Muscles
Extensor Capri Radialis Longus
Origin: lateral supracondylar ridge of humerus
Insertion: base of metacarpal II
Action: extends and adducts hand
Extensor Carpi Radialis Brevis
Origin: lateral epicondyle of humerus
Insertion: base of metacarpal III
Action: extends and adducts hand
Extensor Carpi Ulnaris
Origin: lateral epicondyle of humerus; posterior border of ulna
Insertion: base of metacarpal V
Action: extends and adducts hand
Iliopsoas
Origin: Iliacus – iliac fossa and crest, lateral sacrum; Psoas major – transverse processes, bodies, and discs of T12 and lumbar vertebrae
Insertion: one and just below lesser trochanter of femur
Action: flex trunk at hip joint, flex thigh; lateral flexion of vertebral column (psoas)
Origin: ischial and pubic rami and ischial tuberosity
Insertion: linea aspera and adductor tubercle of femur
Action: adduct and medially rotate and flex thigh
Biceps Femoris
Origin: ischial tuberosity (long head); linea aspera and distal femur (short head)
Insertion: tendon passes laterally to insert into head of fibula and laeral condyle of tibia
Action: extends thigh; flexes leg
Semitendinosus
Origin: ischial tuberosity
Insertion: medial aspect of upper tibial shaft
Action: extends thigh; flexes leg
Semimembranosus
Origin: ischial tuberosity
Insertion: medial condyle of tibia; lateral condyle of femur
Action: extends thigh; flexes leg
Gluteus Maximus
Origin: dorsal ilium, sacrum, and coccyx
Insertion: gluteal tuberosity of femur and iliotibial tract
Action: powerful thigh extensor
Flexor Digitorum Longus
Origin: posterior surface of tibia
Insertion: distal phalanges of toes 2-5
Action: flexes toes
Rhomboids Major
Origin: spinous processes of C7 and T1-T5
Insertion: medial border of scapula
Action: stabilize scapulae
Gluteus Medialis
Origin: upper lateral surface of ilium
Insertion: greater trochanter of femur
Action: adducts and medially rotates thigh
Supinator
Insertion: proximal end of radius
Action: synergist of biceps bracii to supinate forearm
Origin: supraspinous fossa of scapula
Insertion: greater tubercle of humerus
Action: initiates abduction of arm