Lecture 15: Muscles ( in Head and Neck) Flashcards
What are the ways to classify skeletal muscles
- shape
- location
- attachment
- number of heads
- function
- direction of fibers
- size
Name a few muscles classified by shape
deltoid, trapezius, rhomboid
Name a few muscles classified by location
pectoral, intercostal, brachial
Name a few muscles classified by attachment
sternocleidomastoid bone
Name a few muscles classified by number of heads
triceps and biceps
Name a few muscles classified by the function
flexor and extensor muscles
Name a few muscles classified by the direction of the fibers
rectus abdominis and transverse abdominis
Name a few muscles classified by the size
gluteus maximus ,vactus lateralis
How many muscle tissues do we have
three
- skeletal
- smooth
- cardiac
What are the 4 major features of a skeletal muscles
- function
- innervation
- origin
- insertion
Origin of muscle:
attachment of the muscle that typically remains stationary during contraction
Insertion of muscle:
attachment of muscle that typically moves during contraction
Function of the muscle:
movement due to muscle contraction: the distance between the origin and insertion typically become closer during contraction
- muscles may try to bring the insertion and origin to the same plane
Innervation of the muscle:
skeletal muscles are typically governed by the somatic nervous system of the spinal and cranial nerves
What is the main muscle in the scalp
occipitofrontalis muscle
What characterizes superficial muscles
one end is attached to the skin ( so those at the facial region are responsible for the facial expression)
What are the cavities that the muscles surround in the facial region
- nasal cavity
- orbital cavity
- cranial cavity
Name the components of the occipitofrontalis
frontal and occipital bellies that is connected by the galea aponeurotica ( and attached to the skin)
What is responsible for the wrinkles and eyebrow movement
frontal belly
What innervates the epicranius ( occipitofrontalis)
Cranial nerve 7
Oribucularis oculi
- function
- where
- can squeeze eyes, opens the nasolacrimal duct
2. around the eyes
What happens when the nasalis muscles contract
causes the nostrils to flare
Oribicularis oris
- function
- where
- purses lips
2. surrounds the oral fissure, opens mouth
What innervates all the superficial muscles in the facial region
CN 7
How many muscles of mastication are there?
four muscles
What are the muscles of mastication
- masseter muscle
- temporalis muscle
- medial pterygoid muscles
- lateral pterygoid muscles
Where is a definite attachments of the muscles of mastication
mandible
Origin and insertion of the temporalis muscle
origin: temporal fossa
insertion: coronoid process of mandible
function: elevates mandible
Origin, insertion and function of the masseter muscle
origin: zygomatic arch
insertion: ramus of mandible
function: clenches teeth
Origin, insertion and function of the medial muscle
origin: sphenoid bone
insertion: medial surface of the ramus
function: elevates muscle
What joint is locked when your mouth is closed
temporomandibular joint
What has to happen for your mouth to open
the mandible has to be open
How many extra-occular muscles are there?
There are 7 extra-occular muscles
What muscle works to open the eye
levator palpebrae superioris
What nerves innervate the levator palpebrae superioris
sympathetic fibers and cranial nerve 3
What skeletal muscle is the only skeletal muscle that gets innervated by sympathetic fibers
levator palpebrae superioris
Which segment of the spinal cord supplies sympathetic fibers for the head and neck
T1
Where does the T1 spinal cord segment sit
near the lungs, so ptosis occurs when you have a tumor to the lung - because the lung sits close to T1 segments
What is the laryngeal elevators
Muscles of the pharynx that causes larynx elevation
how are the pharyngeal muscles grouped?
inner longitudinal and outer circular muscles
What CN innervates the pharyngeal muscles?
CN 10
What muscle constricts the pharynx and may cause hypoxia?
pharyngeal constrictors
Origin, insertion and function of muscles of the soft palate
origin: base of cranium
insertion: soft palate
function: elevate, depress or stretch soft palate , t prevent food from entering nasal cavity
What innervates the muscles of the soft palate
CN 10
How many muscles are there in the tongue?
19
How are muscles in the tongue classified ?
Intrinsic: both origin and insertion inside the tongue
Extrinsic: origin originates outside the tongue and insert inside the tongue
What CN innervates muscles of the tongue
CN 12
What are the superficial muscles of the neck
- sternocleidomastoid (SCM)
- infrahyoid muscles
- suprahyoid muscles
Origin, Insertion, function and innervation of the SCM
Sternocleidomuscle:
originates: sternum and clavicle
insertion: mastoid process of temporal bone
function: extends neck and rotates the head contra-laterally
innervated: CN 11
