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Extrinsic vs Intrinsic
- Extrinsic:
- superficial and intermediate layers of the back
- attaches the axial skeleton to the appendicular skeleton
- moves the arm and helps in breathing
- nerve innervation-anterior rami/CN XI
- Intrinsic:
- Deep layers of the back
- Connects axial to axial (vertebrae to vertebrae)
- moves the vertebral columb and maintains posture
- innervation-posterior rami
The intrinsic muscles are the only muscles the posterior rami innervate
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Trapezius muscle:
- attaches to spinous process of C7-T12
- external occipital protruberance
lateral clavical, acromion, and spina scapula
innervation- spinal acessory
- Descending- elevates scapula
- Asending-depresses scapula
- Middle-retracts scapula
- Des and Asen-superiorly rotates scapula
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Latissimus dorsi
- points of attachment:
- spinous process (inferior thoracic)
- thoracolumbnar fascia
- iliac crest
- floor of intertubercular sulcus of the humerus
innervation: thoracodorsal nerve (C6,C7,C8)
- Action:
- Extends, adducts and medially rotates humerus
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Levator scapulae
Attachments:
- medial border, superior to spine of scapula
- the transverse processes of C1-C4
- innervation:
- Dorsal scapular nerve (C5)
- Action:
- Elevates the scapula
- inferiorly rotates scapula ( makes the glenoid cavity point down)
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Rhomboid major and minor
- Attachments: major:
- spinous processes of T2-T5
- medial border of scapula inferior to the spine
- Minor: Nuchal ligament
- spinous process of C7-T1
- midial border of the scapula at the level of the spine
- innervation:
- Dorsal scapular nerve (C4,C5)
- Action:
- Retracts scapula
- inferiorly rotates scapula (glenoid cavity points inferiorly)
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If a patient walks into your office and cannot shrug his shoulders against rsistance what muscle is having a problem, what nerve?
- muscle: trapezius
- nerve: spinal accessory (CN11)
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What is a sign of paralysis of the latissimus dorsi
- Difficulty raising trunk to arm
- Cannot pull trunk to arms when arms are in a fixed position
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Describe the boundries of the triangle of auscultation?
less muscles between skin and lungs
- Superiorly and medially, by the inferior portion of the Trapezius
- Inferiorly, by the Latissimus dorsi
- Laterally by the medial border of the Scapula
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what are the muscles of the extrinsic back? what are they intervated by?
- Serratus posterior superior
- Serratus posterior inferior
innervated by the anterior rami
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Serratus posterior superior
- Attachments:
- superior- nuchal ligament
- spinous process of C7-T3
- inferior- ribs 2-4
innervation: anterior rami-intercostal nerves
- action:
- proprioception and elevates ribs, now its thought that its action is to monitor the ribs movement during breathing
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Serratus posterior inferior
- Attachments:
- spinous processes of T11-L2
- Ribs 8-12
- innervation
- Anterior rami through intercostal nerves
- action:
- proprioception and depression of ribs. monitors the movement of ribs during breathing
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what are the muscles of the deep back? what are they innervated by?
- Splenius
- Erector spinae
- Transversospinalis
innervated by the posterior rami of spinal nerves
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Splenius
- Attachments:
- Nuchal ligament
- spinous process C7-T4
- mastoid process
- superior nuchal line of occipital bone
- transverse process C1-C-4
innervation is the posterior rami of spinal nerves
- actions
- unilateral- laterally flexes neck
- rotates head ipsilaterally
- bilateral- extends head and neck
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Errector spinae
- Lateral to medial:
- Iliocostalis, Longissimus, Spinalis
- Attachments:
- posterior iliac crest
- posterior sacrum
- inferior spinous processes of the lumbar spine
- Iliocostalis attachment- cervical transverse process
- angles of lower ribs
- longissimus- posterior ribs
- thoracic and cervical spinous processes
- mastoid process
spinalis- thoracic and cervical spinous processes
- action of the errector spinae:
- unilateral- laterally flexvertebral columb
- bilateral- extend the vertebral columb and neck
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- Transversospinalis group includes:
- semispinalis- attach to transverse spinous
- Mulifidus- conects the transverse processes to the spinous processes
- Rotatores- most deep of the spinal muscles
innervation: posterior rami
action- extension and lateral rotation btween the adjacent vertebrae in the cervical and thoracic vertebral columb
functions to stabalize the vertebral columb
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What are the borders of the suboccipital triangle?
superolateral border- obliquus capitis superior
inferior border- obliquus capitis inferior
superomedial border- rectus capitis posterior major
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what is the significance of the suboccipital triangle?
Can locate the suboccipital nerve (C1) and the vertebral artery(on the groove of C1 Vertebrae) in the triangle.
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Rectus capitus posterior major
makes up the superiomedial border of the suboccipital triangle
- origin: C2 spinous process
- Insertion: inferior nucal line of the occipital bone
innervation: suboccipital nerve
- action:
- unilateral- rotates head ipsilateral
- bilateral-extends head
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Rectus capitus posterior minor
- origin: poterior tuberacle of the C1
- Insertion: inferior nuchal line
Innervation: suboccipital nerve
- action:
- unilateral: rotates head ipsilateral
- bilateral: extension of the head
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Obliquus capitus inferior
- origin: C2 spinous process
- insersion C1 transverse process
Innervation- suboccipital nerve
action- rotates head side to side
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Obliquus Capitus superior
- Attachment:
- origin- at the C1 transverse process
- insertion- occipital bone btw superior and inferior nucal lines
innervation: posterior rami
action: extend the head
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what are the signs of paralysis of the trapizius.
Drooped shoulder, cant elevate shoulder
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What is the difference between a back strain and a back sprian?
- Strain-- when the muscle fibers are injured
- streching or microtears of the fibers
- How--rapid/extensive/strong movements
- heavy lifting
- poor conditioning
- muscles usually effected- errector spinae
- Sprain-- when the ligament is injured
- usually accompanys a bone fracture or dislocation of joint
- how?-excessive/strong/rapid movement
- whiplash/neck hyperextension
- ligament usually effected- anterior longitudinal ligament
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what is the site that is best to hear breath sounds?
The triangle of auscultation which is made up of 3 muscles/bones
- 1. the superiomedial--trapezius
- 2. the inferior is the latissimus dorsi
- 3. the lateral is the medial border of the scapula
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What muscles rotate the head contralaterally?
- Sternocladomastiod
- semispinalis capitis
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what muscles rotate the head ipsilaterally?
- rectus capitus posterior major and minor
- Obliquus capitus inferior
- longissimus capitis
- splenius capitis
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