**3. Anatomy of FAI**

The morphology of the proximal femur and acetabulum can vary significantly, which can have an important clinical relevance and impact on hip joint biomechanics. The detailed anatomy of the hip is well described in the manuals of anatomy. In FAI, two types of hip morphology have been described, namely, the cam type and the pincer type. These two types may exist separately or be associated within the same patient.

Thus, the isolated presence of either cam or pincer morphology is insufficient for a diagnosis of FAI syndrome. It is important to note that these morphologies are thought to be fairly common (around 30% of the general population) including in people without hip symptoms [9, 10].

#### **3.1 Cam morphology**

It describes a flattening or convexity of the femoral head neck junction [6] (**Figures 1**, **2**).

This morphology is more common in men [10].

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**Figure 4.**

**Figure 2.**

**Figure 3.**

*Femoroacetabular Impingement: Anatomy and Pathogenesis*

more generally across the acetabular rim [6] (**Figure 3**). This morphology is more common in women [10].

associated within the same patient (**Figure 4**).

*CAM morphology in a young man with a childhood hip disease.*

*Normal aspect of femoroacetabular junction versus Pincer morphology.*

*Mixed morphology with both aspects of CAM and Pincer morphology.*

It describes the overcoverage of the femoral head by the acetabulum in which the acetabular rim is extended beyond the typical amount, either in one focal area or

These two types (CAM and Pincer Morphology) may exist separately or be

*DOI: http://dx.doi.org/10.5772/intechopen.90296*

**3.2 Pincer morphology**

**Figure 1.** *Normal aspect of femoral head-neck junction versus cam morphology.*
