Joints between typical cervical vertebrae
Cervical vertebrae are the superior most vertebrae of the spine
Typical cervical vertebrae have multiple articulations and ligaments:
Joints:
Intervertebral discs:
- symphysis type joint
- a typical cervical vertebrae articulates with the superior and inferior vertebral bodies via an intervertebral disc (fibrocartilaginous disc, central nucleus pulposus and an annual ligament)
- C3 articulates with C2 via the C2/3 interveterbral disc
- C3 articulates with C4 via the C3/4 intervertebral disc
Zygohypophyseal joints:
- synovial joints between vertebral arches
the superior facets of the vertebrae would articulate with the inferior facets of the vertebrae above it
inferior facets of the vertebrae would articulate with the superior facets of the vertebrae below it
Uncovertebral joints:
superior surface of the vertebra below curves upwards to form a hyaline covered lip
articulates with the inferior bevelled surface of the vertebra above
Ligaments:
anterior longitudinal ligament
- runs along anterior aspect of the vertebral bodies and intervertebral discs
posterior longitudinal liagment
- runs along posterior vertebral bodies and discs
ligamentum flava
- bridging the laminae of the vertebrae
interspinous ligament
- bridging the spinous processes
supraspinous ligament/Nuchal ligament
- bridging the tip of the spinous processes
Blood supply:
arterial: ascending cervical, vertebral arteries
venous: basivertebral veins, internal and external vertebral venous plexi
Innervation:
cervical nerve roots
Variants transitional vertebrae cervical rib fusion of vertebrae hemivertebrae butterfly vertebrae unfused vertebrae
wrist joint
wrist joint is also known as the radiocarpal joint
connection of the forearm to the hand
- condyloid joint
- articulation between the proximal row of the carpal bones: scaphoid, lunate, triquetrum and the distal radius
Articulation:
- Radius articulates with the scaphoid and lunate
- Ulna articulates with the triquetrum by the triangular fibrocartilage complex
- multiple ligaments enforce this joint
Ligaments
- radial collateral ligament
- radiolunate ligament
- radioscapholunate ligament
- radioscaphocapitate ligament
- dorsal radio scaphoid ligament
- dorsal radiolunate
- dorsal radiotriquetral
Relations
Anterior: flexor retinaculum, contents of the carpal tunnel (flexor digitorum profundus, superficialis, flexor pollicis longus, median nerve), ulna nerve and vessels, palmaris longus
Posterior: extensor retinaculum, extensor digitorum tendons, extensor indices, extensor digital minimi, extensor carpi ulnaris, extensor carpi radialias and brevis tendons
Arterial
- radial and ulna arteries
Venous
- radial and ulna veins
Innervation
- anterior interosseous nerve from median nerve
- posterior interosseous nerve from radial nerve
Variants
- ulna variance at the radiolunate articulation: neutral, positive or negative
Lunate
the lunate is one of the bones of the proximal carpal row in the wrist
- proximal carpal row
- in between scaphoid and triquetral bones
- crescenteric shape
- convex proximal and concave distal articular facets
- forms part of the radiocarpal joint
- multiple articulations
articulations
- scapholunate
- lunate-triquetral
- lunate capitate
- lunate hamate
- TFCC
ligaments
- radioscapholunate
- radiolunate (ventral and dorsal)
- scapholunate
- lunate triquetral
- ulnolunate
blood supply
dorsal radiocarpal and intercarpal arch
dorsal venous arch drainage
innervation
anterior and posterior interosseous nerves median and radial respectively
variants scapholunate coaliation lunate triquetral coaliation absent lunate radiocarpal ulna variance accessory ossicles: os epilunatum, os hypotriquetrum, os hypolunatum
lymph node levels in the neck
Cervical lymph nodes are the main lymphatic drainage of the head and neck region
important in SCC grading
divided into 7 levels:
Ia:
- submental lymph nodes
- superiorly bounded by mylohyoid muscle and inferiorly by lower margin of hyoid bone
- in between the anterior bellies of the digastric muscle
Ib:
- submandibular lymph nodes
- bounded anteriorly by the anterior belly of digastric and posteriorly by posterior margin of the submandibular gland
- similar superior and inferior boundaries
IIa:
- internal jugular lymph nodes
- posteriorly bounded by the posterior boundary of sternocleidomastoid
- anterior, posterior, lateral or medial to internal jugular vein
- extending from base of skull to lower margin of hyoid bone
IIb:
- posterior to internal jugular vein with a fat plane between them
- similar boundaries as with IIa
III
- internal jugular lymph nodes
- inferior border of hyoid to inferior border of cricoid cartilage
- posteriorly bound by posterior border of sternocleidomastoid muscle
- lateral to common carotid artery/internal carotid artery
IV
- internal jugular lymph nodes
- inferior border of cricoid to clavicle
- posteriorly bound by posterior border of sternocleidomastoid
- lateral to common carotid artery
Va
- posterior triangle lymph nodes
- posterioly bound by anterior border of trapezius muscle
- superior: base of skull to inferior border of cricoid cartilage
Vb
- inferior border of cricoid to clavicle
VI
- pretracheal/Delphian
- hyoid to manubrium
- anterior to II, III, IV
VII
- superior mediastinal lymph node
- manubrium to brachiocephalic vein
Scalenus anterior
Scalenus anterior is one of the anterior muscles of the neck
- originates from C3-6 transverse processes and vertebral bodies
- inserts onto the scalene tubercle, superior border of 1st rib
- elevates the 1st rib during inspiration
- adjunct in neck rotation and flexion
- covered by pre vertebral fascia
relations
anterior: platysma muscle, subclavian vein, clavicle, phrenic nerve, vagus nerve
posterior: anterior rami of C3-T1, middle scalene muscle, subclavian artery
lateral: sternocleidomastoid muscle, trunks of brachial plexus
Arterial
- ascending cervical artery
Venous
internal jugular vein
Nerves
- ventral rami of cervical nerve roots C3-6
Lymphatics
- level II-IV cervical lymph nodes
Variants
- absent
- asymmetrical
- varying vertebral levels of origin
Constrictor muscles of the pharynx
the pharynx is part of the aerodigestive tract that connects the nasal and oral cavities to the oesophagus
- the pharynx could be divided into nasopharynx, oropharynx and hypopharynx
- nasopharynx, posterior to nasal choanae, extends from the pharyngeal vault to the soft palate
- oropharynx from soft palate to superior tip of epiglottis
posterior to base of tongue - hypopharynx is epiglottis to superior border of cricoid cartilage
- hypopharynx communicates with the larynx anteriorly and oesophagus posteriorly
- external circular superior, middle and inferior pharyngeal constrictors
- internal longitudinal muscles: palatopharyngeus, stylopharyngeus, salpingopharyngeus
Superior:
- origin: pterygoid hamulus, pteyrgomandibular raphe and mandible
- insertion: pharyngeal raphe
- artery: ascending pharyngeal artery
- nerve: pharyngeal plexus
Middle:
- origin: greater cornu and lesser cornu of hyoid, stylohyoid ligament
- insertion: pharyngeal raphe
- artery: ascending pharyngeal, tonsilar artery
- nerve: pharyngeal plexus
Inferior:
- origin: cricoid and thyroid cartilage
- insertion: pharyngeal raphe
- artery: ascending pharyngeal artery
- nerve: pharyngeal plexus
Lymphatics
Retropharyngeal lymph nodes
Sternocleidomastoid
sternocleidomastoid is one of the paired muscles of the neck which helps in head flexion and rotation
- originates from the manubrium and medial clavicle in two heads with a single insertion
- oblique path to insert onto the mastoid process and superior nuchal line of the occipital bone
- invested within the deep cervical fascia
- superficial to the strap muslces, scalene muscles
- deep to the platysma muscle
- divides the neck into anterior and posterior triangles
relations
anterior: trachea, thyroid, cricoid and thyroid cartilage, tracheal rings
posterior: posterior triangle of the neck, level V cervical lymph nodes, trapezius muscle
deep: strap muscles, scalene muscles, common carotid artery, internal jugular vein, carotid sheath
superficial: platysma, deep cervical fascia, external jugular vein
arterial
superior thyroid and occipital arteries
lymphatics
Level II, III, IV deep cervical lymph nodes
innervation
Accessory nerve
Variants absent mastoid insertion absent clavicular or sternal head fusion with trapezius muscle additional clavicular head separate bellies for sternomastoid and cleidomastoid
Phrenic nerve
phrenic nerve is a paired mixed motor and sensory nerve that courses through the neck and thorax to innervate the diaphragm
- paired phrenic nerves
- arising from C3-5 of the cervical plexus
- descends on anterior surface of scalenus anterior muscle
- travels posterior to subclavian vein and anterior to subclavian artery
- enters the thoracic cavity through the superior thoracic aperture
- left and and right have varying courses thereafter
Left
- lateral aspect of the left heart border
- left to the aortic arch, left subclavian artery, left atrium and ventricle
- pierces the left hemidiaphragm
- splits into anterior, lateral and posterior branches to supply the underside of the diaphragm
Right
- lateral aspect of right heart border
- right of the superior vena cava, right atrium and ventricle and inferior vena cava
- exits the thorax through the vena caval hiatus
- divides into anterior, lateral and posterior branches to supply the under surface of the diaphragm
Supply:
Motor: diaphragm
Sensory: pericardium, mediastinal pleura, central diaphragmatic pleura and peritoneum, diaphragm
Variants
- anterior course to subclavian vein
- lateral border of anterior scalene
- pierce anterior scalene
- accessory phrenic nerve
- supply subclavius muscle
Pituitary fossa/gland
the pituitary fossa is a midline dural lined structure in the sphenoid bone which houses the pituitary gland
the pituitary gland is an important neuroendocrine gland
- pituitary gland acts as the main endocrine interface between the central nervous system and the body
- sits within the sella turcica of the sphenoid bone
- the pituitary gland is comprised of 2 lobes: anterior and posterior lobes
- divided in the middle by the pars intermedia
- anterior lobe: pars distalis, pars tuberalis and pars intermedia
- posterior lobe: neurohypophysis
- anterior Rathke’s pouch forms the pars distalis: anterior pituitary lobe whilst its posterior margin regresses into the vestigeal pars intermedius
- pars tuberalis surrounds the anterior aspect of the infundibular stalk
- the posterior pituitary is an extension of the hypothalamus via the infundibular stalk
- oxytocin and ADH are synthesized in the hypothalamus and stored within the posterior pituitary
Boundaries of the pituitary fossa
- pituitary fossa is where the pituitary gland sits
- body of the sphenoid
- anterior: tuberculum sallae
- posterior: dorsum sellae
- inferior: sella turcica
- superior: diaphragm sellae
- lateral walls and roofs are dural slings between the anterior and posterior clinoidprocesses
Contents
- pituitary gland
- pituitary vessels
- anterior and posterior intercavernous sinus
- CSF
Relations
anterior: orbital apex, clinoid ICA, frontal lobes
lateral: temporal lobes, cavernous sinus
inferior: sphenoid sinus
superior: suprasellar cistern, circle of willis, optic chiasm
posterior: dorsum sellae, posterior fossa
Blood supply Circuminfundibular anastomosis inferior hypophyseal arterial circle - superior hypophyseal artery - infundibular artery - prechiamsal artery - inferior hypophyseal artery - capsular artery - artery of the inferior cavernous sinus
venous:
portal venous plexus
cavernous and intercarvernous sinus
variants
- rathke’s cleft cyst
- absent pituitary gland
- hypoplasia
- hyperplasia
- duplication
- partial empty sella turcica
- enlarged fenestration of the diaphragm sellae
Median nerve
one of the 5 main nerves originating from the brachial plexus
- formed from the lateral root from the lateral cord and medial root of the median cord of the brachial plexus
- C5-T1 origin
- the nerve lies lateral to the axillary artery in the axilla
- enters arm at inferior margin of teres major
- adjacent to brachial artery before entering cubital fossa
- at cubital fossa it lies medial to brachial artery and biceps tendon
- enters the fore arm between two head of pronator teres muscle and gives off the anterior interosseous nerve
- courses towards the wrist with ulna nerve and vessels deep to flexor digitorum profundus
- enters carpal tunnel under the flexor retinaculum
- gives off motor and cutaneous branches
Branches
anterior interosseous- flexor digitorum superficialis, flexor carpi radialis, flexor digitorum profundus (radial half), palmaris longus
motor hand: thenar muscles and radial 2 lumbricals
palmar cutaneous branch: innervates thumb, index, middle finger and radial aspect of 4th finger
articular branches to elbow, wrist, carpal, phalangeal joint
variant
- high division
- bifid median nerve
- accessory branching proximal or distal to carpal tunnel
- variant course of thenar branch
- aberrant origin to the motor branch, under or through the flexor retinaculum
Ulna nerve
the ulna nerve is one of the 5 main nerves of the brachial plexus
- motor and sensory supply
- terminal branch of medial cord of brachial plexus
- C8-T1 nerve root fibers
Arm
- medial to axillary artery
- medial to brachial artery on coracobrachilas muscle anterior compartment
- passes through the posterior arm compartment between the medial intermuscular septum and medial head of triceps
- pass posterior to medial humeral condyle into the cubital tumnnel
Forearm
- enter forearm via the two head of flexor carpi ulnaris
- superifical to flexor digitorum profundus
- deep to flexor carpi ulnaris
- runs lateral to FCU at wrist
Hand
- dorsal cutaneous branch then
- enters the hand superficial to the flexor retinaculum inside Guyon’s canal
- divide into terminal branches at pisiform
Branches
- palmar cutaneous
- branch to palmaris brevis
- superficial terminal branch
- deep terminal branch
Supply
- motor:
> flexor carpi ulnaris, flexor digitorum profundus ulna half, hypothenar muscles, 3rd and 4th lumbricals, interossei muscles, palmaris brevis
- sensory:
> articulatar innervation to elbow, wrist, carpal, phalangeal joints
> cutaneous innervation to 4th and 5th digits
Cerebral ventricular system
Cerebral ventricular system composed of CSF filled ventricles and their connecting foraminae
- CSF produced by ependymal cells which line the ventricles
- continuous with the central canal
Ventricles: 2 lateral ventricles - frontal, occipital, temporal horns 1 third ventricle 1 fourth ventrcle
Connections
lateral ventricles connected to third by the interventricular foramen of Monro
Cerebral aqueduct: third to fouth
Median aperture of Magendie: fourth to cisterna magna
2 lateral apertures of Luschka: 4th to cerebellopontine cistern
Cisterns
- discrete named spaces within the subarachnoid space
- CSF pools
- interconnected for CSF circulation
- vessels and cranial nerves pass through them
Named cisterns:
- cisterna magna: largest
- prepontine: anterior to pons
- suprasellar cistern: surrounding infundibulum
- interpeduncular: between cerebral crura
- quadrigeminal cistern: superior cistern
- ambient cistern: back of mid brain
- cerebellopontine cistern
- premedullary
- sylvian cistern
Variants
- cavum septum pellucidm
- cavum septum pellucidum et vergae
- cavum septum interpositi
Pterygopalatine fossa
the pterygopalatine fossa is an important space in the deep face
inverted triangle in shape
neurovascular crossroad of multiple compartments and spaces in the cranium
Boundaries
anterior: posterior wall of maxillary sinus
medial: perpendicular plate of palatine
lateral: continuous with the pterygomaxillary fissure
posterior: sphenoid bone
superior: greater wing of sphenoid and inferior orbital fissure
inferior: narrows into the palatine canals
Connections:
Orbit: via inferior orbital fissure
Masticator space: via pterygomaxillary fissure
Nasal cavity: sphenopalatine foramen
Middle cranial fossa: Meckel cave and cavernous sinus by foramen rotundum & vidian canal
Nasopharynx: palatovaginal canal
Palate: greater and lesser palatine canals
Contents
- PPF ganglion
- descending palatine
- maxillary division of trigeminal
- nerve of pterygoid canal
Larynx
Inferior continuation of the oropharynx
- extends from the epiglottis to inferior aspect of the cricoid cartilage
- inferiorly continues as cervical trachea
- could be divided into the supraglottis, glottis and subglottis larynx
Supraglottis
- tip of epiglottis to laryngeal ventricle
- multiple structures:
epiglottis, arytenoid cartilages, aryepiglottic folds, false vocal cords, para and pre epiglottic space
glottis
- true vocal cords
- anterior and posterior commisure
subglottis
- extends from inferior surface of vocal cord to inferior border of cricoid cartilage
relations
anterior: strap muscles, platysma
posterior: oesophagus, laryngopharnx
superior: hyoid bone, laryngopharynx
inferior: trachea
blood supply:
above vocal cord: superior laryngeal artery
below: inferior laryngeal artery
innervation
- recurrent laryngeal nerve
motor and sensory
lymphatics
deep cervical lymph nodes
Delphian nodes
variants
laryngo-oesophageal fistula
bronchus tertius
sciatic foramen
the sciatic foramen is the connection between the pelvis and the posterior thigh and gluteal region
- divided into the superior and inferior sciatic foramen
Superior sciatic foramen
- divided by the piriformis muscle into suprapiriform and infrapiriform foramen
boundaries:-
posteromedial: sacrotuberous ligament
inferior: sacrospinous ligament and ischial spine
anterolateral: greater sciatic notch
superior: anterior sacroiliac ligament
contents:- Neurovascular: - superior gluteal vessels and nerves - inferior gluteal vessels - internal pudendal vessels - sacral plexus nerves: inferior gluteal nerves, pudendal nerve, sciatic nerve, posterior femoral cutaneous, nerve to obturator internus, nerve to quadratus femoris
Inferior sciatic foramen
boundaries:-
superior: sacrospinous ligament
posterior: sacrotuberous ligament
anterosuperior: ischial spine
anterior lesser sciatic notch
contents:-
pudendal nerve, internal pudendal vessels
obturator internus
nerve to obturator internus
variants
- common peroneal nerve can pierce the piriformis muscle, go above or underneath it
- common trunk for tibial and common peroneal nerve
Pleura and spaces
Pleura is a serous membrane that encloses the lung lines the internal thoracic cavity
- lungs invaginate into the pleura during organogensis
- divided into parietal and visceral pleura
- parietal pleura is in contact with the inner thoracic wall and can be described according to location:
cervical, costal, diaphragmatic, mediastinal - visceral layer overlies the surface of the lung
- visceral layer dives deep and forms fissures to separate adjacent lobes: major or minor fissures
Reflections/spaces:
- costophrenic space
- costomediastinal space
- phrenicomediastinal space
- vertebromediastinal space
blood supply arterial:- pariteal: - internal thoracic, intercostal, phrenic arteries visceral:- - bronchial arteries
venous:-
bronchial and pulmonary veins
innervation branches of the phrenic nerve musculophrenic pericardiophrenic intercostal nerves
variants
- absent pleura
- persistent communication with contralateral lung
- azygos lobe
- accessory upper or lobe lowers
Maxillary sinus and drainage
The maxillary sinuses are a paired paranasal sinus within the maxilla which drains mucociliary products and resonance in phonation
- traingular shaped sinuses with base on lateral aspect of nose and apex pointing towards the zygoma
- paired
- bounded anterior and posterior by the maxillary bone
- inferior border overlies the superior alveolar process
- superior border forms the floor of the orbit
- drains via the maxillary sinus ostia into the infundibulum
- infundibulum is at the posterior end of the hiatus semilunaris
- it drains into the ostiomeatal complex under the middle turbinate
- the ostiomeatal unit is formed by the hiatus semilunaris, unicate process, ethmoid bullae, frontal sinus, infundibulum and the maxilary ostia
Blood supply maxillary artery greater palatine artery infraorbital artery facial artery
venous
- facial veins
- pterygoid plexus
- sphenopalatine vein
innervation
- superior alveolar nerves
- greater palatine nerves
- infraorbital nerves
variants
- unilateral or bilateral agenesis
- asymmetrical in size
- septated
- hypoplastic unilateral or bilateral
- alveolar extension into floor of maxillary sinus
Parietal branches of abdominal aorta
the abdominal aorta provides both visceral and parietal arterial supply within the abdomen
- abdominal aorta starts from T12 after the thoracic aorta pierces through the aortic hiatus of the diaphragm
- it travels on the left side of the posterior abdomen
- terminates at the bifurcation into the right and left common iliac arteries at L4
- parietal branches: four paired lumbar arteries, inferior phrenic arteries, median sacral arteries
Lumbar arteries:
L1-4
right side passes posterior to IVC and sympathetic trunk
after passing quadraum lumborum, enter space between transversus abdominis and internal oblique
anastomoses with lower intercostal, subcostal, iliolumbar, deep iliac circumflex, inferior epigastric and contralateral lumbar arteries
supplies: muscles and fascia of the back, vertebrae and intervertebral disc
Inferior phrenic artery
- arises from abdominal aorta at T12-L2
- ascends to inferior surface of diaphragm
- left passes posterior to oesophagus
- right passes posterior to IVC
- both divide into medial and lateral branches
supplies: diaphragm, oesophagus, liver capsule
median sacral artery
- single small posterior branch
- posterior branch of abdominal aorta above bifurcation
- midline descend anterior to L4-5
- terminates at coccygeal body
- supply L4/5, sacrum, coccyx
Variants
- median sacral giving rise to L5
- L5 lumbar artery, unilateral or bilateral
- inferior phrenic artery may arise from celiac trunk
MCA
middle cerebral artery is one of the terminal branches of the internal carotid artery
main major paired arteries that supply the brain
- paired structure arising from internal carotid termination
- courses initially through the lateral sulcus
- divided into 4 segments
- situated within the suprasellar cistern
M1 (horizontal/sphenoidal):
- from origin to bifurcation or trifurcation
- horizontal course
- branches: medial and lateral lenticulostriate arteries, anterior temporal, polar temporal, uncal artery
M2 (insular):
- bifurcation/trifurcation to the circular sulcus of the insula
- hairpin bend to continue as M3
- superior, middle and inferior branches
- superior branches: lateral, prefrontal Rolandic and Rolandic artery
- inferior bracnhes: anterior, middle, posterior temporal, branch to angular gyrus, anterior and posterior parietal
M3 (opercular):
- within the sylvian fissures
M4 (cortical/terminal):
- emerges from the sylvian fissure into the convex surface of the cerebral hemisphere
Supplies:
- basal ganglia
- parietal lobe
- temporal lobe
- mid brain
Variants
- trifurcation of M2
- early branching of MCA bi or trifurcation
- accessory MCA
- duplicated MCA
- supplied the recurrent artery of Heubner
- fenestration MCA
- hypoplastic MCA
- absent MCA
Ophthalmic artery
ophathalmic artery supplies the globe and orbits
- originates from anterior surace of C6 segment of ICA
- travels to the orbit through the optic canal
- divides into the globe and optic branches
- termination via supratrochlear and dorsal nasal arteries
Ocular branches:
- central retinal artery
- anterior and posterior ciliary artery
- muscular artery
Orbital branches:
- supratrochlear
- lacrimal
- anterior and posterior ethmoidal
- internal palpebral
- dorsal nasal artery
Variants
- Middle meningeal from ophthalmic artery
- ophthalmic from middle meningeal
- ophthalmic from middle cerebral
- ophthalmic from posterior communicating
- multiple anastomoses between MMA with ophthalmic: sphenoidal artery, recurrent meningeal artery, orbital branch of middle meningeal artery
Jugular veins
jugular veins bring deoxygenated blood from the head and neck regions back into the systemic circulation
- can be divided into internal and external jugular veins
Internal jugular vein
- confluence of the inferior petrosal and sigmoid dural venous sinuses distal to the jugular foramen to become the jugular bulb
- paired internal jugular veins
- runs within the carotid sheath
with internal carotid artery with CNX between them
- received tributaries from the face and neck
- descending posterior to the space between two head of the sternocleidomastoid muscle
- unites with subclavian vein to form brachiocephalic vein
External jugular vein
- paired external jugular veins
- formed by the confluence o the retromandibular vein, posterior auricular veins at the angle of the mandible
- runs within the subcuteneous tissue deep to platysma
- anterior to sternocleidomastoid
- drains into the subclavian posterior to the clavicular head of sternocleidomastoid
Tributaries IJV - inferior petrosal sinus - pharyngeal veins - facial vein - lingual vein - superior and middle thyroid
EJV
- anterior jugular
- posterior external jugular
- suprascapular
- transverse cervical
Relations
IJV:-
anterior:
- CNXI, ansa cervicalis, sternocleidomastoid, tendon of omohyoid
posterior:
- lateral mass of C1, middle and anterior scalene muscles
EJV:-
- below platysma
- above sternocleidomastoid
Variants
- hypoplastic unilateral or bilateral internal jugular vein
- segmental fenestration
Vertebral artery
Paired vertebral arteries provide arterial supply to the posterior cerebral circulation
- originates from the 1st part of the subclavian artery
- ascends cranially through the cervical transverse foraminae at C6
- pierces through the dura
- terminates as the basilar artery at the lower border of the pons
- gives off multiple branches
- can be divided into 4 segments:
V1 (pre forminal):
- 1st part of subclavian artery to before entering the transverse foramen of C6
- posterior to common carotid artery
- anterior: C7 and C8 ventral rami, transverse process of C7
- within the colliscalene triangle
V2 (foraminal)
- C6 to C3 transverse foramina
- accompanied by vertebral veins and sympathetic nerves
- enters L shaped C2 transverse foramen
V3 (extra dural)
- emerges from transverse process of C2
- passes through C1 transverse foramen
- passes around posterior border of lateral mass of C1 inferior border of the posterior atlantooccipital membrane
V4 (dural)
- dural segment
- unites with the contralateral to become the basilar artery
Branches:
- Anterior spinal artery
- Posterior spinal arteries
- Posterior inferior cerebellar arteries
- segmental cervical muscular and spinal branches
- anterior and posterior meningeal artery
Supply:
- supplies posterior fossa, occipital lobes
- cerebellum
- supplies segmental vertebral and spinal column blood supply
Variants
- left or right dominance
- co- dominance
- hypoplastic single or bilateral vertebral arteries
- absent unilateral or bilateral vertebral arteries
- fenestrated vertebral artery
