Although strains are not restricted to athletes and can happen while doing everyday tasks, however, people who play sports are more at risk for developing a strain. It should also be noted that it is common for an injury to develop when there is a sudden increase in duration, intensity, or frequency of an activity.

Magnetic resonance imaging (MRI) and ultrasound are comparable in efficacy and helpful in diagnosis although both have a false positive rate of 15 - 20%. MRI can reliably detect most full-thickness tears although very small pinpoint tears may be missed. In such situations, an MRI combined with an injection of contrast material, an MR-arthrogram, may help to confirm the diagnosis. It should be realized that a normal MRI cannot fully rule out a small tear (a false negative) while partial-thickness tears are not as reliably detected. While MRI is sensitive in identifying tendon degeneration (tendinopathy), it may not reliably distinguish between a degenerative tendon and a partially torn tendon. Again, magnetic resonance arthrography can improve the differentiation. An overall sensitivity of 91% (9% false negative rate) has been reported indicating that magnetic resonance arthrography is reliable in the detection of partial-thickness rotator cuff tears. However, its routine use is not advised, since it involves entering the joint with a needle with potential risk of infection. Consequently, the test is reserved for cases in which the diagnosis remains unclear.

Treatment of meniscal cysts consists of a combination of cyst decompression (intraarticular decompression versus open cystectomy) and arthroscopic repair of any meniscal abnormalities. Success rates are significantly higher when both the cyst and meniscal tear are treated compared to treating only one disease process.

The diagnosis may be confirmed by an EMG examination in 5 to 7 days. The evidence of denervation will be evident. If there is no nerve conduction 72 hours after the injury, then avulsion is most likely..

The most advanced diagnostic method is MR imaging of the brachial plexus using a high Tesla MRI scanner like 1.5 T or more. MR helps aid in the assessment of the injuries in specific context of site, extent and the nerve roots involved. In addition, assessment of the cervical cord and post traumatic changes in soft tissues may also be visualised.

Musculoskeletal ultrasound has been advocated by experienced practitioners, avoiding the radiation of X-ray and the expense of MRI while demonstrating comparable accuracy to MRI for identifying and measuring the size of full-thickness and partial-thickness rotator cuff tears. This modality can also reveal the presence of other conditions that may mimic rotator cuff tear at clinical examination, including tendinosis, calcific tendinitis, subacromial subdeltoid bursitis, greater tuberosity fracture, and adhesive capsulitis. However, MRI provides more information about adjacent structures in the shoulder such as the capsule, glenoid labrum muscles and bone and these factors should be considered in each case when selecting the appropriate study.

X-rays may help visualize bone spurs, acromial anatomy and arthritis. Further, calcification in the subacromial space and rotator cuff may be revealed. Osteoarthritis of the acromioclavicular (AC) joint may co-exist and is usually demonstrated on radiographs.

MRI imagining can reveal fluid accumulation in the bursa and assess adjacent structures. In chronic cases caused by impingement tendinosis and tears in the rotator cuff may be revealed. At US, an abnormal bursa may show (1) fluid distension, (2) synovial proliferation, and/or (3) thickening of the bursal walls. In any case, the magnitude of pathological findings does not correlate with the magnitude of the symptoms.

Magnetic resonance imaging is the modality of choice for diagnosis of meniscal cysts. In their most subtle form, meniscal cysts present as focal areas of high signal intensity within a swollen meniscus. It is not uncommon for radiologists to miss this type of meniscal cyst because the signal intensity is not quite as great as fluid on T2 weighted sequences.2 When this fluid is extruded into the adjacent soft tissues, the swollen meniscus subsequently assumes a more normal shape, and the extruded fluid demonstrates a higher T2 signal typical of parameniscal cysts.

Medial meniscus horizontal tear extending into a meniscal cyst.

Sagittal T2 images of a medial meniscus horizontal tear extending into a meniscal cyst.

Large medial meniscus cyst.

The condition is difficult to detect and may go unnoticed, because many patients have no specific symptoms. Diagnosis is further complicated by the fact that many patients with the injury experienced multiple other serious injuries as well, so the attention of hospital staff may be distracted from the possibility of aortic rupture. In fact most cases occur along with other injuries.

A common symptom is unusually high blood pressure in the upper body and very low blood pressure in lower limbs. Another symptom is renal failure where the creatinine level shoots very high and urine output becomes negligible. In most cases, however, the doctors would misinterpret renal failure as due to issues with the kidney itself and may recommend dialysis.

Though not completely reliable, chest X-rays are the first-line treatment, initially used to diagnose this condition when the patient is unstable and cannot be sent to the CT bay. The preferred method of diagnosis used to be CT angiogram until it was found to cause complications in some people; now it is reserved for when CT scans are inconclusive.

The classical findings on a chest X-ray will be widened mediastinum, apical cap, and displacement of the trachea, left main bronchus, or nasogastric tube. A normal chest x-ray does not exclude transection, but will diagnose conditions such as pneumothorax or hydrothorax. The aorta may also be torn at the point where it is connected to the heart. The aorta may be completely torn away from the heart, but patients with such injuries rarely survive very long after the injury; thus it is much more common for hospital staff to treat patients with partially torn aortas. When the aorta is partially torn, it may form a "pseudoaneurysm". In patients who do live long enough to be seen in a hospital, a majority have only a partially torn blood vessel, with the outermost adventitial layer still intact. In some of these patients, the adventitia and nearby structures within the chest may serve to prevent severe bleeding. After trauma, the aorta can be assessed by a CT angiogram or a direct angiogram, in which contrast is introduced into the aorta via a catheter.

Initially, diagnosis can be difficult, especially when other severe injuries are present; thus the condition is commonly diagnosed late. Chest X-ray is known to be unreliable in diagnosing diaphragmatic rupture; it has low sensitivity and specificity for the injury. Often another injury such as pulmonary contusion masks the injury on the X-ray film. Half the time, initial X-rays are normal; in most of those that are not, hemothorax or pneumothorax is present. However, there are signs detectable on X-ray films that indicate the injury. On an X-ray, the diaphragm may appear higher than normal. Gas bubbles may appear in the chest, and the mediastinum may appear shifted to the side. A nasogastric tube from the stomach may appear on the film in the chest cavity; this sign is pathognomonic for diaphragmatic rupture, but it is rare. A contrast medium that shows up on X-ray can be inserted through the nasogastric tube to make a diagnosis. The X-ray is better able to detect the injury when taken from the back with the patient upright, but this is not usually possible because the patient is usually not stable enough; thus it is usually taken from the front with the patient lying supine. Positive pressure ventilation helps keep the abdominal organs from herniating into the chest cavity, but this also can prevent the injury from being discovered on an X-ray.

Computed tomography has an increased accuracy of diagnosis over X-ray, but no specific findings on a CT scan exist to establish a diagnosis. Although CT scanning increases chances that diaphragmatic rupture will be diagnosed before surgery, the rate of diagnosis before surgery is still only 31–43.5%. Another diagnostic method is laparotomy, but this misses diaphragmatic ruptures up to 15% of the time. Often diaphragmatic injury is discovered during a laparotomy that was undertaken because of another abdominal injury. Because laparotomies are more common in those with penetrating trauma then compared to those who experienced a blunt force injury, diaphragmatic rupture is found more often in these persons. Thoracoscopy is more reliable in detecting diaphragmatic tears than laparotomy and is especially useful when chronic diaphragmatic hernia is suspected.

The first-line treatment for a muscular strain in the acute phase include five steps commonly known as P.R.I.C.E.

- Protection: Apply soft padding to minimize impact with objects.

- Rest: Rest is necessary to accelerate healing and reduce the potential for re-injury.

- Ice: Apply ice to induce vasoconstriction, which will reduce blood flow to the site of injury. Never ice for more than 20 minutes at a time.

- Compression: Wrap the strained area with a soft-wrapped bandage to reduce further diapedesis and promote lymphatic drainage.

- Elevation: Keep the strained area as close to the level of the heart as is possible in order to promote venous blood return to the systemic circulation.

Immediate treatment is usually an adjunctive therapy of NSAID's and Cold compression therapy. Controlling the inflammation is critical to the healing process. Cold compression therapy acts to reduce swelling and pain by reducing leukocyte extravasation into the injured area. NSAID's such as Ibuprofen/paracetamol work to reduce the immediate inflammation by inhibiting Cox-1 & Cox-2 enzymes, which are the enzymes responsible for converting arachidonic acid into prostaglandin. However, NSAIDs, including aspirin and ibuprofen, affect platelet function (this is why they are known as "blood thinners") and should not be taken during the period when tissue is bleeding because they will tend to increase blood flow, inhibit clotting, and thereby increase bleeding and swelling. After the bleeding has stopped, NSAIDs can be used with some effectiveness to reduce inflammation and pain.

A new treatment for acute strains is the use of platelet rich plasma (PRP) injections which have been shown to accelerate recovery from non surgical muscular injuries.

It is recommended that the person injured should consult a medical provider if the injury is accompanied by severe pain, if the limb cannot be used, or if there is noticeable tenderness over an isolated spot. These can be signs of a broken or fractured bone, a sprain, or a complete muscle tear.

In patients with bursitis who have rheumatoid arthritis, short term improvements are not taken as a sign of resolution and may require long term treatment to ensure recurrence is minimized. Joint contracture of the shoulder has also been found to be at a higher incidence in type two diabetics, which may lead to frozen shoulder (Donatelli, 2004).

Laximetry is a reliable technique for diagnosing a torn anterior cruciate ligament.

X-ray images (normally during weightbearing) can be obtained to rule out other conditions or to see if the patient also has osteoarthritis. The menisci themselves cannot be visualised with plain radiographs. If the diagnosis is not clear from the history and examination, the menisci can be imaged with magnetic resonance imaging (an MRI scan). This technique has replaced previous arthrography, which involved injecting contrast medium into the joint space. In straightforward cases, knee arthroscopy allows quick diagnosis and simultaneous treatment. Recent clinical data shows that MRI and clinical testing are comparable in sensitivity and specificity when looking for a meniscal tear.

The MRI is perhaps the most used technique for diagnosing the state of the Anterior Cruciate Ligament but it not always the most reliable. In some cases the Anterior Cruciate Ligament can indeed not be seen because of the blood surrounding it.

Death occurs immediately after traumatic rupture of the thoracic aorta 75%–90% of the time since bleeding is so severe, and 80–85% of patients die before arriving at a hospital. Of those who live to reach a hospital, 23% die at the time of or shortly after arrival. In the US, an estimated 7,500–8,000 cases occur yearly, of which 1,000–1,500 make it to a hospital alive; these low numbers make it difficult to estimate the efficacy of surgical options. However, if surgery is performed in time, it can offer a chance of survival.

Though there is a concern that a small, stable tear in the aorta could enlarge and cause complete rupture of the aorta and heavy bleeding, this may be less common than previously believed as long as the patient's blood pressure does not get too high.

Various diagnostic modalities exist to demonstrate blood flow or absence thereof in the vertebral arteries. The gold standard is cerebral angiography (with or without digital subtraction angiography). This involves puncture of a large artery (usually the femoral artery) and advancing an intravascular catheter through the aorta towards the vertebral arteries. At that point, radiocontrast is injected and its downstream flow captured on fluoroscopy (continuous X-ray imaging). The vessel may appear stenotic (narrowed, 41–75%), occluded (blocked, 18–49%), or as an aneurysm (area of dilation, 5–13%). The narrowing may be described as "rat's tail" or "string sign". Cerebral angiography is an invasive procedure, and it requires large volumes of radiocontrast that can cause complications such as kidney damage. Angiography also does not directly demonstrate the blood in the vessel wall, as opposed to more modern modalities. The only remaining use of angiography is when endovascular treatment is contemplated (see below).

More modern methods involve computed tomography (CT angiography) and magnetic resonance imaging (MR angiography). They use smaller amounts of contrast and are not invasive. CT angiography and MR angiography are more or less equivalent when used to diagnose or exclude vertebral artery dissection. CTA has the advantage of showing certain abnormalities earlier, tends to be available outside office hours, and can be performed rapidly. When MR angiography is used, the best results are achieved in the "T" setting using a protocol known as "fat suppression". Doppler ultrasound is less useful as it provides little information about the part of the artery close to the skull base and in the vertebral foramina, and any abnormality detected on ultrasound would still require confirmation with CT or MRI.

In addition to history and exam, it has been recommended to perform projectional radiography of the neck, chest, shoulder, and thoracic inlet to rule out structural abnormalities such as malunited or greenstick fractures. Computed tomography (CT) or magnetic resonance imaging (MRI) are rarely indicated, but may be useful to rule out certain diagnoses if suspected, such as neurofibromatosis-related injury, intervertebral disc disorder, radiculopathy, and tumors.

Between 50 and 80% of diaphragmatic ruptures occur on the left side. It is possible that the liver, which is situated in the right upper quadrant of the abdomen, cushions the diaphragm. However, injuries occurring on the left side are also easier to detect in X-ray films. Half of diaphragmatic ruptures that occur on the right side are associated with liver injury. Injuries occurring on the right are associated with a higher rate of death and more numerous and serious accompanying injuries. Bilateral diaphragmatic rupture, which occurs in 1–2% of ruptures, is associated with a much higher death rate (mortality) than injury that occurs on just one side.

The severity of brachial plexus injury is determined by the type of nerve damage. There are several different classification systems for grading the severity of nerve and brachial plexus injuries. Most systems attempt to correlate the degree of injury with symptoms, pathology and prognosis. Seddon's classification, devised in 1943, continues to be used, and is based on three main types of nerve fiber injury, and whether there is continuity of the nerve.

1. Neurapraxia: The mildest form of nerve injury. It involves an interruption of the nerve conduction without loss of continuity of the axon. Recovery takes place without wallerian degeneration.

2. Axonotmesis: Involves axonal degeneration, with loss of the relative continuity of the axon and its covering of myelin, but preservation of the connective tissue framework of the nerve (the encapsulating tissue, the epineurium and perineurium, are preserved).

3. Neurotmesis: The most severe form of nerve injury, in which the nerve is completely disrupted by contusion, traction or laceration. Not only the axon, but the encapsulating connective tissue lose their continuity. The most extreme degree of neurotmesis is transsection, although most neurotmetic injuries do not produce gross loss of continuity of the nerve but rather, internal disruption of the nerve architecture sufficient to involve perineurium and endoneurium as well as axons and their covering. It requires surgery, with unpredictable recovery.

A more recent and commonly used system described by the late Sir Sydney Sunderland, divides nerve injuries into five degrees: first degree or neurapraxia, following on from Seddon, in which the insulation around the nerve called myelin is damaged but the nerve itself is spared, and second through fifth degree, which denotes increasing severity of injury. With fifth degree injuries, the nerve is completely divided.

Because there are various causes for back injuries, prevention must be comprehensive. Back injuries are predominant in manual labor so the majority low back pain prevention methods have been applied primarily toward biomechanics Prevention must come from multiple sources such as education, proper body mechanics, and physical fitness.

Early stages may be treated conservatively using the R.I.C.E methods.

1. Rest

2. Ice

3. Compression

4. Elevation

Exercises involving eccentric muscle contractions of the quadriceps on a decline board are strongly supported by extant literature. A physical therapist may also recommend specific exercises and stretches to strengthen the muscles and tendons, eg. cycling or swimming. Use of a strap for jumper's knee and suspension inlays for shoes may also reduce the problems.

Should this fail, autologous blood injection, or platelet-rich plasma injection may be performed and is typically successful though not as successful as high volume saline injection (Crisp "et al."). Uncommonly it may require surgery to remove myxoid degeneration in the tendon. This is reserved for patients with debilitating pain for 6–12 months despite conservative measures. Novel treatment modalities targeting the abnormal blood vessel growth which occurs in the condition are currently being investigated.

New research shows that knee operations in most cases have no better effects than exercise programs, and that most knee operations thus can be avoided.

Magnetic resonance imaging (MRI) can be helpful in assessing for a ligamentous injury to the medial side of the knee. Milewski et al. has found that grade I to III classification can be seen on MRI. With a high-quality image (1.5 tesla or 3 tesla magnet) and no previous knowledge of the patient’s history, musculoskeletal radiologists were able to accurately diagnose medial knee injury 87% of the time. MRI can also show associated bone bruises on the lateral side of the knee, which one study shows, happen in almost half of medial knee injuries.

Knee MRIs should be avoided for knee pain without mechanical symptoms or effusion, and upon non-successful results from a functional rehabilitation program.

If the knee is swollen and red and warm to the touch when compared to the other knee, a doctor may be concerned about inflammation due to rheumatoid arthritis or a crystalline arthritis, such as gout or pseudogout, or joint infection. Besides sending the joint fluid to a laboratory for analysis, blood tests may requested to determine a white blood cell count, erythrocyte sedimentation rate, and perhaps the level of C-reactive protein or uric acid. If blood tests reveal Lyme disease antibodies forming, the condition may be attributed to it.

DAI currently lacks a specific treatment beyond what is done for any type of head injury, including stabilizing the patient and trying to limit increases in intracranial pressure (ICP).

Anterior-posterior (AP) radiographs are useful for reliably assessing normal anatomical landmarks. Bilateral valgus stress AP images can show a difference in medial joint space gapping. It has been reported that an isolated grade III sMCL tear will show an increase in medial compartment gapping of 1.7 mm at 0° of knee flexion and 3.2 mm at 20° of knee flexion, compared to the contralateral knee. Additionally, a complete medial ligamentous disruption (sMCL, dMCL, and POL) will show increased gapping by 6.5 mm at 0° and 9.8 mm at 20° during valgus stress testing. Pellegrini-Stieda syndrome can also be seen on AP radiographs. This finding is due to calcification of the sMCL (heterotopic ossification) caused by the chronic tear of the ligament.