The Shoulder 3.1B

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Questions and Answers

What is the primary action of the levator scapulae muscle?

Elevation of the scapula (correct)

Depression of the scapula

Flexion at the shoulder joint

Protraction of the scapula

Which muscle primarily facilitates abduction of the upper limb from 0° to 15°?

Trapezius

Supraspinatus (correct)

Serratus anterior

Deltoid

Which nerve innervates the deltoid muscle?

Suprascapular nerve

Spinal accessory nerve

Axillary nerve (correct)

Long thoracic nerve

Where do the rhomboid muscles insert?

Medial border of the scapula Signup and view all the answers

Which muscle contributes primarily to retraction of the scapula?

Rhomboid major Signup and view all the answers

What is the range of motion of the upper limb at the shoulder joint during abduction, from 15° to 90°?

Deltoid Signup and view all the answers

Which of the following nerves innervates the supraspinatus muscle?

Suprascapular nerve Signup and view all the answers

What is the primary function of the serratus anterior muscle?

Protraction and stabilization of the scapula Signup and view all the answers

Which muscle is primarily responsible for the retraction of the scapula?

Rhomboid major Signup and view all the answers

What movement is NOT associated with the trapezius muscle?

Adduction Signup and view all the answers

Which structure primarily innervates the latissimus dorsi muscle?

Thoracodorsal nerve Signup and view all the answers

Which of the following muscles assists in shoulder adduction?

Latissimus dorsi Signup and view all the answers

What role does the levator scapulae muscle serve?

Elevation of the scapula Signup and view all the answers

What is the primary action of the anterior part of the deltoid muscle?

Flexion and medial rotation Signup and view all the answers

Which muscle acts on the humerus at the glenohumeral joint?

Pectoralis major muscle Signup and view all the answers

What is the innervation of the deltoid muscle?

Axillary nerve Signup and view all the answers

Which of the following actions is NOT contributed by the pectoralis major muscle?

Abduction Signup and view all the answers

What is the insertion point of the pectoralis major muscle?

Intertubercular groove Signup and view all the answers

Which heads of the pectoralis major muscle contribute to flexion?

All heads Signup and view all the answers

Which nerve primarily innervates the pectoralis major muscle?

Medial and lateral pectoral nerves Signup and view all the answers

Which action is primarily contributed by the posterior part of the deltoid muscle?

Extension and lateral rotation Signup and view all the answers

What is the primary function of the coracoacromial ligament?

To deepen the joint socket Signup and view all the answers

What does a shoulder separation involve?

Tearing of the acromioclavicular ligaments Signup and view all the answers

Which ligament helps limit superior dislocation of the humerus?

Coracoacromial ligament Signup and view all the answers

What type of joint is formed where the head of the humerus articulates with the scapula?

Ball-and-socket joint Signup and view all the answers

When the ligaments in the shoulder are torn, which of the following results?

Shoulder separation Signup and view all the answers

Which component of the shoulder joint deepens the socket?

Glenoid labrum Signup and view all the answers

What injury is characterized by a grade 3 shoulder separation?

Complete tear of both acromioclavicular and coracoclavicular ligaments Signup and view all the answers

Which structure is NOT associated with stabilizing the shoulder joint?

Intertubercular groove Signup and view all the answers

What type of dislocation occurs when the humerus moves from the glenoid cavity in an anterior/superior direction?

Anterior/superior dislocation Signup and view all the answers

Which nerve associated with the shoulder is impacted by dislocation of the humerus from the glenoid cavity?

Axillary nerve Signup and view all the answers

What is the primary function of muscles in relation to joints?

Muscles can only cause action at a joint if they cross that joint. Signup and view all the answers

Which muscle is identified as the primary muscle of the rotator cuff that originates from the anterior scapula?

Subscapularis Signup and view all the answers

Where does the subscapularis muscle insert?

Lesser tubercle Signup and view all the answers

Which of the following statements about muscle actions is true?

Muscles can pull but not push. Signup and view all the answers

What is the role of the musculocutaneous nerve in relation to the shoulder?

It can be impacted by shoulder dislocation. Signup and view all the answers

Which structure is least likely to be directly affected by an anterior/superior dislocation of the humerus?

Biceps tendon Signup and view all the answers

Study Notes

Shoulder Separations

Coracoacromial and coracoclavicular ligaments help stabilize the bones of the shoulder
When these ligaments tear, it results in a shoulder separation (not a dislocation)
Coracoacromial ligament stretches between two parts of the scapula
Coracoacromial ligament helps to deepen the joint socket, reducing the risk of superior dislocation of the humerus

Shoulder Dislocations

The head of the humerus articulates with the glenoid cavity of the scapula within the glenohumeral (shoulder) joint
Dislocation of the humerus from the glenoid cavity can impact neurovascular structures in the axilla
Anterior/ superior dislocation and inferior dislocation are the most common types

Muscles of the Rotator Cuff

Subscapularis muscle contributes to flexion, medial (internal) rotation, and abduction
Deltoid muscle is a large muscle that contributes to abduction, flexion, extension, internal and external rotation
Muscles can only cause an action at a joint if they cross that joint

Muscles of the Shoulder

Pectoralis major muscle (sternocostal, clavicular, and abdominal heads) contributes to medial (internal) rotation, adduction, flexion, and transverse adduction
Trapezius, levator scapulae, rhomboid major, and rhomboid minor muscles all act on the scapula at the sternoclavicular joint (and scapulothoracic 'joint')
Levator scapulae, rhomboid major, and rhomboid minor muscles contribute to elevation and retraction of the scapula

Full Range of Motion

Abduction of the upper limb at the shoulder joint involves 4 different muscles, supplied by 4 different nerves, to achieve the full range of motion from 0 - 180 degrees
Supraspinatus muscle works from 0 - 15 degrees
Deltoid muscle works from 15 – 90 degrees
Trapezius muscle works from 90 - 160 degrees
Serratus anterior muscle works from 160 - 180 degrees

Simplified Muscle Chart

Subscapularis, latissimus dorsi, trapezius, levator scapulae, rhomboid major, and rhomboid minor muscles are all shoulder muscles that can be easily identified and remembered with the help of this chart

Learning Outcomes

Identify and describe the bones, joints, and ligaments related to the shoulder
Describe basic movements of the scapula and humerus
Identify muscles that act to move the scapula and humerus, and describe their innervations and functions
Predict functional implications of musculoskeletal injuries to the shoulder region

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Description

Test your knowledge on shoulder anatomy, including shoulder separations, dislocations, and the rotator cuff muscles. This quiz covers the ligaments involved, types of dislocations, and muscle functions related to shoulder movement.