Session 1.2b - CTF-led Tutorial Flashcards
Workbook/Slides
Why is it important to understand the actions of the muscles of the head and neck?
In clinical practice, you will ask patients to demonstrate actions of these muscles so that the integrity of the cranial nerves supplying them can be determined. It is important, therefore, to understand the action of these muscles and the functional consequences that arise as a result of injury to the nerves supplying them e.g. inability to close the eyelid.
- It is not expected that you learn the origins/insertions of these muscles in detail!*
- However, it is important that you understand where these muscles are found and what their action is; this in itself necessitates a general understanding of muscle origin and insertion!
Pathway of the facial nerve - what are the five terminal branches?
Temporal Zygomatic Buccal Mandibular Cervical
To Zanzibar By Motor Car
Slide 3
a) Label the structures
b) Draw the segmentation of the five terminal branches of the facial nerve
See image
What is the action of the platysma muscle?
- Depresses lower jaw
- Small function in drawing down lower lip
- Tenses skin (e.g. shaving)
What is the innervation of the platysma muscle?
Cervical branch of facial
How is the function of the platysma muscle examined?
Not usually examined
An example of the level of detail expected is demonstrated for the platysma muscle:
- Function/action
- Rough origin/insertion
- Relation to other structures (deep/superficial)
Depresses angles of mouth; also used to tense skin of neck e.g. during shaving; arises from skin/fascia of lower face and mandible, inserts into fascia covering anterior chest wall; runs superficial to SCM and over clavicles
What is the rough origin/insertion of the platysma muscle?
Skin/fascia of lower face and mandible, to the fascia covering the anterior chest wall (See image page 4/workbook page 25)
What is the 3D anatomical relationship of the platysma to other structures?
It runs deep to the skin but superficial to the SCM and clavicles. (See image page 4/workbook page 25)
What is the action of orbicularis oculi?
Closes the eye (although separate parts have separate actions)
What is the innervation of orbicularis oculi?
Temporal and zygomatic branches of facial nerve
How is the function of orbicularis oculi examined?
Close eyes and resist opening
What is the rough origin/insertion of orbicularis oculi and its 3D relationship?
A sphincter muscle around the eye (see image page 5), lying superficially over the skull and deep to the skin.
What are the two parts of orbicularis oculi?
The orbital and palpebral part (there is also a lacrimal section; lacrimal obicularis)
Where is the orbital part of orbicularis oculi found?
Orbital ocularis surrounds the orbital margin.
What is the function of the orbital part of orbicularis oculi (orbital ocularis)?
It is a thick muscle used to consciously close the eye - used for forceful closure.
Where is the palpebral part of orbicularis oculi found?
Palpebral orbicularis is found in the eyelid.
What is the function of the palpebral part of orbicularis oculi (palpebral ocularis)?
Used for unconscious ‘light’ closure of the eye in blinking/sleep.
The platysma muscle is a muscle of ___?
Facial expression
Orbicularis oculi is a muscle of ___?
Facial expression
What is the function of levator palpebrae superioris?
Elevates upper eyelid
What is the innervation of levator palpebrae superioris?
Oculomotor nerve
take note of its nerve supply
How is the function of levator palpebrae superioris examined?
Inspection of eyes for ptosis (drooping of upper eyelid)
What is the rough origin/insertion of levator palpebrae superioris and its 3D relationship to other structures?
It arises from the sphenoid bone and inserts into the upper eyelid; it is the most superior of the eyelid muscles (see image page 7).
Is levator palpebrae superioris a muscle of facial expression or mastication?
It is neither! (Hence nerve supply is not facial nerve)
This muscle we be revisited in Session 9: The Eye, Ocular Muscles and the Orbit
What is the function of occipitofrontalis?
Elevates eyebrows
What is the innervation of occipitofrontalis?
Frontal belly - temporal branch of facial nerve
dual innervation
Occipital belly - posterior auricular branch of facial nerve
How is the function of occipitofrontalis examined?
Elevate eyebrows against resistance
What are the two parts of occipitofrontalis?
Frontalis (anterior)
Occipitofrontalis (posterior)
What is the rough origin/insertion of occipitofrontalis and its 3D relationship to other structures?
From orbicularis oculi (frontal belly) to the superior nuchal line of the occipital bone and mastoid process (occipital belly) - connected via the galea aponeurotica. It is a superficial scalp muscle.
Occipitofrontalis is a muscle of ___?
Facial expression
Occipitofrontalis, namely its ___________, forms ___ of the layers of the _____.
Occipitofrontalis, namely its aponeurosis, forms one of the layers of the scalp.
Epicranial aponeurosis can otherwise be known as ___?
Galea aponeurotica
Galea aponeurotica can otherwise be known as ___?
Epicranial aponeurosis
What are the layers of the scalp?
S: Skin C: dense Connective tissue A: Aponeurosis of occipito-frontalis L: Loose connective tissue P: Pericranium
(see image page 9)
Which layers of the scalp form a single functional layer?
The first 3 layers: skin, dense CT, aponeurosis (S.C.A.)
What is the action of orbicularis oris?
Closes mouth
What is the innervation of orbicularis oris?
Buccal branch of facial nerve
How is the function of orbicularis oris examined?
Face inspection - drooping angle of the mouth in CNVII palsy (facial nervy palsy)
Where is the rough origin/insertion of orbicularis oris and its 3D relationship to other structures?
It forms a sphincter around the lips, attaching to the maxilla and mandible. It lies superficially underneath the skin.
Orbicularis oris is a muscle of ___?
Facial expression
What is the action of the dilator muscles of the lips?
Separate the lips
What is the innervation of the dilator muscles of the lips?
Buccal and mandibular branches of facial nerve
How is the function of the dilator muscles of the lips examined?
Not individually examined routinely
Give two examples of dilator muscles of the lips
Zygomaticus muscles
Risorius
(You do not need to know all the individual muscles that act to dilate the mouth)
What is the rough origin/insertion and 3D relationship of the dilator muscles of the lips?
They (generally) lie superiorly and inferiorly, whilst attaching to, orbicularis oris. Many are superficial muscles although some lie slightly deeper.
Dilator muscles of the lips are muscles of ___?
Muscles of facial expression
Slide 4
Name the muscle highlighted
Platysma
Slide 5
Label the arrowed muscle (and any others you know)
Orbicularis oculi
Slide 6
Label the orbital and palpebral part of orbicularis oculi
See image
Slide 7
Label the arrowed muscle
Levator palpebrae superioris
Slide 8
Label the muscle highlighted in green (an any other muscles known)
Occipitofrontalis
Slide 9
Label the layers of the scalp
- Skin
- Dense connective tissue
- Aponeurosis of occipitofrontalis
- Loose connective tissue
- Pericranium
Slide 10
Label the muscle in red (and any bones)
Orbicularis oris
Slide 11
Label the muscles
Levator labii superioris alaeque nasi; Levator labi superioris; Zygomaticus minor; Zygomaticus major; Risorius; Platysma; Depressor anguli oris; Depressor labii inferiors; Mentalis; Orbicularis oris; Buccinator; Levator anguli oris
What is the action of the buccinator muscle?
Flattens cheek - holds cheek close to teeth when chewing - prevents food pooling between cheek and gums
What is the innervation of the buccinator muscle?
Buccal brand of the facial nerve
How is the function of the buccinator muscle examined?
Blow out cheeks and resist expulsion of air
What is the origin/insertion of the buccinator muscle, and its 3D anatomical relationship to other structures?
The buccinator occupies the interval between the maxilla and mandible, inserting into orbicularis oris, to form the anterior part of the cheek/lateral wall of the oral cavity. It lies deep to risorius and zygomaticus major.
Slide 12
Label the muscle in red (and any other muscles)
Buccinator
The buccinator muscle is a muscle of ___?
Facial expression
Muscles of mastication are innervated by the ___?
Trigeminal nerve (mandibular branch)
Slide 14
Label the image
Trigeminal nerve; Opthalmic branch (V1); Maxillary branch (V2); Mandibular branch (V3); Superior alveolar nerve; Inferior alveolar nerve; Lingual nerve
What is the action of the lateral pterygoid muscle?
Protrude mandible, opens jaw, contralateral excursion
What is the action of the medial pterygoid?
Elevator, contralateral excursion
What is the innervation of the lateral and medial pterygoids?
Mandibular branch of trigeminal nerve
How is the function of the pterygoid muscles examined?
Open mouth against resistance. Move jaw side to side.
What is the rough origin/insertion of the lateral pterygoid and its 3D relationship to other structures?
It lies superior the to the medial pterygoid, running transversely (horizontal) along the cheek, lying deep to the mandible. It has two heads.
The lateral pterygoid is a muscle of ___?
Mastication
What is the rough origin/insertion of the medial pterygoid and its 3D relationship to other structures?
It lies inferiorly to the lateral pterygoid, running longitudinally (along the sagittal plane) across the cheek, lying deep (and inserting into) the mandible. It has two heads.
Slide 15
Label the muscles shown (and any bones/anatomical landmarks if known)
Lateral pterygoid; medial pterygoid
What is the action of the masseter muscle?
Elevates mandible (closes jaw), stronger than medial pterygoid
What is the innervation of the masseter muscle?
Mandibular branch of trigeminal nerve
How is the function of the masseter muscle examined?
Palpation during jaw clench
What is the rough origin/insertion of the masseter muscle and what is its 3D relationship to other structures?
It arises from the zygomatic arch and inserts into the mandible. The masseter is the most superficial of the muscles of mastication, and one of the strongest.
The medial pterygoid is a muscle of ___?
Mastication
The masseter muscle is a muscle of ___?
Mastication
Slide 16
Label the muscle arrowed (and the other muscle/any bony landmarks)?
Masseter
How can you palpate the masseter muscle?
You can palpate the contraction of this muscle as you clench your jaw.
How can you palpate the temporalis muscle?
You can palpate the contraction of this muscle as you clench your jaw.
Which muscles can you palpate as you clench your jaw?
Masseter and temporalis
What is the action of the temporalis muscle?
Elevates mandible (also retrusion of mandible)
What is the innervation of the temporalis muscle?
Mandibular branch of trigeminal
How is the function of temporalis examined?
Palpation during jaw clench
What is the rough origin/insertion of temporalis and its 3D relationship to other structures?
It arises from the temporal lines on the parietal bone of the skull, and inserts into the coronoid process of the mandible. It lies deep to some of the muscles of facial expression.
Temporalis is a muscle of ___?
Mastication
Slide 17
Label the muscle shown (and any bony anatomical landmarks)?
Temporalis
Name two muscles of the neck that are landmarks of the anterior/posterior triangles
SCM and trapezius
What is the action of sternocleidomastoid?
- Head rotation to opposide side (one side contracts)
- Lateral neck flexion (one side contracts)
- Neck flexion (both contract)
What is the innervation of sternocleidomastoid?
Accessory nerve
take note
How is the function of SCM examined?
Turn head against resistance (remember turn to right = left SCM!)
What is the rough origin/insertion of SCM and its 3D relationship to other structures?
Its two heads arise from the manubrium (sterno-) and medial portion of the clavicle (-cleido-), inserting into the mastoid process of the temporal bone (-mastoid). It lies immediately deep to the platysma (in the investing layer of deep cervical fascia).
What borders does SCM form in important anatomical triangles of the neck?
- The ANTERIOR margin of SCM forms the LATERAL border of the ANTERIOR triangle
- The POSTERIOR margin of SCM forms the ANTERIOR border of the POSTERIOR triangle
- The ANTERIOR margin of SCM forms the LATERAL border of the CAROTID triangle
Slide 19
Label the two branches (heads) of the SCM muscle
Sternal branch; Clavicular branch (correctly labelled)
What is the action of trapezius?
- Upper and lower fibres rotate scapula (acromion and inferior angles move up)
- Middle fibres retract scapula
- When scapulae stable, contraction of both sides extends the neck
What is the innervation of trapezius?
Accessory nerve
take note
How is the function of trapezius examined?
Elevate shoulder
What is the rough origin/insertion of trapezius and its 3D relationship to other structures?
It arises from the external occipital protuberance, spinous processes of vertebrae C7-T12, nuchal ligament and occipital bone; inserting into the nuchal ligament, posterior border of the lateral 1/3 of the clavicle, acromion process and spine of scapula. It is a large, superficial muscle of the neck (and back).
What borders does trapezius form in important anatomical triangles of the neck?
The ANTERIOR margin of trapezius forms the POSTERIOR border of the POSTERIOR triangle
Slide 20
Label the muscle shown (and any anatomical landmarks)
Trapezius