Shoulder Girdle

KIN 245

Bones of the Shoulder Girdle

Scapula (shoulder) Clavicle (small key) Link to Axial skeleton via sternoclavicular joint (an

anterior joint) Lack of posterior attachment to the axial skeleton

allows for a wide ROM Functions to allow attachment areas for numerous

muscles that move the shoulder and elbow

Landmarks

Borders superior, medial, lateral

Angles inferior, superior

Acromion process Spine of scapula Glenoid fossa Coracoid process (like a crow’s beak) Supraspinatus, Infraspinatus, Subscapular fossa

Joints of theShoulder Girdle Sternoclavicular

sternum (manibrum) and clavicle arthrodial (gliding) joint ligaments

anterior sternoclavicular ligament posterior sternoclavicular ligament costoclavicular ligament interclavicular ligament

Joints of theShoulder Girdle Acromioclavicular

Acromion Process of scapula and clavicle arthrodial (gliding) joint ligaments

coracoclavicular ligaments trapezoid ligament conoid ligament

superior & inferior acromioclavicular ligaments

Joints of theShoulder Girdle Scapulothoracic Joint

Scapula and thoracic region not really synovial joint supported by muscles, not ligaments

Movements allowed bythe Shoulder Girdle Abduction (Protraction) Adduction (Retraction) Inward (downward) rotation: inferior angle

moves medially Outward (upward) rotation Depression: inferior movement Elevation: superior movement

Muscles of theShoulder Girdle Posterior

trapezius levator scapula rhomboids (major and minor)

Anterior pectoralis minor seratus anterior subclavius

Trapezius (p134)

Origin: Superior nuchal line Occipital protuberance Ligamentum nuchae C7 and T12 vetebrae

Trapezius

Insertion Lateral 1/3 of clavicle Acromion process of scapula Spine of scapula

Trapezius

Action Scapula

adduction elevation depression outward rotation

Head extension / hyperextension rotation lateral flexion

Levator Scapulae (p129)

Origin Transverse processes of the 1st four cervical

vertebrae Insertion

Vertebral (medial) border of the scapula above base of scapular spine

Action Scapula elevation, inward rotation, adduction

Rhomboid Muscles (p131)

Origin Lower part of ligamentum nuchae Spinous process of the 7th cervical and 1st five

thoracic vert. Insertion

Vertebral border of the scapula

Rhomboid Muscles

Action Scapular

adduction inward rotation elevation

Serratus Anterior (p132)

Origin lateral, anterior surface of the upper 8/9 ribs

Insertion Anterior aspect of the vertebral border of the

scapula

Serratus Anterior

Action Scapular

abduction outward rotation depression

Pectoralis Minor (p130)

Origin Anterior surfaces of the 3rd - 5th ribs

Insertion Coracoid process of scapula

Action Rib elevation Scapular depression

Subclavius (p133)

Origin Superior aspect of 1st rib (around costal cartilage)

Insertion Inferior groove mid-portion of clavicle

Action scapular depression stabilization of sternoclavicular jt.

Summary

Shoulder Girdle bones: clavicle, scapula joints:

sternoclavicular acromioclavicular scapulothoracic

muscles anterior: pectoralis minor, serratus anterior, subclavius

posterior: levator scapulae, rhomboids, trapezius

Shoulder Girdle

The arm travels through a wide range of movements, the scapula cooperates by placing the glenoid fossa in the most favorable position for the head of the humerus (scapulohumeral rhythm)

Movements of the Shoulder Girdle Clavicle

elevation, depression protraction, retraction (or forward and backward horizontal

movements)

Scapula elevation, depression abduction, adduction inward and outward rotation

Muscle Analysis Chart

Identify muscles that move the scapula abduction adduction elevation depression upward rotation downward rotation

Muscles that move the scapula abduction

serratus anterior pectoralis minor

adduction trapezius (middle and lower fibers) rhomboids

Muscles that move the scapula elevation

trapezius (upper & middle fibers) levator scapulae rhomboids (slight)

depression trapezius (lower fibers) pectoralis minor subclavius (clavicle depression)

Muscles that move the scapula outward rotation

trapezius (middle and lower fibers) serratus anterior

inward rotation rhomboids Levator scapulae