Antero-posterior View of Hip :

Shenton's line is formed from the continuity of the inferior aspect of the femoral neck through to the inferior aspect of the superior pubic ramus. This gives a good guide to the normal relationship of the head of the femur to the pelvis. Synovial membrane is very extensive around the hip joint and, like the capsule, comes well down the femoral neck, especially anteriorly. Note the normal pattern of the bone trabeculae in the femoral neck, indicating the lines of stress. Fractures of the femoral neck are common, especially in the old, and as they may be impacted they are sometimes difficult to visualize. If severe separation of the femoral head occurs, then the possibility of avascular necrosis exists and it must therefore be checked on follow-up films.

   Lateral View of Hip :

This view demonstrates the femoral neck and the relationship of the femoral head to the acetabulum. Fractures of the femoral neck can again be visualized on this film and, in particular, the degree of angulation can be assessed. Dislocations around the hip are not infrequent in road traffic accidents. In most cases, the displacement is posterior due to the impact a patient receives whilst in the sitting position. Dislocations in an anterior direction are much less common. Associated fracture dislocations must be checked for.

   Antero-posterior, Lateral and Skyline Views of Knee :

The knee joint is complicated anatomically and consists of three articulations: two between the condyles of the femur and the tibia, and the third between the femur and the patella. The synovial cavity is common to all three joints, but is indented by the two menisci between the femur and the tibia. These menisci are best seen on the MRI. Fractures of all three bones can occur and can be visualized on these views. A fracture of the patella may only be visible on the skyline view. It should not be confused with a congenital bipartite patella, which is often present bilaterally. To assess whether there is free fat within the joint space, an x-ray with a horizontal beam should be performed and, if positive, is a fair indication of bone damage. A tunnel view has not been included, but is of use when looking for a loose body or evidence of osteochondritis dissecans. Note also on the skyline view that the lateral femoral condyle projects higher than the medial condyle to resist lateral dislocation of the patella. The tibia and fibula are connected by an interosseous membrane similar to that of the forearm. Again, with paired long bones, fracture of one bone is often accompanied by a fracture of the other. As mentioned before with the forearm radiograph, if one bone is fractured with considerable displacement, then both proximal and distal joints should be checked for dislocation of the other bone. Note that the head of the fibula does not form part of the knee joint, but has a separate synovial joint with the tibia. Fractures of the tibia and fibula are often compound because of the lack of soft tissues anteriorly. Fractures of the mid-tibial shaft are prone to non-union because of the apparent poor vascularity. Paget's disease and syphilis are causes of 'sabre tibia'.

   Lateral and Antero-posterior Views of Ankle and Axial View of Calcaneus :

Numerous sesamoid bones and supernumerary bones occur around the foot and ankle. The os trigonum appears in about 8% of adults as an extra bone posterior to the ankle joint adjacent to the talus. Fractures and dislocations are common at the ankle joint, due in part to the thin fibrous capsule. Potts' fractures are of three types: first degree, fracture of one malleolus; second degree, fracture of both malleoli often with subluxation of the talus; third degree, associated backwards displacement of the talus and disruption of the ankle mortise. Talar and calcaneal fractures also occur. Crush fractures of the calcaneus through the body often occur when patients fall from a height onto their heels; occupations such as parachuting, window-cleaning and cat-burglary have an especially high incidence! These calcaneal fractures are often bilateral. Medial and lateral ligament tears may be visualized radiographically by strain views to show movement of the talus in relation to the distal tibia in the AP projection.

   Dorsoplanter and Dorsoplanter Oblique Projections of Foot :

The weight-bearing parts of the foot are the inferior aspect of the calcaneus and the heads of the metatarsals. Common fracture sites include the base of the fifth metatarsal which should not be confused with an epiphysis frequently present on the tubercle of the base of this bone. A stress fracture (march fracture) is often seen along the distal shaft of the second and third metatarsals. There is a strong incidence of such fractures in occupations such as new army recruits on route marches and long-distance walkers. The foot is also the site of two special forms of osteochondritis seen before epiphyseal fusion: the first in the metatarsal head (Freiberg), and the second in the tarsal navicular (Köhler).

   Antero-posterior View of Cervical Spine:

This projection is taken with the jaw moving, but with the head and cervical spine firmly fixed. This allows C1 and C2 to be visualized and not be obscured by the mandibular shadow. The odontoid process of the axis is formed embryologically from the centrum of the atlas. The spinous processes should be in line and are often bifid in the cervical region. Tomography of the odontoid process in this plane may be needed to show fractures, avascular necrosis and involvement by rheumatoid arthritis. Look for cervical ribs from C7; though rare (0.5-1%), they may have important clinical manifestations. Air in the trachea and larynx can be seen to overlie the lower cervical spine, and ossification in the thyroid cartilage can occasionally cause confusion in identifying the normal anatomy.

   Lateral View of Cervical Spine :

This is a very important view and should include from the base of the occiput to at least the level of T1. The C7/T1 disc space must be visible on a lateral film, particularly in cases of injury so that a fracture or dislocation is not missed. Note that two important lines are visible, formed by the posterior margins of the bodies of the cervical vertebrae and the posterior limit of the cervical spinal canal. Both of these should be continuous lines and any irregularity may be due to an unsuspected dislocation. Often views in hyperextension and flexion may be needed to show vertebral subluxation or atlantoaxial subluxation. The anteroposterior sagittal diameter of the cervical spinal canal should not be less than 10 mm and is normally between 14 and 21 mm. If less than 10 mm, there is likely to be spinal cord compression.

   Oblique View of Cervical Spine :

This view shows the exit foramina for the spinal nerves and the articular facet joints. Fractures involving the laminae can be seen. Disruption of the normal facet articulation may only be visible on this view. Any degenerative disease which occurs in the cervical spine may cause osteophyte formation between the vertebral bodies, which may impinge on the cervical spinal nerves. This projection allows the foramina to be screened for these osteophytes. The foramen transversarium of C3 is visualized - this contains the vertebral vein and artery. Note that there are eight cervical spinal nerves, but only seven cervical vertebrae.