Shoulder Flashcards

1
Q

What are the types of scapula motion

A

Around vertical axis – glenoid
turns anteriorly

  • Around horizontal axis –
    glenoid turns superiorly or
    inferiorly
  • Motions possible because
    scapula can slide over
    posterior rib cage
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2
Q

Describe the glenohumeral joiunts

A
  • Tradeoff – a highly mobile
    but also unstable joint
  • Stability due to muscles and
    ligaments:
  • Glenoid labrum
  • Biceps tendon
  • Arch of coracoid and acromion
  • Synovial and fibrous joint
    capsule membranes
  • Rotator cuff muscles
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3
Q

What are the 4 bursae of the shoulder

A

subacromial
subdeltoid
tendon sheath
subscapular

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4
Q

What muscles make up the rotator cuff

A

Supraspinatus (anterior superior)
Infraspinatus
subscapularis
teres minor (posterior inferior)

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5
Q

What is the origin, insertion, action and nerve supply of the trapezius

A

Origin – midline of back
(occipital protuberance and
spinous processes C7 – T12)
* Insertion – lateral 1/3 of
clavicle, acromion and spine of
scapula
* Innervation – Cranial nerve XI
(accessory nerve), C3, C4
* Action – rotates scapula to
elevate arm; also elevates,
depresses and retracts scapula;
extends and rotates head

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6
Q

What is the origin, insertion, innervation and action of the levator scapulae

A
  • Origin – transverse processes of
    CI - CIV
  • Insertion – upper medial
    border of scapula
  • Innervation – C3, C4, and dorsal
    scapular nerve (C4, C5)
  • Action – elevates scapula
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7
Q

What are myotomes and peripheral nerves

A

Myotome = a region of skeletal muscle largely supplied by a single spinal cord
level
* Peripheral nerve = contributions from multiple spinal levels that powers
multiple muscles
Most individual muscles are powered by MORE than one spinal cord level so
testing myotomes usually involves certain movements or muscle groups

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8
Q

Describe the origin, insertion, nerve supply and action of latissimus dorsi

A

Origin – spinous processes of
T6-L5, sacrum, iliac crest, ribs
10-12
* Insertion – floor of
intertubercular sulcus
* Innervation – thoracodorsal
nerve (C6, C7, C8)
* Action – powerful adduction,
medial rotation and extension
of the arm

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9
Q

What is the origin, insertion, nerve supply and action of pectoralis major

A
  • Origin – 2 heads, medial half of
    clavicle, anterior surface of
    sternum and first 7 costal
    cartilages
  • Insertion – lateral lip of
    intertubercular sulcus
  • Innervation – medial and
    lateral pectoral nerves (C5 – T1)
  • Action – powerful adduction,
    flexion, extension and medial
    rotation of the arm
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10
Q

What are fan shaped muscles

A

Two large, fan-shaped
muscles pull the humerus
posteriorly relative to body
and pulls body forward
relative to ground
* Evolved for bounding or
galloping locomotion

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11
Q

Describe the origin, insertion, innervation and action of pectoralis minor

A

Origin – anterior surfaces of
ribs III to V
* Insertion – coracoid process
* Innervation – medial pectoral
nerve (C5 – T1)
* Action – rotates and protracts
scapula

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12
Q

Describe the origin, insertion, innervation and action of the subclavius muscle

A

Origin – first rib (at costal
cartilage)
* Insertion – middle 1/3 of
clavicle
* Innervation – nerve to
subclavius (C5, C6)
* Action – depresses clavicle and
stabilizes joint

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13
Q

Describe the origin, insertion, innervation and action of coracobrachialis

A

Origin – corocoid process
* Insertion – medial aspect
of humerus
* Innervation –
musculocutaneous nerve
(C5-C7)
* Action – flexes arm

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14
Q

Describe the origin, insertion, innervation and action of serratus anterior

A

Origin – lateral surfaces of ribs
1 – 8/9
* Insertion – medial border of
scapula (costal surface)
* Innervation – long thoracic
nerve (C5-C7)
* Action – protracts and rotates
scapula, prevents ‘winging’

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15
Q

Origin, insertion, innervation and action of supraspinatus

A

Origin – supraspinous fossa of
scapula
* Insertion – superior facet of the
greater tubercle of humerus
* Innervation – suprascapular
nerve (C5,C6)
* Action – initiates abduction of
arm (first 15 degrees)

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16
Q

Origin, insertion, innervation and action of infraspinatus

A
  • Origin – infraspinous fossa of
    scapula
  • Insertion – middle facet of the
    greater tubercle of humerus
  • Innervation – suprascapular
    nerve (C5,C6)
  • Action – lateral rotation of arm
17
Q

Origin, insertion, innervation and action of teres minor and major

A

Teres minor
* Origin – lateral infraspinous fossa
* Insertion – inferior facet of the
greater tubercle of humerus
* Innervation – axillary nerve (C5, C6)
* Action – lateral rotation of arm

Teres major (not rotator cuff)
* Origin – posterior surface of
scapula near inferior angle
* Insertion – medial lip of
intertubercular sulcus
* Innervation – inferior subscapular
nerve (C5, C6)
* Action – medially rotates and
extends arm

18
Q

Origin, insertion, innervation and action of subscapularis

A

Subscapularis
* Origin – subscapular fossa
* Insertion – lesser tubercle of
humerus
* Innervation – superior and
inferior subscapular nerves (C5,
C6, C7)
* Action – medial rotation of arm

19
Q

What are the posterior nerves of the shoulder?

A

Suprascapular nerve
from brachial plexus (superior trunk),
travels THROUGH the suprascapular
foramen between bone and
supraspinatus muscle, through
greater scapular notch to
infraspinatus
Axillary nerve
from brachial plexus (posterior cord),
passes posterior to surgical neck of
humerus – IN DANGER IF
FRACTURED! Innervates teres minor
and deltoid, and “regimental
badge

20
Q

Describe the arterial anastomoses of the shoulder

A

Subclavian-Axillary anastomosis
from Subclavian:
Thyrocervical trunk >
suprascapular a. > circumflex
scapular a. > subscapular a. >
axillary a.
Thyrocervical trunk > transverse
cervical a. > deep branch/dorsal
scapular a. > circumflex scapular a.
> subscapular a. > axillary a.
from Axillary
humeral circumflex aa. (anterior
and posterior)
thoracoacromial trunk
Axillary-Axillary anastomosis
between humeral circumflex aa. and
with profunda brachii a.