Flashcards in Head And Neck Session 1 Deck (115):
What forms the primitive gut tube by the end of week 4?
Folding of the embryo
Describe the embryonic face and neck at the beginning of week 4.
No distinguishing external features
Accounts for approx. 1/2 length of the embryo
What forms a complex tissue system that involves the heart, great vessels, brain and special sensory organs?
How many pharyngeal arches are there?
What does each pharyngeal arch consist of?
Ectoderm and endoderm covering
What causes the frontonasal prominence to arise?
Swelling of the neural tube
How are the pharyngeal arches numbered?
How does the size of the pharyngeal arches change as you move from 1 through to 6?
Become progressively smaller
Which areas of the brain are predominantly involved in the pharyngeal arches?
What are the 3 vesicle stages of neural tube development?
Prosencephalon = forebrain
Mesencephalon = midbrain
Rhombencephalon = hindbrain
How can the cranial nerves be classified?
Which cranial nerves are not derived from the mid- or hindbrain?
I and II (olfactory and optic)
Which cranial nerves have mixed sensory and motor functions to supple the derivatives of the pharyngeal arches?
Which cranial nerves are involved in the development of the pharynx and tongue?
Where does the facial skeleton derive from?
PA1 and frontonasal prominence
Where do the muscles of mastication arise from?
What innervation does cranial nerve V, the Trigeminal nerve, provide?
Sensory: skin of face, lining of mouth and nose
Motor: muscles of mastication and muscles derived from mandibular process
What does PA1 divide into?
Maxillary and mandibular processes
What is Meckel's cartilage?
Prominent ossified cartilage of mandibular prominence of PA1 that forms template of mandible
What process allows formation of the mandible from Meckel's cartilage?
What happens to the aortic arch of PA1?
What happens to the aortic arch of PA2?
Where do the muscles of facial expression derive from?
Which cranial nerve is associated with PA2?
Which cranial nerve is associated with PA1?
What structures does the facial nerve pass through?
What function does the facial nerve have?
Motor: muscles of facial expression
Sensory: taste buds in anterior 2/3 of tongue
Which PA is associated with Reichert's cartilage?
What does Reichert's cartilage develop into?
Middle ear development --> stapes
Styloid process, lesser cornu and upper body of hyoid bone
Which muscles derives from PA3?
Which cranial nerve derives from PA3?
What function does the glossopharyngeal nerve have?
Sensory: general and special innervation to posterior 1/3 of tongue and pharynx
What does the cartilage of PA3 form?
Remainder of hyoid bone
What happens to the aortic arch of PA3?
Forms internal carotid
Which muscles derive from PA4?
Constrictors of pharynx
Which cranial nerve is associated with PA4?
What is the 4th arch branch of the vagus nerve?
Superior laryngeal nerve-supplies cricothyroid and pharynx constrictors
What happens to the aortic arch of PA4?
Forms arch of aorta on the L
Forms brachiocephalic artery on R
What does the mesenchyme of PA4 become?
Where do the cartilages of the larynx derive from?
Cartilage bars of PA4
What are the three cartilages of the larynx?
Where do the intrinsic muscles of the larynx derive from?
What happens to the aortic arch of PA6?
Forms pulmonary arch
Which cranial nerve is associated with PA6?
What is the 6th arch branch of the vagus nerve?
Recurrent laryngeal nerve supplying intrinsic muscles of the larynx
What does the mesenchyme of PA6 form?
What do the cartilage bars of PA6 form?
What does the size of cartilage bar associated with a PA depend on?
Size of PA itself
What do the cartilage bars of each PA derive from?
Neural crest cells
What lies in the floor of the primitive pharynx?
Mesenchyme of 4th and 6th PA
What forms the palatine tonsil?
Epithelial proliferation followed by lymphoid precursor colonisation of 2nd pharyngeal pouch
Where do the parathyroid glands derive from?
Dorsal aspect of 3rd and 4th pharyngeal pouches (3rd inferior and 4th superior)
Where does the thymus derive from?
Ventral aspect of the 3rd and 4th pouches (2 lobes migrate)
What forms the ossicles of the middle ear?
Cartilage bar derivatives from PA1&2
What forms the tympanic cavity and auditory tube?
1st pharyngeal pouch
Why usually does only the 1st pharyngeal cleft remain?
PA2 grows down to cover others and hence obliterate them
When do brachial cysts or fistulae occur?
If cervical sinus is not obliterated
Where in the neck can brachial cysts or fistulae be located?
Anywhere along the anterior border of SCM
When does the neural tube form?
What is the parapharyngeal space?
Potential space parallel to the pharynx that extends down to T2/3 level
Where does the carotid sheath extend from and to?
Base of skull to thoracic mediastinum
What are the two divisions of the pretracheal layer?
What is enclosed by the two divisions of the pretracheal layer?
Visceral: thyroid, trachea and oesophagus
Muscular: infrahyoid muscles
What is the fascial covering of the pharynx called?
Where does the retropharyngeal space extend to?
What are the attachments of the prevertebral fascia?
Superior: base of skull
Anterior: transverse process of vertebral bodies
Posterior: ligamentum nuchae
Inferior: endothermic fascia of the rib cage
What does the prevertebral fascia form?
Floor of posterior triangle
What are the attachments of the deep investing fascia?
Superior: external occipital protuberance and superior nuchal line
Anterior: hyoid bone
Inferior: spine and acromion of scapula, clavicle, manubrium of sternum
Posterior: along ligamentum nuchae
At what vertebral level does the common carotid artery branch?
Where does the first branch of the internal carotid artery go?
To the eye
What are the branches of the external carotid artery?
Which major vein is located in the posterior triangle of the neck?
Which major vein is located in the anterior triangle of the neck?
What gives neural supply to the muscles of facial expression?
CN VII-facial nerve
What are the branches of the facial nerve?
What gives neural supply to the muscles of mastication?
What are the branches of the trigeminal nerve?
Which muscles are supplied by the Trigeminal nerve?
Medial and lateral pterygoid
What gives innervation to sternocleidomastoid?
What are the nerves roots of the accessory nerve?
What gives innervation to trapezius?
Where does trapezius attach?
Ligamentum nuchae, spinous processes of C7-T12, clavicle, acromion and scapula spine
What gives innervation to platysma?
Where do the two heads of platysma arise from?
Fascia of pec major and deltoid
What is the action of platysma at the mandible?
Releases pressure on superficial veins
What is the action of platysma at its inferior attachment?
Draws corners of mouth into a grimace to convey stress/tension
Which are the suprahyoid muscles?
What is the action of the suprahyoid muscles?
Elevate hyoid and larynx during swallowing
What is the action of the infrahyoid muscles?
Depress hyoid and larynx during swallowing and speech
Which are the infrahyoid muscles?
Which hyoid muscles does the hypoglossal nerve supply?
Geniohyoid and thyrohyoid
What gives innervation to stylohyoid and digastric?
What gives innervation to mylohyoid?
Inferior alveolar nerve
Which nerve roots supply Omohyoid?
Which nerve roots supply sternothyroid?
What sensation do the accessory nerves give?
Pain and proprioception
What forms the borders of the posterior triangle of the neck?
Anterior: posterior border of SCM
Posterior: anterior border of trapezius
Inferior: middle 1/3 of clavicle
What splits the posterior triangle of the neck into subdivisions?
Describe the occipital triangle of the neck.
Larger, superior subdivision of the posterior triangle which is crossed by the accessory nerve
Describe the subclavian triangle of the neck.
Smaller, inferior subdivision of the posterior triangle that contains the distal subclavian artery
What are the borders of the anterior triangle of the neck?
Superior: inferior border of the mandible
Medial: imaginary sagital line down the midline
Lateral: medial border of SCM
What are the 4 subdivisions of the anterior triangle of the neck?
What are the borders of the submandibular triangle?
Anterior: anterior belly of digastric
Posterior: posterior belly of digastric
What does the submandibular triangle contain?
What are the borders of the sub mental triangle?
Lateral: anterior belly of digastric
What does the sub mental triangle contain?
What are the borders of the carotid triangle?
Superior: posterior belly of digastric
Inferior: superior omohyoid
What does the carotid triangle contain?
Common carotid artery
Internal jugular vein
What are the borders of the muscular triangle of the neck?
Superior: hyoid bone
Superolateral: superior omohyoid belly
Inferolateral: inferior SCM
What are the contents of the muscular triangle of the neck?
Which are the superficial suprahyoids?
Digastric and stylohyoid
Which is the intermediate suprahyoid?
Which is the deep suprahyoid?
Which are the superficial infrahyoids?
Sternohyoid and omohyoid