Shoulder Girdle

Shoulder (Pectoral) Girdle

Attachment for upper limbs to the trunk.

Bones of the shoulder girdle

Scapula and Clavicle.

Glenohumeral Joint

Joint formed by the scapula and humerus.

Key Bony Landmark: Manubrium

The upper part of the sternum where the clavicles attach.

Key Bony Landmark: Clavicle

Bone acting as a brace to hold the shoulder girdle away from the thorax.

What is the role of the Acromial end of the clavicle?

Joins with the acromion of the scapula.

What is the Sternal end of the clavicle?

Joins with the manubrium of the sternum.

How does the shoulder girdle's structure affect fractures?

Curved shape can lead to fractures occurring anteriorly.

Key Bony Landmark: Coracoid process

A hook-like structure on the scapula.

Key Bony Landmark: Acromion process

The highest point of the shoulder formed by the scapula.

What is the Glenoid fossa?

The shallow cavity in the scapula that receives the head of the humerus.

Lateral border

The edge of the scapula facing away from the spinal column.

Inferior angle of scapula

The lowest point of the scapula where its borders meet.

Medial border

The edge of the scapula nearest to the spinal column.

Superior angle of scapula

The uppermost point of the scapula.

Spine of the scapula

Also known as scapular spine; it divides the back surface.

Movement of the Sternoclavicular (SC) Joint

Multiaxial movements including protraction, retraction, elevation, and depression.

SC Joint Protraction

Movement anteriorly by 15 degrees.

SC Joint Retraction

Movement posteriorly by 15 degrees.

What stabilizes the SC Joint against superior displacement?

Costoclavicular and interclavicular ligaments.

Acromioclavicular (AC) Joint

A syndesmotic type joint that enhances stability.

Coracoclavicular ligaments

Ligaments that reinforce the AC Joint.

What is a characteristic of the Scapulothoracic Joint?

Lacks ligamentous support but is muscle-supported.

Scapular abduction (protraction)

Scapula moves laterally away from the spinal column.

Scapular adduction (retraction)

Scapula moves medially toward the spinal column.

Scapular Depression

Downward movement of the scapula.

Scapular Elevation

Upward movement of the scapula.

Downward rotation of scapula

Inferior angle moves inferomedially toward the spinal column.

What does upward rotation of the scapula involve?

Turning glenoid fossa upward and moving the inferior angle superolaterally.

Lateral tilt (outward tilt)

Scapula rotates about its vertical axis during abduction.

Medial tilt (inward tilt)

Scapula rotates about its vertical axis during extreme adduction.

Anterior tilt (upward tilt)

Superior border moves anteroinferiorly during hyperextension.

Posterior tilt (downward tilt)

Superior border moves posteroinferiorly during hyperflexion.

Trapezius muscle functions

Elevation, depression, adduction, and rotation of the scapula.

Rhomboids Function

Adduction (retraction) and downward rotation of the scapula.

Levator scapula function

Elevates the medial margin of the scapula.

Serratus anterior function

Abduction (protraction) and upward rotation of the scapula.

Pectoralis minor function

Abduction (protraction), downward rotation, and depression of the scapula.

Aggregate Muscle Actions: Scapular Abduction

Scapula moves laterally away from the vertebral column.

Agonists in Scapular Abduction

Pectoralis minor and Serratus anterior.

Aggregate Muscle Actions: Scapular Adduction

Return from abduction, occurring with retractions.

Agonists in Scapular Adduction

Trapezius (mid/lower fibers) and Rhomboids.

Aggregate Muscle Actions: Scapula Upward Rotation

Lateral and upward movement of the scapula.

Agonists in Scapula Upward Rotation

Trapezius (mid/lower fibers) and Serratus anterior.

Aggregate Muscle Actions: Scapula Downward Rotation

Rotates the glenoid fossa downward during shoulder joint movement.

Agonists in Scapula Downward Rotation

Pectoralis minor and Rhomboids.

Aggregate Muscle Actions: Scapula Elevation

Lifting scapula without rotation in the anatomical position.

Agonists in Scapula Elevation

Levator scapula, Trapezius (upper fibers), and Rhomboids.

Aggregate Muscle Actions: Scapula Depression

Movement that lowers the scapula.

Agonists in Scapula Depression

Trapezius (lower fibers) and Pectoralis minor.