Humerus and Scapula: Anatomy, Definition, Ligaments & Bones | Kenhub

Kenhub - Learn Human Anatomy・2 minutes read

Dislocated shoulders can be easily fixed with the right technique, despite dramatic portrayals in media. Understanding the anatomy of the humerus and scapula is crucial for comprehending the structure and function of the shoulder joint.

Insights

  • Dislocated shoulders are often portrayed dramatically, but in reality, they can be easily fixed with the right technique, emphasizing the importance of proper knowledge and approach in managing such injuries.
  • Understanding the detailed anatomy of the humerus and scapula is essential for grasping the complexity and function of the shoulder joint, highlighting the significance of structural nuances in maintaining joint stability and mobility.

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Recent questions

  • What structures form the shoulder joint?

    Humerus and scapula articulate to form the joint.

  • What are the key features of the humerus?

    Humerus has distinct structures like tubercles and necks.

  • What defines the structure of the scapula?

    Scapula has angles, borders, and distinct surfaces.

  • How does the scapula connect to the clavicle?

    Acromion of scapula articulates with clavicle at joint.

  • What supports the humerus head in the shoulder joint?

    Rotator cuff muscles provide support to the head.

Related videos

Summary

00:00

Shoulder Joint Anatomy: Humerus and Scapula

  • Dislocated shoulders are often portrayed dramatically in movies and TV shows, but in reality, they can be fixed with minimal effort and the right technique.
  • The shoulder joint is formed by the articulation of the humerus and scapula, known as the glenohumeral joint, and is highly flexible but also unstable.
  • The humerus has distinct structures such as the head, greater tubercle, lesser tubercle, and necks (anatomical and surgical) that play crucial roles in its function.
  • The shaft of the humerus has features like the deltoid tuberosity, radial fossa, coronoid fossa, capitulum, and trochlea, which articulate with other bones and muscles in the arm.
  • The humerus also has landmarks like the medial and lateral epicondyles, medial and lateral supracondylar ridges, and the radial groove for the radial nerve.
  • The scapula, or shoulder blade, has three angles (inferior, superior, and lateral) and three borders (medial, lateral, and superior) that define its structure.
  • The scapula's anterior surface features the subscapular fossa, costal surface, and coracoid process, which serves as an attachment site for various muscles.
  • The posterior aspect of the scapula includes the spine, supraspinous fossa, and infraspinous fossa, which provide attachment for muscles like the rotator cuff.
  • The body of the scapula is thin and translucent, allowing light to pass through, showcasing its delicate nature.
  • Understanding the anatomy and landmarks of the humerus and scapula is essential for comprehending the structure and function of the shoulder joint.

15:27

Anatomy of the Scapula and Shoulder Joint

  • The scapula has thickened medial and lateral borders, with the body sandwiched between the subscapularis and infraspinatus muscles.
  • The spine of the scapula has a triangular base medially and terminates in a large flattened process known as the acromion.
  • The acromion articulates with the acromial end of the clavicle bone at the acromioclavicular joint, crucial for shoulder joint positioning.
  • The glenoid cavity on the scapula articulates with the head of the humerus to form the glenohumeral joint, a ball-and-socket joint.
  • Support for the humerus head is provided by the rotator cuff muscles due to the shallow and barely concave glenoid cavity.
  • Bony landmarks near the glenoid cavity include the supraglenoid tubercle and infraglenoid tubercle for muscle attachments.
  • The scapular spine base aligns with the third or fourth thoracic vertebrae, the inferior angle between ribs seven and eight, and the medial margin parallel to the spinous processes in the abducted arm position.
  • Ligaments related to the scapula and humerus include the coracoclavicular ligament, coracoacromial ligament, and glenohumeral ligaments, crucial for joint stabilization.
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