1. Arteries, veins and lymphatic drainage of the head and neck. The epithelial tissue. The development of blood vessels.

1. Arteries, veins and lymphatic drainage of the head and neck. The epithelial tissue. The development of blood vessels.

Anatomy:  Arteries, veins and lymphatic drainage of the head and neck.

Arteries of Head & Neck

For this topic, you will need to discuss the branches of common carotid a, subclavian a, the veins that follow them, and superficial and deep lymph nodes of the head and neck.

In this topic, if you have time, you may want to review infratemporal fossa, carotid triangle, scalenotracheal fossa, scalenus hiatus & tent

Common Carotid a:

General Info:

• Emerges from brachiocephalic a on R side, and aortic arch on L side
• ascends in carotid sheath, w/ CN X, Int Jugular v and number of other structures (will discuss soon)
• divides into int/ext carotid at superior border of thyroic cartilage
• Has two receptors:
  • Carotid Body
    • located at the bifurcation of common carotid (Body = Bifurcation)
    • chemoreceptor = sensory receptor to detect levels of O2 & CO2
    • Or, remember that since it is located lower to the sinus, and closer to the lungs than the sinus – lungs = O2,CO2
  • Carotid Sinus
    • located at the beginning of the int carotid a (Sinus = Internal carotid)
    • baroreceptor = detects blood pressure
    • Remember that it is the one closest to the head, so need to keep track of blood pressure in the head.

Int carotid a:

• no branches in the neck,
• ascends in carotid sheath w/ CN X and IJV
• enters skull via carotid canal
• only major branch to head and neck region is ophthalmic a – exits skull via optic canal

Ext Carotid a

• emerges @ upper border of thyroid cartilage
• runs in carotid sheath, then to neck of mandible
• pierces the parotid glang, where it gives its 2 terminal branches = maxillary, and superficial temporal
• 8 main branches = Superior Thyroid, Lingual, Facial, Asc Pharyngeal, Greater Auricular, Occipital, Maxillary, Superficial Temporal.

NOTE: How to remember all the branches?

St. Louis FATSIS Apt to GO to Max Stein —- like fat people from St. Louis need to go to this famous weight loss instructor, Max Stein. Sounds stupid, but hang on – it works.

• Superior Thyroid a – St.
  • emerges at level of greater horn of hyoid bone
  • also in carotid sheath
  • branches = br. to infrahyoid m, br to SCM, sup laryngeal (which peirces the thyrohyoid membrane), br to cricthyroid m, glands
• Lingual a – Louis
  • emerges @ level of greater horn of hyoid bone
  • passes deep to hyoglossus m.
  • located w/in Pyrogov’s Triangle – Clinical note – by pushing at the location of triangle, can stop bleeding from branches of lingual a
    • Borders:
      • ant = mylohyoid m
      • post = post digastric m
      • sup = hypoglossal n (CN XII)
      • floor = hyoglossus m
    • part of the Submandibular triangle (see salivary gland topic)
  • branches = suprahyoid a, dorsal lingual a, sublingual a, deep lingual a
  • supplies most of blood supply of tongue
• Facial a  – Fatsis
  • emerges just above lingual a, goes forward, deep to post digastric m & stylohyoid m
  • hooks around lower border of angle of mandible @ ant border of masseter (jsut deep to platysma)
  • run diagonally to the medial corner of the eye, running deep to zygomatic major & levator labii superiorus
  • major blood supply to face, terminates with angular a.
  • branches = FATSIS – is an abbreviation for facial and all its branches
    • F = facial
    • A = asc palatine
    • T = tonsillar
    • SI = Sup/Inf labial
    • S = submental
• Asc Pharyngeal a – Apt
  • in carotid triangle
  • asc b/w int carotid & wall of pharynx
  • branches = pharyngeal, palatine, inf tympanic, meningeal branches
• Greater (Posterior) Auricular a – G
  • arises just above post digastric –> deep to parotid –> runs superficial to styloid process
  • branches = stylomastoid, auricular, and occipital branches
• Occipital a – O
  • emerges just above the hyoid bone –> passes deep to post digastric –> occipital groove –> on mastoid process
  • branches =
    • a to SCM – over CN XII, anatomosis w. SCM branch of sup thyroid a
    • decending br – has 2 branches
      • superficial – anatomosis w/ superficial br of transverse cervical a
      • deep – anatomosis w/ deep br of deep cervical a (from costocervical trunk of subclavian a
• Maxillary a – Max
  • lies in infratemporal fossa
  • many many branches  = How to remember them? DAAM I Bite SPAIDS.
  • divided into 3 parts by lat pterygoid m
    • Part 1 = Mandibular = DAAM I – 5 branches
      • Deep auricular a
      • Ant tympanic a
      • Acc meningeal a
      • Middle meningeal a – can be shown in practical exam
      • Inf alveolar a – can be shown in practical exam
    • Part 2 – Pterygoid = Bite (Bite = muscle of mastication) – 5 branches
      • lat & med pterygoid a
      • massteric a
      • buccal a
      • deep temporal
    • Part 3 – Pterygopalatine = SPAIDS – 7 branches
      • Sup (post/mid) alveolar a
      • Pharyngeal a
      • A. of pterygoid canal
      • Infraorbital a
      • Desc Palatine a
      • Sphenopalatine a
• Superficial Temporal a
  • terminal branch
  • emerges on face b/w TMJ and ear
  • runs w/ auriculotemporal n, sup temporal v
  • branches = transverse facial a (b/w zyg arch & parotid duct), frontal/parietal br
  • transv. facial a gives blood supply to parotid gland, duct, masseter and skin of face

Subclavian a

• br of Brachiocephalic trunk on R, arises from arch of aorta on L
• Pathway: enters neck behind the sternoclavicular joint –> runs towards the apex of pleura along the mediastinal surface –> over the apex –> turns forward and down along sternocostal surface of apex –> exits neck to enter thorax @ scalenus hiatus w/ brachial plexus
• has 3 divisions, separated by ant scalene m.
• NOTE = to remember the # of branches – its opposite of part # – i.e. Part 1 has 3 branches, Part 2 has 2 branches, and Part 3 has 1 branch (sometimes)
  • 123=321

Thoracic part = medial to ant scalene m – 3 branches, b/w trachea and ant scalene m

• Vertebral a – has a med/sup path –> goes thru transverse foramen of  C6-C1 –> thru post occipital membrane –> foramen magnum
• Int Thoracic a – runs along the inside of thoracic wall
  • 1st 6 ant intercostal a
  • sup epigastric – medistinal, thymic, sternal br
  • musculophrenic – gives the ant intercostal arteries 7-10
• Thyrocervical trunk – 3 branches again
  • Transverse cervical a – under  SCM –> occipital triangle –> runs below trapezius m
  • Suprascapular a – runs parallel to clavicle w/ a/v/n — anatomosis w/ circumflex scapular a
  • Inf thyroid a – asc along thyroid gland and anatomosis w/ asc cervical a

Muscular part = behind ant scalene m. – 2 branches, = Costocervical trunk

• Supreme IC a – gives 1st 2 post IC a
• Deep cervical a – blood supply to deep m of back, asc along levator scapulae m.

Cervial part = lat to ant scalene m – 1 branch, sometimes

• dorsal scapular a – only present if suprascapular a is missing
• usually no branches here

Veins of Head & Neck

Veins mostly follow the arteries, so there is no need to go into each branch. Also, veins have an extremely variable branching pattern, so your body may be different from what is laid out here. We’ve seen a body with 2 Ext Jugular v!

To learn veins of any area – just draw the picture a bunch of times. Hell, draw it on the exam.

Here’s an “in general” flow pattern of the veins:

• Supraorbital v + Supratrochlear v = angular v at the corner of the eye
• angular v + deep facial v = facial v
• Maxillary v + Superficial temporal v = Retromandibular v
• ant branches of Retromandibular v + Facial v —> flows into IJV, w/ a bunch of other v
• post branches of Retromandibular v + Post Auricular v = EJV
• Ant Jugular —> flows into EJV
• Subclavian v collect veins that follow the arteries that branch off subclavian a
• Subclavian v + IJV = Brachiocephalic v —- called angulus venosus, also where major lymph ducts of the the body drain into
• EJV can flow into Subclavian v OR IJV OR angulus venosus itself (the intersection of the 2 veins)

Other vein info, specifics: Doubt you have to know this, but rather give u extra info, than not at all.

• Supratrochlear v = begins as a collection of veins connected to the frontal branches of superficial temporal v
• Supraorbital v = begins also in the forehead, where it connects w/ branches from supratrochlear, superfical temporal v, and middle temporal v, a branch of it passes through supraorbital notch to anatomose w/ superior ophthalmic v
• Together, these 2 v. drain ant part of scalp and forehead
• Facial v = runs from medial angle of eye and inf border of orbit, starting from angular v, is much straighter than than facial a
  • receives pterygoid venous plexus (via deep facial v), sup/inf labial v
  • branch of it anatomose w/ superior ophthalmic v
  • drains ant scalp, forehead, eyelids, ext nose, ant cheek, lips, chin, submandibular gland
• Superficial temporal v = receives a number of v of scalp/zygomatic arch, runs thru parotid gland
  • drains side of scalp, superficial aspect of temporalis m, ext ear
• Retromandibular v = formed by union of superficial temporal & maxillary v
  • is post to ramus of mandible, goes thru parotid gland, has ext carotid a behind and facial n in front of it
  • drains masseter m, and parotid gland

Lymph Drainage of Head & Neck

The head and the neck, each have a set of superficial & deep lymph nodes and vessels. The superficial lymph nodes and vessels run with veins, deep lymph nodes and vessels run with arteries. All lymph from head and neck drains into deep cervical lymph nodes, that run w/ IJV.

Superficial lymph nodes of Head:

• In general, the face, scalp, and ear –> drains into occipital, retroauricular, parotid, buccal, submandibular, submental, superficial cervical l.n.
• lat face, including eyelids –> parotid l.n. –> deep cervical l.n
• upper lip, lat lower lip –> submandibular l.n.
• chin, central lower lip –> submental l.n.

Deep lymph nodes of Head:

• middle ear –> retropharyngeal & upper deep cervical l.n.
• nasal cavity/ pasanasal sinuses –> submandibular, retropharyngeal, upper deep cervical l.n.
• tongue –> submental, submandibular, upper/lower deep cervical l.n.
• larynx –> upper/lower deep cervical l.n.
• pharynx –> retropharyngeal, upper/lower deep cervical l.n.
• thyroid –> lower deep cervical, prelaryngeal l.n., pretracheal l.n., paratracheal l.n.

Superficial cervical lymph nodes:

• lie along the ext jugular v in posterior triangle & along ant jugular v in anterior triangle
• drain into deep cervical nodes

Deep cervical lymph nodes:

• Superior
  • lie along int jugular v, in carotid triangle of neck
  • receive: lymph from back of head and neck, tongue, palate, nasal cavity, larynx, pharynx, trachea, thryroid gland, & esophagus
  • efferent vessels that join those of the inf deep cervical nodes to from jugular trunk –> thoracic duct on L, and angulus venosus on R
• Inferior
  • lie on the IJV, near subclavian v
  • receive lymph from ant jugular, transverse cervical, axillary nodes

Histology:  The epithelial tissue.

Epithelium = sheets of cells that cover external surfaces of the body, line internal cavities, form various organs,glands and ducts. Remember that it is avascular – no blood vessels!

Epithelium can be classified in 3 ways: functionally, # of cell layers,  & structure of surface cells

Functional groups:

• Lining epith – formation of barrier on surface of body, ex/ skin, inner stomach
• Glandular epith – production/secretion of substances to extra cellular territory in high amt
• Sensory epith – for special sensations, ex/ taste buds, olfactory

Epithelium has what is called functional polarity = basically, this means that different sides of the cells have different functions.

• Basal side:
  • attached to basement membrane = basement lamina + reticular fibers
  • has hemidesmosomes
  • protein, polysaccharides rich layer
• Lateral side:
  • intracellular junctions = tight, adherent, desmosomes
• Apical side:
  • microvilli – inc surface absorption
  • kinocilia – move substances across apical surface
  • stereocilia – sensory function, absorption

Cell-Cell Junctions

• Occluding/Tight Jxns: impermeable and allow epithelia cells to functions as a barrier
  • form primary intercellular diffusion barriers b/w adjacent cells
  • located @ most apical part
  • Proteins:
    • occludins – maintain barrier b/w cells, @ apical/lateral domains, not in all tight jxns
    • claudins – form backbone of each strand, form extracellular H2O  channels for ions and small molecules
    • JAM (Junctional adhesions molecule) – immunoglobulin, w/ claudins, interactions b/w endothelium & monocytes
• Anchoring Junctions: mechanical  stability to epithelium, by linking cytoskeleton of 1 cell to adjacent cell.
  • interact w/ both actin & intermediate filaments
  • lateral cell surface, basal domain
  • signal transductions capability, cell-cell recognition, cell differentiation, morphogenesis
  • Zonula adherens – interact w/ network of actin filaments inside cell, lateral adhesion
  • Macula adherens (desmosomes) – interact w/ network of intermediate flaments
• Communication Junctions (Gap): direct communications b/w adjacent cells by diffusion of small molecules
  • epithelia, smooth m, cardiac m, and nerves
  • open communication – quicker exchange of ions, regulatory molecules, small metabolites
  • easier to coordinate activity
  • Proteins = connexons, in 6 subunits of 2 = connexin

Apical Modifications:

• Microvilli
  • small, non motile projections that cover all absorptive cells in SI and prox convoluted tubules in kidney
  • proteins = villin, actin filaments, fimbrin, fascin, myosin I in core, and spectrin & myosin II in base
  • sit on intermed filaments
• Kino cilia
  • motile structures that are found in uterin tubes, uterus, repiratory system
  • move substances across a surface
  • dark line @ apical surface

  • 2 microtubules in center, surrounded by 9 doublets of microtubles, w/ dynein, & nexin
• Sterocilia
  • long, non motile branched microvilli of sorts that cover cells in epididymis & vas deferens
  • absprption!
  • Proteins: actin filaments, erzin, fimbrin in core, and alpha -actinin in base

Classification by layers

• Simple – one layer of cells only, attached directly to basement membrane
• Stratified – multiple layers of cells
• Pseudostratified – one layer of cells, all attached to basement membrane, but have varying heights, so appear stratified

Classification by morphology

• squamous – flat cells
  • Simple squamous –
    • called mesothelium on the outside surfaces of lungs, heart, digestive organ == i.e. where-ever there is pleura, pericardium, or peritoneum, there is mesothelium anatomically – Histo wise, this is called a serosa covering.
    • called endothelium on the internal surface of arteries, lymph vessels, and internal surface of heart
  • Stratified squamous –
    • keratinized – top cells are dead & have no nuclei, are instead filled w/ keratin protein  – located in external areas of body ex/ skin
    • non-keratinized – live surfaces, all cells of epithelium alive – located in areas exposed to outside elements, but not on external areas of body ex/ oral mucosa, pharynx, vagina, anal canal, esophagus.
• Cuboidal – height = width
  • Simple cuboidal – excretory ducts, like prox convoluted tubules of kidney, very common in glands
  • Stratified cuboidal – not as common, ducts of salivary glands and pancreas
• Columnar – height > width
  • Simple columnar – characteristic of digestive organs, like in stomach and gallbladder, SI, LI – tend to have microvilli
  • Stratified columnar – limited in body, ducts again
• Transitional Epithelium = Urothelium
  • located in urinary system, like bladder and ureter, and minor/major calices – NOT IN URETHRA
  • Cell Types:
    • Umbrella cells – binucleated, is dome shaped when urinary structures are empty, flat when full
    • Piriform cells – in the middle
    • Basal cells – single layer on bottom , right above BM

Embryology:  The development of blood vessels

Blood vessels develop in two ways:

• vasculo genesis – vessels arise from the combination of blood islands aka angioblasts – mainly dorsal aorta, & cardinal veins
• angiogenesis – vessels arise from existing vessels

Development of arteries

• Aortic sac develops from distal part of truncus arteriosus
• sac gives a set of aortic arches, one to each pharyngeal arch
• arches terminate in two (R&L) dorsal aortas
• aorticopulmonary septum divides outflow part of truncus arterious into ventral aorta & pulmonary trunk
• dorsal aorta b/w 3rd and 4th arch disappears (carotid duct)
• R dorsal aorta disappears b/w 7th segmental aorta and L dorsal aorta
• heart is pushed into thoracic cavity by folding of embryo
• because of the heart movement – this is why recurrent laryngeal a is in diff location in R & L side

Aortic Arches:

• Arch I = part of maxillary a, by day 27
• Arch II = part of stapedial a & hyoid a
• Arch III = part of R &L common carotid a, R&L int carotid a
• Arch IV = part of R subclavian a, and part of aortic arch on L
• Arch V = disappears
• Arch VI = part of R &L pulmonary a, ductus arteriosus – connection b/w pul a & arch of aorta, is ligamentum arteriosum in non fetal life

Dorsal Aorta

• R & L dorsal aortae combines into dorsal aorta.
• from dorsal aorta, originates posterolateral a, lateral a, and ventral a
• Posterolateral a = a to upper and lower limb, IC, lumbar and lateral sacral arteries
• Lateral a = renal, suprarenal, and gonadal arteries *NOTE = paired visceral arteries of abdominal aorta
• Ventral a
  • Vitelline a = celiac, superior mesenteric, inf mesenteric a *NOTE = unpaired visceral arteries of abdominal aorta
  • Umbilical a = part of Int Iliac, superior vescical arteries, run in medial umbilical ligaments. = PELVIS

Coronary a – from 2 sources

• angioblasts formed elsewhere and sent over the heart surface
• from epicardium – some of its epithelial cells will become mesenchymal cells due to some reaction from underlying mesenchyme
  • new mesenchyme and neural crest cells create smooth m cells in these arteries
  • endothelial cells from these arteries push into aorta

Development of Veins

• develop mainly from three pairs of veins = vitelline v, umbilical v, and cardinal v —> empty blood into sinus venosus
• vitelline v = carry blood from yolk sac
  • become hepatocardiac part of IVC, hepatic v &sinusoids, ductus venosus, portal v, inf mesenteric v, sup mesenteric v, splenic v
  • form plexus around duodenum and pass thru septum transversum, pushing into liver to form sinusoids
  • the duodenal plexus becomes the portal v
• umbilical v = from chorionic villi and carries O2 blood to embryo
  • pass on each side of liver, some connect to sinusoids
  • only L umbilical v remains to carry blood from placenta to liver — becomes ligamentum teres of liver, and ductus venosus, to become ligamentum venosum in life.
• cardinal v = drains embryo itself
  • Ant =drain cephalic part of embryo intially–> SVC, int jugular v, L brachiocephalic v
  • Post = drain rest of embryo initially –> part of IVC, R common iliac v
  • Subcardinal v = drain kidneys –> renal v, part of IVC, gonadal v
  • Sacrocardinal = drain lower limb –> sacrocardinal part of IVC, L common iliac v
  • Supracardinal v = drain body wall via IC v (takes over fxn of post cardinal v) –>part of IVC, IC v, azygos system

Anim = Development of Aorta, Pulmonary Trunk, and Interventricular Septum

Anim = Aortic Arch Vessels