Flashcards in Head and neck Deck (149)
State the borders of the anterior and posterior triagles of the neck
-Anterior triangle -> ant=midline, post =ant SCM, sup=mandible, floor=vertebrae
-Posterior triangle-> ant=post SCM, post=ant trapezius, inf=clavicle, floor=scalene
State the contents of the anterior and posterior triangles
-Ant = carotid sheath (CCA, IJV, CNX), CNXII, submandibular, thyroid and parathyroid, lymph nodes
-Post = CNXI, subclavian a, EJV, brachial plexus trunks, lymph nodes
Where does the CCA bifurcate?
What are the advantages of the neck being separated by fascial planes?
-Allows ease of movements of individual compartments, limits infection
Describe the hyoid bone, state its functions and describe the muscles associated with it.
-Horseshoe shaped bone situated at c3 anchored by strap muscles. Elevates and depresses the larynx in order to aid swallowing
-Elevation by suprahyoid muscles -> digastric, stylohyoid, mylohyoid and geniohyoid
-Depression by infrahyoid muscles -> omohyoid, thyrohyoid, sternohyoid and sternothyroid
Name the layers of the neck
-Deep Cervical fascia
What lies within the deep fascia of the neck?
State the layers of the pretracheal fascia and what is contained within this layer. Why is it beneficial that these structures are separated?
-Muscular and visceral layers
-Trachea, oesophagus, thyroid and infrahyoid muscles
-Allow independant movement during swallowing
What are superficial infections like cellulitis limited to the superficial space?
-Cannot cross deep investing fascia
What is the retropharyngeal space? Why is there a danger space within here?
-Area between pretracheal fascia and paravertebral fascia
-Split into two by alar fascia which joins carotid sheath
-Behind alar fascia lies danger space which connects to diaphragm and therefore would allow infections to spread into the thorax
Why would a parapharyngeal abscess be potentially life threatening?
-Could compress the carotid sheath and lead to IVC thrombosis
State the muscles of facial expression, the nerve which innervate them (and its branches), which pharyngeal arch its related to and state 2 diseases which can affect these muscles
-Frontalis, orbicularis oculi, orblicularis oris, zygomatic mj and mn, buccinator
-CNVII (temporal, zygoatic, buccal, mandibular, cervical)
-Stroke and Bells palsy
State the muscles of mastication, the nerve which innervate them, which pharyngeal arch its related to
-Massater, Temporalis, med and lateral pterygoids
What are the branches of the ECA?
Name the branches of trigem and state their functions
-Opthalmic ->sensory to forehead, upper eyelids and dorsum of nose
-Maxillary -> sensory to cheeks, wings of nose, upper lip/teeth,hard palate and sinuses
-Mandibular -> sensory to temple, mandible, lower lip/teeth, motor to MoM
What is the most common cause of non-traumatic facial palsy? How does facial palsy present?
-Inflammation of CNVII near exit through stylomastoid foramen
-Total unilateral facial paralysis including forehead, inability to close eyelid, loss of integrity of oral cavity
Describe the pharyngeal arch system
-5 external buldges which have a mesenchymal core, ectodermal covering and endodermal lining
-In between each arch exteriorly there is a pharyngeal cleft and interiorly there is a pharyngeal pouch
-Undergo extensive modification to become embryonic head and neck
-Each arch as an associated artery, nerve and cartilage bar
State the borders of the sections of the pharynx
-Naso = Back of nasal cavity to soft palate in line with C1
-Oro = soft palate to epiglottis in line with c2/3
-Laryngo = epiglottis to inferior border of cricoid cartilage in line with c3-c6
Briefly describe the formation of the neural tube. What disease occurs when there is defects in neural tube formation?
-The notochord signals to overlying ectoderm to become neuroectoderm. Neuroectoderm thickens and the edges elevate out of the neural plate and curl towards each other. Fuse to form the neural tube.
-Expanstion of the cranial end produces 3 vesicles named proencephalon, mesencephalon and rhombencephalon which become the forebrain, midbrain and hindbrain respectively.
Where is the facial skeleton derived from?
-Frontonasal prominences and neural crest of PhA1
Describe the derivatives of the 1st pharayngeal arch (artery, nerve, muscles, cartilage, cleft and pouch)
-Artery regresses, nerve is CNV, muscles of mastication, cartilage is meckels and produces the mandible, malleous and incus, cleft forms external auditory meatus and pouch forms middle ear cavity and eustachian tube
Describe the derivatives of the 2nd pharayngeal arch (artery, nerve, muscles, cartilage, cleft and pouch)
-Muscles of facial expression
-Reicherts cartilage -> Stapes, styloid process, lessercornu and upper body of hyoid bone
-Cleft -> obliterated by growth of 2PA
-Pouch -> Palatine tonsil
Describe the derivatives of the 3rd pharayngeal arch (artery, nerve, muscles, cartilage, cleft and pouch)
-Artery becomes internal carotid
-Nerve -> glossopharyngeal
-Muscles -> stylopharyngeus
-Cartilage -> greater cornu and lower body of hyoid bone
-Cleft -> Obliterated by growth of 2nd arch
-Pouch -> Thymus and parathyroid gland
Describe the derivatives of the 4th and 6th pharayngeal arch (artery, nerve, muscles, cartilage, cleft and pouch)
-4th artery = L Arch of aorta, Right Brachiocephalic
-6th artery -> pulmonary trunk
-Nerve -> Vagus
-Muscles -> Intrinsic muscles of the larynx and epiglottis
-Cartilage -> Thyroid, artynoid and cricoid cartilage
-Cleft -> obliterated by the growth of the 2nd PA
-Pouch -> 4th contributes to parathyroid gland
Describe the function of CNIX
-Innervates stylopharyngeus and provides special sensation to posterior 1/3 tongue
-Provides sensation to external and middle ear,pharynx, tonsils and soft palate
-Carotid bodies and carotid sinus
-Parasymp to parotid (lesser petrosal nerve)
Describe the course of the vertebral arteries
-Arise from the base of the L and R subclavian and ascend through transverse foramina of C1-6 and unite to form basilar artery
Which vessels anastamose to form the circle of willis?
-Basilar and ICA
Which vessels arise from the base of the subclavian?
-Vertebral, thyrocervical trunk and internal thoracic
Give the branches of the thyrocervical trunk
-Ascending and transverse cervical