Submandibular Triangle Flashcards
On the superior margin of the ramus of the mandible, there are two bony processes. What are they called and which one is more anterior?
Coronoid (more anterior) process and condylar process
What is the depression between the coronoid and condylar process on the mandible called?
mandibular notch
What bony feature of the mandible separates the submandibular fossa from the sublingual fossa?
the mylohyoid line (p1033 grays)
Origin and Insertion of anterior belly of digastric muscle?
origin: digastric fossa of mandible
insert hyoid bone via digastric tendon
Origin and insertion of posterior belly of digastric muscle?
origin: medial aspect of mastoid process
insertion: hyoid bone via digastric tendon
What innervates the anterior belly of digastric?
Mylohyoid nerve (CN V3) branch of inferior alveolar nerve off trigeminal
What are the actions of the anterior belly of digastric?
lowers mandible or raises hyoid
What are the actions of the posterior belly digastric?
elevates and retracts hyoid
What innervates the posterior belly of digastric?
CN VII (facial)
Origin and insertion of mylohyoid muscle?
origin: mylohyoid line of mandible
insert: hyoid bone and mylohyoid raphe
What innervates the mylohyoid?
Mylohyoid nerve (CN V3) branch of trigeminal
Origin and insertion of geniohyoid?
origin: inferior mental spine of mandible
insert: hyoid bone
What innervates the geniohyoid?
C1 branch travelling with CN XII (hypoglossal)
What are the actions of the mylohyoid muscle?
supports and elevates floor of mouth; raises hyoid
What are the actions of the geniohyoid muscle?
draws mandible and hyoid toward eachother
Origin and insertion of stylohyoid muscle?
orign: styloid process
insert: body of hyoid bone
What innervates stylohyoid muscle?
CN VII (facial)
What are the actions of stylohyoid muscle?
elevates and retracts the hyoid.
What are the extrinsic muscles of the tongue?
Hyoglossus, genioglossus, styloglossus, palatoglossus
Origin and insertion of hyoglossus?
origin: greater horn of the hyoid bone
insert: lateral tongue
What innervates the hyoglossus muscle?
CN XII (hypoglossal
What are the actions of the hyoglossus muscle?
depresses and retracts the tongue
Origin and insertion of genioglossus muscle?
origin: superior mental spine
insert: hyoid bone, tongue
What innervates the genioglossus muscle?
CN XII (hypoglossal)
What are the actions of the genioglossus muscle?
protrudes, depreses and retracts the tongue
Origin and insertion of the styloglossus muscle?
orign: styloid process
insert: lateral tongue
What innervates the styloglossus muscle?
CN XII (hypoglossal)
What are the actions of the styloglossus muscle?
retract and elevate the tongue
Origin and insertion of the palatoglossus muscle?
origin: posterior margin of the hard palate, palatine aponeurosis
insert: lateral tongue
What innervates the palatoglossus?
pharyngeal branches of CN X (vagus)
What are the actions of the palatoglossus muscle?
depress the palate, elevate the back of the tongue.
What muscle forms the boundaries of the submandibular triangle?
the anterior and posterior bellies of the digastric muscle.
Rank the attachment of these extrinsic tongue muscles from most lateral to most medial attachment on the tongue:
hyoglossus, genioglossus, styloglossus
Styloglossus, hyoglossus, genioglossus
Does the lingual artery pass superficial or deep to the hyoglossus? The lingual nerve? The hypoglossal nerve?
The lingual artery from the external carotoid enters the tongue deep to the hyoglossus, between the hyoglossus and genioglossus.
The Lingual nerve (branch of mandibular nerve CN V3), comes from the infratemporal fossa and enters the tongue on the external (superficial) surface of the hyoglossus.
The hypoglossal nerve (CN XII) also passes superficial to the hyoglossus, but comes from the neck, inferior to the lingual nerve.
What muscle does the submandibular gland ‘hook’ around?
the mylohyoid muscle
Which part of the submandibular gland is larger: the deep or superficial hook?
The superficial hook is larger and outside the oral cavity.
What nerve crosses the submandibular duct?
lingual nerve starts lateral then passes underneath the duct to loop back up and medial
If the patient is asked to stick their tongue out and say ‘ahh’, and the tongue deviates to the right, which side is there a nerve lesion and in which nerve?
The only muscle we have learned that protrudes the tongue is the genioglossus, which is innervated by CN XII (hypoglossal). It is the only ‘pushing’ muscle in the body. If the tongue deviates to the right, the nerve lesion is on the right. (in almost every other part of the body, the deficit will be on the side opposite of the deviation. Ex: If radial nerve is damaged, the triceps will be knocked out so the elbow flexors will cause the arm to be flexed away from the muscles with the lesion)
Note: the tongue muscles don’t actually push, but the alignment of the fibers when they contract give it this effect
Which extrinsic muscle of the tongue does the styloglossus muscle blend into?
Blends with the hyoglossus
What muscle flattens the tongue?
hyoglossus
Are most spinal nerves mixed or just sensory/just motor? What about C1?
Almost all spinal nerves are mixed motor and sensory.
C1 is an exception in that it is solely motor. It has a branch that travels with the hypoglossal nerve to innervate the geniohyoid as well as providing the superior loop of ansa cervicalis and nerve to thyrohyoid
What ganglia is in the submandibular region?
The submandibular ganglion (parasympathetic)
Which nerve is more inferior: the hypoglossal or the lingual?
hypoglossal. It runs along the level of the mandible
Does the submandibular duct come off the deep or superficial part of the submandibular gland?
deep.
Describe the relationship of the lingual nerve to the submandibular duct.
The lingual nerve starts out lateral then crosses underneath the submandibular duct inferiorly to reach the tongue
What is the sublingual caruncle?
the opening of the submandibular duct into the mouth, beneath the tongue along the side of the frenulum
What does the lingual nerve do?
GSA innervation to the anterior 2/3 of the tongue. Nothing else.
Where do the cell bodies of the lingual nerve reside?
semilunar ganglion in the middle cranial fossa
Does the lingual nerve cross the styloglossus laterally or medially?
Laterally. See Plate 59 in Netters or in lecture
What runs with the lingual nerve and provides taste fibers to the anterior 2/3 of the tongue.
Chorda tympani of faical nerve CN VII
What else runs with the lingual nerve besides SA from the chorda tympani?
Pre-ganglionic parasympathetic motor fibers (GVE) to the submandibular and sublingual ducts. These come from the chorda tympani
As the facial artery makes its course from the deep part of the mandible to the superficial part, does it pass deep or superficial to the submandibular gland? What about the facial vein?
The artery is deep to the submandibular gland then wraps around the mandible to pass superficially.
The facial vein is superficial to the submandibular gland.
(Plate 60 Netters)
What is a sialolith?
stone that blocks the salivary ducts or glands.
Where are the SA cell bodies that run in the chorda tympani found?
the geniculate ganglion (sensory ganglion of facial nerve CN VII)
What sensory losses would you expect from a CN V3 lesion below the chorda tympani?
GSA sensation and SA taste to the anterior 2/3 of the tongue as well as parasympathetics to the submandibular and sublingual glands. Though the lingual nerve only has GSA fibers, the chorda tympani carries SA and runs in the same sheath.
Where do the post-ganglionic cell bodies that innervate the submandibular gland reside? Pre-ganglionic?
Postganglionic parasympathetic cell bodies are located in the submandibular ganglion.
The presympathetic cell bodies are located in motor ganglia of CN VII in the brain. They travel from the geniculate ganglion through the chorda tympani to follow the lingual nerve.
