Major Muscles and Their Origins, Insertions, and Actions for BIOL 131

These flashcards cover the major muscles, their origins, insertions, and actions as outlined in the prepared notes for BIOL 131.

Deltoid

Originates from clavicle and scapula; inserts on humerus; action: abducts and rotates humerus.

Trapezius

Originates from occipital bone and vertebrae C7-T12; inserts on clavicle, acromion, and spine of scapula; action: adducts, elevates, and depresses scapula.

Pectoralis major

Originates from clavicle, sternum, and cartilages of ribs 1-6; inserts on humerus; action: flexes, adducts, and medially rotates humerus.

Biceps brachii

Originates from scapula; inserts on radial tuberosity (radius); action: flexes radius (forearm) at elbow and humerus at shoulder.

Triceps brachii

Originates from scapula and humerus; inserts on olecranon process of ulna; action: extends ulna (forearm) at elbow and humerus at shoulder.

Latissimus dorsi

Originates from lumbar fascia, ribs 9-12, and iliac crest; inserts on humerus; action: extends, adducts, and medially rotates humerus.

External oblique

Originates from ribs 5-12; inserts on linea alba, iliac crest, pubic tubercle, and crest; action: lateral flexion of vertebral column (one); compresses abdomen and flexes vertebral column (both).

Internal oblique

Originates from lumbar fascia and iliac crest; inserts on linea alba, pubic crest, and ribs 9-12; action: same as external oblique.

Rectus abdominis

Originates from pubic crest; inserts on xiphoid process and cartilage of ribs 5-7; action: flexes and rotates lumbar region of vertebral column.

Transversus abdominis

Originates from iliac crest, lumbar fascia, and cartilages of last 6 ribs; inserts on linea alba and pubic crest; action: compresses abdomen.

Diaphragm

Originates from lumbar vertebrae and inferior margin of rib cage; inserts on central tendon of diaphragm; action: pulls central tendon down, increasing volume of thoracic cavity.

Gastrocnemius

Originates from lateral and medial condyles of femur; inserts on calcaneus; action: plantar flexion of foot and flexion of tibia at knee.

Gluteus maximus

Originates from dorsal ilium, sacrum, and coccyx; inserts on gluteal tuberosity (femur); action: extension, abduction, and lateral rotation of femur at hip.

Quadriceps femoris group: Rectus femoris

Originates from anterior spine of ilium; inserts on patella and tibial tuberosity; action: flexion of femur at hip and extension of leg at knee.

Quadriceps femoris group: Vastus lateralis

Originates from lateral surface of femur; inserts on patella and tibial tuberosity; action: extension of tibia at knee.

Quadriceps femoris group: Vastus medialis

Originates from medial surface of femur; inserts on patella and tibial tuberosity; action: same as vastus lateralis.

Quadriceps femoris group: Vastus intermedius

Originates from upper anterior surface of femur; inserts on patella and tibial tuberosity; action: same as vastus lateralis.

Hamstring group: Biceps femoris

Originates from ischial tuberosity and femur; inserts on fibula and lateral epicondyle of tibia; action: extension of femur at hip and flexion of tibia at knee.

Hamstring group: Semitendinosus

Originates from ischial tuberosity; inserts on medial condyle of tibia; action: same as biceps femoris.

Hamstring group: Semimembranosus

Originates from ischium; inserts on medial condyle of tibia; action: same as biceps femoris.