03-04: The Shoulder Girdle Flashcards
Shoulder Complex
Scapula, Clavicle, Sternum, Humerus, Rib Cage, Sternoclavicular Joint, Acromioclavicular Joint, Glenohumeral Joint, Scapulothoracic articulation
Shoulder Girdle
Scapula, Clavicle, Sternum
Motions of Shoulder Girdle
Elevation and Depression, Protraction (ABD) and Retraction (ADD), Upward and Downward Rotation, Anterior Tilt (Sagittal Plane Adjustment), Internal and External Rotation (Horizontal Plane Adjustment)
Upward and downward rotation
Upward rotation - Inferior angle away from spine
Downward rotation - Inferior angle towards spine
Anterior tilt (sagittal plane adjustment)
Inferior angle moves away from thoracic wall
Internal and external rotation - “winging”
Vertebral border moves away from thoracic wall
Resting position of scapula
Superior angle - T2
Spine of the scapula - T3
Inferior Angle - T7-T8
Between T2 and T7/T8, 2”-3” lateral from spinous processes of the verterbrae, Spine of the scapula is level with spinous process of T3/T4
Three major ligaments of sternoclavicular joint
Sternoclavicular ligament, Interclavicular Ligament, Costoclavicular Ligament, Articular disk (inside SC ligament)
Sternoclavicular ligament
- Connects clavicle to sternum
- Provides reinforcement to the joint capsule
Interclavicular ligament
- Top of the manubrium, connecting superior sternal ends of the clavicles
- Limits the amount of clavicular depression
Costoclavicular ligament
- Connects the inferior surface of the clavicle to the superior surface of the costal cartilage of the 1st rib; Short, flat, rhomboid-shaped
- Limits the amount of clavicular elevation
Coracoclavicular ligament
- Not directly on joint, but provided stability to joint
- Limits elevation of scapula laterally
- Trapezium - lateral, Conoid - medial
Coracoacromial ligament
- Does not cross joint, but forms arch over the head of the humerus; Protects subacromion elements
- Starts and ends on scapula (coracoid to acromion)
Acromioclavicular joint
- Connects scapula to axial skeleton; Triaxial joint
- Two ligaments: acromioclavicular ligament, Coracoacromial ligament
Separated shoulder
Injury where coracoclavicular ligament tears upon force
Scapulothoracic joint (ST)
- Not a true joint
- Wide ROM of shoulder complex
- ST Motion = AC Motion + SC Motion (creates scapular movement
Sternoclavicular joint
- Convex and Concave ends
- Glide changes dependent on which way the scapula moves
Primary movements of scapulothoracic joint (ST)
Elevation and Depression, Retraction and Protraction, Downward and Upward Rotation
ST Elevation
- SC joint elevation + downward rotation at AC joint
- Convex on Concave at SC joint
- Occurs in frontal plane, sagittal axis @ SC joint
ST Upward Rotation
- SC joint elevation + upward rotation at AC joint
ST Protraction and Retraction
- Rotation around vertical axis @ SC joint
- Occurs in horizontal plane
- Concave (clavicle) on Convex (sternum)
- Anterior Glide (Protraction), Posterior Glide (Retraction)
ST Anterior Tilt
- Posterior Rotation of Clavicle
- Posterior Glide
- Occurs in sagittal plane, frontal axis @ SC joint
Three planes of motion for AC joint
IR/ER - Horizontal Plane Adjustment “winging” - vertical axis
Upward/Downward Rotation - Sagittal axis
Anterior Tipping - Sagittal Plane Adjustment - Frontal Axis
AC & CL movements
- Both convex ends = unstable
- Cartilagenous disk between ends provides stability (convex on concave)
Muscles of the Shoulder Girdle
Trapezius (3), Levator Scapula, Rhomboids (2), Serratus Anterior, Pectoralis Minor
Upper Trapezius
O: Occiput, Nuchal Ligament, SPs of C1-C6
I: Lateral 1/3 of clavicle, acromion (anterior aspect)
A: Scapular elevation (prime mover), upward rotation, assist with retraction
N: Cranial Nerve XI (Accessory)
- Upward Line of Pull
Middle Trapezius
O: SPs of C7-T3
I: Spine of Scapula
A: Scapular retraction (prime mover), upward rotation
N: Cranial Nerve XI (Accessory)
- Middle Line of Pull
Lower Trapezius
O: SPs of T4-T12
I: Base of spine of scapula
A: Scapular depression (prime mover), upward rotation, assist with retraction
P: Cranial Nerve XI (Accessory)
- Downward (Vertical) Line of Pull
Rotational Movement of Scapula (Upward/Downward)
Force Couple - Lower and Upper trap work opposite directions of each other; assisted by serratus anterior
Levator Scapula
O: TPs of C1-C4
I: Superior angle of scapula down to spine of scapula
A: Assist with scapular elevation, downward rotation
N: Dorsal Scapular (C5 Root)
- Ribbon shaped; very thin, so susceptible to injury; deep to trapezius
Rhomboids
O: Minor - SPs of C7-T1, Major - SPs of T2-T5
I: Vertebral border of scapula from base of spine to inferior angle (Minor - Base of Spine, Major - Bottom of Base)
A: Retraction (with downward rotation component, lifts scapula slightly - elevation)
N: Dorsal Scapular (C5 Root)
Serratus Anterior
O: Lateral aspect of ribs 1-8
I: Anterior aspect of vertebral border of scapula
A: Scapular protraction (prime mover), upward rotation
N: Long Thoracic (C5, C6, C7 Roots)
- Reaches under costals to reach vertebral border
- Deepest muscle of shoulder girdle
- Holds scapula against thoracic wall
- If weak or gone, scapula will “wing”
Pectoralis Minor
O: Anterior aspect of ribs 3-4
I: Coracoid process of scapula
A: Scapular depression, Anterior tilt (sagittal plane adjustment), downward rotation
N: Medial pectoral
- Deep to pectoralis major
- Neurovascular bundle runs under pec major (compress and symptoms over upper extremities = TOS)
Reverse Action - Upper Trapezius
Extends head and neck, ipsilateral lateral head bend, contralateral head rotation
Reverse Action - Lower Trapezius
Assist in elevating trunk
Reverse Scapula - Levator Scapula
Rotate and laterally bend neck
