anatomy of the elbow bony anatomy of the elbow the elbow is made of the humerus the radius and the ulna the lower end of the humerus have two epicondyles the lateral epicondyle and the medial epicondyle and it also has the capitellum laterally and the trochlea medially The proximal ulna is made of the olecranon process, the trochlear notch, and the coronoid process. The bursa lies on top of the olecranon process. The radius is made of the radial head, neck, and radial tuberosity.
The primary stabilizer of the elbow is the unhumeral joint. The cronoid process is the anterior buttress of the olecranon. It prevents posterior dislocation of the elbow. Fracture of the cronoid process more than 50% of the height will lead to elbow instability.
Let's start with the structures on the medial side. The medial elbow ligaments. The medial which is ulnar collateral ligament. The MCL is composed of three bands, the anterior, the posterior, and the transverse bundles.
The anterior band is the strongest primary stabilizer to valgus stress in 90 degree of flexion. The medial collateral ligament originates from the posterior. medial epicondyle of the distal humerus.
It inserts into the sublime tubercle of the medial coronoid process. Late locking and early acceleration will give the highest valgus torque to the medial collateral ligament. Deficiency of this ligament is diagnosed with valgus or moving valgus stress test. The clinical exam of that ligament is not as good as the MRI. MRI is the best study to diagnose complete tear of the MCL of the elbow.
The posterior bundle of the MCL is tight in elbow flexion. If you want to get more flexion of the stiff elbow, release the contracted posterior band. of the medial collateral ligament. What are the muscles on the medial side of the elbow?
It is the pronator teres muscle and the flexor muscle group of the forearm attached to the medial epicondyle. You can also find the ulnar nerve in the cubital tunnel. How about the posterior elbow? You find the posterior elbow muscle, the triceps muscle and tendon, and we also find the bursa, the ulnar bursitis. The lateral collateral ligament consists of several parts.
The lateral ulnar collateral ligament is the important ligament, the lateral radial collateral ligament, the accessory lateral collateral ligament, and the annular ligament. The lateral unarculateral ligament is the key anatomic structure which prevents post-trilateral instability. The lateral unarculateral ligament acts like a sling for the radial head. It is located in the post-trilateral aspect of the radial head.
It arises from the lateral humeral epicondyle. and it inserts into the crista subinators of the proximal anna. The postrolateral rotatory instability of the elbow occurs with the lateral anacolateral ligament deficiency. It is diagnosed as a pivot shift.
The test includes axial load, spination, and valgus. Impaction fracture of the intermedial cronoid facet is usually associated with lateral collateral ligament tear. This will lead to post-intermedial instability of the elbow.
Sometimes this fracture is not easily seen on x-rays, and it can be missed. Fracture of the cronoid process can also be a part of the terrible elbow triad, an elbow dislocation associated with a cronoid fracture and radial head fracture. So what are the muscles on the lateral side?
The muscles on the lateral side are the common extensor tendon muscles, which is the extensor carbi radialis longus and brevis, extensor digitorum muscle, extensor carbi and narus muscle. How about the anterior elbow? What do you find in the anterior elbow?
The most important thing you will find is the cubital fossa. You find the pronator teres and the brachioradialis. You find the biceps.
Lateral to the biceps is the radial nerve. Medial to the biceps is the brachial artery and the median nerve. You will find that the biceps is inserted into the radial tuberosity and above the biceps.
is the radial recurrent arteries. You will find also the branch from the musculocutaneous nerve, which is the lateral antebrachial cutaneous nerve, which is commonly injured in distal bicep surgery. Thank you very much. I hope that was helpful.