Muscles Flashcards
Sternocleidomastoid:
- Location
- BLMs
- Origin
- Insertion
- Nerve
- Action
Location: Superficial - anterior and lateral neck
BLMs: Mastoid process, medial clavicle
Origin: (2 heads)
- Sternal Head: Top of Manubrium
- Clavicular Head: Medial 1/3 of clavicle
Insertion:
- Mastoid process of temporal bone
- the lateral portion of superior nuchal line of occiput
Nerve:
- Spinal accessory 6 nerve, C2, C3
Action:“Flex your neck” or “inhale deeply”
- Bilaterally*
- FLEX neck
*assist to ELEVATE the ribcage during inhalation
Unilaterally
- LATERALLY FLEX the head/neck same side
- ROTATE head/neck to opposite side
Where is the carotid artery in relation to the SCM?
Deep and medial to the SCM
Where is the external jugular vein in relation to the SCM?
superficial to the carotid artery, which is deep and medial to the SCM
How would you palpate the SCM?
- Pt supine. Locate the origin and insertion: the top of manubrium, medial clavicle and the mastoid process.
- Can ask pt to elevate head slightly to locate the SCM, or rotate to opposite side and ask to flex neck
What muscle are you using when:
- Shaking head “no” (opposite side rotation) or “yes” (bilateral flexion)
- Cocking head to hear what someone is saying
- Stabilizing head while riding a roller coaster
Sternocleidomastoid
What muscle has these pain symptoms and what are the possible causes?
- “Ram’s Horn Effect”
- pain in eye, face, ear, frontal region
- dizziness
- excessive forward head posture
- whiplash
- sleeping on 2 pillows
- torticollis (kinked and twisted on one side)
- Soreness in neck
- “stiff neck”
- tilting of head to same side
- tension headache
- Pain to
- face and cranium
- Forehead, ear and occiput
- Strongly around eyebrows
Sternocleidomastoid
- Poor posture
- Excessive forward head posture
- Sitting with head turned to side for long period
- protracted neck extension
- whiplash injury
What are the associate TPs and Differential Diagnoses for Sternocleidomastoid?
TPs:
- opposite sternocleidomastoid
- scalenes
- levator scapula
- trapezius
Differential diagnoses:
- vascular headache
- atypical facial neuralgia
- trigeminal neuralgia
- meniere’s disease
Scalenes (anterior, middle, posterior)
- Location
- BLMs
- Origin
- Insertion
- Nerve
- Action
- Location: Lateral neck, laterally adjacent to SCM
- BLMs: Transverse processes of cervicals, first rib
- Origin:
- Anterior*
- Transverse processes of C3-C6 (anterior tubercles)
- Middle*
- Transverse processes of C2-C7 (posterior tubercles)
- Posterior*
- Transverse processes of C6-C7 (posterior tubercles)
- Insertion:
- Anterior and Middle*
- 1st Rib
- Posterior*
- 2nd Rib
- Nerve
- Anterior, Middle -* C(3), 4-8
- Action: “Inhale into your upper chest” or “flex your neck”
- Bilaterally*
- ELEVATE ribs during inhalation
- (Anterior) FLEX head/neck
Unilaterally
- (with ribs fixed) LATERAL FLEX head/neck SAME side
- ROTATE head/neck OPPOSITE side
Where are the 3 scalenes located?
What is their function with inhalation?
What important structures pass through the anterior and middle scalene?
- They are sandwiched between the SCM and the anterior flap of the trapezius on the anterior, lateral neck.
- The anterior lies partially tucked beneath the SCM, directly accessible
- The middle is slightly larger and lies lateral to the anterior scalene, directly accessible
- The smaller posterior scalene is located between the middle scalene and levator scapula. Can be difficult to distinguish due to small size and buried location
- They perform the vital task of elevating the upper ribs
- The large branches of the brachial plexus and subclavian artery pass through a small gap between the anterior and middle scalene.
- individual nerves of the brachial plexus may penetrate through or in front of the anterior scalene
- the sublavian vein passes in front of the anterior scalene, behind the clavicle
What muscle are you using what:
- taking a deep breath into the upper chest
- Holding a phone between your ear and shoulder
- stabilizing your head when reading in a reclined position
Scalenes
Masseter
- Location
- BLMs
- Origin
- Insertion
- Nerve
- Action
Location: Superficial, sides of the face
- BLMs: angle of mandible, zygomatic arch
- Origin:
- Zygomatic arch
- Insertion:
- angle of mandible
- ramus of mandible
- Nerve
- Trigeminal (V) nerve (mandibular division)
- Action: “Clench your jaw”
-
ELEVATE the mandibe (TM joint)
- May assist to PROTRACT mandible (TMJ)
What is the strongest muscle in the body, relative to its size?
How many pounds of pressure?
- Masseter
- 150 lb pressure, enough to bite off a finger
