The relationship between additional heads of the quadriceps femoris, the vasti muscles, and the patellar ligament
Table 1
Classification of the proximal attachment by Olewnik et al. [7].
Type
Subtype
Description
Origin
Number/percentage
I
A
Single fifth head and independent muscle
Originates from the upper level of the greater trochanter’s anterior surface where it joins the intertrochanteric and gluteus medius ridge. The muscle belly runs laterally to the VI.
20 (29.4%)
B
Originates from the upper level of the greater trochanter’s anterior surface where it joins the intertrochanteric and gluteus medius ridge; however, the muscle belly runs medial to the VI.
10 (14.7%)
II
A
The fifth head grows out from other muscles
From the VL.
16 (23.5%)
B
From the VI.
3 (4.5%)
C
From the gluteus medius.
2 (2.9%)
III
A
Multiple supplementary heads
Two heads with a single common tendon. The first (lateral head) originates from the upper level of the greater trochanter’s anterior surface where it joins the intertrochanteric and gluteus medius ridge; the second (medial head) originates from the femur’s anterior surface just above the VI muscle’s proximal attachment.
4 (5.9%)
B
Two heads with two separate tendons. The first head (lateral head) originates from the upper level of the greater trochanter’s anterior surface where it joins the intertrochanteric and gluteus medius ridge; the second (medial head) originates from the femur’s anteromedial surface just above the VI muscle proximal attachment.
10 (14.7%)
C
Three heads (lateral, intermediate, and medial). The lateral and intermediate heads originate from the VL, while the medial head originates from the upper level of the greater trochanter’s anterior surface where it joins the intertrochanteric and gluteus medius ridge. The intermediate and medial heads join and form a common tendon.
2 (2.9%)
D
Four heads (bifurcated lateral and bifurcated medial). The bifurcated medial form consists of medial and lateral heads. The medial originates from the femur’s innominate tubercle [28], and the lateral originates from the inferior level of the greater trochanter’s anterior surface; these two heads join to form a common tendon. In addition, the bifurcated lateral form consists of medial and lateral heads: the medial originates from the inferior level of the greater trochanter’s anterior surface and from the intermediate part of the VL; the lateral originates from the intermediate part of the VL and from the anterolateral surface of the shaft of the femur, lateral to the VI, and then the two heads join and form a common tendon.
