Elbow Joint: Bones, Muscles & Movement - Human Anatomy | Kenhub

Summary

This detailed tutorial explores the anatomy and function of the elbow joint, highlighting the three bones that form it: the humerus, ulna, and radius. It delves into the joint's structure, including the synovial membrane, ligaments, and muscles that enable movement. The elbow is classified as a hinge joint, allowing flexion and extension, with additional support from key ligaments like the ulnar and radial collateral ligaments. The video also covers common clinical issues such as radial head fractures and osteoarthritis, making it a comprehensive resource for students studying elbow anatomy and related injuries.

Takeaways

• 😀 The elbow joint is a synovial hinge joint formed by three bones: the humerus, ulna, and radius.
• 😀 The humerus has key landmarks like the medial and lateral epicondyles, the trochlea, and the capitulum which interact with the ulna and radius.
• 😀 The ulna is the stabilizing bone of the forearm, with important features such as the trochlear notch and coronoid process for articulation with the humerus.
• 😀 The radius has a concave head that articulates with the capitulum of the humerus and the radial notch of the ulna.
• 😀 The elbow joint allows primarily for flexion and extension but also plays a role in pronation and supination through the proximal radioulnar joint.
• 😀 Muscles responsible for flexion include the biceps brachii and brachialis, while extension is controlled by the triceps brachii.
• 😀 The elbow joint has a complex arrangement of ligaments, including the ulnar collateral ligament (UCL), radial collateral ligament, and annular ligament.
• 😀 The elbow joint is surrounded by an articular capsule filled with synovial fluid to lubricate the joint and facilitate smooth movement.
• 😀 Common injuries to the elbow include radial head fractures, dislocations, and the 'terrible triad,' which involves fractures of the ulna and radius with dislocations.
• 😀 The elbow joint is supplied by blood from the brachial, deep brachial, radial, and ulnar arteries, and is innervated by branches of the musculocutaneous, median, radial, and ulnar nerves.
• 😀 The elbow's structure allows it to perform a hinge movement, but due to its ligaments and joint design, it also supports rotational movement at the proximal radioulnar joint.

Q & A

What bones make up the elbow joint?

The elbow joint is formed by three bones: the humerus (upper arm), the ulna (larger bone of the forearm), and the radius (smaller bone of the forearm).

What is the role of the humerus in the elbow joint?

The humerus contributes to the elbow joint with its distal end, which includes the trochlea that articulates with the ulna and the capitulum that articulates with the radius.

How does the ulna contribute to the elbow joint?

The ulna's proximal end features the trochlear notch, which fits into the humerus' trochlea, and the olecranon process that fits into the olecranon fossa of the humerus to provide stability.

What type of joint is the elbow joint, and what movements does it allow?

The elbow joint is a synovial hinge joint, allowing primarily for flexion and extension movements.

How do the radius and ulna interact at the elbow joint?

The radius articulates with the humerus via the capitulum and with the ulna at the radial notch. The ulna and radius are connected by the annular ligament, which holds the radius in place and allows for rotation during supination and pronation.

What are the primary muscles responsible for elbow flexion?

The primary muscles responsible for elbow flexion are the biceps brachii and brachialis. The brachioradialis also assists in flexion, particularly when there is resistance.

Which muscle is the chief extensor of the elbow?

The chief extensor of the elbow is the triceps brachii, with assistance from the anconeus muscle.

What are the key ligaments that stabilize the elbow joint?

The key ligaments stabilizing the elbow joint are the ulnar collateral ligament (medial), radial collateral ligament (lateral), and annular ligament, which secures the radius to the ulna.

What is the role of synovial fluid in the elbow joint?

Synovial fluid lubricates the elbow joint, reducing friction between the articulating surfaces of the bones and allowing smooth movement.

What are some common injuries associated with the elbow joint?

Common injuries at the elbow joint include radial head fractures, often from falls on an outstretched arm, and anterior dislocations of the radius. A more severe injury is the 'terrible triad,' which involves fractures of the coronoid process of the ulna, the head of the radius, and posterior dislocation of the proximal radioulnar joint.