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Questions and Answers
What type of joint is the shoulder joint classified as?
What type of joint is the shoulder joint classified as?
Which part of the shoulder joint is described as the weakest?
Which part of the shoulder joint is described as the weakest?
What fibrous structure deepens the glenoid cavity of the shoulder joint?
What fibrous structure deepens the glenoid cavity of the shoulder joint?
Which ligaments are considered thickenings of the fibrous capsule of the shoulder joint?
Which ligaments are considered thickenings of the fibrous capsule of the shoulder joint?
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What is the role of the coracoacromial ligament?
What is the role of the coracoacromial ligament?
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Which muscle initiates the first 15 degrees of shoulder flexion?
Which muscle initiates the first 15 degrees of shoulder flexion?
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Which muscles are responsible for lateral rotation of the shoulder joint?
Which muscles are responsible for lateral rotation of the shoulder joint?
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What does the transverse humeral ligament connect?
What does the transverse humeral ligament connect?
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What is the most common cause of anterior dislocation of the gleno-humeral joint in athletes?
What is the most common cause of anterior dislocation of the gleno-humeral joint in athletes?
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Which nerve is most likely injured during an anterior dislocation of the shoulder joint?
Which nerve is most likely injured during an anterior dislocation of the shoulder joint?
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What symptom is NOT typically associated with a shoulder dislocation?
What symptom is NOT typically associated with a shoulder dislocation?
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Which muscle is involved in flexion of the elbow joint?
Which muscle is involved in flexion of the elbow joint?
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What is the action of the triceps brachii muscle?
What is the action of the triceps brachii muscle?
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Which of the following statements about the musculocutaneous nerve is true?
Which of the following statements about the musculocutaneous nerve is true?
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During an anterior dislocation, where does the humeral head typically come to lie?
During an anterior dislocation, where does the humeral head typically come to lie?
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Which of the following is a symptom that might occur due to injury of the upper lateral cutaneous nerve of the arm?
Which of the following is a symptom that might occur due to injury of the upper lateral cutaneous nerve of the arm?
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Which muscle is primarily responsible for weak lateral rotation in the context of shoulder dislocation?
Which muscle is primarily responsible for weak lateral rotation in the context of shoulder dislocation?
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What immediate symptom is indicative of injury to the axillary nerve following shoulder dislocation?
What immediate symptom is indicative of injury to the axillary nerve following shoulder dislocation?
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Which joint receives the humeral head following an anterior dislocation?
Which joint receives the humeral head following an anterior dislocation?
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Which of the following actions is primarily affected due to the musculocutaneous nerve injury?
Which of the following actions is primarily affected due to the musculocutaneous nerve injury?
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Which nerve could potentially lead to 'pins and needles' sensation in the upper arm if injured?
Which nerve could potentially lead to 'pins and needles' sensation in the upper arm if injured?
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How is excessive lateral rotation of the humerus related to shoulder dislocation?
How is excessive lateral rotation of the humerus related to shoulder dislocation?
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What characteristic distinguishes the triceps brachii from the muscles in front of the arm?
What characteristic distinguishes the triceps brachii from the muscles in front of the arm?
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What is the primary function of the glenoid labrum in the shoulder joint?
What is the primary function of the glenoid labrum in the shoulder joint?
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Which muscle action is associated with the posterior fibers of the deltoid?
Which muscle action is associated with the posterior fibers of the deltoid?
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What anatomical structure is primarily involved in the stability of the shoulder joint during dislocation?
What anatomical structure is primarily involved in the stability of the shoulder joint during dislocation?
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Which of these statements accurately describes the coracohumeral ligament?
Which of these statements accurately describes the coracohumeral ligament?
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Which muscle assists in flexion of the elbow joint alongside the biceps brachii?
Which muscle assists in flexion of the elbow joint alongside the biceps brachii?
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Which muscle primarily contributes to maintaining shoulder stability during lateral rotation?
Which muscle primarily contributes to maintaining shoulder stability during lateral rotation?
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What role does the transverse humeral ligament serve in relation to the biceps tendon?
What role does the transverse humeral ligament serve in relation to the biceps tendon?
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Which muscle groups are involved in shoulder adduction?
Which muscle groups are involved in shoulder adduction?
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Where does the humeral attachment of the fibrous capsule occur?
Where does the humeral attachment of the fibrous capsule occur?
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What is unique about the lower and medial parts of the capsule in the shoulder joint?
What is unique about the lower and medial parts of the capsule in the shoulder joint?
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What is a significant characteristic of the gleno-humeral ligaments?
What is a significant characteristic of the gleno-humeral ligaments?
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What initiates the first 15 degrees of shoulder flexion?
What initiates the first 15 degrees of shoulder flexion?
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What is the structural significance of the scapular attachments of the fibrous capsule?
What is the structural significance of the scapular attachments of the fibrous capsule?
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Study Notes
Shoulder Joint
- Type: Synovial
- Shape: Ball and Socket
- Number of bones: Two (articulating bones)
- Articular surfaces: Glenoid cavity of scapula, head of humerus
- Acromion, articular cartilage, coracoid process, scapula, humerus, glenoid are key anatomical structures
Ligaments of the Shoulder
- Fibrous capsule
- Scapular attachments: Margins of the glenoid fossa, supraglenoid tubercle with long head of biceps
- The lower and medial parts of the capsule are lax and weakest (lack muscular support)
- Humeral attachments: Surround anatomical neck, attached to shaft 1½" below anatomical neck (medially-weak part)
- Gap in capsule for passage of biceps tendon in inter-tubercular groove
- Synovial membrane lines inner surface of capsule
Glenoid Labrum
- Glenoid cavity is shallow, accommodating only 1/3 of humeral head
- Glenoid cavity deepened by fibrocartilaginous collar (glenoid labrum) attached to its margin
- Deepens the socket for a better fit of the head
Glenohumeral Ligaments
- Superior, middle, and inferior glenohumeral ligaments
- Extend from anterior glenoid margin to lesser tubercle of humerus
- Considered thickenings of the fibrous capsule of the shoulder joint
- Strengthen the anterior surface of the capsule
Coracohumeral Ligament
- Between coracoid process and greater tubercle of humerus
- Aids in resisting inferior dislocation of the shoulder, particularly in dependent arm positions
Coracoacromial Ligament
- Between coracoid process and acromion
- Prevents upward displacement of humeral head
Relations of Shoulder Joint
- Anterior: Subscapularis
- Posterior: Infraspinatus, teres minor
- Superior: Supraspinatus
- Inferior: Axillary nerve
Movements of the Shoulder
- Flexion: Anterior fibers of deltoid, pectoralis major, coracobrachialis, biceps brachii
- Extension: Posterior fibers of deltoid, teres major, latissimus dorsi, long head of triceps
- Abduction: Supraspinatus (first 15 degrees), middle fibers of deltoid (up to 90 degrees), scapular movement (beyond 90 degrees—trapezius & serratus anterior)
- Adduction: Subscapularis, pectoralis major, latissimus dorsi, teres major
- Medial rotation: Subscapularis, pectoralis major, latissimus dorsi, teres major
- Lateral rotation: Infraspinatus, teres minor, posterior fibers of deltoid
Clinical Anatomy-Shoulder Dislocation
- Anterior dislocation of the glenohumeral joint most common in athletes
- Usually caused by excessive extension and lateral rotation of humerus
- Hard blow to humerus with abducted glenohumeral joint can tilt humeral head inferiorly, dislocating it
Immediate Symptoms of Shoulder Dislocation
- Immediate swelling within the shoulder region
- Extremely difficult shoulder movements due to pain and weakness (axillary nerve injury)
- Loss of abduction from 15 to 90 degrees (deltoid), weak lateral rotation (teres minor)
- Pins and needles on upper arm skin due to injury to upper lateral cutaneous nerve of the arm (branch of axillary nerve)
Arm Muscles (Anterior)
- Coracobrachialis
- Biceps brachii
- Brachialis
- Nerve supply: Musculocutaneous nerve
- Action: Flexion of elbow joint
Arm Muscles (Posterior)
- Triceps brachii
- Nerve supply: Radial nerve
- Action: Extension of elbow joint
Musculocutaneous Nerve
- Branch of lateral cord (C5, C6, C7)
- Enters arm by penetrating coracobrachialis muscle
- Appears laterally to biceps tendon at elbow
- Penetrates deep fascia, continuing as lateral cutaneous nerve of forearm
- Supplies coracobrachialis, biceps, and brachialis muscles and skin of lateral forearm
Brachial Artery
- Continuation of axillary artery at lower border of teres major muscle
- Main arterial supply to arm
- Terminates at neck of radius, dividing into radial and ulnar arteries
- Branches: Profunda brachii, superior ulnar collateral, inferior ulnar collateral, radial, ulnar
Cubital Fossa
- Triangular depression anterior to elbow joint
- Laterally: brachioradialis muscle
- Medially: pronator teres muscle
- Base: imaginary horizontal line between medial and lateral epicondyles
Cubital Fossa-Roof and Floor
- Roof: Skin, superficial fascia, median cubital vein, bicipital aponeurosis
- Floor: Brachialis and supinator muscles
Contents of Cubital Fossa
- Radial nerve laterally
- Biceps tendon
- Brachial artery with terminal branches (radial and ulnar arteries)
- Median nerve medially
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Description
Test your knowledge on the anatomy of the shoulder joint, including its structure, ligaments, and the glenoid labrum. This quiz will cover key anatomical features and their functions essential for understanding shoulder mechanics.
