Muscles Flashcards
Platysma
O: mandible
I: connective tissue of upper neck and shoulder
A: tense skin of the neck
N: facial nerve (CV VII)
Sternocleidomastoid
O: manubrium of sternum, medial clavicle
I: mastoid process of temporal bone
A: bilaterally - flexes head/neck, unilaterally - ipsilateral side bending of neck, contralateral rotation of head
N: accessory nerve (CN XI)
Trapezius
O: external occipital protuberance, nuchal ligament, spinous processes-T12
I: lateral clavicle, acromion, spine of scapula
A: upper - elevates and superiorly rotates scapula, ipsilateral neck sidebending, contralateral head rotation
N: accessory nerve (CN XI)
Torticollis
Shortening/spasm/fibrosis of SCM on one side
Congenital or acquired
Usually positions head and neck in ipsilateral sidebending and contralateral rotation
What borders the anterior triangle?
SCM, mandible, midline of neck
What borders the posterior triangle?
SCM, clavicle, upper trapezius
Which vein runs obliquely across SCM
External jugular vein
Which are the infrahyoid muscles?
Sternohyoid
Omohyoid
Sternothyroid
Thyrohyoid
Sternohyoid
O: manubrium of the sternum
I: hyoid bone
A: pull hyoid down after being elevated, stabilize hyoid to prevent elevation
N: ansa cervicalis (C1-C3)
Omohyoid
Superior/inferior belly connected by intermediate tendon
O: Inferior attached to scapula
I: superior attached to hyoid
Intermediate tendon attached to clavicle by fascial sling
A: depress/stabilize hyoid
N: ansa cervicalis (C1-C3)
Sternothyroid
O: manubrium of sternum
I: oblique line of thyroid cartilage
A: depress hyoid and larynx
N: ansa cervicalis (C2-C3)
Thyrohyoid
O: oblique line of thyroid cartilage
I: hyoid
A: depress hyoid, elevate larynx
N: C1 nerve branch
Where does the thyroid gland sit
Deep to sternohyoid and sternothyroid muscles
At level of C5-T1
Which are the suprahyoid muscles?
Digastric
Stylohyoid
Mylohyoid
Geniohyoid
Digastric
Anterior/posterior belly connected with intermediate tendon
Anterior - digastric fossa of mandible
Posterior - mastoid notch of temporal bone
Intermediate tendon attached to hyoid bone with a fascial sling
A: depress mandible (hyoid stable), elevate hyoid (mandible stable)
N: anterior - mandibular division of trigeminal (V3), posterior - facial (CN VII)
Stylohyoid
O: styloid process of temporal bone
I: hyoid
Runs with posterior belly of digastric and splits around intermediate tendon to insert on hyoid
A: elevate/retract hyoid during swallowing
N: facial (CN VII)
Mylohoid
Sling like muscle along floor of oral cavity
O: mylohyoid line of mandible
I: mylohyoid raphe, hyoid
A: elevate hyoid, depress mandible, elevates floor of mouth and tongue during swallowing and speaking
N: mandibular division of trigeminal (V3)
Geniohyoid
O: inferior mental spine of mandible
I: hyoid
A: pull hyoid anteriorly/superiorly, shorten floor of oral cavity, widen pharynx during swallowing
What borders the muscular triangle? What is located there?
Superior belly of omohyoid, SCM, midline of neck
Infrahyoid muscles and thyroid gland here
What borders the carotid triangle? What is located here?
Superior belly of omohyoid, posterior belly of digastric, SCM
Carotid artery, internal jugular vein, ansa cervicalis, cervical sympathetic trunk, and vagus nerve (CN X) here
What borders the submandibular triangle? What is located here?
Mandible and digastric muscle (posterior and anterior belly)
Aka digastric triangle
Mylohyoid makes up the floor
Lymph nodes and submandibular gland here
What borders the submental triangle? What structures are here?
Right and left anterior belly of digastric, hyoid
Mylohyoid makes up floor
Lymph nodes here
How to test strength of trapezius
Shrug shoulders against resistance
If there is weakness on one side - check SCM to see if it’s a neural problem
Splenius capitis
O: spinous processes C4-T6 (muscle splits)
I: posterior aspect of mastoid process
A: unilaterally - rotates head and neck ipsilaterally, bilaterally - cervical extension
N: dorsal rami of cervical spinal nerves
Splenius cervicis
O: spinous processes C4-T6 (muscle splits)
I: transverse processes C1-C4
A: unilaterally - rotates head and neck ipsilaterally, bilaterally - cervical extension
N: dorsal rami of cervical spinal nerves
Levator scapulae
O: transverse processes C1-C4
I: superior angle of scapula
A: elevate scapula, sidebend neck ipsilaterally
N: dorsal scapular nerve (C5) (brachial plexus)
What can be seen when trapezius is reflected laterally?
Accessory nerve (XI) and transverse cervical artery leaving posterior triangle of the neck and running lateral to to levator scapulae
Semispinalis capitis
O: transverse processes of thoracic vertebra (muscle splits)
I: posterior skull
A: unilaterally - Rotate head/neck contralaterally, bilaterally - cervical extension
N: posterior rami of cervical spinal nerves
Semispinalis cervicis
O: transverse processes of thoracic vertebrae
I: spinous processes of cervical vertebrae
A: unilaterally - rotate head/neck contralaterally, bilaterally - cervical extension
N: posterior rami of cervical spinal nerves
What makes up the suboccipital triangle?
Rectus capitis posterior minor
Rectus capitis posterior major
Obliquus capitis inferior
Obliquus capitis superior
Rectus capitis posterior major
O: inferior nuchal line of skull
I: spinous process C2
A: proprioception
N: suboccipital nerve (branch of dorsal ramus of C1 spinal nerve)
Rectus capitis posterior minor
O: inferior nuchal line of skull
I: posterior tubercle C1
A: proprioception
N: suboccipital nerve (branch of dorsal ramus of C1 spinal nerve)
Obliquus capitis superior
O: inferior nuchal line of skull
I: transverse process of C1
A: proprioception
N: suboccipital nerve (branch of dorsal ramus of C1 spinal nerve)
Obliquus capitis inferior
O: spinous process of C2
I: transverse process of C1
A: proprioception
N: suboccipital nerve (branch of dorsal ramus of C1 spinal nerve)
What is inside the carotid sheath?
Poorly organized -
Common carotid artery
Internal jugular vein
Vagus nerve
What fascia contribute to the carotid sheath?
Investing
Pretracheal
Prevertebral
What are the borders of the supraclavicular triangle?
Clavicle, posterior SCM, inferior belly of omohyoid
Division of posterior triangle
What are the borders of the occipital triangle?
Division of the posterior triangle
Posterior SCM, superior trapezius, inferior belly of omohyoid
Anterior scalene
O: transverse processes C3-C6
I: 1st rib
A: forced inhalation (vertebra stable), sidebending of neck (ribs stable)
Middle scalene
O: transverse processes C2-C7
I: first rib
A: forced inhalation (vertebra stable), sidebending of neck (ribs stable)
Posterior scalene
O: transverse processes C5-C7
I: 2nd rib
A: forced inhalation (vertebra stable), sidebending of neck (ribs stable)
Scalene interval/triangle
Space between anterior and middle scalene
Brachial plexus and subclavian artery course through this space
Thoracic outlet syndrome
Caused by compression of brachial plexus and subclavian artery (scalene interval/triangle)
Compression of brachial plexus causes paresthesia (tingling)
Superior rectus (eye)
A: adduction, elevation of eye
N: Oculomotor (III)
Medial rectus (eye)
A: adduction
N: Oculomotor (III)
Inferior rectus (eye)
A: depression, adduction
N: Oculomotor (III)
Superior oblique (eye)
A: depression, abduction
N: Trochlear (IV)
Lateral rectus (eye)
A: abduction
N: Abducens (VI)
Inferior oblique (eye)
A: elevation, abduction
N: Oculomotor (III)
Levator palpebrae superioris
A: raises upper eyelid
N: Oculomotor (III)
All the muscles of facial expression develop from _____
Mesoderm in the second pharyngeal arches
Also platysma - interconnected with intermingling fibers
Orbicularis oculi
Sphincter-like muscle around eye
Palpebral part: eyelids - closing eye
Orbital part: margins attached to bone - closing eye tightly
N: Facial (VII)
Frontalis
Anterior belly of the occipitofrontalis muscle
A: raising eyebrows
N: Facial (VII)
Epicranial aponeurosis
Intermediate tendon of occipitofrontalis muscle
Corrugator supercili
Deep to frontalis - medial margin of supraorbital ridge
A: draws eyebrows together
N: Facial (VII)
Procerus
Bridge of nose - interdigitates with frontalis
A: wrinkles skin on bridge of nose
N: Facial (VII)
Orbicularis oris
Sphincter-like muscle around lips
A: closes lips tightly, pucker
N: Facial (VII)
Zygomaticus major
Zygomatic bone - commissure of mouth
A: elevate corner of mouth - smiling
N: Facial (VII)
Zygomaticus minor
Zygomatic bone - levator labii superioris
A: elevate upper lip, show upper teeth
N: Facial (VII)
Levator labii superioris
Infraorbital margin of mx bone - upper lip
A: raising upper lip, showing upper teeth
N: Facial (VII)
Levator labii superioris alaque nasi
Part of levator labii superioris
Runs along side of nose
A: elevation upper lip, showing upper teeth
N: Facial (VII)
Nasalis (transverse part)
Runs transversely over dorsum of nose
A: compress nose
N: Facial (VII)
Levator anguli oris
Deep to other muscles of facial expression
Infraorbital part of mx bone - commissure of mouth
A: raise corner of mouth, smiling
N: Facial (VII)
Risorius
Connective tissue of cheek - commissure of mouth
Superior to buccinator and buccal fat pad
A: white people smile
N: Facial (VII)
Depressor anguli oris
Mandible - commissure of mouth
A: depress corner of mouth, frown
N: Facial (VII)
Depressor labii inferioris
Meidal and partially deep to depressor anguli oris
Mandible - lower lip
A: pull down lower lip, show lower teeth
N: Facial (VII)
Mentalis
Angle of mandible (chin) - skin of chin - lower lip
A: tense skin of skin, curl lower lip, pouting
N: Facial (VII)
Buccinator
Deep to buccal fat pad
A: tenses cheek
N: Facial (VII)
Auricularis muscles
A: connect ear to side of head, wiggle ears
N: Facial (VII)
Nasalis (alar part)
A: flares nostrils
N: Facial (VII)
What are the boundaries of the temporal fossa?
Posterior - Temporal lines Anterior - Frontal/zygomatic bones Laterally - Zygomatic arch Inferiorly - Infratemporal crest Floor - lateral skull Roof - temporal fascia
Temporal fascia
Covers temporalis
Attaches to superior temporal line - zygomatic arch
Tenses when chewing to pull up on zygomatic arch to counteract pulling down of masseter
Borders of infratemporal fossa
Laterally - ramus of mandible
Medially - lateral pterygoid plate of sphenoid bone
Anteriorly - posterior maxilla
Posteriorly - mastoid and styloid processes of temporal bone
Communicates with temporal fossa under zygomatic arch
Opens to pterygomaxillary fissure
Pterygomaxillary fissure
Infratemporal fossa opens to it
Leads to pterygopalatine fossa
Sphenopalatine foramen
Opening in medial wall of pterygopalatine fossa
Leads to nasal cavity
Superficial layer of temporalis fascia
Attaches to superior edge of zygomatic arch
Counteract action of masseter
Deep layer of temporalis fascia
Travels with full length of temporalis
Temporalis
O: temporal fossa
I: coronoid process and anterior ramus of mandible
A: elevate, retract mandible
N: mandibular division of trigeminal (V3) via deep temporal nerves
Masseter
O: superficial head - zygomatic bone and anterior aspect of zygomatic arch, deep head - posterior portion of zygomatic arch
I: angle and lateral aspect of mandible
A: elevate, protrude mandible
N: mandibular division of trigeminal (V3)
Lateral pterygoid
O:
- Superior head: infratemporal surface of greater wing of sphenoid bone
- Inferior head: lateral surface of lateral pterygoid plate of sphenoid bone
I: neck of mandible, articular disc and capsule of TMJ
A: bilaterally - protraction and depression of mandible, unilaterally - lateral movement to contralateral side
N: lateral pterygoid branches of mandibular division of trigeminal (V3)
Superficial head of Medial pterygoid
O: Mx tuberosity
I: medial aspect of the angle of mandible
A: bilaterally - elevates and protrudes mandible, unilaterally - excursion = contralateral movement (grinding)
N: medial pterygoid branches of mandibular division of trigeminal (V3)
Deep head of medial pterygoid
O: medial surface of the lateral pterygoid plate
I: medial aspect of the angle of the mandible
A: bilaterally - elevates and protrudes mandible, unilaterally - excursion = contralateral movement (grinding)
N: medial pterygoid branches of the mandibular division of the trigeminal nerve (V3)
What happens if there is damage to the lateral pterygoid muscle on one side?
Mandible will be deviated to the damaged side
Symptoms of subcondylar fracture on one side?
Only the lateral pterygoid on the opposite side is functional - mandible swings towards side of fracture
List muscles involved in opening of mouth
Suprahyoid
Infrahyoid - stabilize hyoid while suprahyoids depress mandible
Lateral pterygoids
List muscles involved in closing the mouth
Temporalis
Masseter
Medial pterygoids
List muscles that protrude the mandible
Masseter
Medial and lateral pterygoids
List muscles that retract the mandible
Temporalis
List the muscles that cause excursion of the mandible
Medial and lateral pterygoids
