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