muscles of the neck Flashcards
what is the origin and insertion of the platysma muscle?
O: superficial fascia over the pec major and deltoid muscles
I: lower border of mandible and angle of mouth
what is the origin and insertion of the sternocleidomastoid muscle?
O: sternal head from the front of the manubrium, clavicular head from the medial third of the clavicle
I: lateral surface of the mastoid process, lateral half of superior nuchal line
what is the origin and insertion of the trapezius muscle?
O: ALL MIDLINE- EOP, ligamentum nuchae, spinous processes of C7 and all thoracic vertebrae
I: lateral 3rd of clavicle, spine of scapula and acromion process
what is the nerve supply of the platysma muscle?
cervical branch of facial nerve CNVII
what is the nerve supply of SCM?
accessory nerve CNXI
what is the nerve supply of the trapezius?
accessory nerve CNXI and C3, C4 from cervical plexus
what is the function of the platysma muscle?
depress the mandible and draw down corners of mouth
what is the function of the SCM?
chief flexor of head
what is the function of the trapezius?
upper portion elevates, middle retracts and lower depresses the scapula
what are the infrahyoid muscles?
4 ribbon like muscles that attach to the hyoid bone
omohyoid, sternohyoid, sternothyroid and thyrohyoid
what do the infrahyoid muscles do?
move the hyoid bone and larynx
what are the 2 superficial and 2 deep infrahyoid muscles?
superficial- omohyoid and sternohyoid
deep- sternothyroid and thyrohyoid
which of the 4 infrahyoid muscles has a different nerve supply?
thyrohyoid and it is supplied by C1 through hypoglossus nerve
what is the nerve supply of the other 3 infrahyoid muscles?
ansa cervicalis C1-3
what is the function of the omohyoid and sternohyoid muscles?
depress hyoid bone and larynx
what is the function of the sternothyroid muscle?
depress the larynx
what is the function of the thyrohyoid muscle?
depress the hyoid bone
what is the origin and insertion of the omohyoid?
2 bellies
O: inferior belly- upper border of scap; superior- extends upward from intermediate tendon
I: body of hyoid bone
what is the origin and insertion of the sternohyoid?
O: posterior surface of manubrium, medial end of clavicle
I: body of hyoid
what is the origin and insertion of sternothyroid?
O: posterior surface of manubrium, inferior to sternohyoid
I: oblique line on lamina of thyroid cartilage
what is the origin and insertion of the thyrohyoid?
O: oblique line on lamina of thyroid cartilage
I: body of hyoid bone
what are the 4 reasons we have so many muscles to depress hyoid and larynx?
- swallowing
- respiration
- speech
- if hyoid is fixed by infrahyoid muscles, digastric depresses the mandible
