CFB: The Tongue Flashcards
What are intrinsic muscles?
Muscles originate and attach to other structures within the tongue
How many pairs of intrinsic muscles are there?
4
What are the intrinsic muscles named by?
Direction in which they travel
Name the 4 intrinsic muscles
Superior longitudinal
Inferior longitudinal
Transverse
Vertical
What nerve supplies the motor function of the intrinsic muscles?
Hypoglossal
What are the extrinsic muscles?
Originate from structures outside the tongue and insert onto it
Names of extrinsic muscles
Genioglossus
Hyoglossus
Styloglossus
Palatoglossus
What nerve innervates the extrinsic muscles
Hypoglossal nerve EXCEPT palatoglossus which is innervates by vagus
Attachments of Genioglossus
Arises from the Mandibular symphysis.
Inserts onto the body of the hyoid bone and the entire length of the tongue
Function of Genioglossus
Protrusion and depression of tongue
Innervation of Genioglossus
Hypoglossal
Attachments of hyoglossus
Arises from the hyoid bone
Inserts onto the lateral aspect of the tongue
Function of hyoglossus
Depression and retraction of the tongue
Innervation of hyoglossus
Hypoglossal
Attachments of styloglossus
Originates from styloid process of temporal
Inserts onto the lateral aspect of the tongue
Function of styloglossus
Retraction and elevation of tongue
Innervation of styloglossus
Hypoglossal
Attachments of palatoglossus
Arises from the palatine aponeurosis
Inserts broadly along tongue
Function of palatoglossus
Elevation of posterior tongue
Innervation of palatoglossus
Vagus nerve
What nerve provides general sensation to anterior 2/3 of tongue?
Trigeminal nerve- lingual nerve branch of mandibular nerve
What nerve provides taste in the anterior 2/3 of tongue?
Facial nerve- in petrous part of temporal bone, facial nerve gives off three branches- chorda tympani which travels through middle ear and continues to tongue
What nerve supplies both sensory and taste to posterior 1/3 of tongue?
Glossopharyngeal nerve
Vasculature of tongue
Lingual artery- branch of external carotid (most of supply)
Tonsillar artery- branch of facial artery (provides some collateral circulation)
Drainage by lingual nerve
Lymphatic drainage of anterior 2/3 of tongue
Initially into the submental and submandibular node which empty onto deep cervical lymph nodes
Lymphatic drainage of posterior 1/3 of the tongue
Directly into the deep cervical lymph nodes
When does the tongue start to develop?
4th week of gestation
What is the tongue derived from?
Pharyngeal arches 1-4 (forms mucosa of tongue)
Occipital somites (forms musculature of tongue p)
Lateral lingual swellings of tongue (during development)
Derived from 1st pharyngeal arch
Contribute to mucosa of anterior 2/3 of tongue
How many lingual swelling are there during development?
2
Medial swellings of tongue (during development)
Tuberculum impar: derived from 1st pharyngeal arch. Contributes to anterior 2/3 mucosa
Cupola: derived from 2nd,3rd,4th pharyngeal arch. Forms posterior 1/3 mucosa
Epiglottal swelling: derived from 4th pharyngeal arch. Forms the epiglottis
How is the anterior 2/3 mucosa formed
During 5th week of development
Lateral lingual swellings overgrown the tuberculum impar and merge together
Line of fusion is marked by the median sulcus of tongue
What happens within the cupola to form the mucosa of posterior 1/3
During 5th week of development
3rd pharyngeal arch component overgrows the 2nd arch
What happens during week 8 of gestation in relation to tongue development?
Anterior 2/3 and posterior 1/3 fuse
Forms a v shapes groove called the terminal sulcus- at the centre of this groove is the foramen cecum which represents the place of origin of the thyroid gland
Development of lingual frenulum
Tongue is initially tethered to the floor of the oral cavity
Process of carefully programmed cell death known as sculpting apoptosis releases the tongue
Occipital somites
Segments of mesoderm in the region of the upper neck
Intrinsic and extrinsic muscles are derived from occipital somites
The somites migrate from the neck anteriorly to give rise to tongue muscles
