Triangles of the Neck Flashcards
what divides the two triangles?
sternocleidomastoid muscle
boundaries of anterior triangle
anterior: midline of neck
posterior: anterior border of SCM
base: mandible
what are the 4 parts of the anterior triangle?
submental
submandibular
carotid
muscular
what is in the submental part of the anterior triangle?
submental lymph nodes
beginning of the anterior jugular vein
what is in the submandibular part of the anterior triangle?
submandibular salivary gland lymph nodes facial artery and vein carotid sheath hypoglossal nerve
what is in the carotid part of the anterior triangle?
carotid sheath
branches of ECA
internal jugular vein
hypoglossal, accessory and vagus nerves
what is in the muscular part of the anterior triangle?
sternohyoid and sternothyroid (from floor beneath)
what branches of the ECA are present in the anterior triangle?
superior thyroid
lingual
facial
where is the platysma found?
fascia above pectoralis major and clavicle –> lateral neck onto mandible
what innervates platysma?
facial nerve (CN VII)
what are the root values of the cervical plexus and what type of innervation does it provide?
anterior rami C1-4
somatic motor and sensory (and sympathetic)
where do the suprahyoid muscles run?
between the hyoid and the skull/mandible
which suprahyoid muscles are pharyngeal muscles?
digastric
stylohyoid
mylohyoid
what are the functions of the suprahyoid muscles?
raise hyoid bone depress mandible (mylohyoid and digastric)
what are the names of the four suprahyoid muscles and what innervates each one?
digastric - facial nerve (CN VII, post. belly), mandibular division of trigeminal (CN V3, anterior belly)
stylohyoid - facial nerve (CN VII)
mylohyoid - mandibular division of trigeminal (CN V3)
geniohyoid - C1 (via hypoglossal, CN XII)
where are the infrahyoid muscles found?
between the hyoid bone and sternum or thyroid cartilage
what are the names of the infrahyoid muscles?
omohyoid
sternohyoid
thyrohyoid
sternothyroid
what innervates the infrahyoid muscles?
ansa cervicalis (except thyrohyoid which is innervated by C1 via hypoglosssal CN XII)
what is the function of the infrahyoid muscles?
depress the hyoid bone/thyroid cartilage
where do the left and right common carotid arteries arise from?
left: arch of aorta
right: branch of brachiocephalic trunk
what are the terminal branches of the common carotid artery?
internal and external carotid arteries
what do the internal and external carotid artery supply?
internal: brain
external: head, face and scalp
what is found in the carotid sheath?
external and internal cartoid arteries
internal jugular vein
vagus nerve
what branches of the subclavian arteries are found in the triangles of the neck?
internal thoracic suprascapular transverse cervical vertebral artery inferior thyroid
in which triangle does the external jugular vein run?
posterior triangle
in which triangle does the internal jugular vein run?
anterior triangle
what is the root value of the vagus nerve?
CN X
what is the route of the vagus nerve?
descends down the neck in the carotid sheath
passes through the thoracic inlet into the superior mediastinum to supply parasympathetic innervation to the thorax and abdomen
what are the main branches of the vagus nerve?
recurrent laryngela (to muscles of larynx, left around arch of aorta, right around subclavian) internal and external laryngeal branches
what connects the two lobes of the thyroid gland?
isthmus and capsule
where is the thyroid gland found?
lamina of thyroid cartilage –> 6th tracheal ring
ishmus is over tracheal ring 2/3
where are the parathyroid glands found?
embedded on posterior surface of thyroid
what arteries supply the thyroid?
superior thyroid (first anterior branch of the external carotid) inferior thyroid (branch of thyrocerivcal trunk of subclavian)
what provides venous drainage from the thyroid?
superior, middle and inferior thyroid vein
left and right inferior thyroid veins drain into the left brachiocephalic vein (superior and middle into internal jugular)
where does the duct of submandibular salivary gland open into?
between the first and second lower incisor (either side of the frenelum)
what innervates the submandibular salivary gland?
facial nerve (CN VII)
what are the borders of the posterior triangle?
anterior: posterior border SCM
posterior: anterior border trapezius
base: clavicle
contents of the posterior triangle
external jugular vein
roots of brachial plexus
accessory nerve
cervical and supra-clavicular lymph nodes etc.
what cutaneous nerves are found in the neck (and what are their root values)?
lesser occipital (C2) greater auricular (C2+3, runs with EJV) transverse cervical (C2+3) lateral supraclavicular (C3+4) intermediate supraclavicular (C3+4) medial supraclavicular (C3+4)
what does the phrenic nerve cross obliquely over the anterior surface of?
anterior scalene
what are the names of the two heads of the sternocleidomastoid and where are they found?
sternal head: manubrium of sternum –> mastoid process and superior nuchal line
clavicular head: medial clavicle –> mastoid process and superior nuchal line
what innervates the SCM?
motor: spinal accessory (CN XI)
pain + proprioception: cervical plexus (C2+3)
where is trapezius found?
external occipital protuberance, spinous processes of vertebrae C7-T12 –> nuchal ligament, posterior border of lateral 1/3rd clavicle, acromion process and spine of scapula
what innervates trapezius?
motor: spinal accessory nerve (CN XI)
pain + proprioception: cervical plexus (C3+4)
what is the function of SCM?
lateral flexion w/rotation
extension at atlanto-occipital joints
flexion of cervical vertebrae
function of trapezius
depress scapula (ascending part) retract scapula (transverse part) elevate scapula, rotate glenoid cavity (descending part)
where is the splenius capitis found?
nuchal ligament + spinous processes of C7-T3 –> mastoid process of temporal and occipital bone
innervation of splenius captiis
dorsal rami of middle cervical nerves
function of splenius capitis
extend and rotate the neck
where is levator scapulae found?
transverse process of atlas and axis and C3+4 –> medial scapular border between superior angle and medial end of scapular spine
function of levator scapulae
control scapular position
elevate shoulder
if shoulder fixed can laterally flex the neck to the same side
what innervates levator scapulae?
direct c3-5 via dorsal scapular nerve
where is the anterior scalene found?
transverse processes C3-6 –> rib 1 (scalene tubercle)
what innervates anterior scalene?
anterior rami C3-7
where is the middle scalene found?
transverse processes C2-7 –> rib 1 (behind subclavian artery groove)
what innervates middle scalene?
anterior rami C4-7
where is the posterior scalene found?
transverse processes C4-6 –> rib 2
what innervates middle scalene?
anteiror rami C5-7
what are the functions of the scalene muscles?
flex neck (bilateral)
tilt head to same side (unilateral)
elevate upper rubs
