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What limit does the ligament serve regarding arm movement?
Flexion and extension occur in the frontal plane.
False
What is the range of motion (ROM) for abduction?
120 degrees
In internal rotation, the greater tubercle is __________ by the coracoacromial arch.
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Match the following movements with their respective axes:
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Which bones are involved in the shoulder complex?
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The glenohumeral joint has the least mobility among the true joints.
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What are the types of joints involved in the shoulder complex?
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The movement of the shoulder is due to the combined motion of the scapula, clavicle, and _____
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Match the following components to their respective functions in shoulder motion:
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What is the type and subtype of the sternoclavicular joint?
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The SC joint disc is a cartilaginous structure that enhances joint congruency.
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Name the two articular surfaces of the sternoclavicular joint.
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What function does the Superior AC Ligament serve?
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The Conoid Ligament is part of the Coracoclavicular Ligament and limits inferior translation of the acromion.
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What are the two parts of the Coracoclavicular Ligament?
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The glenoid fossa moves __________ during Internal Rotation.
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Match the following kinematic terms with their definitions:
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Which ligament limits the upward rotation of the scapula at the AC Joint?
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The Glenohumeral Joint is a type of fibrous joint.
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What is the type and subtype of the Glenohumeral Joint?
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What is the primary function of the disc in the joint space?
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The acromioclavicular joint has only one degree of freedom for movement.
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What are the two attachments of the disc in this joint?
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The __________ ligament limits the excess depression of the clavicle.
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Match the following ligaments with their functions:
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What type of joint is formed between the clavicle and acromion process?
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The capsule of the acromioclavicular joint is strong and stable.
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What helps maximize scapula contact with the thorax?
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The __________ rotation of the clavicle occurs during upward movement.
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Which ligament limits the motion of the medial end of the clavicle?
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What is the primary function of the Superior GH Ligament?
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The Middle GH Ligament helps limit anterior translation of the humeral head at any angle of abduction.
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Name the three components of the Inferior GH Ligament.
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The ________ is the major ligament for joint stability, especially after 45 degrees of abduction.
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Match the following ligaments with their primary functions:
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Which ligament assists in resisting inferior translation of the humeral head during abduction?
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The Coracohumeral Ligament consists of one band originating from the coracoid process.
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What occurs during abduction combined with external rotation regarding the anterior band of the Inferior GH Ligament?
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Study Notes
Shoulder Complex - Introduction
- Half of the upper limb's mass is in the shoulder complex.
- The Glenohumeral (GH) joint has the most movement capacity.
- The Sternoclavicular (SC) joint connects the upper extremity (U/E) to the trunk.
- The Scapulothoracic (ST) joint movement is due to the combined motion of the SC and Acromioclavicular (AC) joints.
- The shoulder's overall movement is achieved through the combined action of the scapula, clavicle, and humerus.
- The ST joint contributes approximately 1/3 of the shoulder complex's total motion.
- The GH joint also contributes about 1/3 of the shoulder complex's total motion.
Sternoclavicular Joint - Introduction
- The SC joint is the only structural attachment between the axial skeleton and the upper extremity.
- It's a synovial joint, specifically a saddle type, allowing for 3 degrees of freedom (DOF).
- Movements include:
- Elevation
- Depression
- Protraction
- Retraction
- Anterior Rotation
- Posterior Rotation
Sternoclavicular Joint - Articular Surfaces
- Consists of two articular surfaces:
- The medial end of the clavicle
- A notch formed by the manubrium and the 1st costal cartilage.
- The joint congruency is minimal.
- The medial clavicle's superior and posterior portions don't contact the sternum.
- These areas serve as attachment sites for:
- SC Joint Disc
- Joint Capsule
- Interclavicular ligament
Sternoclavicular Joint - SC Joint Disc
- A fibrocartilaginous structure within the joint space, positioned diagonally.
- It enhances joint congruency, making the joint more stable.
- It has two attachments:
- Upper portion: Posterosuperior aspect of the clavicle
- Lower portion: Manubrium and 1st costal cartilage
- During clavicle elevation and depression, the clavicle's medial articular surface rolls and slides on the disc. The disc stays stationary, with the upper attachment acting as the pivot point.
- During protraction and retraction of the clavicle, the disc and the medial articular surface of the clavicle roll and slide together on the manubrium facet. The disc's lower attachment serves as the pivot point.
Sternoclavicular Joint - Ligaments
- Sternoclavicular ligament:
- Two ligaments (anterior and posterior)
- Restrict the medial end of the clavicle's anterior and posterior translation.
- Costoclavicular ligament:
- Has two laminae (anterior and posterior)
- Limits clavicle elevation and superior force from the sternocleidomastoid and sternohyoid muscles.
- Interclavicular ligament:
- Limits excessive depression.
- Protects the brachial plexus and subclavian artery.
Acromioclavicular Joint - Introduction
- The articulation between the clavicle and the acromion process.
- It's a synovial joint, specifically a plane type, allowing for 3 DOF.
- Movements include:
- Internal Rotation
- External Rotation
- Anterior Tilting
- Posterior Tilting
- Upward Rotation
- Downward Rotation
Acromioclavicular Joint - Introduction (continued)
- Contributes to:
- Increased upper extremity motion.
- Glenoid positioning.
- Maximizing scapula contact with the thorax.
Acromioclavicular Joint - Articular Surfaces
- Contains two articular surfaces:
- Lateral end of the clavicle
- A facet on the acromion process.
- The joint congruency is minimal.
- Initially, it's a fibrocartilaginous union, but a joint space develops and leaves a meniscal homologue in time due to usage.
- The size of the joint space can vary among individuals.
Acromioclavicular Joint - Capsule & Ligaments
- The AC joint capsule is weak.
- The ligaments are important for stability.
- Three ligaments provide stability to the AC joint:
- Superior AC ligament
- Inferior AC ligament
- Coracoclavicular ligament
- The superior AC ligament limits movement caused by anterior force on the lateral clavicle.
- This ligament is connected to the trapezius and deltoid tendons, making it stronger.
- The coracoclavicular ligament provides stability in the superior, inferior, and rotational directions. It has two parts:
- Medial (conoid ligament) - vertical - limits inferior translation of the acromion.
- Lateral (trapezoid ligament) - horizontal - limits posterior translation of the lateral clavicle.
Acromioclavicular Joint - Capsule & Ligaments (continued)
- Both ligaments limit scapular upward rotation at the AC joint.
- When medial forces are applied to the humerus and transferred to the glenoid fossa, the trapezoid portion of the coracoacromial ligament prevents medial displacement of the scapula on the clavicle.
Acromioclavicular Joint - Kinematics
- Internal and external rotation:
- Axis - Vertical
- Plane - Transverse
- During internal rotation, the glenoid fossa moves anteromedially.
- During external rotation, the glenoid fossa moves posterolaterally.
- This occurs with clavicle protraction and retraction.
- Anterior and posterior tilting:
- Axis - Frontal
- Plane - Sagittal
- Anterior tilting:
- Acromion moves forward
- Inferior angle moves backward
- Posterior tilting:
- Acromion moves backward
- Inferior angle moves forward
- Upward and downward rotation:
- During upward rotation, the glenoid tilts upward, and the inferior angle moves laterally.
- During downward rotation, the glenoid tilts downward, and the inferior angle moves medially.
- The coracoclavicular ligament limits the range of motion (ROM) at the AC joint.
Glenohumeral Joint - Introduction
- The articulation between the glenoid fossa and humeral head.
- It's a synovial joint, specifically a ball and socket type, allowing 3 DOF.
- Bones involved:
- Scapula
- Humerus
- Articular surfaces:
- Glenoid fossa of the scapula
- Head of the humerus
Glenohumeral Joint - Structure
- Proximal articular surface:
- The glenoid fossa is the proximal articular surface.
- Superior GH ligament:
- Extends from the superior glenoid labrum towards the upper neck of the humerus, inserting deep to the coracohumeral ligament.
- Superior GH ligament + superior capsule + coracohumeral ligament = Rotator Interval Capsule (RIC)
- The RIC forms a bridge between the supraspinatus and subscapularis tendons. This ligament limits anterior and inferior translation of the humeral head at 0 degrees of abduction.
- Middle GH ligament:
- Runs obliquely from the superior anterior labrum to the anterior aspect of the proximal humerus, below the superior GH ligament.
- This ligament limits anterior translation of the humeral head up to 45 degrees of abduction.
- Inferior GH ligament:
- Has three components:
- Anterior ligament band
- Axillary pouch
- Posterior ligament band
- Also known as the Inferior GH Ligament Complex (IGHLC).
- It's a major stabilizing ligament.
- Primarily provides stability after 45 degrees of abduction with rotation.
- Has three components:
Glenohumeral Joint - Structure (continued)
- During abduction:
- The axillary pouch is taken up, resisting inferior head translation.
- During abduction and external rotation:
- The anterior band expands, providing anterior stability and resisting anterior and inferior translation.
- During abduction and internal rotation:
- The posterior band expands, providing posterior stability, and resisting inferior translation.
- Coracohumeral ligament:
- Has two bands originating from the base of the coracoid process.
- One band inserts at the edge of the supraspinatus tendon on the greater tuberosity.
- The other band inserts at the subscapularis tendon on the lesser tuberosity.
- These two bands form a tunnel that serves as a pathway for the tendon of the long head of the biceps.
- This ligament limits inferior translation and resists lateral rotation when the arm is adducted.
Glenohumeral Joint - Kinematics
- Movements include:
- Flexion
- Extension
- Abduction
- Adduction
- Internal Rotation
- External Rotation
Glenohumeral Joint - Kinematics (continued)
- Flexion and Extension:
- Axis - Frontal
- Plane - Sagittal
- ROM - 180 degrees
- Flexion:
- Humerus moves anteriorly.
- Sliding - Posterior
- Rolling - Anterior
- Extension:
- Humerus moves backward.
- Sliding - Anterior
- Rolling - Posterior
- Abduction and Adduction:
- Axis - Sagittal
- Plane - Frontal
- ROM - 120 degrees
- Abduction:
- Abduction decreases if the humerus is in a neutral position or medial rotation due to resistance against the coracoacromial arch by the greater tubercle.
- When the humerus rotates laterally to 35-40 degrees, the greater tubercle passes under or behind the arch. In this position, abduction occurs smoothly.
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Description
This quiz explores the anatomy of the shoulder complex, emphasizing the significance of the Glenohumeral and Sternoclavicular joints. Participants will learn about the movements and contributions of these joints to overall shoulder motion. Perfect for students and professionals in anatomy or physiotherapy.