Anatomy of the neck Flashcards
(37 cards)
what and where is the neck
transitional area
sup = base of cranium
inf = clavicles
What is fascia?
thin sheath of connective tissue enclosing muscle or other organ
What are the 4 fascial layers of the neck and what do they contain
investing fascia - round the whole neck
pretracheal layer - trachea, oesophagus, thyroid gland and infrahyoid muscles
Prevertebral layer - vertebral column and its assoc. muscles
carotid sheath - paired structure containing IJV, CCA and vagus nerve
What are the boundaries of the anterior triangle?
- inf border fo mandible
- ant border fo SCM
- midline of the neck
What is the fascia of the ant triangle
roof = investing fascia around muscles floor = pretracheal + carotid sheath
what are the subdivisions of the ant triangle
- submandibular (digastric) division
- submental
- carotid
- muscular (omotracheal)
What does the submandibular division contain and what are its boundaries
angle of mandible to pos+and digastric muscles
Contains:
- submandibular gland
- lymph nodes
- part of CN XII
- Mylohyoid nerve
- part of facial artery and vein
What does the submental division contain and what are its boundaries
ant belly of digastric
midline of neck between AoM and hyoid bone
body of hyoid bone
Contains:
- submental lymph nodes
- small veins
What does the carotid division contain and what are its boundaries
ant border of SCM
sup belly of omohyoid
pos belly of digastric
Contains:
- thyroid gland
- deep cervical lymph nodes
- larynx
- pharynx
- carotid sheath and its contents
- br’s of cervical plexus
- superior root of ansa cervicallis
- part of Cn XI and XII
What does the muscular division contain?
- sternohyoid muscle
- sternothyroid muscle
- thyroid gland
- parathyroid glands
Name the suprahyoid and infrahyoid muscles (muscles of the ant triangle)
Suprahyoid
- mylohoid
- digastric
- stylohyoid
- geniohyoid
Infrahyoid
- sternohyoid
- sternothyroid
- omohyoid
- thyrohyoid
what is the function of the suprahyoid muscles
raise the hyoid bone as required during swallowing
what is origin, insertion, innervation and function of the mylohyoid?
origin = mylohyoid line on mandible insertion = body of hyoid and fibres fo opp mylohoid action = raises hyoid and floor of mouth & support floor of the mouth innervation = nerve to mylohoid (inf alveolar br of V3)
what is origin, insertion, innervation and function of the digastric?
ant belly
- origin = digastric fossa on lower medial aspect of mandible
- insertion = attachment of their intermediate tendon at hyoid
- function = raises hyoid + opens mouth by lowering mandible
- innervation = V3 (nerve to mylohoid)
Pos belly
- origin = mastoid notch on medial aspect of mastoid process
- insertion = attachment of their intermediate tendon at hyoid
- function = raises and retracts the hyoid
- innervation = VII (digastric branch)
what is origin, insertion, innervation and function of the Stylohyoid?
origin = styloid process insertion = hyoid (laterally) Function = raises hyoid bone (posterosuperiorly) innervation = VII
what is origin, insertion, innervation and function of the geniohyoid?
origin = mental spine of mandible insertion = body of hyoid function = - if fixed mandible = elevates and pulls hyoid forward - if fixed hyoid = lowers and moves mandible inwards innervation = ant ramus of C1 (travels with CN XII)
What is the role of infrahyoid (strap) muscles?
depress hyoid after elevation during swallowing
what is origin, insertion, innervation and function of the sternohyoid?
origin = pos surface of sternoclavicular joint and manubrium insertion = medial body of hyoid action = depress hyoid after elevation during swallowing innervation = ant rami of C1 - C3
what is origin, insertion, innervation and function of the omohyoid?
ant belly
- origin = intermediate tendon
- insertion = hyoid bone laterally
pos belly
- origin = sup border of scapula
- insertion = intermediate tendon in pos triangle
action of both = depresses and fixes hyoid
innervation = ant rami of C1-C3
what is origin, insertion, innervation and function of the thyrohyoid?
origin = oblique line on thyroid cartilage insertion = greater horn and adjacent body of hyoid action = depress hyoid, if hyoid fixed = raises larynx innervation = ant rami of C1 (runs with CN XII)
what is origin, insertion, innervation and function of the sternothyroid?
origin = pos surface of manubrium insertion = oblique line on thyroid cartilage action = draws the larynx downwards innervation = ant rami of C1 -C3
Describe the thyroid gland anatomy
2 lateral lobes
- extends from thyroid cartilage to 5th tracheal ring
midline isthmus
- level of 3rd tracheal ring
midline pyramidal lobe (variably preset, remnant of thyroglossal duct)
what is the arterial supply of the thyroid gland
sup thyroid ar - 1st br of ECA
inf thyroid ar - branch of thyrocervical trunk from subclavian
describe the venous drainage of the thyroid gland
thyroid venous plexus
- sup thyroid vein = into IJV
- middle thyroid vein = into IJV
- inf thyroid vein = into brachiocephalic
