**3.2 Pincer morphology**

*Essentials in Hip and Ankle*

arthroscopy.

**2. Methods**

femoral head and even femoral neck fracture [6–8].

patients followed and treated at our university hospital.

referenced in the selected papers were retrieved individually.

PubMed, MEDLINE, and ScienceDirect.

pathogenesis, and hip arthroscopy.

people without hip symptoms [9, 10].

This morphology is more common in men [10].

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

**3. Anatomy of FAI**

**3.1 Cam morphology**

(**Figures 1**, **2**).

Nakano [6], in a systematic review published in 2017, reported a complication rate of 3.3% after hip arthroscopy, and potential complications include neurovascular injuries, chondral and labral injuries, muscle pain, and avascular necrosis of

This chapter reviews the bony, muscular, and neurovascular anatomies of the hip joint with specific attention to structures of greatest relevance to FAI and hip

Anatomy figures were drawn by us to explain some anatomical relationships as well as the pathogenesis of FAI. Other figures are photographs and radiographs of

Concerning the literature research, the data sources used in our manuscript were

All study types were included, including case reports and review articles. Studies

The search terms used were femoroacetabular impingement OR FAI, anatomy,

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

It describes a flattening or convexity of the femoral head neck junction [6]

This chapter is a descriptive study of FAI anatomy and pathogenesis.

**26**

**Figure 1.**

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 more generally across the acetabular rim [6] (**Figure 3**).

This morphology is more common in women [10].

These two types (CAM and Pincer Morphology) may exist separately or be associated within the same patient (**Figure 4**).

**Figure 2.** *CAM morphology in a young man with a childhood hip disease.*

**Figure 3.** *Normal aspect of femoroacetabular junction versus Pincer morphology.*

**Figure 4.** *Mixed morphology with both aspects of CAM and Pincer morphology.*

#### *Essentials in Hip and Ankle*

Recently, several studies have shown that the prominence of the anterior-inferior iliac spine (AIIS) could also contribute to a conflict with the cervico-cephalic junction even if the hip anatomy is normal. This subspine impingement can simulate FAI and thus represents a differential diagnosis [11, 12].
