The Anatomy of the Elbow, Wrist and Hand

I thought I'd cover these three joints in one piece as they are already similar to the ones we have covered in previous entries, so by now you should be familiar with the type of joints we have.

Lets begin with the elbow joint...

The elbow is made up of three bones.  We have the humerus (upper arm), ulna and radius (bones of lower arm).  The articulation between the distal end of the humerus and the proximal end of the ulna means like the knee it is a synovial hinge joint and aids movements such as flexion and extension.  However unlike the knee it doesn't aid movements such as medial and lateral rotation as those movements occur at the shoulder joint.  Now like all bones it is possible to dislocate the elbow joint and what happens is the humerus shunts forwards and sits on the superior anterior surface of the ulna.  Not pretty right...

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Well let me run a few bony prominences past you to help you understand the structure further.  The elbow bone is anatomically referred to as the olecranon.  Along with the olecranon we have a medial and lateral epicondyle which are the bony surfaces of the elbow found on either side of the elbow joint.  I presume the term 'funny bone' rings a bell with you.  In case you're confused, it's that really annoying tingling sensation you can feel sometimes when you hit the medial aspect of your elbow against something.  What essentially happens is when you strike the medial epicondyle, the ulnar nerve causes this tingling sensation of the inside of your elbow.  The reason it's so easy to strike your 'funny bone' is because it protrudes posterior to the humerus and makes it easier to strike in comparison to the lateral epicondyle.

The elbow also consists of numerous ligaments similar to the knee.  Firstly we have internal ligaments known as our ulna collateral ligament and radial collateral ligament.  These ligaments connect our ulna and radius to our humerus and maintain lateral and medial stability of the joint.  We also have an external ligament called our annular ligament which wraps around the anterior aspect of the radius and attaches to the ulna, aiding stability in the joint.  This allows movements such as pronation and supination to occur.  These movements occur in our radioulnar joint which is a pivot joint.

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Pronation is palm downward (radius crosses over ulna)
Supination is palm upward

The annular ligament aids the pronation between the joint, allowing the radius to cross over the ulna as shown in the picture (right).  We then have two more joints on the posterior surface of the humerus and ulna called the humeroulnar joint and we also have a joint between the humerus and radius called the humeroradial joint.  These joints prevent our elbow falling into hyper extension.

At the wrist we have two more bony prominences which can be palpated on the medial and lateral aspect.  These are called our styloid processes also referred to as our ulnarstyloid and radialstyloid processes.  We then have our scaphoid process which is the first carpal in our hand and can be palpated when we extend our fingers laterally to the tendon in our thumb.  It's a common injury that can occur in our everyday lives, and usually as a result of falling and landing on the palm of our hands.  This sort of injury can take a while to heal due to the bad blood supply to the bone and often requires surgery.  The movements we get at the wrist are flexion, extension, abduction and adduction. 

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In the hand we have our carpals, metacarpals and phalanges.  In total we have eight carpals all with different names which I won't bore you with.  We then have five metacarpals and three phalanges in each finger except the thumb in which we only have two, like the foot.  The opposable thumb allows us to grip, hold and pick up objects, it is a milestone in the evolution of human beings.  Now the joints...

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Well, between each section I just mentioned we have a joint.  The first joint is our radiocarpal joint which can be palpated between the radius and carpals.  We then have our carpometacarpal joint which is located between the carpals and metacarpals.  The third joint we have in the hand is our metacarpophalangeal joint (a mouthful I know) which is located between the metacarpals and the phalanges.  Finally we have interphalangeal joints, just like the foot.  Therefore using anatomic terminology we can distinguish each one.  The joints between our second and third phalanges are our distal interphalangeal joints.  That means the ones between our first and second are our proximal interphalangeal joints.  Now as we know our thumb only has two phalanges so the joint between these two is simply just our interphalangeal joint.

Like the foot the hand has palmer fascia which helps hold everything in place and stretches across the palms of our hands.  As well as palmer fascia our fingers are made up of numerous medial and lateral collateral ligaments connecting each phalangeal bone to eachother. 

The elbow, wrist and hand are very similar to the other joints I've covered in my previous blogs...  In addition to the hand though I'd like to leave you with this thought.  The hand very much similar to the foot is a tool we use every day of our lives.  For example right now as I type this I am putting strain on the tendons and ligaments of my hand, thus having a knock on effect to the muscles that move the tendons in my hand making them tighter and causing muscular imbalances.  We all put strain on the tendons, ligaments and joints of our hands every day yet we forget to aid these joints with therapy.  Similarly to the foot our hands our always under tension, whether it be pulling, pushing, twisting or typing, etc... Most of us forget to do the basic movements such as stretching them.  In order for our anatomical shape to maintain structural integrity it is vital that we give our bodies therapy and medicine through natural basic activities such as stretching.  Whether you find your therapy through yoga, pilates, massage therapy etc... It's vital we give our bodies down time and therapy time!