W7: Anatomy L Muscles Of Head And Neck Flashcards
Does the face have deep fascia?
No, only superficial fascia and skin
Pharyngeal arch 1 and its nerves
Trigeminal nerve, V2 and V3
Pharyngeal arch 2 and its nerves
Facial nerve
Pharyngeal arch 3 and its nerves
Glossopharyngeal nerve
Pharyngeal arch 4 and 6 and its nerves
Vagus nerve
What pharyngeal arch are the muscles of the face developed from?
Second pharyngeal arch
What nerve innervated the muscles of the face?
Facial nerve CNVII
6 groups of muscles of facial expression
Orbital, nasal, a oral, auricular, SCALP, neck
Orbital group muscles and their actions
Orbicularis oculi (palpebral and orbital) - orbital sphincter to close eyelids gently and tight closing of eye (wink) Corrugator supercilli - draws eyebrows medially and inferiorly
Nasal group muscles and their actions
Nasalis (transverse and alar part) - transverse compresses nostrils and alar dilates the nostrils
Depressor septi
Procerus - winkles skin on nose and draws eyebrows medially
Oral group muscles
Levator labii superioris alaeque nasi, levator labii superioris, zygomaticus minor, zygomaticus major, risorius, depressor anguli oris, depressor labii inferioris, mentalis, orbicularis oris, buccinator, levator anguli oris
What does orbicularis oris do?
Closes lips, can compress and protrude (kissing), can resist distension (blowing) when working with buccinator
What does the buccinator do?
Prevent accumulation of food in the vestibule of the mouth, help with compression of the cheeks and in babies helps during breastfeeding. Helps stabilise dentures.
What does the levator labii superioris do?
Dilates mouth, elevates the upper lip
What do the zygomaticus major and minor do?
Bilateral action - smiling
Unilateral action - sneering
What does the levator anguli oris do?
Dilator of the mouth, widens mouth when grinning
What does the risorius and depressor anguli oris do?
Depresses corners of the mouth to convert sadness in frowning
What does the depressor labii inferioris do?
Retracts lower lip and everts (pouting or sadness)
What does mentalis do?
Elevates and protrudes the lower lip
What are the auricular group muscles?
Anterior auricular, superior auricular, posterior auricular
What are the SCALP group (occipitofrontalis) muscles and their actions?
Frontalis (frontal belly of occipitofrontalis) - elevates eyebrows and wrinkles forehead
Occipitalis (occipital belly of occipitofrontalis) - wrinkles back of head
Both in epicranial aponeurosis
What are the neck group muscles and actions?
Platysma - depresses mandible, tenses skin of inferior face and neck
5 branches of the facial nerve
Temporal Zygomatic Buccal Marginal mandibular Cervical (Two zebras but my cat)
Where does the facial nerve exit the skull?
Stylomastoid foramen
Where does the facial nerves terminal branches branch from?
The parotid gland
What is Bell’s palsy?
Dysfunction of the facial nerve
Generally unilateral
Swelling of the nerve during its pathway of the bony canal will produce pressure on the nerve fibre, generating loss of the function of the nerve, so a LMN paralysis.
Affects muscles of facial expression
Signs of Bell’s palsy
Dripping of saliva, dropping of the mouth, not proper closing of eyes
Cervical vertebra in the neck
C1-7
What level does the hyoid bone lie?
C3
What is unique about the hyoid bone?
It does not articulate with any other bone
What fascia is the neck surrounded by?
Superficial cervical fascia and deep cervical fascia
What is in the superficial cervical fascia?
Platysma and the nerves that innervate it
Cutaneous nerve of the cervical plexus
What are the three layers of deep fascia? (Pic at pt3 min3)
Superficial, pre-tracheal layer, deep layer
Describe the superficial part of deep fascia - light green on image
Encloses trapezius posteriorly and SCM anteriorly. Encloses submandibular gland and splits to form the fibrous capsule of the parotid gland.
Describe the pre-tracheal layer of the deep fascia - purple on diagram
Includes a thin muscular part enclosing the infrahyoid muscles and visceral part. Encloses thyroid gland, trachea and oesophagus. Blends lateral with the carotid sheath which surrounds important structures like the internal jugular vein, internal carotid artery, common carotid artery and vagus nerve.
Describe the deep layer of deep fascia
Prevertebral layer (blue) will surround the vertebra and muscles that are associated with it. Alar layer (orange).
Function of the fascia
Determine the direction in which an infection might spread
Provide slipperiness allowing structures within the neck to pass over the others without being painful and damaging the other structures
Layers will form natural cleavage which will help with separating tissues during surgery
What triangles are in the anterior triangle of the neck?
Submental, submandibular, carotid, muscular
What triangles are in the posterior triangle of the neck?
Occipital and subclavian triangles
What separates the anterior and posterior triangles?
SCM
Origin and insertion of SCM
Origin: sterno and clavicular head
Insertion: mastoid process and superior nuchal line
What is SCM innervated by?
Accessory nerve CNXI
What happens when the SCM contracts unilaterally and bilaterally?
Unilateral: lateral flexion of the neck
Bilateral: flexion of the neck
Boundaries of the posterior triangle
Anterior: posterior border of SCM
Posterior: anterior border of trapezius
Base: middle third of clavicle
What divides the occipital and subclavian triangles?
Omohyoid muscle (inferior belly)
Arteries in the posterior triangle
Subclavian artery Suprascapular artery Transverse cervical artery Occipital artery Dorsal scapular
Veins of the posterior triangle
Subclavian vein
External jugular vein
Nerves of the posterior triangle
Trunks of brachial plexus
Branches of the cervical plexus
Spinal accessory nerve
Muscles and structures of the posterior triangle
Omohyoid muscle Lymph nodes (other structures)
Boundaries of the anterior triangle of the neck
Anterior: midline of the neck
Posterior: anterior border of SCM
Base: inferior border of the mandible
What are the suprahyoid muscles?
Mylohyoid
Digastric
Stylohyoid
Geniohyoid
What are the infrahyoid muscles?
Omohyoid, sternohyoid, sternothyroid, thyrohyoid muscles
