The femur is the longest and strongest bone in the body and primary bone of the thigh. The femur articulates with the acetabulum (hip joint) and tibia and patella (knee joint). The knee joint enables flexion, extension, and minimal rotation and supports the weight of the body during static positions and dynamic movement during gait.
ACTIONS OF THE KNEE COMPLEX
The articulations between the femur, tibia, and patella form the knee joint and enable the following actions (Figure 36-1A):
Flexion. Bending the knee joint.
Extension. Straightening the knee joint.
Internal and external rotation. Small rotational movements in the vertical axis.
A. Actions of the knee joint. B. Compartments of the thigh. C. Muscles of the anterior compartment of the thigh.
The muscles of the thigh are divided by their fascial compartments (anterior, medial, and posterior) and act on the joint(s) the individual muscles cross (Figure 36-1B and Table 36-1).
TABLE 36-1.Muscles of the Thigh ||Download (.pdf) TABLE 36-1. Muscles of the Thigh
|Muscle ||Proximal Attachment ||Distal Attachment ||Action ||Innervation |
|Anterior compartment of the thigh |
|Psoas minor ||T12–L1 vertebral bodies and discs ||Pectin pubis ||Lumbar spine flexion, posterior pelvic tilt ||Anterior rami (L1) |
|Psoas major ||T12–L5 transverse processes, vertebral bodies, and discs ||Lesser trochanter of femur ||Flexes and externally rotates thigh at hip joint; flexes trunk (psoasmajor) ||Anterior rami (L1–L3) |
|Iliacus ||Iliac fossa ||Femoral n. (L2, L3) |
|Sartorius ||Anterior superior iliac spine ||Inferomedial to tibial tuberosity (pes anserinus) ||Flexes thigh at hip joint and flexes leg at knee joint ||Femoral n. (L2, L3) |
|Rectus femoris ||Anterior inferior iliac spine ||Flexes thigh at hip joint and extends leg at knee joint ||Femoral n. (L2–L4) |
|Vastus lateralis ||Lateral part of intertrochanteric line, margin of greater trochanter, lateral margin of gluteal tuberosity, lateral lip of linea aspera ||Quadriceps femoris tendon ||Extends leg at knee joint |
|Vastus medialis ||Medial part of intertrochanteric line, pectineal line, medial lip of linea aspera, and medial supracondylar ridge |
|Vastus intermedius ||Femur: upper two-thirds of anterior and lateral surfaces |
|Medial compartment of the thigh |
|Pectineus ||Pectineal line ||Oblique line extending from base of lesser trochanter to linea aspera on posterior surface of proximal femur ||Adducts and flexes thigh at hip joint ||Femoral n. (L2, L3) |
|Adductor longus ||Body of pubis ||Linea aspera ||Adducts and medially rotates thigh at hip joint ||Obturator n. (anterior division) (L2–L4) |
|Adductor brevis ||Body of pubis and inferior pubic ramus ||Obturator n. (anterior division) (L2, L3) |
|Adductor magnus || |
Adductor part: ischiopubic ramus
Hamstring part: ischial tuberosity
Adductor part: linea aspera
Hamstring part: Adductor tubercle
|Adducts and medially rotates thigh at ...|