B16 - Tongue, blood supply and innervation, development

Question 1

Structures to mention on the tongue

Answer 1

• Corpus linguae
• Radix linguae (Caudal to papillae vallatae, → hyoid bone)
• Apex linguae
• Dorsum linguae (Dorsal part of the tongue)
• Torus linguae (Ru) (Prominence of the dorsum caudal to the fossa linguae)
• Fossa linguae (bo) (Deep pit on the dorsum linguae)
• Facies ventralis linguae
• Frenulum linguae (Ventral median fold that attaches the tongue to the floor of the mouth, sus, bo: doubled)
• Papillae linguales (Covers the dorsal surface)
  
  • Papillae filiformes
  • Papillae conicae
  • Papillae fungiformes (Have tastebuds)
  • Papillae lentiformes (Ru) (Mechanical)
  • Papillae vallatae (Have tastebuds)
  • Papillae foliatae (ø ru?) (Have tastebuds)
  • Papillae marginales (car, sus) (Present in newborns)
• Sulcus medianus linguae (Median dorsal groove)
• Septum linguae
• Lyssa (ca) (It continues caudally between mm. genioglossi by a cord)
• Cartilago dorsi linguae (eq)

Musculi linguae:

• M. genioglossus
• M. hyoglossus
• M. styloglossus
• M. lingualis proprius
  
  • Fibrae longitudinales superficiales
  • Fibrae longitudinales profundae
  • Fibrae transversae
  • Fibrae perpendiculares

Question 2

Give the interspecies differences of the tongue

Answer 2

• Lyssa (car)
• Sulcus medianus (eq, car)
• Torus linguae (ru)
• Fossa linguae (bo)
• Cartilago dorsi linguae (eq)
• Papilla lentiformis (ru)
• Papilla foliatae (ø ru)
• Papilla marginalis (car, su) (newborns)
• Fibrae longitudinalis profundae (eq) (intrinsic muscles of the tongue)
• Number of circum vallate papillae:
  
  • ​Eq: 1
  • Bo: 5-7
  • Sus: 1
  • Ca: 2
  • Fe: 3

Question 3

Where does the radix linguae attach

Answer 3

Hyoid bone

Question 4

Draw the tongue of:

1. Bo
2. Ca
3. Eq

Answer 4

Question 5

1. List the muscles of the tongue
2. Draw the muscles

Answer 5

Intrinsic muscles:

1. ​Fibrae longitudinalis superficialis
2. Fibrae longitudinalis profunda
3. Fibrae transversa
4. Fibrae perpendicularis

​Extrinsic muscles:

1. M. styloglossus
2. M. hyoglossus
3. M. genioglossus

Other muscles acting on the tongue

1. M. geniohyoideus
2. M. mylohyoideus
3. M. sternohyoideus
4. M. thyrohyoideus
5. M. sternothyroideus
6. M. occipitohyoideus

Question 6

Extrinsic muscles

M. styloglossus

Answer 6

• Origin: Stylohyoid bone
• Insertion: Middle of tongue
• Action: Retract and elevate tongue

Question 7

Extrinsic muscles

M. hyoglossus

Answer 7

• Origin:
  
  • ​Thyrohyoid
  • Basihyoid
• Insertion: Radix linguae
• Action: Retracts and depress tongue

Question 8

Extrinsic muscles

M. genioglossus

Answer 8

• Origin: Symphysis and adjacent surface of the body of mandibula
• Insertion: Left and right join at the median plane
• Action:
  
  • ​Caudal fibers: protrude tongue
  • Rostral fibers: retract apex

Question 9

Other muscles acting on the tongue

M. geniohyoideus

Answer 9

• Origin: Symphysis mandibularis
• Insertion: Basihyoid
• Action Draws the hyoid apparatus and larynx rostrally

Question 10

Other muscles acting on the tongue

M. mylohyoideus

Answer 10

• Origin: Basihyoid caudally
• Insertion: Midventral raphe, om the muscle from the other side
• Action: Supports tongue

Question 11

Other muscles acting on the tongue

M. sternohyoideus

Answer 11

• Origin:
  
  • ​Sternum
  • 1^st costal cartilage
• Insetion: Basihyoid
• Action: Pull the hyoid bone, radix linguae and larynx caudally

Question 12

Other muscles acting on the tongue

M. thyrohyoideus

Answer 12

• Origin: Cartilago thyroidea
• Insertion: Thyrohyoid bone
• Action:?

Question 13

Other muscles acting on the tongue

M. sternothyroideus

Answer 13

• Origin: 1^st costal cartilage
• Insertion: Cartilago thyroidea
• Action: Draws larynx and tongue caudally

Question 14

Blood supply of the tongue

Answer 14

1. A. lingualis​​
   
   • Ca, sus: ex a. carotis externa
   • Eq, ru: ex tr. linguofascialis
   • Runs with stylohyoid bone, then enters into linguae: a. profunda linguae
2. A. sublingualis
   
   • ​Ca, eq: a. submentalis, ex a. fascialis
   • Ru, sus: ex a. lingualis
3. V. lingualis from v. linguofascialis (arcus hyoideus)
4. V. sublingualis
   
   • ​Ca, sus, ru: ex v. ingualis
   • Eq: ex v. fascialis

Question 15

Innervation of the tongue

Answer 15

• 5 pairs of cranial nerves:
  
  • N. mandibularis ex n. trigemini (V)
  • N. fascialis (VII)
  • N. glossopharyngeus (IX)
  • N. vagus (X)
  • N. hypoglossus (XII) (only motor nerve of the tongue)
• The other nerves (ø n. hypoglossus) are:
  
  • Sensory
    
    • Tactile
    • Pain
    • Gustatory
    • Temperature

Question 16

Development of the tongue

Answer 16

• The tongue developes in the floor of the mouth
• Formed by the emergence of several swellings
• Median (distal) swelling:
  
  • Aappears on the pharyngeal floor between the lower ends of the mandibular arches
  • Later fuse with lateral swellings over the adjacent parts of these arches
• Caudal (proximal) swelling:
  
  • Extends from the floor into the ventral parts of the 2^nd, 3^rd and 4^th pharyngeal arches
  • Divides, and the caudal part becomes epiglottis
• Separation of the tongue from the floor is gradual
  
  • Separation is more complete for the part that derives from the median swelling and the 1^st arches (apex and corpus)
  • Separation is not complete from the part that derives from the proximal swelling (radix linguae)
• Origin: pharyngeal arches
  
  • ​Medial fusin of mandibular and hyoid pharyngeal arches
• Origin of tongue muscles: somite mesodum
• Origin of masticatory muscles: unsegmented somitomeus