Gross 2 Neck and Head Region *Muscle attachments, Nerves, and Actions* Flashcards
What are the attachments of Platysma?
Superior/Medial: Inferior border of mandible, skin, and subcutaneous tissues of lower face
Inferior/Lateral: Fascia covering superior parts of pectoralis major and deltoid muscles.
What nerve innervates the Platysma?
CN VII
What are the actions of Platysma?
Draws corners of mouth inferiorly and widens it as in expressions of sadness and fright; draws skin of neck superiorly when teeth are clenched.
- Assist in Mandibular depression
What are the attachments of Sternocleidomastoid (SCM)?
Superior/Medial: Lateral surface of mastoid process of temporal bone and lateral half of superior nuchal line
Inferior/Lateral: Sternal Head - Anterior surface of manubrium of sternum
Clavicular Head - Superior surface of medial third of clavicle
What nerve innervates Sternocleidomastoid (SCM)?
Spinal Accessory Nerve (CN XI)
What are the actions of Sternocleidomastoid (SCM)?
(Unilateral and Bilateral contraction)
Unilateral Contraction: Tilts the head to same side (laterally flexes neck), and rotates it so face is turned superiorly toward opposite side.
Bilateral Contraction: (1) Extends neck at atlanto-occipital joint. (2) Flexes cervical vertebrae so that chin approaches manubrium. (3) Extends superior cervical vertebrae while flexing inferior vertebrae
What are the attachments for Trapezius?
Superior/Medial: Medial third of superior nuchal line, external occipital protuberance, nuchal ligament, spinous processes of C7-T12 Vertebrae
Inferior/Lateral: Lateral third of clavicle, acromion, and spine of scapula
What nerve innervates Trapezius?
Spinal Accessory Nerve (CN XI)
What are the actions of Trapezius?
(Superior Fibers, Middle Fibers, Inferior Fibers, Superior and Inferior fibers together)
Superior Fibers: Elevate scapulae/shoulders; maintain level of shoulders against gravity or resistance
Middle Fibers: Retract Scapula
Inferior Fibers: Depress scapulae/shoulders
Superior and Inferior Fibers Together: Rotate spinous process of scapulae superiorly. With shoulders fixed, bilateral contraction extends neck; unilateral contraction produces lateral flexion to same side.
What are the attachments for Longus Colli?
Superior: Anterior Tubercle of C1 vertebrae (Atlas); bodies of C1-C3 and transverse process of C3-C6 vertebrae
Inferior: Bodies of C5-T3 vertebrae; Transverse process of C3-C5 vertebrae
What is the action of Longus Colli?
Flexes neck with rotation (torsion) to opposite side if acting unilaterally
What nerve innervates Longus Colli?
Anterior Rami
What are the attachments for longus Capitis?
Superior: Basilar part of occipital bone
Inferior: Anterior tubercles of C3-C6 transverse process
What is the action of Longus Capitis?
Flex head
What nerve innervates Longus Capitis?
Anterior Rami
What are the attachments of Rectus Capitis Anterior?
Superior: Base of cranium, just anterior to occipital condyle
Inferior: Anterior surface of lateral mass of atlas (C1)
What is the action of Rectus Capitis Anterior?
Flex head
What nerve innervates Rectus Capitis Anterior?
Anterior Rami
What are the attachments of Anterior Scalene?
Superior: Transverse process of C3-C6 vertebrae
Inferior: 1st rib
What is the action of Anterior Scalene?
Flex head
What nerve innervates Anterior Scalene?
Anterior Rami
What are the attachments for Rectus Capitis Lateralis?
Superior: Jugular Process of occipital bone
Inferior: Transverse process of Atlas (C1)
What nerve innervates Rectus Capitis Lateralis?
Anterior Rami
What is the action of Rectus Capitis Lateralis?
Flexes head and helps stabilize it
What are the attachments for Splenius Capitis?
Superior: Inferior half of nuchal ligament and spinous processes of superior 6 thoracic vertebrae
Inferior: Lateral aspect of mastoid process and lateral third of superior nuchal line
What nerve innervates Splenius Capitis?
Posterior Rami
What is the action of Splenius Capitis?
Laterally flexes and rotates head and neck to same side; if acting bilaterally, extends head and neck
What are the attachments of Levator Scapulae?
Superior: Posterior Tubercles of transverse process C2-C6
Inferior: Superior part of medial boarder of scapula
What nerve innervates Levator Scapulae?
Dorsal Scapular N.
What is the action of Levator Scapulae?
Downward rotation of the scapula and tilts glenoid cavity inferiorly
What are the attachments of Middle Scalene?
Superior: Posterior tubercles of Transverse processes of C5-C7 vertebrae
Inferior: Superior surface of 1st rib; posterior groove for subclavian artery
What nerve innervates Middle Scalene?
Anterior Rami
What is the action of Middle Scalene?
Flexes neck laterally; elevates 1st rib during forced inspiration
What are the attachments for Posterior Scalene?
Superior: Posterior Tubercles of Transverse processes of C5-C7 vertebrae (Same as middle scalene)
Inferior: External boarder of 2nd rib
What nerve innervates Posterior Scalene?
Anterior Rami
What is the action of Posterior Scalene?
Flexes neck laterally; elevates 2nd rib during forced inspiration
What are the attachments for Sternohyoid?
- Manubrium of sternum and medial end of clavicle
- Body of Hyoid
What nerve innervates Sternohyoid?
Ansa Cervicalis
What is the action of Sternohyoid?
Depresses hyoid after elevation during swallowing
What are the attachments for Omohyoid?
- Superior boarder of scapula near suprascapular notch
- Inferior border of hyoid
What nerve innervates Omohyoid?
Ansa Cervicalis
What is the action of Omohyoid?
Depresses, retracts and steadies hyoid
What are the attachments for Sternothyroid?
- Posterior surface of manubrium of sternum
- Oblique line of thyroid cartilage
What nerve innervates Sternothyroid?
Ansa Cervicalis
What is the action of Sternothyroid?
Depresses hyoid and larynx
What are the attachments for Thyrohyoid?
- Oblique line of thyroid cartilage
- Inferior border of body and greater horn of hyoid
What nerve innervates Thyrohyoid?
Ansa Cervicalis
What is the action of Thyrohyoid?
Depresses hyoid and elevates larynx
What are the attachments for Mylohyoid?
- Mylohyoid line of mandible
- Mylohyoid raphe and body of hyoid
What nerve innervates Mylohyoid?
Nerve to Mylohyoid (Branch from Mandibular Nerve, CN V)
What is the action of Mylohyoid?
Elevates hyoid, floor of mouth, and tongue during swallowing and speaking
What are the attachments for Geniohyoid?
- Inferior mental spine of mandible
- Body of hyoid
What nerve innervates Geniohyoid?
Hypoglossal Nerve (CN XII)
What is the action of Geniohyoid?
Pulls hyoid anterosuperiorly; shortens floor of mouth; widens pharynx
What are the attachments of Stylohyoid?
- Styloid process of temporal bone
- Body of hyoid
What nerve innervates Stylohyoid?
Stylohyoid Branch of Facial Nerve (CN VII)
What is the action of Stylohyoid?
Elevates and retracts hyoid, thus elongating floor to mouth
What are the attachments for Digastric?
(Superior Belly)
- Digastric fossa of mandible
(Inferior Belly)
- Mastoid notch of temporal bone
(Both Bellies)
- Intermediate tendon to body and greater horn of hyoid
What nerve innervates Digastric?
(Anterior belly)
- Nerve to Mylohyoid, a branch of Inferior Alveolar Nerve of Mandibular Nerve (V3)
(Posterior belly)
- Digastric (Cervical???) branch of Facial Nerve (CN VII)
What is the action of Digastric?
Working with infrahyoid muscles, depresses mandibular against resistance; elevates and steadies hyoid during swallowing and speaking
