BLOCK 3: AHE: (3.2) PART 2: MUSCLES OF THE SHOULDER AND ARM

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Questions and Answers

Which muscle primarily assists in the lateral rotation of the upper limb?

Teres Major

Triceps Brachii

Infraspinatus (correct)

Subscapularis

What is a common result of rotator cuff disorders?

Inability to flex the elbow

Difficulty lifting the arm above the head (correct)

Numbness in the lower arm

Increased range of motion in the shoulder

Which anatomical structure is primarily associated with the acromioclavicular joint's limited space?

Scapular spine

Coracoclavicular ligament (correct)

Glenohumeral ligaments

Supraspinatus muscle

Which of the following best describes how arm muscles are organized within the brachial fascia?

Into two compartments Signup and view all the answers

What effect can repeated trauma to the rotator cuff have on athletic performance?

Possible impingement and pain Signup and view all the answers

What occurs if excessive fluid builds up around the shoulder structures?

Impingement of vessels and nerves Signup and view all the answers

Which muscle is critical for arm abduction and may be affected in rotator cuff disorders?

Supraspinatus Signup and view all the answers

Which muscle separates the teres major from the teres minor?

Triceps Brachii Signup and view all the answers

Which muscle is primarily responsible for abducting the arm?

Supraspinatus Signup and view all the answers

What is the primary action of the teres minor and infraspinatus muscles?

Lateral rotation of the arm Signup and view all the answers

Which muscle is NOT considered a part of the rotator cuff?

Teres Major Signup and view all the answers

The attachment location of which muscle helps in the stabilization of the upper limb?

Subscapularis Signup and view all the answers

What shared action is performed by the teres major and latissimus dorsi?

Medial rotation of the arm Signup and view all the answers

What primary action does the pectoralis major muscle facilitate at the shoulder joint?

Medial rotation of the humerus Signup and view all the answers

Which muscle is primarily responsible for stabilizing the clavicle?

Subclavius Signup and view all the answers

Which muscle sits in the subscapular fossa?

Subscapularis Signup and view all the answers

Compartment syndrome in the arm is most likely associated with which of the following?

Increased pressure within muscle compartments Signup and view all the answers

Which muscle is involved in pulling the scapula toward the rib cage?

Serratus anterior Signup and view all the answers

Which nerve is primarily responsible for the innervation of the supraspinatus muscle?

Suprascapular nerve Signup and view all the answers

What is a potential clinical implication of injuries to the muscles attached to the scapula?

Impaired stabilization of the humerus Signup and view all the answers

Which muscles assist in the elevation and support of the upper limb?

Trapezius and levator scapulae Signup and view all the answers

Which muscle's action includes depressing the clavicle?

Subclavius Signup and view all the answers

What is a common characteristic of rotator cuff disorders?

Weakness or pain in shoulder movements Signup and view all the answers

Which area of the arm is most affected by compartment syndrome?

Forearm Signup and view all the answers

Study Notes

Shoulder and Arm Muscles

Rotator Cuff:
- Key Muscles: Supraspinatus, Infraspinatus, Teres Minor, Subscapularis
- Function: Stabilize and rotate the shoulder joint
Supraspinatus:
- Location: Above the spine of the scapula
- Action: Abducts the arm (raises the arm above the head)
Infraspinatus:
- Location: Below the spine of the scapula
- Action: Laterally rotates the arm
Teres Minor:
- Location: Below the Infraspinatus
- Action: Laterally rotates the arm
Subscapularis:
- Location: Anterior surface of the scapula
- Action: Medially rotates and helps stabilize the arm
Clinical Correlation:
- Rotator cuff injuries are common due to repetitive arm usage.
- Swelling and impingement of vessels and nerves can occur, especially in the space between the acromion and the clavicle.
Pectoralis major:
- Location: Chest
- Action: Flexes and medially rotates the arm
Pectoralis minor:
- Location: Deep to pectoralis major
- Action: Depresses and protracts the scapula
Subclavius:
- Location: Between the clavicle and the first rib
- Action: Depresses and stabilizes the clavicle
Serratus Anterior:
- Location: Anterior aspect of the scapula
- Action: Protracts and stabilizes the scapula
Trapezius, Rhomboids, and Levator Scapulae:
- Function: Support and move the upper limb
- Not covered in detail as they were previously introduced
Scapula-Humeral Joints:
- Include muscles that cross the shoulder joint
- Directly connect the posterior axis to the upper limb
Deltoid:
- Action: Abducts the arm
- Location: Not explicitly described in this text, but is a common shoulder muscle
Brachial Fascia:
- Encases the muscles of the arm
- Contains two compartments: anterior and posterior
- Anterior compartment: Flexors
- Posterior compartment: Extensors
Importance of Limb Rotation during Development:
- Explains the arrangement of flexors and extensors in the arm
Greater Tuberosity:
- Located on the humerus, where the supraspinatus, infraspinatus, and teres minor muscles attach
Lesser Tuberosity:
- Located on the humerus, where the subscapularis muscle attaches
Coracoid Process:
- Located on the scapula, where the pectoralis minor and short head of the biceps brachii muscles attach
Landmark Identification:
- The triceps brachii muscle splits the teres major and teres minor.
- The spine of the scapula helps determine muscle location (above = supraspinatus, below = infraspinatus).

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Description

Test your knowledge about the anatomy and functions of the shoulder and arm muscles, including key muscles of the rotator cuff. This quiz covers muscle locations, actions, and common clinical correlations related to injuries. Discover how these muscles work together to stabilize and move the arm.