The Mouth and Face 2 Flashcards
Which muscles form a muscular bed for the tongue to rest on and provide a framework for 2 important salivary glands - the submandibular gland and the sublingual glands?
- 2 muscles run into the floor of the mouth from the skull base
- another spans the mandible from side to side
How does the posterior belly of the digastric muscle arise?
It arises as a fleshy belly from a groove on the inner side of the mastoid process.
How does the posterior belly of the digastric muscle change?
It tapers to a tendon which slides through a fibrous sling that is attached near the lesser cornu of the hyoid bone.
What is the intermediate tendon of the posterior belly of the digastric muscle surrounded by?
It is surrounded by a synovial sheath.
What is the path of the anterior belly of the digastric muscle?
It passes forwards on the undersurface of the mylohyoid muscle.
Where does the anterior belly of the digastric muscle insert?
It inserts into the lower border of the mandible beneath the chin.
What is the function of the anterior belly of the digastric muscle when it acts with the lateral ptergoid muscle?
It depresses the chin and opens the mouth when it acts with the lateral pterygoid muscle.
Where does the stylohyoid muscle arise from?
It arises from the styloid process.
What does the stylohyoid muscle run along?
It runs along the upper border of the digastric muscle.
What happens to the stylohyoid muscle at the hyoid bone?
It splits and inserts into the greater cornu of thje hyoid bone.
What are the posterior belly of the digastric muscle and the stylohyoid muscle derivitives of?
They are derivitives of the second pharyngeal arch.
What is the nerve supply to the posterior belly of the digastric and the stylohyoid?
Facial nerve.
What is the function of the stylohyoid muscle?
It retracts and elevates the hyoid and is active during swallowing.
What does the mylohyoid form across the floor of the mouth?
It forms a sling or diaphragm across the floor of the mouth.
Where does the mylohyoid muscle arise from?
It arises on both sides from the inner aspect of the mandible.
On the inner aspect of the mandible it raises an oblique ridge on the body of the mandible that is called the mylohyoid line.
Where does the mylohyoid muscle insert?
It inserts into the front of the body of the hyoid bone.
Where do the 2 mylohyoid muscles meet?
They meet in the midline at a raphe or seam that extends from the front of the hyoid bone to the mandibular symphysis anteriorly.
What is the function of the mylohyoid muscle?
Like the digastric and the stylohyoid muscle, it can elevate the hyoid bone.
What does contraction of the mylohyoid muscle bring about?
It raises the whole floor of the mouth.
What is the nerve supply to the mylohyoid bone?
This is supplied by a branch of the mandibular nerve that leaves the inferior alveolar nerve by the mandibular foramen at the posterior end of the mylohyoid line.
This nerve gives motor supply to the mylohyoid muscle and the anterior belly of the digastric muscle. Therefore these muscles are derived from the first pharyngeal arch.
