Neck Muscles Flashcards
SCM: origins (2 heads)
Sternal head: manubrium
Clavicular head: medial 1/3 of clavicle
Sternocleidomastoid (SCM): action and insertions
Action: unilateral head tilt, contralateral head rotation
Bilateral neck extension but also flexion of cervical vertebrae, bilateral chin thrust, respiration aid when head steady
Insertion: mastoid process of temporal bone, superior nuchal line of occipital
SCM: vascular and nervous supply
Vascular: occipital and superior thyroid artery
Nervous: CNXI and VPR C2-C3
What back muscles are also included in the neck?
Trapezius, descending part (posterior)
Splenius capitis and cervicis (posterior)
Platysma: action and insertions
Action: tenses neck skin, depresses mandible, and depresses/wrinkles skin of lower face/mouth
Insertion: inferior border of mandible, skin of lower FACE/angle of the mouth
Platysma: origins
Skin of lower NECK and upper lateral thorax
Platysma: vascular and nervous supply
Vascular: submental and suprascapular artery
Nervous: cervical branch of facial nerve (CNVII)
Rectus capitis posterior: action and insertions (2 parts)
Action: extends the head, ipsilateral head rotation
Insertions:
Major - occipital bone (middle 1/3 of INFERIOR nuchal line)
Minor - occipital bone (INNER 1/3 of inferior nuchal line)
Rectus capitis posterior: origins (2 parts)
Major - spinous process C2
Minor - posterior tubercle C1
Rectus capitis posterior: nervous
DPR (C1, suboccipital nerve)
Obliquus capitis: actions and insertions (2 parts)
Action: both the superior and inferior part extend the head…superior can ipsilaterally tilt but CONTRALATERALLY rotate, while inferior ipsilaterally rotates
Insertions:
Superior - middle 1/3 of inferior nuchal line (just above rectus capitis posterior major)
Inferior - transverse process C1
Obliquus capitis: origins
Superior: transverse process C1
Inferior: spinous process C2
Obliquus capitis: nervous supply
DPR C1 (suboccipital nerve)
Name the suprahyoid muscles and what do they do?
Digastric
Stylohyoid
Mylohyoid
Geniohyoid
Accessory muscles of mastication, and all insert on the hyoid bone
Digastric: action and insertions (2 bellies)
Action: elevate hyoid during swallowing, helps open mandible
Insertions:
Both the anterior and posterior belly insert on the body of the hyoid
Digastric: origins (2 bellies)
Anterior belly: mandible at digastric fossa
Posterior belly: temporal bone at mastoid notch
Digastric: nervous supply (2 bellies)
Nervous:
Anterior belly - mylohyoid, CNV3 branch
Posterior belly - facial nerve CN VII
Stylohyoid: action and insertion
Action: elevates hyoid bone for swallowing, helps open mandible
Insertion: hyoid
Stylohyoid: origin
Styloid process (of temporal bone)
Stylohyoid: nervous supply
Nervous: facial nerve CNVII
Mylohyoid: action and insertion
Action: elevates oral floor, draws hyoid forward for swallowing, helps open mandible and move side-to-side for mastication
Insertion: hyoid
Mylohyoid: origin
Mandible at mylohyoid line
Mylohyoid: nervous supply
Mylohyoid nerve, CNV3 branch
Geniohyoid: action and insertion
Action: draws hyoid forward for swallowing, helps open mandible
Insertions: hyoid
Geniohyoid: origin
Mandible at inferior mental spine
Geniohyoid: nervous supply
Nervous: VPR C1 by the hypoglossal nerve CNXII (branches join)
List the infrahyoid muscles and what do they do together?
Omohyoid
Sternohyoid
Thyrohyoid
Sternothyroid
Depresses hyoid and tenses cervical fascia
What are the insertions of the infrahyoid muscles and their individual actions?
Action:
Omohyoid, sternohyoid, and sternothyroid all depress/fix hyoid, pull larynx and hyoid down for phonation and terminal swallowing phase
Thyrohyoid also depresses/fixes hyoid but RAISES the larynx during swallowing
Insertion:
All insert on the hyoid except the sternoTHYROID (inserts on the thyroid cartilage’s oblique line)
List the origins of the infrahyoid muscles
Omohyoid - superior border of scapula
Sternohyoid - manubrium and posterior sternoclavicular joint
Sternothyroid - posterior manubrium
Thyrohyoid - thyroid cartilage at oblique line
The cervical plexus innervates all the infrahyoid muscles except ________.
Thyrohyoid is innervated by CN1 via the CNXII hypoglossal (bc very superior location)
Omohyoid and sternohyoid (C1-C3) and the sternothyroid (C2-C3) are all innervated by the ansa cervicalis
List the deep neck muscles
Prevertebral muscles
- longus capitis and longus colli
- rectus capitis anterior and rectus capitis lateralis
Scalenes (anterior, middle and posterior)
Suboccipital muscles
- rectus capitis posterior major
- rectus capitis posterior minor
- obliquus capitis inferior
- obliquus capitis superior
What do the rectus capitis anterior and lateralis do, their insertion and what innervates them?
Action: lateral flexion of head at atlanto-occipital joint, or just head flexion if both sides contract
Insertion: occipital bone
Anterior - basilar part
Lateralis - also basilar part but lateral to occipital condyles
Innervation: VPR C1, C2
Rectus capitis anterior and lateralis: origin
Anterior - Lateral mass of C1
Lateralis - transverse process of C1
What do the scalenes do and what innervates them?
Depends on whether the ribs are fixed or mobile
Mobile = elevates upper ribs when inhale Fixed = ipsilaterally bends cervical spine, flexed neck bilaterally
Innervation from direct branches of both cervical and brachial plexus (C3-C8)
Scalene: insertions (3 parts)
Anterior - scalene tubercle of rib 1
Middle - rib 1 posterior to subclavian artery groove
Posterior - rib 2 outer surface
Scalenes: origin (3 parts)
Anterior - transverse processes anterior tubercles from C3-C6
Middle - transverse processes C1-C2, transverse processes posterior tubercles C3-C7
Posterior - transverse processes posterior tubercles C5-C7
List the prevertebral muscles of the neck
Longus capitis
Longus colli
Rectus capitis anterior
Rectus capitis lateralis
Longus capitis: action and insertion
Action: flexion of head at atlanto-occipital joint
Insertion: occipital bone at basilar part
Longus capitis: origin
Transverse processes anterior tubercles from C3-C6
Longus capitis: nervous supply
Cervical plexus direct branches C1-C3
Longus colli: action and insertions (3 parts)
Action: contralaterally tilts and rotates cervical spine or if acting bilaterally…forward flexion of cervical spine
Insertions:
Vertical (intermediate part) - anterior surface C2-C4
Superior oblique - atlas anterior tubercles
Inferior oblique - transverse processes anterior tubercles C5-C6
Longus colli: origins (3 parts)
Vertical (intermediate part) - vertebral bodies anteriorly from C5-T3
Superior oblique - transverse processes anterior tubercles from C3-C5
Inferior oblique - vertebral bodies anteriorly from T1-T3
What are the borders of the anterior cervical triangle?
Anterior border of SCM
Inferior border of mandible
Midline from chin to jugular notch
What are the 4 subdivisions of the anterior cervical triangle? What are the contents of each?
Submandibular/digastric triangle: contains submandibular gland and lymph nodes, hypoglossal nerve, facial artery and vein
Submental triangle: submental lymph nodes
Muscular triangle: sternothyroid and sternohyoid, thyroid and parathyroid gland
Carotid triangle: carotid bifurcation and carotid body, hypoglossal and vagus nerves
What lies in the SCM a region of the neck?
SCM Common carotid artery Internal jugular vein Jugular lymph nodes Vagus nerve
What are the borders of the lateral cervical region (aka posterior triangle)?
Posterior border of SCM
Anterior border of trapezius
Superior nuchal line where the two muscles join
Middle 1/3 of the clavicle
What are the subdivisions of the lateral cervical region/posterior triangle? What is contained in them?
Omoclavicular/subclavian triangle: subclavian artery, subscapular artery, supraclavicular lymph node
Occipital triangle: spinal accessory nerve, trunks of brachial plexus, transverse cervical artery, posterior branches of cervical plexus
Where is the suboccipital triangle and why do you have to be careful around here?
Located in deep part of superior posterior cervical region
Careful injecting high and lateral into this neck region, you might hit the vertebral artery
What is contained in the posterior cervical region (not posterior triangle)?
Nuchal muscles, vertebral artery, cervical plexus
