Fascial Layers/ Muscles of the Neck Flashcards
Give overview of fascial layers
superficial fascia - platysma (+ superficial veins/ lymph nodes/ fat)
deep fascia:
- superficial (investing layer) = SCM + trapezius
- middle = pretracheal fascia + carotid sheath
- deep = prevertebral fascia
What is the function of the platysma muscle?
- muscle of fascial expression - depresses mandible
- shaving muscle - tenses skin of neck when contracted
- forms wrinkles in neck with age
What is the innervation of the platysma muscle?
cervical branch of facial nerve
What superficial vein is found in superficial fascia?
external jugular vein
Give the attachments of the superficial layer of deep fascia
superior: superior nuchal line/ occipital protuberance
inferior: spine/ acromion/ clavicle/ manubrium
anterior: hyoid bone
posterior: nuchal ligament of posterior column
What is the function of the SCM?
- unilateral contraction: ipsilateral flexion of neck & contralateral rotation
- bilateral contraction: head & neck extension, accessory inspiratory muscle
What is the innervation of the SCM?
- accessory nerve
- branches of the cervical plexus C2-C3
What can be felt in the middle 1/3 of the front edge of SCM?
lies over the carotid sheath = carotid pulse
What landmark is used for insertion of central line?
medial edge of SCM
Where is Erb’s point and what is its significance?
dorsal to SCM -branches of plexus merge for puncture of LA
What vein passes over lateral border of SCM to pass behind the clavicle and join the subclavian vein?
external jugular vein
What is the innervation of the trapezius?
spinal accessory nerve
Where does the pretracheal layer span between?
hyoid bone & thorax where it fuses with the pericardium
What does pretracheal fascia enclose?
muscle: infrahyoid muscles
viscera: thyroid gland, trachea & oesophagus
What are the contents of the carotid sheath?
- common and internal carotid artery
- internal jugular vein
- vagus nerve
- deep cervical lymph nodes
What does the prevertebral layer surround?
vertebral column and muscles associated with it + muscles of the back
Name the 4 suprahyoid muscles
- stylohyoid
- mylohyoid
- geniohyoid
- digastric
What action do the suprahyoid muscles produce?
elevate hyoid bone to initate swallowing?
What is the arterial supply of the suprahyoid muscles?
branches of the facial artery, occipital artery & lingual artery
Give another action of geniohyoid and its innervation
- depresses mandible
- C1 root within hypoglossal nerve
Give another action of mylohyoid and its innervation
- floor of oral cavity/ supports floor of mouth
- inferior alveolar nerve (branch of V2)
Give another action of digastric and its innervation
- depresses mandible
- anterior belly: inferior alveolar nerve
- posterior belly: digastric branch of facial nerve
Give another action of stylohyoid and its innervation
- pulls hyoid bone posterior & superior direction
- stylohyoid branch of facial nerve (proximal to parotid gland)
Which suprahyoid muscle is a thin (short diameter) muscle?
stylohyoid