Download 213: HUMAN FUNCTIONAL ANATOMY: PRACTICAL CLASS 10

213: HUMAN FUNCTIONAL ANATOMY:
PRACTICAL CLASS 10 Mouth and mastication
OSTEOLOGY
Study a skull and identify bony features associated with the mouth and mastication:
Mandible
Ramus
Angle
Body
Head
Notch
Coronoid process
Genial tubercles
Digastric fossae
Mylohyoid line
Locate the areas of attachment of:
temporalis, masseter, medial
pterygoid, lateral pterygoid,
mylohyoid, genioglossus, geniohyoid and digastric.
Maxilla
Alveolar margin
Maxillary tuberosity
Palate
Incisive foramen.
Palatine bone
Palate
Palatine foraminae
Temporal bone
Mandibular fossa
Articular eminence
Post-glenoid tubercle
Styloid process
Stylomastoid foramen
Mastoid process
Sphenoid bone
Foramen ovale
Spine of the sphenoid
Lateral pterygoid plate
Medial pterygoid plate
Pterygoid hamulus.
MUSCLES OF MASTICATION AND THE TEMPOROMANDIBULAR JOINT
Surface Anatomy
With your mouth closed, feel the head of the mandible, just in front of the tragus of your
auricle. Open and close your mouth, and feel the head of mandible slip forwards, out from
under your finger. Feel your temporalis and masseter muscles while; clenching and
unclenching your teeth; and protracting and retracting your jaw.
Use the wet specimens to examine the TMJ (temporomandibular joint) and the muscles of
mastication. There is also a bottle which shows each muscle of mastication, but be sure to
identify them on a specimen as well.
On superficial dissections of the side of the face identify the temporalis and masseter muscles
and the TMJ.
On deeper dissections in the infratemporal fossa identify the medial and lateral pterygoid
muscles. Identify the intra-articular disc of the TMJ, and the insertion of the lateral pterygoid
muscle to this disc and the neck of the mandible.
All these muscles are supplied by the mandibular division of the trigeminal nerve. Two other
muscles associated with movements of the mandible are supplied by the mandibular nerve
(nerve to mylohyoid). Find mylohyoid muscle and the anterior belly of digastric under the
chin.
Make sure you understand the movements of the TMJ, and the muscles involved in each case:
Elevation
Protraction
Retraction
Depression
What is the function of bilateral protraction of both TMJs?
What is the function of unilateral protraction and retraction?
Also in the infratemporal fossa, find the mandibular division of the trigeminal nerve
emerging from the foramen ovale, and the maxillary artery. Identify the lingual and inferior
alveolar nerves, and the nerve to mylohyoid. You may also be able to see the chorda
tympani; this branch of the facial nerve (carrying taste and parasympathetic fibres) emerges
from the petrotympanic fissure just medial to the TMJ, and joins the lingual nerve.
ORAL CAVITY
Look into a partner's mouth and, with the tongue depressed and protracted, identify
and draw:
1. Teeth - Incisors (2), canines (1), premolars (2) and molars (3); (determine which teeth
are missing from the adult complement).
2. Dorsum of the tongue with small papillae all over, you may be able to see a row of
large (vallate papillae) at the back of the anterior two thirds of the tongue.
3. Palate, soft palate and uvula
4. palatoglossal and palatopharyngeal folds
5. Tonsils may be visible between those two folds
6. Posterior pharyngeal wall
With the tongue elevated, identify and draw
1. Frenulum of the tongue with papillae of the submandibular ducts
2. Sublingual glands in the floor of the mouth
Find these structures on a hemisected head.
THE SALIVARY GLANDS AND PARASYMPATHETIC NERVE SUPPLIES
There are three main salivary glands (parotid, sublingual and submandibular), However the
whole lining of the mouth, nose and pharynx is a mucus membrane, with many tiny glands in
the mucosa.
On a superficial prosection of the face identify the parotid gland, with its duct passing
forwards across the masseter muscle. The parotid duct enters the mouth by piercing
buccinator adjacent to the 2nd upper molar.
Study a superficial prosection of the submandibular region; the submandibular gland is
obvious below the body of the mandible. The facial artery hooks over the submandibular
gland before coming onto the face. The submandibular gland is folded over the posterior
edge of the mylohyoid muscle, so that its duct passes over the muscle into the floor of the
mouth. The submandibular duct is accompanied by the lingual nerve, and as it passes the
gland, you should be able to see the submandibular ganglion hanging off the nerve. Also in
this region identify the hypoglossal nerve.
The parasympathetic nerves to the glands of the head:
Parasympathetic Origin
Ganglion
Distributed with
nerve
Chorda tympani
Facial (CNVII)
Submandibular Lingual (V1)
Greater
nerve
Lesser
nerve
petrosal Facial (CNVII)
Pterygopalatine
petrosal Glossopharyngea
l (CNIX)
Otic
Glands
Submandibular
Sublingual
Maxillary(V2)
Nasal, palatine
and lachrymal
Auriculotemporal Parotid
(V3)
Use colour to trace the Taste and Parasympathetic branches of the Facial and
Glossopharyngeal nerves on the diagram below. Also identify the parasympathetic ganglia
and the branches of the trigeminal nerve that carry some of these fibres
MUSCLES OF THE TONGUE
On the lateral view of the tongue, indicate all the extrinsic muscles (and nerve supplies):
Styloglossus (XII)
Palatoglossus (X)
Genioglossus (XII)
Hyoglossus (XII)
Add the accessory muscles of the tongue;
Digastric (VII+V)
Geniohyoid (XII)
Mylohyoid (V).
Consider what extrinsic muscles would be involved in
the movements of the tongue:
Protraction
Retraction
Elevation
Depression
What muscles would perform movements like rolling the tongue?
THE DENTIST AND THE TRIGEMINAL NERVE
Consider which branches of the trigeminal nerve, the dentist needs to anaesthetise in order to
work on:
Lower teeth
Upper front teeth
Upper back teeth
Palate and internal aspect of the gums
Cheeks and outer aspect of the gums
Practical anatomy checklist
Osteology
The skull and mandible
You should know all the features of the skull (from week 8) and especially the mandible and
features associated with mastication.
Temporomandibular joint
Muscles of mastication
The Mouth
The Oral cavity
Salivary glands
Muscles and movements of the tongue