Apparato locomotore 33: Muscoli della Spalla

Summary

This video explores the anatomy of the shoulder muscles, focusing on the connections between the shoulder girdle and the humerus. It highlights key muscles, including the deltoid, supraspinatus, infraspinatus, teres minor, teres major, and subscapularis, detailing their origins, insertions, and actions. The deltoid is emphasized for its role in arm abduction, while the supraspinatus contributes to stabilization and external rotation. Each muscle's unique contribution to shoulder movement and stability is thoroughly analyzed, making it an essential guide for understanding shoulder anatomy.

Takeaways

• 😀 The shoulder muscles connect the scapula to the humerus, facilitating essential arm movements.
• 💪 The deltoid muscle is large and triangular, crucial for arm abduction up to 90°.
• 🔄 The anterior fibers of the deltoid flex and internally rotate the humerus, while the posterior fibers extend and externally rotate it.
• 🔝 The supraspinatus muscle initiates arm abduction and externally rotates the humerus, also stabilizing the shoulder joint.
• 🔄 The infraspinatus muscle primarily externally rotates the arm and reinforces shoulder joint stability.
• ⚙️ The teres minor, located beneath the infraspinatus, aids in external rotation of the arm.
• 🔼 The teres major adducts and internally rotates the humerus, contributing to shoulder movements.
• 🏋️‍♂️ The subscapularis muscle adducts and internally rotates the arm while stabilizing the shoulder joint.
• 📏 The deltoid muscle originates from the spine and acromion, while the supraspinatus originates from the supraspinous fossa.
• 🧠 This video uses Anatomy Learning, a web application that provides valuable insights into human anatomy.

Q & A

What is the primary muscle analyzed in the video?

The primary muscle analyzed in the video is the deltoid muscle.

Where does the deltoid muscle originate?

The deltoid muscle originates from the outer two-thirds of the spine of the scapula, the acromion, and the lateral third of the clavicle.

What action does the deltoid muscle perform?

The deltoid muscle abducts the humerus by about 90 degrees and assists in flexion, internal rotation, extension, and external rotation depending on the muscle fibers.

What are the main functions of the supraspinatus muscle?

The supraspinatus muscle abducts the humerus and externally rotates it, while also stabilizing the glenohumeral joint.

Which muscles are located beneath the infraspinatus muscle?

The teres minor and teres major muscles are located beneath the infraspinatus muscle.

What is the function of the teres major muscle?

The teres major muscle adducts and internally rotates the humerus.

How does the infraspinatus muscle contribute to shoulder stability?

The infraspinatus muscle stabilizes the glenohumeral joint while also externally rotating the humerus.

What is the role of the subscapularis muscle?

The subscapularis muscle adducts and internally rotates the humerus and helps stabilize the shoulder joint.

What anatomical feature does the term 'triangular space' refer to?

The triangular space refers to the area formed by the teres minor, teres major, and the humerus.

What web application is mentioned for learning anatomy?

The video mentions 'Anatomy Learning' as a web application for studying anatomy.