Broad sheet fo fibres, but may be atrophic / not seen in
Superficial to deep cervical fascia of neck and to jugular veins.
From midline down beyond clavicals and up to mandibles; little posterior to EJV
Suplied by cervical br of facial nerve
Suture it seperately from skin so it can contract.
Not removed in neck dissections
Elevate the platysma with the skin when making skin flap, staying superficial to the ext/ant jugular veins
- supplies useful blood to overlying skin.
Superior thyroid, lingual, facial as per written notes
From back of external carotid level with facial artery
¨ deep to lower border of posterior belly digastric;
- grooves base of skull deep to digastric notch on mastoid process
¨ through apex of posterior triangle to back of scalp
- 2 braches to SCM (upper is guide to accessory nerve in front of upper border of that muscle).
At its origin the artery crosses lateral to XII, which hooks around it, looped over by low branch to SCM
Arises above digastric in substance of parotid ¨ superficial to styloid process
¨ crosses surface of mastoid process ¨ scalp
Auricular branches ¨ pinner and ear
Stylomastoid branch ¨ stylomastoid foramen ¨ facial nerve.
Just above commencement of external carotid from deep ¨ up side wall of pharynx deep to ICA
¨ pharyngeal wall and soft palate
¨ meningeal branches through nearby foramina (lacerum, jugular foramen, hypoglossal canal)
Arises from bifurcation of common carotid ¨ up in carotid sheath
Carotid sinus at commencement = small bulge (baroreceptors)
Carotid body behind bifurcation receives 2-3 small glomic arteries (chemoreceptors)
- carotid body tumours swell at anterior border of SCM at bifurcation
Is lateral to ECA at origin, soon passes posterior ¨ medial and deeper
Enters carotid canal at base of skull
Posterior (outside sheath) = symp trunk, pharyngeal veins and superior laryngeal branch of vagus.
Medial = ascending pharyngeal artery
Lateral = IJV, and vagus nerve deep b/n artery and vein
Superficial, near origin, it is crossed by: lingual vain, facial vein (64), occipital artery, XII, and superior root of ansa cervicalis (embedded in the sheath).
Overlapped higher by SCM, and posterior border of digastric, stylohyoid and posterior auricular artery
- and by those structures separating it from carotid artery (see notes)
Line from bifurcation of common carotid artery ¨ head of mandible.
Exposed in neck by incising along anterior border SCM; retracted backwards
- lingual & facial veins need dividing
- incise the sheath
Safeguard XII, may need to divide lower SCM branch of occipital artery to allow this.
Can tell difference from ECA by branches on
External Jugular Vein
Starts at lower border of lower border of parotid where posterior division of retromandibular vein and posterior auricular vein join.
Descends across SCM deep to platysma on top of deep fascia
Penetrates deep fascia above midpoint of clavicle and joins subclavian.
Tributaries = posteiror external jugular (midway in course) and transverse cervical / suprascapular veins
All join posteriorly
Great auricular nerve runs in a parallel course to its upper third.
Emerges from jugular bulb at posterior compartment of jugular foramen.
- inferior and superior ends have bulbs; inferior bulb has 2 valves
First lies on transverse process of atlas ¨ crossed by XI.
Passes down lateral side of ICA in sheath (X deep between artery and vein)
Overlaid by SCM in lower part of course.
Deep cervical nodes adjacent through course.
Posterior: cervical plexus (on levator scapulae & scalenus medius) and phrenic on scalenus anterior
- thoracic duct crosses behind left vein at C7 level.
Anterior: tendon of omohyoid crosses low, heads of SCM at its base
- inferior root of ansa cervicalis curls around lateral border ¨ unites with superior root (from XII) at variable level in front of vein.
Joins subclavian ¨ brachiocephalic behind sternal end of clavicle.
First petrosal sinus = first tributary (just below skull base medial to IX,X,XI)
Descending: pharyngeal, lingual, facial, superior and middle thyroid
- lingual and facial may do so with common trunk (with retromandibular vein and possibly superior thyroid)
From lobule of ear ¨ sternal end of clavicle; b/n 2 heads of SCM
Catheterise b/n two heads of SCM usually
- direct needle caudally, parallel to sagittal plane entering vein ~4-5cm
Emerges b/n ICA and IJV ¨ hooks around occipital artery
¨ curves over external carotid and loop of lingual artery (\ crosses 3 arteries)
Then lies just below post belly digastric and above greater horn of hyoid
- here superior root of ansa cervicalis leaves it
Runs forward on lateral hyoglossus ¨ gives of branch to thyrohyoid ¨ deep to mylohyoid to mouth.
Is deep to cervical fascia, filling submandibular triangle between anterior and posterior bellies of digastric and inferior border of mandible.
Spills over these borders
Anterior = from fossa near midline on back of
- passes backwards and downwards to intermediate tendon held by a fibrous sling to hyoid bone at jx b/n body and greater cornu
- anterior supplied by nervei to mylohyoid
Posterior = passes back and up to its insertion on medial mastoid.
- supplied by branch of facial nerve
- crosses the internal and external carotids, hypoglossal nerve, internal jugular vein, transverse process of atlas and splinal accessory nerve; only facial vein is superficial to it.
Mandibular and Cervical Branches of Facial Nerve
banches of F n.
often closely related to submandivular gland.
Mandibular branch exits parotid near angle of mandible, curves up to cross mandible close to facila artery, then supplies lower lip / chin m's.
- usually doesn't lie much lower than
inferior border of the mandible; can be 2.5cm below.
--> if divided, get a noticeable facial deformity with depresion of the corner of the lip and drooling.
Cevical Br is more likely to get damaged
- runs deep to platysma in a down direction, 1-2cm behind angle of mandible.
- at 2cm below angle, it divides; posterior --> platysma; anterior --> corner of mouth
--> division of anterior branch will cause
some drooping of the mouth but usally improves with months
- usually doesn't pass >3cm below lower border of mandible.
- so make incisions 4cm or below and through platysma at same level.
The structures superficial to the gland are the facial artery, vein and submental artery and vein.
Descends across face from inner angle of eye to cross border of mandible ~2cm from its angle.
- lies deep to platysma on the gland.
Submental vein passes back across gland to enter facial vein.
Behind gland, facial vein receives anterior division of retromandibular vein --> passes down as common facial vein --> into IJV
- overlies carotid bifurvation in this course, where it receives the anterior jugular vein from lalong sternomastoid.
Arises from external carotid distal to lingual branch and passes up, deep to digastric, to loop over posterior belly in a sigmoid fashion.
Then arches over the posteiror submandibular gland, forming a groove.
Passes forward between gland and medial mandible, then over it to face, making a groove.
- closely related to mandibular branch of
facial nerve;gives off largest branch = submental artery -->
Muscle Bed of Gland
Most lies on the mylohyoid, but sine oisteruir oirtuib kues ib gtigkissys
- this extends forward deep to mylohyoid with the submandibular duct.
Mylohyoid = from inner mandible to body of hyoid bone, joining in midline raphe
- n. is inferior alveolar br of mandibular division of trigeminal n.
- hypoglossal nerve lies deep to hylohyoid below the deep submandibular gland.
- lingual nerve lies deep tomylohyoid above the deep part of the gland.
Lingual Nerve is a branch of posterior division of mandibular br of trigeminal n.
--> sensation of floor f mouth, side of gums, and anterior 2/3 tongue (latter from chorda tymapani; joins early in its course)
- curves forward on hyoglossus, above deep portion of the gland, passes in a spiral under submandibular duct and up medial side.
- submandibular ganglion hangs off nerve above deep gland.
--> if inflammatory, the nerve can become adherent to the gland and is at risk.
Hyoglossus is from cornu and body of
hyoid to insert into tongue.
- separates lingual artery (deep) from hypoglossal nerve (superficial).
- lingual a. gives off sublingual br, runs
--> Preserve the sublingual artery with submandibular dissection to safeguard the nerve.
Secretomotor ganglion of SL and SM glands.
Preganglionic from superior salivatory nucleus --> facial nerve, chorda tympani and lingual.
Runs between hylohyoid and hyoglosses, then b/n sublignual gland and genioglossus
Opens at the sublingual papilla.
Reeives ducts from sublingual gland.
Closely related to lingual nerve.
Immediate nodes are related to the gland by fascial condensations; may be mistaken for gland.
Submental --> submandibular nodes, together with oral cavity nodes and gland itself, which --> deep cervical chain.
Transverse Cervical Bessels