Dance Anatomy & Kinesiology

160 Dance Anatomy and Kinesiology

the lower limbs and axial skeleton, and the lumbosa-

cral joint is key for describing the movements of the

pelvis relative to the axial skeleton. The pelvic girdle

also protects and supports vital lower abdominal

organs and, in females, the developing fetus.

Pubic Symphysis

The pubic symphysis (G. symphysis, a growing

together) is a cartilaginous joint (figure 4.1C)

that is heavily reinforced by ligaments on all sides.

Normally this joint only allows slight movement

that is important for shock absorbency. However,

during pregnancy the width of the cartilage mark-

edly increases and the ligaments become more lax

to allow the slight spreading of the os coxae that is

associated with pregnancy.

Sacroiliac Joints

The sacroiliac joints (L. sacrum, sacred) are formed

between paired lateral C-shaped concave articular

surfaces of the sacrum and slightly convex articular

surfaces of the right and left ilium (figure 4.1A). The

paired sacroiliac joints can be palpated just adjacent

to each posterior superior iliac spine. The PSIS are

at the level of the spine of the second sacral vertebra

(S2). These strong joints are complex and evade easy

classification, demonstrating characteristics in dif-

ferent regions of cartilaginous, fibrous, and synovial

joints (Bechtel, 2001; Chen, Fredericson, and Smuck,

2002; Papadopoulos and Khan, 2004).

The sacroiliac joints are generally quite stable

due to the restraints offered by the fibrocartilage

and fibrous tissue within the joints, the presence

FIGURE 4.2 Bony landmarks of the femur (right femur). (A) Anterior view, (B) posterior view.