Elbow Region: General Principles

00:01 The elbow is an important hinge joint located on the upper extremity.

00:04 It bridges the shoulder and the hands and the main function of the elbow is to position and maximally stabilize the hand when you try to perform task and when you try to do anything such as work.

00:16 So on the dorsal surface, you can note that there is a cubital fossa and frequently this is where you would check for access when you're drawing blood and for venipunctures.

00:27 Posteriorly, this is where you'll find the triceps tendon when you're testing for a motor function of the triceps and also you'll find the ulnar groove where the ulnar nerve passes through.

00:39 So the elbow joint consist of articulations between the humerus and two bones in the forearm, the ulna and the radius This is primarily a hinge joint, so the ulna and humerus primarily do flexion and extension there.

00:53 The radius articulates with the capitulum of the humerus and the ulna articulates with the trochlea.

01:01 So there are many ligaments that helps to support and stabilize the elbow joint.

01:07 There is the medial ulnar collateral ligament on the medial aspect.

01:12 We have the lateral collateral ligament on the lateral aspect and then you have a lateral ligament of the radius which kinda wraps around that radial head and helps to stabilize the radius and the elbow joint.

01:27 There's a interosseous membrane that lies between the ulna and the radius a lot of blood vessels, nerves, may transport through there.

01:35 The fibers vary in different orientation and it helps to stabilize the ulna and the radius.

01:41 This is also an important site for lymphatic drainage of the upper extremity any sort of twist, restrictions may potentially decrease lymphatic drainage from the upper extremities and the hand.

01:52 So the two basic motions of the elbow include flexion and extension.

01:56 So the major muscles that help with ulnar-humeral flexion include the brachialis, brachioradialis and biceps brachii.

02:05 So the brachialis is more on the lower side of the humerus and inserts into the tuberosity of the ulna while the brachioradialis also supinates slightly during extreme pronation The brachiaradialis is one of those muscles that we test for reflexes, checking for C5.

02:26 The biceps brachii is the main elbow flexors.

02:29 It also has properties to supinate based on its attachment on the coracoid process The brachialis is the main muscle used when the elbow is flexed slowly.

02:40 The other function of the elbow is extension.

02:43 So the main muscle that helps with that is the triceps muscle.

02:46 There's some help with the anconeus muscle but the triceps really is main extensor of the elbow It has attachments from the shoulder and so motion of the shoulder and position of the shoulder will affect it's efficiency.

03:01 If you have hyperextension, there is risk of injuring and damaging the olecranon.

03:06 You could also tear capsules and ligaments in the region and sometimes you could also damage the blood vessels in the region.

03:14 So when discussing motion testing at the elbow joint, we have two main motions.

03:20 We could talk about flexion and extension and then we could also talk about supination and pronation.

03:25 which is the articulation between the ulna and the radius.

03:29 So the normal range for extension is 0 to 5 degrees so when we talk about the anatomical neutral position, this is our anatomical neutral where our elbow is extended and so extension of the elbow is 0.

03:46 Flexion then could come up all the way to about a 130-145 degrees with active range of motion.

03:54 If I then possibly try to push the elbow further into flexion, you could get to about maybe 150 - 160 degrees.

04:03 Pronation and Supination.

04:05 Pronation you get average about 75 degrees of pronation is with your hands in a vertical position, you're going to bring your palm facing towards the floor.

04:17 Supination is going the other way, we're gonna bring your palms facing the ceiling.

04:22 A simple way to remember supination is that in order to hold a bowl of soup, you have to turn your palm facing up.

04:28 And so supination is usually a little bit more than pronation about 85 degrees.

04:33 So there is limited motion in the coronal plane at the elbow.

04:37 The elbow based on anatomy is more flexion and extension and since as a hinge joint, it has very little lateral and medial motion Valgus motion is the motion named when the forearm and the hand moves a little bit more laterally.

04:51 The motion is coupled with forearm ABduction in supination and is the movement of the hand and forearm away from the body.

04:59 The simple way to remember valgus is that there's a letter "L" in the word.

05:03 And so when you're kind of bringing the hand further away, it sort of makes a letter L.

05:07 Varus is the other motion.

05:09 So varus motion is coupled with forearm ADduction and pronation and that is the movement of the forearm and hand towards the body, a little bit more medial.

05:19 So everybody has a carrying angle.

05:21 So when we're on anatomical neutral, our elbow will valgus a little bit more.

05:26 Normally you have 5 to 15 degrees of valgus.

05:29 Males is a little bit less than females, this is due to the shape of our different articulating surfaces and allows the elbow to fit more closely to the waist.

05:41 Sometimes you may have abnormality in that carrying angle, so Gunstock deformity is also called Cubitus varus So here, the elbow is stuck more in a varus position as opposed to valgus.

05:55 Sometimes this could be due to a fracture at the supracondylar or the epicondylar region.

06:02 So there are 2 main articulations at the elbow joint, flexion and extension occurs about the elbow joint, that's the true elbow joint, it's a hinge joint and it's the articulation between humeral trochlea and ulnar trochlear notch.

06:17 Pronation and supination motion of the forearm is considered elbow motion but it really is a motion of the radius and ulna articulating over each other.

06:28 So in supination, our ulnar radius are gonna be straight and then in pronation, the ulna is going to cross over the radius bone.

06:39 The epicondyles are where most of the muscles in the forearm originate.

06:43 The medial epicondyle primarily has attachment of the flexor muscles and the pronator muscles whereas the lateral epicondyle usually has the extensors and supinator muscles.

06:55 This is important to remember because different pathologies of the wrist and elbow could be traced back anatomically to the origin and insertion of these muscles.