Structures in the neck Flashcards
How you would you confirm that the thyroid gland is swollen (Goiter) ?
Gulp -
head tilted slightly backwards and patient swallows sips of water.
- moves with trachea when gulping as it is attached to the Pre -tracheal fascia.
assessment of goitre
- need to percuss upper central part of sternum - check for retrosternal goiter
Swelling - downward migration of swelling can occur - Pre tracheal space continuous with mediastium
(inferior movement of swelling- most likely as anatomical barriers preventing movement in other directions e.g thyroid cartilage , vertebrae , strap muscles )
What are the fascial planes of the neck ?
Dermis / skin - most superior outside the fascia (not part of it )
MOST SUPERFICIAL
1. Superficial cervical fascia
- Deep cervical fascia - 3 layers
1. (deep)
Investing
fascia- Pre -
tracheal
fascia - Pre -
vertebral
fascia
- Pre -
What does the superficial cervical fascia contain ?
contains Platysma -
o 2 headed muscle originates from fascia of pectoralis major & deltoid muscle
o 2 heads meet in mid line then attached to inferior border of mandible.
o innervated by cervical branch of facial nerve.
What does the Investing fascia contain ?
contains SCM & Trapezius (encircles them )
o arises from nuchal ligament
o pierced by cervical plexus & EJV (vein )
o roof of posterior triangle
What does the pre - tracheal cervical fascia contain ?
Contains the trachea , thyroid and parathyroid gland , esophagus & left and right recurrent laryngeal nerves.
Infrahyoid muscles.
anterior - extends from hyoid bone to ————————–> pericardial sac (enters it )
(* on the way encircles thyroid gland )
Posterior -
extends from skull to mediastitum.
What does the preveterbral fascia contain ?
Contains :
o Anterior , middle & posterior scalene
o Brachial plexus ( located btw anterior & middle scalene )
o forms axillary sheath - fascia pulls away and forms it
- contains :
o Subclavian a & v.
o Brachial plexus
- base / back part of posterior triangle (inside layer )
What is the carotid sheath ?
Made from contributions of Pretracheal , prevetebral & investing fascia (layers of deep cervical fascia )
Contains : o IJV , o Common carotid - also bifurcates into external & internal carotid arteries o Vagus nerve o Carotid sinus Deep cervical nodes.
Courses from base of skull into mediastitum.
What is the Buccopharyngeal fascia ?
posterior aspect of pre tracheal fascia.
What is the pharyngeal space ?
between Buccopharyngeal fascia (posterior aspect of pre tracheal ) & Alar fascia (anterior aspect of preveterbral fascia )
What is the danger space ?
btw alar & preveterbral fascia
o extends from skull base to mediastitum
o 2nd base behind retropharyngea space .
potential path for the spread of infections from pharynx to mediastitum
What are the infrahyoid muscles ?
Divided into 2 groups
- Superfical plane -
o
Omohyoid - depress hyoid bone
-2 bellies
inferior belly - from scapula ——————-> under SCM —————————–> hyoid bone -inferior border.
Superior belly - from clavicle ———————> attaches to inferior belly by tendon ——————-> inferior part of thyroid bone (together with inferior )
o
Sternohyoid
- Depress hyoid bone
- from sternum / sternoclavicular joint to Inferior border of hyoid bone.
- Deep -
o sternothyroid - - Depress thyroid cartilage
o from Maniburium —————> attaches to thyroid cartilage.
o Thyrohyoid.
o continuation of sternothyroid muscle
o from thyroid bone ———————–> hyoid bone
- Depresses hyoid bone , ca elevate larynx if hyoid bone is fixed.
Supply of intrinsc muscles of larynx
recurrent layngeal nerve - branches of vagus n.
Left recurrent - wraps around aortic arch
Right recurrent - wraps around under subclavian
a.
Superior laryngeal n. - 2 branches
o internal -mainly sensory function.
o external
recurrent laryngeal nerve - (inferior laryngeals nerve - branch of recuurent nerve ) - innervates all intrinsic mucles - apart from cricothyroid m.
Superlayrngeal n - external branch - innervates cricothyrid m.
What are the intrinsic muscles ?
Cricothyroid - 2 parts
o Straight 0 inserts onto inferior horn of thyroid cartilage (TC)
o oblique part - inferior posterior horn of TC
Action - forward & downward movement (anterioinferior ) of thyroid cartilage when m contracts
———————————————-> lengthen vocal ligaments —————> more tension in vocal cords —————————-> higher pitch
What are the intrinsic muscles ?
o Cricothyroid m.
o Cricoarytenoid m.
- posterior
- Lateral
o Arytenoid m . - Transverse
- Oblique
o Thyroarytenoid m.
What are the cricarytenoid m. ?
2 types -
o Posterior - paired - 1 on each side
o Lateral - bilateral
POSTERIOR
0 Location
on posterior surface of of Cricoid cartilage
—————————–> fibers ascend and converge towards a narrower insertion onto muscular process of Arytenoid cartilage.
0 Attachment
o attach from Cricoid carilage to Arytenoid cartilage.
0 Action
o abducts vocal cords - opening Rima glottidis
o assist the instrinsic m in legthening vocal cords - allowing passage of air during insp/exi ration
- rima glottidis - opening BTW true vocal cords and arytenoid cartilages.
LATERAL
0 Location
originates from upper margin of arch of Cricoid c. ———————————–> attaches to anterior surface of muscular process of Aryteniod c.
(* same place as posterior Cricoarytenid - but anteriorly vs posteriorly )
Function
o Adduction of vocal cords - closing anterior part of rima glottidis.
(* transverse & oblique arytenoid m. - close posterior part )
- on its own - if posterior part remained opened -air will pass through causing whispering.
when both part close - air passes through causing vibration of vocal cords causing voiced sounds.
