infrahyoid muscles?
Omohyoid
Sternohyoid
Sternothyroid
Thyrohyoid
Which two infrahyoid muscles are deeper?
Thyrohyoid and sternothyroid
What are the attachments of sternohyoid?
Sternum and sternoclavicular joint to hyoid bone
What are the actions of the infrahyoid muscles?
All act to depress the hyoid. If the hyoid is fixed, then thyrohyoid can also elevate the larynx
What supplies the infrahyoid muscles?
All supplied by the anterior rami of C1-C3, carried by a branch of ansa cervicalis
EXCEPT for thyrohyoid. This is supplied by anterior ramus of C1, carried within the hypoglossal nerve
What are the attachments of omohyoid?
Inferior belly arises at scapula. Superior belly attaches to hyoid. Joint in the middle by a tendon which is attached to clavicle by the deep cervical fascia, deep to sternocleidomastoid
What are the attachments of thyrohyoid?
Thyroid cartilage to hyoid bone
What are the attachments of sternothyroid?
Manubrium of sternum to thyroid cartilage
What is the function of the skull?
To enclose and protect the brain and special sense organs
Site of attachment for muscles and meninges
What kind of joints are the sutures of the skull?
Fibrous
What is the structure of cranial bones?
Two layers of compact bone surrounding a spongy diploe
How can the cranium be subdivided?
Calvaria which covers the cranial cavity that contains the brain
Cranial base
Facial skeleton
What are the main components of the calvaria?
Parietal Frontal Temporal Occipital Ethmoid
What are the main components of the cranial base?
Spenoid
Temporal
Occipital
What are the main facial bones?
Maxilla Nasal Lacrimal Palatine Zygomatic Inferior nasal conchae Vomer
What is the glabella?
Depression between the two superciliary arches of the frontal bone
Where is the supraorbital foramen?
The medial part of the superior orbital rim, formed by the frontal bone
What separates the paired nasal bones?
The naison
What is the piriform aperture?
Large opening in the nasal region
What structures can be visualised through the piriform aperture?
Nasal crests which end anteriorly as the anterior nasal spine
What’s the name of the inferior part of the maxilla, where teeth start?
Alveolar process
Where is the infraorbital foramina? m
Just below the inferior rim of the orbit, in the maxillary bone
What is the mental protuberance?
A midline swelling of the base of the mandible
Where are the mental tubercles?
Just lateral to the mental protuberance of the mandible
Where does the mandible articulate with the rest of the skull? ?
At the temporomandibular joint.
Coronoid process of mandible comes into contact with zygomatic bone
Which parts of the mandible unite at the angle of the mandible?
Anterior body and posterior ramus
What is the oblique line of the mandible?
A ridge that runs from the front of the ramus to the body for muscle attachment
What are some notable features of the ethmoid bone?
Horizontal cribriform plate with crista galli perpendicular to this. Also has oblique plate containing ethoid sinuses/ air cells and a perpendicular plate
What are some notable features of the sphenoid?
Has lesser wings superiorly and greater wings inferiorly. Point where these meet is a supraorbital fissure.
Also has downward projecting pterygoid process
What features are found on the internal surface of the parietal bone?
Groove for middle meningeal artery
Sagittal sulcus
Granular pits for CSF valves
Grooves for sigmoid sinus
What are some notable features of the temporal bone?
Flat squamous part superiorly, articulates with parietal bone
Zygomatic process that projects out laterally and articulates with temporal process of zygomatic bone
Styloid process projecting inferiorly
Mastoid part articulates with parietal and occipital bones. Mastoid process projects inferiorly from mastoid part
Tympanic part is immediately below origin of zygomatic process and has external acoustic opening
What are some notable features of the occipital bone?
Flat squamous part.
Superior and inferior nuchal lines either side of the external occipital crest.
Occipital condyles surrounding the foramen magnum with hypoglossal canal lateral to these condyles
What is the purpose of the cranial floor foramina?
TO reduce skull weight
To allow passage of vessels
Weaken cranial floor
What structures enter through the cranial floor foramina?
Arteries
Sensory nerves
Sympathetic fibres
(infections)
What structures leave through the cranial floor foramina
Cranial motor nerves Parasympathetic outflow Veins Lymphatics (Infections)
Where is the transverse suture?
Between the hard palate of the maxilla and the hard palate of the palatine bone
Where is the sagittal suture?
Between two parietal bones
Where is the coronal suture?
Between the frontal and parietal bones
Where is the pterion?
Point where greater wing of sphenoid, parietal, temporal and frontal bones meet
Where is the lamboid suture?
Between the parietal and occipital bones
Where is the parietotemporal suture?
Also squamous suture. Between parietal bone and squamous part of temporal bone
What is the bregma?
Point where the coronal and sagittal sutures meet
What is the lamba?
Point where sagittal and lamboid sutures meet
What are the remnants of the anterior and posterior fontanelles?
Anterior becomes bregma
Posterior becomes lambda
What is the purpose of fontanelles in newborns?
Points where sutures haven’t fully close. Adjacent bones are held together by a thick, membranous connective tissue matrix. They allow for the cranial bones to be pushed together and interlock via their serrated edges in labour, to protect the brain. Can be too wide to interlock in preterm births, however.
What are some of the typical features of a cervical vertebra?
Bifid spinous process
Transverse foramina for passage of vertebral arteries
Pedicle joining transverse process to body
Which cervical vertebrae are atypical?
C1 - has no spinous process of body
C2 - has large odontoid peg for articulation with C1
C7 - prominent, non bifid spinous process
large transverse process.
Where is the lacrimal bone?
Anteromedial wall of orbit
What are the two surfaces of the lacrimal bone?
orbital surface
Nasal surface
What are some notable features of the lacrimal bone?
On orbital surface has a vertical lacrimal crest with a lacrimal sulcus that runs anterior. The sulcus is continuous with the frontal process of the maxilla and this forms the lacrimal fossa where the lacrimal sac is found
Where is the palatine bone?
At posterior nasal cavity between the maxilla and the pterygoid process of sphenoid
Where is the skull vulnerable to fracture?
Squamous parts of temporal and parietal bones
Foramen magnum and inner sphenoid wing
Middle cranial fossa
Posterior cranial fossa
What is a depressed fracture?
A local indentation due to a sever localised blow. Bone fragment may compress or injure underlying brain
What is a linear fracture?
Fracture lines radiating away from point of impact in more than two directions. Often due to skull vault trauma
What is a comminuted fracture?
Where bone is broken into several pieces
What is a counterblow fracture?
Where fracture occurs at the opposite side of the cranium
What is a simple fracture?
Where there’s a break in the bone but no break in the skin
What is a compound fracture?
Where there’s break in or loss of skin and splintering of the bone. Accompanied by brain injury and bleeding
What is a basillar fracture?
Fracture of base of skull which can cause extravasation of blood along the path of the posterior auricular artery so presentation may be with battle’s sign/ mastoid ecchymosis
What are some symptoms of skull fracture?
Bleeding from wound, nose, ears of eyes COnfusion Dizziness Drowsiness Convulsions Bruising Draining of CSF from nose or ears Balance difficulties Headache Loss of consciousness Nausea/vomiting Visual disturbances Stiff neck Slurred speech
How can infections from scalp cause osteomyelitis?
Can spread through emissary and diploic veins
What are facial fractures most commonly caused by?
Car accidents, fist fights and falls
What is the most common facial fracture?
Of nasal bones
What can happen if there’s a hard blow to the lower jaw?
Neck of mandible can fracture with dislocation from the temporomandibular joint
What causes a black eye?
Skin bruising around orbit and accumulation of blood and tissue fluid in the surrounding connective tissue
What is malar flush?
Reddening of the skin over the zygomatic bones
What is a burst fracture?
Fracture of arches of C1. Often due to head first fall from a height
What is a hangmans fracture?
Fracture of C2 due to hyperextension of the head
What can happen as a result of a dens fracture?
If it’s displaced then may injure the spinal cord, causing quadriplegia or, if it damages brain stem, will be fatal
Why are cervical vertebrae prone to dislocation?
Due to the way that they are stacked on top of one another, can easily slip out of position.
Why may dislocation of cervical vertebrae not necessarily damage spinal cord?
Due to the large cervical canal, there’s room for manoeuvre
What changes to cervical vertebrae occur with age?
Intervertebral foramina narrow
What can happen if there’s hyperflexion of the neck?
Rupture of the lower cervical intevertebral discs, resulting in nerve root compression so can cause neck, should, arm and hand pain
What can happen if there’s hyperextension of the neck?
Can tear the anterior and posterior longitudinal ligaments, fracture of spinous processes, disc rupture and injury of muscles and blood vessels.
Where are the zygopophyseal joints?
Between articular facets of vertebrae
What can happen if there’s arthritis in zygopophyseal joints?
May be osteophyte formation. Osteophytes may affect spinal nerves, causing pain along their dermatomes and muscle spasm of corresponding myotome
What are the most common sites of cervical spine injury?
C2, C6, C7
Injuries at which spinal levels may be fatal?
C1-2
Which vessels make up the upper systemic vascular loop?
Common carotid arteries
Vertebral arteries
Internal, external and anterior jugular veins
What’s the arrangement of the main structures within the carotid sheath?
Internal jugular vein lies lateral to the common carotid artery
Vagus nerve lies posterior to both
What structure lies posteromedial to the carotid sheath?
The sympathetic trunk
Behind which anatomical structure does the right common carotid artery originate?
From brachiocephalic trunk, behind the right sternoclavicular joint
Between which anatomical structures do the common carotids bifurcate?
Midway between the angle of the mandible and the mastoid process of the temporal bone. Good landmark is the upper border of the thyroid cartilage (C4)
What bifurcation occurs within the parotid gland?
That of the external carotid artery into the maxillary artery and the superficial temporal artery
What structures run through the parotid gland?
External carotid into superficial temporal and maxillary
Retromandibular vein
Facial nerve
What are the different layers of the scalp?
Skin Loose connective tissue Aponeurosis Loose connective tissue Periosteum
Why can a laceration to the epicranial aponeurosis cause profuse bleeding?
Joins two bellies of occipitofrontalis which will then pull in opposing directions and form a gaping wound
What is the arterial supply to the dura mater and the skull?
Both supplied by middle meningeal artery via the maxillary artery
What is the distribution of the facial artery?
Supplies muscles of facial expression and the face
What is the distribution of the superior labial artery?
Supplies upper lip and the ala and septum of the nose
What is the distribution of the inferior labial artery?
Lower lip
What is the distribution of the maxillary artery?
Deep structures of the face
What is the distribution of the lateral nasal artery?
Skin of the ala and bridge of nose