3) Myology Shoulder Region Flashcards
What are the 3 groups of the shoulder region
Group 1: Muscles connecting upper limb to Vertebral column
Trapezius Latissimus dorsi Levitator scapulae Rhomboid major Rhomboid minor
Group 2: Muscles connecting upper limb to Thoracic wall
Serratus anterior
Pectoralis minor
Subclavius
Pectoralis major
Group 3: Muscles connecting upper limb to Scapula
*Formed by muscles which have a proximal attachment at scapula and distal attachment at humerus = responsible for movements at the glenohumeral joint.
Coracobrachialis
Deltoid
Teres major
Rotator Cuff
Muscles that retract pectoral girdle
Rhomboid major
Rhomboid minor
Trapezius
Muscles that protract pectoral girdle
Serratus anterior
Pectoralis minor
Muscles that elevate pectoral girdle
Trapezius - upper fibres
Levator scapulae
Muscles that depress pectoral girdle
Trapezius- lower fibres
Pectoralis minor
Muscles that medially rotate pectoral girdle
Rhomboid major
Rhomboid minor
Pectoralis minor
Levator scapulae
Muscles that laterally rotate pectoral girdle
Trapezius
Serratus anterior
What movements does the trapezius perform
Retraction
Elevate- upper fibres
Depress- lower fibres
Laterally rotate
Trapezius
Superficial muscle of the back
Covers posterolateral neck and thorax
Pectoral girdle to skull and VB column
Shoulder and Cx movements
S: 🔺large
O: Medial 1⁄3 superior nuchal line of occipital bone External occipital protuberance
Ligamentum nuchae
C7 – T12 spinous processes
supraspinous ligaments
I: Upper fibres
Posterior border of lateral 1⁄3 clavicle
Middle fibres
Medial margin of the acromion Superior lip of crest of spine of scapula
Lower fibres
Tubercle at medial end of spine of scapula
D: Upper fibres - Downwards and laterally
Middle fibres - Horizontally
Lower fibres - Superiorly and laterally
A: Upper fibres Elevation of shoulder girdle Bilaterally - Extension of Cx. spine Unilaterally- Side-flexion of Cx.spine working with reversed origin and insertion
Middle fibres
Retraction of the shoulder girdle
Lower fibres
Depression of the shoulder girdle
Lateral rotation of scapula (due to combined action of all fibres working with serratus anterior)
F:
NS: Spinal accessory nerve C2,3,4
Latissimus Dorsi
S:🔺large
O: Posterior layer of thoracolumbar fascia
T7 – S5 spinous processes and intervening supraspinous and interspinous ligaments
Posterior part of outer lip of iliac crest
Outer surfaces of ribs 9 – 12
Inferior angle of scapula
I: Floor of intertubercular groove of humerus
D: upwards and laterally
A: Extension of the previously flexed shoulder
Adduction and medial rotation of the shoulder
This muscle is also capable of numerous functional activities
F:
NS: Thoracodorsal nerve C6,7,8
Importantane of latissimus Dori
Important in functional activities
When arms are fixed above the head it is important in climbing activities raises trunk upwards working with a reversed origin and insertion
Rowing and swimming
Rehabilitation Thx spinal injuries it has a high nerve root value = x paralysis
Forced expiration as it compresses thorax
Levator scapulae
Posterior neck superficial to neck extensors
> Upper part deep sternomastoid
> Middle part forms part of floor of posterior triangle
> Lower part to trapezius
S: strap like
O: tendinous slips transverse process C1-4
I: medial margin scapula between sup angle and base of spine
D: inferolaterally
A:Working with trapezius =elevation and retraction of pectoral girdle
Resistant upward movement when carrying something
Bilaterally = neck extension
Unilaterally = lateral flexion of neck
Medial rotation = stabilise scapula
NS: scapular nerve C5 ventral rami C3,4
Rhomboid major
S: Qudralateral
O: T2 – T5 spinous processes
supraspinous ligament
I: Medial border of the scapula between the base of the spine and inferior angle
D: upwards laterally
A: Retraction and medial rotation of the scapula
Important stabilisers of the scapula when other muscles attaching to the bone are actively working
F:
NS: Dorsal scapulae nerve C5
Rhomboid minor
S: Quadralateral
O: C7 – T1 spinous processes Lower part of ligamentum nuchae and supraspinous ligament
I: Small triangular area at base of spine on medial border of the scapula
D: upwards and laterally
A: Retraction and medial rotation of the scapula
Important stabilisers of the scapula when other muscles attaching to the bone are actively working
F:
NS: Dorsal scapulae nerve C5
Serratus anterior
Main protractor
S: large flat muscular sheet
Loose fascia between deep surface ribs and superficial surface and subscapularis
Forms medial wall of of axilla
O: fleshy digitation anterior midaxilla.
outer surface upper 8 ribs and intercostal fascia.
I: costal surface medial boarder of scapula between sup and inf angles. Lower 4 = cord
D: Posteriorly
A: protraction pectoral girdle stabilises scapula when arm is flexed in front of body. laterally rotates scapula. Prevents winging of scapula
F: thrusting pushing punching
NS: Long thoracic nerve C5,6,7
Subclavius
**stabilises clavical
S: under the clavical deep to pectoralis major
O: small fleshy belly floor of subclavian groove underside clavical
I: first rib near costal cartilage
D: medially
A: steady clavical pulling it towards disc of sternoclavicular joint- depress lateral end clavical
F:
NS: subclavius C5,6
Pectoralis major
S:thick 🔺most superficial
Anterior surface thorax
Passes forwards twisting and forming the anterior axilla fold
O:
clavical part: medial 1/2 ant surface clavical
Sternocostal part: ant surface manubrium + body of sternum. Upper 6 cc ribs. Ant part 6th rib.
Aponeurosis of external oblique
I: laminated tendon into lat lip of intertubercular groove humerus
D: ant: downwards
Post: upwards
A: adducts medial rotates humerus
Clavical: flex humerus medial rotate adduction
Sternoclavicular: extend flexed humerus medial rotate adduction
F: climbing when arm is above head pull trunk upwards pushing punching throwing. Seat belt
NS: medial pectoral nerve C8 T1 - sternocostal part
lateral pectoral nerve C5,6,7- clavical part
Pectoralis minor
S: thin flat 🔺
Anterior chest wall deep to pectoralis major
O: coracoid process
I: outer surface 3rd,4th,5th rib and intercostal fascia
D: superolaterally
A: scapula pulled forwards and downwards medial rotation scapula inspiration when scapula is fixed
F: pushing punching, leaning on hand supports trunk
NS: medial + lateral pectoral nerve C6,7,8
Coracobrachialis
S: strap like
O: rounded tendon with sort head of bicepe
Apex of coracoid process scapula
I: medial shaft humerus midpoint between bicepes and triceps
D: downwards
A: adductor weak flexor arm at shoulder joint
F:
NS: musculocutaneous C6,7
Deltoid
S: thick 🔺 rounder shoulder appearance
3 parts= anterior,middle(multi-pennate),posterior
O:
ant = ant boarder lat 1/3 clavicle
Middle= 4 tendionous slips lat margin of acromion
Post= inferior spine of the scapula
I: deltoid tuberosity humerus (strength but mechanical disadvantage)
D: ant+post fibres =obliquely
Middle= shorter oblique
A: abduction- needs to be initiated by supraspinatus
Upward shearing of head of humerus resisted by rotator cuffs
Ant part= flexion medial rotation
Post part= extension lateral rotation
F: holding position lower arm eccentricity
NS: axillary nerve C5,6
Teres major
S: thick and chunky
posterior fold axilla with lat dorsi, forms boundary of upper triangular and quadrangular spaces
O: oval dorsal surface of scapula near inferior angle and fascia
I: flat tendon med lip of intertrabecular groove of humerus
D: upwards lateral
A: adducts medially rotates
Helps extend a flexed arm
F: climbing muscle working lats and pec major pulls trunk upwards when arms are fixed
NS: lower subscapular nerve C5,6
What is the axilla
Pyramid shaped inferomedial to shoulder
Space between arm and thorax which allows vessels to pass through
Blood vessels and nerves
Quadrangular and triangular space
Quadrangular space
Axilar nerve
Posterior circumflex humeral artery
Triangular space
Circumflex subscapular ordinary
