Osteophytes (bone spurs) are bony projections that form at joints. Osteophytes occur when there are changes to bone formation via aging, mechanical instability, degeneration, and disease, including arthritis (which is the most common cause of osteophyte formation). Osteophytes form naturally on the spine via degeneration of the vertebrae with aging. Osteophytes do not cause pain, but may impinge on nerves which will lead to pain, and/or numbness and tingling sensations. Chondrocytes are cartilage cells.

Enthesophytes are bony projections that form at ligament or tendon attachments. 

Osteoporosis is a breakdown of bone, commonly due to a lack of calcium, which is typically lost faster in females due to a menstruation cycle, and chronic breakdown with age. Also, females have less bone density to begin with.

Osteo- (which is going to be a Latin based root word for bone) will help you eliminate the other answers, which are all inflammation of non-bony structures within the body. 

These are tests for femur fractures, specifically for fractures of the femoral neck. The fulcrum test involves having the patient sit with his/her affected leg hanging off the edge of a surface, then the examiner will place his/her forearm under the shaft of the femur. If the patient experiences pain in the femur upon applying downward force on the knee, the result is positive, and the patient has fractured the femur. The patellar-pubic percussion test involves the use of a stethoscope on the lateral aspect of the pubic symphysis of the leg being examined. The patella is tapped with the tip of a finger or a tuning fork. Normally, there will be a distinct, loud sound that is caused by each tapping; if the sound is dissipated or muffled, this indicates a femoral fracture. 

Inability to take more than 4 steps with the injured leg is one of the criteria of the is used order x-rays for suspected fractures around the knee complex, per the Ottawa knee rules. The other criteria are as follows: isolated tenderness at the patella or tenderness at the fibular head or patient age greater than 55 or inability to flex the knee past .

Although diagnostic imaging is needed to conclusively to rule in a fracture, the closed fist percussion sign has good diagnostic value in detecting vertebral compression fractures. Given that this tests involves hitting a patient in the back, clinicians may be hesitant to use this test. In such cases, the supine sign (increased pain with lying supine) can also be used to screen for vertebral compression fractures.

As their names suggest, the Ottawa knee and ankle rules, and the Amsterdam wrist rules are used to determine which patients should receive x-rays for suspected ankle, knee, and wrist fractures respectively. Well's criteria are used to screen for pulmonary embolisms (PEs) and deep vein thromboses (DVTs). It should be noted that there are distinct Well's criteria for PEs and DVTs.

It is likely that the compartment syndrome is compromising the femoral nerve, which would result in an inability to extend the knee. We need to know that the femoral nerve runs close to the femur in the anterior compartment of the thigh. The high compartment pressures have cut off blood supply and compromised the femoral nerve, as evidenced by sensory deficits in the anterior thigh.

The femoral nerve arises from L2-L4 in the lumbar plexus and innervates the quadriceps muscles, which serve to extend the knee.

Flexion of the knee is accomplished by the hamstring muscles, which are supplied by common peroneal and tibial nerves. Eversion of the foot is a function of the peroneus longus and brevis, innervated by the superficial peroneal nerve. Plantar flexion is accomplished by the tibialis anterior, supplied by the deep peroneal nerve. Dorsiflexion is by the tibialis posterior, supplied by the tibial nerve.

The posterior cruciate ligament (PCL) is a large ligament located in the center of the knee behind the anterior cruciate ligament. The primary role of the PCL is to provide stability and prevent posterior deviation of the tibia relative to the femur. A posterior drawer test or tibial sag test can be used to assess PCL injury or damage.

In contrast, the anterior cruciate ligament (ACL) prevent anterior deviation of the tibia relative to the femur. Damage to the ACL can be assessed with an anterior drawer test.

The axilla is an important area housing a large region of the brachial plexus. It is located between the rib cage, scapula, and humerus. More specifically, it is bounded by:

• The pectoralis major muscle anteriorly
• The latissimus dorsi, teres major, and subscapularis muscles posteriorly
• The shaft of the humerus laterally
• The serratus anterior and rib cage medially

The clavicle, supraspinatus, deltoid, and biceps brachii all lie outside of the axilla region. 

Although it's function has only recently been described, surgical literature suggests that the anterolateral ligament functions to provide additional rotary stability to the knee. Because of this, some patients who have had an ACL reconstruction, but not an ALL reconstruction, will demonstrate a positive pivot-shift sign, a sign of knee rotational instability upon flexion of the tibia at the knee during medial rotation.