Kinesiology Ch.5

Shoulder Complex

scapula, humerus, clavicle

Scapula

2nd-7th rib, shoulder girdle with 3 borders and 3 angles, positions glenoid fossa for humeral motion

scapula- Medial (vertebral) border

longest, anchor for rotation, abduction and adduction

Scapula- Superior border

elevate and upwardly rotate

Lateral ( axillary) border

thick, important for muscle attachments

Clavicle

links chest and upper arm, positions humera laterally away from upper body

humerus

connects trunk and forearm

Shoulder Complex Joints

▪ Scapulothoracic joint
▪ Sternoclavicular joint
▪ Acromioclavicular joint
▪ Glenohumeral joint

Scapulothoracic Joint

atypical

gliding ( elevation, depression, abduction, adduction)

rotation ( internal, external, upward, downward)

tilt ( anterior, posterior)

Sternoclavicular Joint

saddle/ball-and socket

triaxial

movements:

elevation, depression, protraction, retraction, posterior rotation, anterior rotation

Acromioclavicular Joint

Biaxial

movements:

anterior/posterior gliding

superior/inferior gliding

connect scapula to clavicle “makes a roof”

Glenohumeral Joint

triaxial

ball-and-socket

Movements:

flexion, extension, abduction/adduction, internal/external rotation, horizontal abduction/adduction

Axioscapular Muscles

attach scapula to skeleton

trap

levator scapulae

rhomboids

serratus anterior

pectoralis minor

Trapezius

stabilizes and mobilizes scapula

upper, middle, and lower fibers

Levator Scapulae

elevation and downward rotation of scapula

Rhomboids

elevation and downward rotation of scapula

adduction of scapula

Serratus Anterior

maintains position of scapula against rib cage

Pectoralis Minor

stabilizes scapula anteriorly against rib cage

Elevation

trap

rhomboids

levator scapulae

Depression

Trap

Serratus anterior

pectoralis minor

Upward rotation

trap

serratus anterior

downward rotation

rhomboids

levator scapulae

pectoralis minor

Protraction

serratus anterior

pectoralis minor

Retraction

trap

rhomboids

Scapulohumeral muscles

stabilize humeral head against glenoid fossa and supplies force for movement

Rotator cuff (SITS)

deltoid

teres major

coracobrachialis

(active when:reaching, placing, or throwing)

Rotator Cuff Muscles

supraspinatus

infraspinatus

teres major

subscapularis

Deltoid

caps proximal humerus

flexion, abduction, extension

Teres Major

adduction

internal rotation

Coracobrachialis

shoulder flexion

shoulder adduction

Axiohumeral Muscles

links axioskeleton and humerus

pectoralis major

lattisimus dorsi

pectoralis major

divided into clavicular and sternocostal fibers that connect on the humerus

Latissimus Dorsi

spans pelvis trunk and humerus

shoulder extension

shoulder adduction

shoulder internal rotation

Glenohumeral Joint- Abduction

deltoid

supraspinatus

Glenohumeral Joint-Adduction

Latissimus dorsi

teres major

infraspinatus

teres major

pectoralis major

triceps brachii

coracobrachialis

Glenohumeral Joint-Horizontal adduction

deltoid anterior fibers

pectoralis major

Glenohumeral Joint-Flexion

Deltoid (anterior fibers)

Pectoralis major

biceps brachii

coracobrachialis

Glenohumeral Joint- Extension

deltoid ( posterior fibers )

latissimus dorsi

teres major

pectoralis major

triceps brachii

Glenohumeral Joint-external rotation

deltoid ( posterior fibers0

infraspinatus

teres major

Glenohumeral Joint-Internal Rotation

Deltoid

latissimus dorsi

teres major

subscapularis

pectoralis major

Scapula: foundation of UE Motion

offers base of support, many ADLs require shoulder elevation

Scapulohumeral Rhythm

Cooperative mechanical pattern of scapula and humerus to produce specific movements, scapuls 1: 2 humerus movement ratio

Subacromial Impingement

Compression of the soft tissues between acromion and humeral head

Thoracic Outlet Syndrome (TOS)

compression of structures

Glenohumeral Subluxation

humeral head partially dislocates inferiorly

Subluxation

result of instability, weakness, or paralysis, pull of gravity through humerus

Rotator Cuff Tear

due to forceful loading of shoulder while elevator ( supraspinatus most commonly injured)

Glenohumeral Joint Dislocation

Most commonly dislocated joint in body

damage to labrum