Question

Highlight and name the origin and insertion areas for the; Iliopsoas, Pectineus, Rectus Femoris, Sartorius, and Tensor Fasciae Latae. Then, show their primary and secondary (and tertiary if they have three functions) functions/movements they produce. Which of the five muscles (counting the Iliopsoas as 1 whole muscle) has the GREATEST force generating capacity, and which has the LEAST and why?

Answer 1

MUSCLE	ORIGIN	INSERTION
ILIOPSOAS	Iliacus from iliac fossa of hip bone. Psoas major from transverse processes, bodies and vertebral discs of T12-L5 vertebrae.	Lesser trochanter of femur
PECTINEUS	From the pectineal line of the superior pubic ramus	The upper end of linea aspera of femur
RECTUS FEMORIS	Reflected head- From ilium just above the acetabulum Straight head- From anterior inferior iliac spine	Tibial tuberosity
SARTORIUS	From anterior superior iliac spine	The upper part of the medial surface of the shaft of the tibia.
TENSOR FASCIAE LATAE	From anterior superior iliac spine	Iliotibial tract

Functions/movements of these muscles are:-

Muscle	Primary function	Secondary function	Tertiary function
Iliopsoas	Flexion of the hip joint	External rotation of the thigh at the hip	Lateral flexion of the trunk
Pectineus	Adducts the thigh	Flexes the hip joint	External and internal rotation of the high Pelvic stabilization
Rectus femoris	Extension of the knee	Flexion of the hip	-
Sartorius	Flexes the thigh at the hip joint	Flexes the leg at the knee joint	Abduction and lateral rotation of the thigh
Tensor fasciae latae	Flexion of the hip	Internal rotation if the hip	Abduction of the hip

Greatest force-generating capacity- Rectus femoris

Rectus femoris is a part of the quadriceps muscle which has the greatest force-generating capacity. It also acts as the major extensor of the knee.

Least force-generating capacity- Tensor fasciae latae

The force-generating capacity of the muscle depends upon the cross-sectional area of the muscle. The larger the cross-sectional area, greater is the force-generating capacity. The reason behind this is as the cross-sectional area increases, the fibres of the muscle have more surface tension and become capable of generating higher force.