Elbow Tumors
Normal Elbow and Forearm Anatomy
The elbow and forearm form a functional unit whose primary role is to accurately position the hand in space. The elbow has a long lever arm and moves the forearm and hand 130 degrees covering much of the functional space used in our activities of daily living and in this sense the elbow is considered the most important single joint of the upper limb, second only to the thumb carpometacarpal joint. The functional space is defined as the space directly in front of a person’s body that lies below eye level and above the belly button. Because the elbow joint covers the entire functional space by virtue of its arc of motion, there has never been a satisfactory position to fuse an elbow joint if it were ever destroyed by injury or disease.
The elbow anatomy is best understood by thinking of it in three layers. The first layer is the bony layer, the second layer is the ligament layer and the third layer is the muscular layer within which the arteries and nerves travel.
Elbow & Forearm Elbow Joint Front View & Side View
The first layer is comprised of three bones that unite to form the elbow joint. The elbow joint is located at the lower end of the arm bone (humerus), and the proximal end (towards the shoulder) of the radius and ulna which are the two forearm bones. These three bones allow the elbow to bend (Flex) and straighten (Extend) in a hinged type motion and the forearm to rotate the hand in a palm up (supination) and palm down position (pronation). The joint surfaces of the elbow are covered by hyaline cartilage which forms a cushioned layer that allows for smooth gliding and painless elbow motion.
Elbow & Forearm Ligament LayerElbow Joint Ligament Layer
Lateral Elbow Ligament View Medial Elbow Ligament View
The second layer in the elbow and forearm is the capsular ligament layer made up of collagen tissue. The ligament layer in the forearm is called the interosseous membrane. The collagen tissue forming the elbow joint capsule is normally very thin except on the inside (medial) and outside (Lateral) sides of the elbow where thickenings in the collagen substance form the ligaments of the elbow. These ligaments provide passive stability to the elbow joint keeping the humerus, radius and ulna together, allowing them to function as a unit.
Foerarm Flexor CompartmentForearm Flexor & Mobile Wad Compartments
Elbow Flexor Muscles Elbow Extensor Muscles
The third layer of the elbow and forearm is the muscle layer and is formed by the various muscle groups that pass through the elbow and forearm either originating (beginning) or ending in the elbow and forearm. The muscles of the arm that pass through the elbow include the triceps muscle in the back of the arm and the brachialis and biceps muscles in the front of the arm. The forearm muscles that cross the elbow joint are divided into three compartments with each compartment containing several muscles that work to move the elbow, forearm, wrist and hand in specific directions. The three compartments are: 1. the extensor compartment 2. the flexor compartment and 3. the mobile wad of Henry compartment. The median, ulnar, and radial nerves pass through the elbow and forearm within the muscle layers and innervate the muscles within these compartments as well as, the muscles of the hand.
Pathology
Tumors are divided into benign and malignant types. A benign tumor is an abnormal growth of a particular cell type presenting as a mass. The benign tumor is normally excised when the size of he mass is large enough to put pressure on the surrounding tissue and cause pain or when the mass is cosmetically unsightly. Malignant tumors which bear the common name of cancer are those tumors that divide aggressively and destroy the tissue planes around them and eventually metastasize or travel to other parts of the body. The only tumors treated at ROC about the elbow are benign tumors whichinclude lipomas or fatty tumors that cause symptoms due to their large size, articular (joint) ganglion cysts that commonly develop in patients with rheumatoid arthritis, and bony tumors like osteochondromatosis, or heterotopic ossification whose presence causes pain due to the space occupying effect. Malignant tumors about the elbow are referred to MD Anderson because of their expertise and success in handling malignant tumors with a team approach and because of their proximity to our office.
Treatment
Benign tumors about the elbow are treated by simple excision. If tumor excision requires deep dissection to the joint, therapy after surgery to avoid an elbow contracture is often used. Most benign soft tissue tumors excised about the elbow have full return of elbow function within four weeks of surgery.