Kinesiology- Shoulder Complex

Anterior Deltoid

Anterior Deltoid O: lateral 1/3 of the clavicle I: deltoid tuberosity A: shoulder abduction, flexion, medial/internal rotation, horizontal adduction N: Axillary nerve

Anterior Deltoid Actions

Anterior: 1)Horizontal Add 2)Abduction 3)Flexion 4)Medial(internal) rotation

Joints: Glenohumeral joint--Bicipital groove

Bicipital Groove: (b/t greater & lesser tubercle) Biceps tendon restrained by coracohumeral and transverse humeral ligament. During shoulder motion, humerus moves on tendon. Tendon subject to wear and tear as well as impingement. This is why you laterally rotate humerus before abduction--do not want to tear

Joints: Glenohumeral joint--Coracoacromial Arch

Coracoacromial arch: 1)Forms "roof" of GH joint 2)Subacromial space between humeral head and acromion 3)Coracoacromial ligament 4)Subacromial impingement syndrome (SAIS)--shifted out of place. Soft tissue pinched under arch causing pain & limited mobility

Coracobrachialis

Coracobrachialis O: coracoid process I: medial surface of the middle humerus A: stabilized the shoulder joint N: musculocutaneous

Joints---Sternoclavicular (Disc)

Disc: (b/t sternum & clavicle) Separates joint into two cavities Motion takes place between clavicle and disc and between disc and sternum Serves as a hinge for motion Really a saddle joint

Clavicle

Gives glenohumeral mobility to reaching & climbing activities. S-shaped; similar to a crank. Tubular at sternal end (next to sternum); flatter at acromial end(next to acromion).

Muscles of the Shoulder Complex: Glenohumeral Stabilizers

Glenohumeral stabilizers: 1) Supraspinatus 2) Infraspinatus/teres minor 3) Subscapularis 4) Biceps/triceps brachii

Scapula

Glenoid Fossa (labrum-cartilage) 1)Supraglenoid tubercle 2)Infraglenoid tubercle Coracoid Process Acromion Process

Glenohumeral Motion

Glides - inferiorly during Abduction Rolls - across glenoid fossa during Abduction Spins - under the Acromion process during rotation

Humerus

Head Neck Shaft Greater tubercle Lesser tubercle Intertubercular (bicipital) groove

Scapular Movements: Levator Scapulae

Levator Scapulae O: transverse process of first 4 cervical vertebrae I: vertebral board of scapula between the superior angle and spine A: scapula elevation and downward rotation N: 3rd and 4th cervical nerves and dorsal scapula nerves

Joints---Sternoclavicular (Ligaments)

Ligaments: So sternum doesn't move out of place Provides protection from ant./post. forces 1)Anterior/posterior--forces 2)Interclavicular--clavicle to clavicle 3)Costoclavicular—clavicle to first rib (keeps it set)

Scapular Movements: Lower Trapezius

Lower Trapezius O: spinous processes of middle and lower thoracic vertebrae I: Base of scapula spine A: Scapular depression and upper rotation N: Spinal accessory Lower trap inserts on base of scapular spine

Middle Deltoid

Middle Deltoid O: acromion process I: deltoid tuberosity A: shoulder abduction N: axillary nerve

Scapular Movements: Middle Trapezius

Middle Trapezius O: spinous processes C7 to T3 I: scapular spine A: Scapular retraction N: Spinal accessory

The shoulder maximizes _______, but at the sake of _______

Mobility at the sake of Stability

Function of Muscles of the Shoulder Complex

Muscle activity during functional motions Placing hand behind head Pulling

Scapular Movements: Pectoralis Minor

O: anterior surface, 3rd through 5th ribs I: coracoid process A: depression, protraction, downward rotation, and scapular tilt N: medial pectoral nerve

Pectoralis Major

Pectoralis Major O: medial third of clavicle, sternum, costal cartilage of first 6 ribs I: lateral lip of bicipital groove A: adduction, medial/internal rotation, horizontal adduction N: lateral and medial pectoral nerve

Posterior Deltoid

Posterior Deltoid O: spine of the scapula I: deltoid tuberosity A: shoulder abduction, extension, lateral/external rotation, horizontal abduction N: axillary nerve

Joints--Glenohumeral joint (Resting & Closed Packed Position)

Resting position: 20-30° of horizontal abduction; 55° flexion Close-packed position: (Joint surfaces most congruent) Full abduction and lateral rotation

Scapular Movements: Rhomboids

Rhomboids O: spinous processes of C7 to T5 I: vertebral scapular border between spine and inferior angle A: scapular retraction, downward rotation, and elevation N: Dorsal scapular nerve

Scapula

Scapular Spine Supraspinatus Fossa Infraspinatus Fossa

Muscles of the Shoulder Complex

Scapular stabilizers: 1) Serratus anterior 2) Trapezius 3) Rhomboid major/minor 4) Pectoralis minor 5) Levator scapulae

Functional Deficiency Applications--Serratus Anterior

Serratus anterior: Limited ability of scapula to upwardly rotate Possibly long thoracic nerve palsy?

Manubrium

Shield Superior aspect—contains shallow depression for medial clavicular attachments(below are notches for first rib). Sternal or jugular notch(tracheotomy performed here).

Joint Movements (Osteokinematic)

Shoulder girdle movements 1)Elevation/depression 2)Protraction/retraction 3)Upward rotation/downward rotation 4)Scapular tilting—A-P; M-L

Scapula

Superior Angle Inferior Angle Vertebral Border Axillary Border Scapular Spine Supraspinatus Fossa Infraspinatus Fossa Subscapular Fossa

Teres Major

Teres Major-little helper of lats O: axillary border of scapula near inferior angle I: crest below lesser tubercle inferior to latissimus dorsi attachment A: shoulder extension, adduction, medial/internal rotation N: Lower subscapula

Rotator Cuff: Teres Minor

Teres Minor O: axillary border of scapula I: greater tubercle A: lateral/external rotation, horizontal abduction N: axillary nerve

How many synovial joints is a shoulder composed of?

Three Synovial Joints

Functional Deficiency Applications--Trapezius

Trapezius: Spinal accessory nerve palsy—rare Extreme limitation of shoulder elevation

How many functional joints is a shoulder composed of?

Two Functional Joints

GH Joint Is Inherently Stable or Unstable?

Unstable

Scapular Movements: Upper Trapezius

Upper Trapezius O: occipital bone, nuchal ligament on upper cervical spinous processes I: Outer third of clavicle, acromion process A: Scapular elevation and upward rotation N: Spinal accessory

Shoulder Stability

With a gradual stretching out of the ligaments and joint capsule 1) Labrum to increase the depth of the glenoid fossa 2) Joint capsule - acts as a vacuum 3) Ligaments 4) Rotator cuff 5) Other shoulder Mm. Loss of these muscles results in subluxation ie. in stroke pts.

Scapular Movements: Serratus Anterior

Without it we get winging of the scapula O: anterior and superior aspects of ribs #1-9 I: vetebral board of the scapula, anterior surface A: Scapular protraction and upward rotation N: Long thoracic nerve

Shoulder injuries are common and occur when....

a "breakdown" of any one of the links occurs

Acromioclavicular

covers the joint in the shoulder & keeps it together 1)Coracoclavicular Ligament 2)Acromioclavicular Ligament 3)Coracoacromial Ligament

Scapulohumeral Rhythm

"Setting Phase"--highly variable---time period where scapula is not moving. Why hand is on the scapula during PROM Some degrees of movement humerus can do without the scapula about 30 degrees After 30degrees, 2:1 ration evident (for every 2 degrees of glenohumeral movement, there is 1 degree of scapula movement)

Joints---Sternoclavicular

(where sternum meets clavicle) Connects upper extremity to axial skeleton 3 degrees of freedom 1)Elevation/depression 2)Protraction/retraction 3)Rotation--on its long axis

Joints: Glenohumeral joint—arthrokinematics

1) Flexion/extension—spin (head of humerus on glenoid fossa) 2) Abduction—superior roll; inferior glide (if didn't, it'd hit acromion) 3) Lateral rotation—posterior roll; anterior glide (readjust to stay in socket) 4) Medial rotation—anterior roll; posterior glide (opposite of lateral rotation)

Joints: Glenohumeral joint

1)Triaxial 2)Ball and socket; three degrees of freedom--(flex/ext., ab/ad, ext.int rotation) 3)Inherently unstable 4)Humeral head more than twice the size of glenoid 5)Labrum deepens socket (suction cup--increases surface area & depth)--not deep inferiorly 6)Large capsule; redundant inferiorly 7)Held in a cavity by soft tissue 8)Head so much bigger than glenoid fossa

7 Components of the Shoulder Complex

1)Trunk (sternum) 2)Sternoclavicular (S/C) joint 3)Clavicle 4)Acromioclavicular (A/C) joint 5)Scapula 6)Glenohumeral (G-H) joint 7)Humerus

Joints: Glenohumeral joint--Bursae

Bursae: Soft, fluid-filled cushions/pillows. Reduce friction b/t bony prominence. Could get bursitis. 1)Subacromial--padding between supraspinatus tendons & coracoid acromial 2)Subdeltoid--padding between deltoid and supraspinatus tendon

Joints: Glenohumeral Joint--Capsular reinforcements

Capsular reinforcements: 1)Superior/middle/inferior GH ligaments (holds in place) 2)Coracohumeral ligament (ligaments tougher, coracoid process---humeral head) 3)Long head of biceps/triceps 4)Rotator cuff tendons blend with capsule keeps humeral head in glenoid fossa

Joints: Glenohumeral joint—osteokinematics

Degrees of Freedom (3): 1) Abduction/adduction—frontal plane; sagittal axis 2) Flexion/extension—sagittal plane; frontal axis 3) Medial/lateral rotation—transverse plane; vertical axis

Scapula

Flat triangular bone Vertebral border positioned between T2 and T7 (2-3 finger widths) Provides location for glenohumeral (GH) muscles to originate(attach) and provides stable base from which GH joint can operate

Rotator Cuff: Infraspinatus

Infraspinatus O: Infraspinous fossa I: greater tubercle A: lateral/external rotation, horizontal abduction N: suprascapular nerve

Rotator Cuff: Subscapularis

Internal or medial rotator SITS muscle easier way to remember Supraspinatous, infraspinatous, Teres minor, and subscapularis O: subscapular fossa I: Lesser tubercle A: medial/internal rotation N: Upper/ lower subscapular nerve

Total shoulder motion is a result of:

Intricate balance between joints of shoulder Proper functioning and synchronization of muscles

Muscles of the Shoulder Complex: Large Movers

Large movers: 1)Deltoid 2)Latissimus dorsi 3)Teres major 4)Pectoralis major 5)Coracobrachialis

Latissimus Dorsi

Latissimus Dorsi O: spinous processses of T7 to L5 I: medial floor of bicipital groove A shoulder extension, hyperextension, adduction, medial/internal rotation

Clavicle-Picture

Sternal End Acromial End Body

Joints & Ligaments

Sternoclavicular joint: Costoclavicular ligament--first rib to clavicle

Bones & Landmarks: Scapula

Subscapular Fossa Axillary (lateral) border Vertebral (medial) border

Joints: Scapulothoracic

Subscapular bursae(space)/serratus(muscle)anterior Functions include: 1)Maintain length-tension relationship of rotator cuff/deltoid 2)Position glenoid to receive humeral head--so it can fit (arm hand freely & gravity pulls it down) 3)Absorb shock---soft tissue 4)Permit elevation of body (via scapular depression)--crutches--elevate & depress 5)Enhance shoulder ROM

Rotator Cuff: Supraspinatus

Supraspinatus O: supraspinous fossa I: greater tubercle A: shoulder abduction N: Suprascapular nerve

Rotator Cuff

Works with the Deltoid during abd. and flex to keep the humerus seated in the gleniod fossa to prevent impingement. Of the biceps tendon which is the only tendon that travels btw two bones

Primary purpose of the shoulder?

position hand for function