elbow extended, the long axis of the humerus and that of the ulna coincide. at the same time, the articular surfaces on both bones are located in front of those axes and deviate from them at an angle of 45°. additionally, the forearm muscles that originate at the elbow are grouped at the sides of the joint in order not to interfere with its movement. the wide angle of flexion at the elbow made possible by this arrangement — almost 180° — allows the bones to be brought almost in parallel to each other. carrying angle normal radiograph; right picture of the straightened arm shows the carrying angle of the elbow when the arm is extended, with the palm facing forward or up, the bones of the upper arm (humerus) and forearm (radius and ulna) are not perfectly aligned. the deviation from a straight line occurs in the direction of the thumb, and is referred to as the "carrying angle". the carrying angle permits the arm to be swung without contacting the hips. women on average have smaller shoulders and wider hips than men, which tends to produce a larger carrying angle (i.e., larger deviation from a straight line than that in men). there is, however, extensive overlap in the carrying angle between individual men and women, and a sex-bias has not been consistently observed in scientific studies. the angle is greater in the dominant limb than the non-dominant limb of both sexes, suggesting that natural forces acting on the elbow modify the carrying angle. developmental, aging and possibly racial influences add further to the variability of this parameter. pathology left: lateral x ray of a dislocated right elbowright: ap x ray of a dislocated right elbow the types of disease most commonly seen at the elbow are due to injury. tendonitis two of the most common injuries at the elbow are overuse injuries: tennis elbow and golfer's elbow. golfer's elbow involves the tendon of the common flexor origin which originates at the medial epicondyle of the humerus (the "inside" of the elbow). tennis elbow is the equivalent injury, but at the common extensor origin (the lateral epicondyle of the humerus). fractures there are three bones at the elbow joint, and any combination of these bones may be involved in a fracture of the elbow. patients who are able to fully extend their arm at the elbow are unlikely to have a fracture (98% certainty) and an x-ray is not required as long as an olecranon fracture is ruled out. acute fractures may not be easily visible on x-ray. dislocation x-ray of ventral dislocation of the radial head. there is calcification of annular ligament, which can be seen as early as 2 weeks after injury. elbow dislocations constitute 10% to 25% of all injuries to the elbow. the elbow is one of the most commonly dislocated joints in the body, with an average annual incidence of acute dislocation of 6 per 100,000 persons. among injuries to the upper extremity, dislocation of the elbow is second only to a dislocated shoulder. a full dislocation of the elbow will require expert medical attention to re-align, and recovery can take approximately 8–14 weeks. infection infection of the elbow joint (septic arthritis) is uncommon. it may occur spontaneously, but may also occur in relation to surgery or infection elsewhere in the body (for example, endocarditis). arthritis elbow arthritis is usually seen in individuals with rheumatoid arthritis or after fractures that involve the joint itself. when the damage to the joint is severe, fascial arthroplasty or elbow joint replacement may be considered. bursitis main article: olecranon bursitis olecranon bursitis, tenderness, warmth, swelling, pain in both flexion and extension-in chronic case great flexion-is extremely painful. elbow pain main article: elbow pain elbow pain occurs when the tenderness of the tissues in the elbow become inflamed. frequent exercise of the inflamed elbow will assist with healing. clinical significance elbow pain can occur for a multitude of reasons, including injury, disease, and other conditions. common conditions include tennis elbow, golfer's elbow, distal radioulnar joint rheumatoid arthritis, and cubital tunnel syndrome. tennis elbow tennis elbow is a very common type of overuse injury. it can occur both from chronic repetitive motions of the hand and forearm, and from trauma to the same areas. these repetitions can injure the tendons that connect the extensor supinator muscles (which rotate and extend the forearm) to the olecranon process (also known as “the elbow”). pain occurs, often radiating from the lateral forearm. weakness, numbness, and stiffness are also very common, along with tenderness upon touch. a non-invasive treatment for pain management is rest. if achieving rest is an issue, a wrist brace can also be worn. this keeps the wrist in flexion, thereby relieving the extensor muscles and allowing rest. ice, heat, ultrasound, steroid injections, and compression can also help alleviate pain. after the pain has been reduced, exercise therapy is important to prevent injury in the future. exercises should be low velocity, and weight should increase progressively. stretching the flexors and extensors is helpful, as are strengthening exercises. massage can also be useful, focusing on the extensor trigger points. golfer’s elbow golfer's elbow is very similar to tennis elbow, but less common. it is caused by overuse and repetitive motions like a golf swing. it can also be caused by trauma. wrist flexion and pronation (rotating of the forearm) causes irritation to the tendons near the medial epicondyle of the elbow. it can cause pain, stiffness, loss of sensation, and weakness radiating from the inside of the elbow to the fingers. rest is the primary intervention for this injury. ice, pain medication, steroid injections, strengthening exercises, and avoiding any aggravating activities can also help. surgery is a last resort, and rarely used. exercises should focus on strengthening and stretching the forearm, and utilizing proper form when performing movements. rheumatoid arthritis rheumatoid arthritis is a chronic disease that affects joints. it is very common in the wrist, and is most common at the radioulnar joint. it results in pain, stiffness, and deformities. there are many different treatments for rheumatoid arthritis, and there is no one consensus for which methods are best. most common treatments include wrist splints, surgery, physical and occupational therapy, and antirheumatic medication. cubital tunnel syndrome cubital tunnel syndrome, more commonly known as ulnar neuropathy, occurs when the ulnar nerve is irritated and becomes inflamed. this can often happen where the ulnar nerve is most superficial, at the elbow. the ulnar nerve passes over the elbow, at the area known as the “funny bone”. irritation can occur due to constant, repeated stress and pressure at this area, or from a trauma. it can also occur due to bone deformities, and oftentimes from sports. symptoms include tingling, numbness, and weakness, along with pain. first line pain management techniques include the use of nonsteroidal anti-inflammatory oral medicines. these help to reduce inflammation, pressure, and irritation of the nerve and around the nerve. other simple fixes include learning more ergonomically friendly habits that can help prevent nerve impingement and irritation in the future. protective equipment can also be very helpful. examples of this include a protective elbow pad, and an arm splint. more serious cases often involve surgery, in which the nerve or the surrounding tissue is moved to relieve the pressure. recovery from surgery can take awhile, but the prognosis is often a good one. recovery often includes movement restrictions, and range of motion activities, and can last a few months (cubital and radial tunnel syndrome, 2). society and culture the now obsolete length unit ell relates closely to the elbow. this becomes especially visible when considering the germanic origins of both words, elle (ell, defined as the length of a male forearm from elbow to fingertips) and ellbogen (elbow). it is unknown when or why the second "l" was dropped from english usage of the word. the ell as in the english measure could also be taken to come from the letter l, being bent at right angles, as an elbow. the ell as a measure was taken as six handbreadths; three to the elbow and three from the elbow to the shoulder. another measure was the cubit (from cubital). this was taken to be the length of a man's arm from the elbow to the end of the middle finger. other primates though the elbow is similarly adapted for stability through a wide range of pronation-supination and flexion-extension in all apes, there are some minor difference. in arboreal apes such as orangutans, the large forearm muscles originating on the epicondyles of the humerus generate significant transverse forces on the elbow joint. the structure to resist these forces is a pronounced keel on the trochlear notch on the ulna, which is more flattened in, for example, humans and gorillas. in knuckle-walkers, on the other hand, the elbow has to deal with large vertical loads passing through extended forearms and the joint is therefore more expanded to provide larger articular surfaces perpendicular to those forces. derived traits in catarrhini (apes and old world monkeys) elbows include the loss of the entepicondylar foramen (a hole in the distal humerus), a non-translatory (rotation-only) humeroulnar joint, and a more robust ulna with a shortened trochlear notch. the proximal radioulnar joint is similarly derived in higher primates in the location and shape of the radial notch on the ulna; the primitive form being represented by new world monkeys, such as the howler monkey, and by fossil catarrhines, such as aegyptopithecus. in these taxa, the oval head of the radius lies in front of the ulnar shaft so that the former overlaps the latter by half its width. with this forearm 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