ALLEN - Anatomy 7202 - Intro to Shoulder Biomechanics/SC Jt

What are the bones included in the shoulder complex?

Clavicle, scapula, humerus

What are the 4 articulations of the shoulder complex?

Sternoclavicular jt, acrmioclavicular jt, glenohumeral jt, and scapulothoracic jt

What is the only attachment between the axial skeleton and the UE?

Sternoclavicular jt

What are the movements of the clavicle?

Elevation/depression, protraction/retraction, anterior/posterior rotation

On the medial end of the clavicle, what is the shape superior to inferior?

Convex moving on concave (opposite)

On the medial end of the clavicle, what is the shape anterior to posterior?

Concave moving on convex (same)

There is an articular disc in the sternoclavicular joint. What is the disc made of?

Fibrocartilage

What are the functions of the sternoclavicular disc? (4)

Improve joint congruity/stability, absorb/dissipate force, prevent medial dislocation, limit scapular depression

What type of sternoclavicular joint dislocations are the most common? Which are the most severe (and why)?

Anterior dislocations are more common; posterior dislocations are more severe due to the structures behind the clavicle

What are the ligaments of the sternoclavicular joint? (3)

Interclavicular ligament, sternoclavicular ligament, costoclavicular ligament

What is the role of the interclavicular ligament?

Limits depression of lateral clavicle

What is the role of the sternoclavicular ligament?

Limits anterior/posterior movement of medial clavicle

What is the role of the costoclavicular ligament?

Limits elevation of the lateral clavicle

Which mm. act on the sternoclavicular jt?

None

What action does the subclavius m. perform?

Depress lateral end of clavicle, resists clavicular elevation

What movements are performed by the sternoclavicular jt?

Elevation/depression, protraction/retraction, ant/post rotation

What plane does SC jt elevation/depression occur in?

Frontal plane

What is the shape of the clavicle on sternum when considering elevation/depression?

Convex on concave

What is the arthrokinematic motion for clavicular elevation at the SC jt? Clavicular depression?

Elevation is inferior slide; depression is superior slide

What SC jt ligament(s) become taut with clavicular elevation? Which are slackened?

Costoclavicular ligament is taut; sternoclavicular and interclavicular ligaments are slackened

What SC jt ligament(s) become taut with clavicular depression? Which are slackened?

Sternoclavicular and interclavicular are taut; costoclavicular is slackened

Which has a greater ROM: clavicular elevation or clavicular depression?

Elevation (45); depression is only 15

What plane does clavicular protraction/retraction occur in?

Horizontal (transverse)

What is the shape of the clavicle on sternum when considering protraction/retraction?

Concave on convex (same)

What is the arthrokinematic motion for clavicular protraction at the SC jt? Clavicular retraction?

Protraction is anterior slide; retraction is posterior slide

What plane does clavicular rotation occur in?

Sagittal plane

Which has a greater ROM: clavicular anterior rotation or posterior rotation?

Posterior rotation is greater (50); anterior is only 10

What movement is posterior rotation of the clavicular necessary for?

Overhead movements

What is the shape of the clavicle on sternum when considering rotation?

Concave on convex (same)

What is the arthrokinematic motion for clavicular anterior rotation at the SC jt? Posterior rotation?

Anterior rotation is anterior roll (ant spin); posterior rotation is posterior roll (post spin)

What is the open packed position for the SC jt?

Arm resting at one's side

What is the closed packed position for the SC jt?

Full posterior rotation via maximal arm elevation and scapular rotation

What is the capsular pattern for the SC jt?

Pain with horizontal adduction and full elevation