Muscle Groups and Functions

Muscle Overview

Major Muscle Groups and Functions

Understanding the different muscle groups and their functions is essential for anatomy and physiology studies.

Upper Body Muscles

• Triceps Brachii

  • Function: Extends elbow.
  • Origin: Humerus (proximal 1/3), scapula.
  • Insertion: Olecranon of ulna.

• Biceps Brachii

  • Function: Flexes elbow.
  • Origin: Long head from glenoid (supra-glenoid tubercle), short head from coracoid process.
  • Insertion: Radial tuberosity of the radius.

• Deltoid

  • Function: Extends, abducts, laterally rotates humerus.
  • Origin: Clavicle and scapula.
  • Insertion: Deltoid tuberosity of the humerus.

Lower Body Muscles

• Gastrocnemius

  • Function: Plantar flexes foot.
  • Origin: Femur (medial and lateral condyles).
  • Insertion: Calcaneus via the Achilles tendon.

• Soleus

  • Function: Plantar flexes foot.
  • Origin: Posterior surface of the tibia and fibula.
  • Insertion: Calcaneus via the Achilles tendon.

• Tibialis Anterior

  • Function: Dorsiflexes foot.
  • Origin: Lateral condyle of the tibia.
  • Insertion: Medial cuneiform and base of the first metatarsal.

Major Thigh Muscles

• Semimembranosus

  • Function: Extends thigh at hip, flexes knee, medially rotates leg.
  • Origin: Ischial tuberosity.
  • Insertion: Medial condyle of the tibia.

• Semitendinosus

  • Function: Extends thigh at hip, flexes knee, medially rotates leg.
  • Origin: Ischial tuberosity.
  • Insertion: Upper part of the medial surface of the tibia.

• Biceps Femoris

  • Function: Extends thigh and flexes knee.
  • Origin: Ischial tuberosity (long head), femur (short head).
  • Insertion: Head of the fibula.

Quadriceps Group

• Muscles: Vastus Medialis, Vastus Lateralis, Rectus Femoris
  • Function: Extends knee.
  • Origin: Various points on the femur.
  • Insertion: Patellar tendon to tibial tuberosity.

Summary of Muscle Functions in Locomotion

The functioning of muscles like the gastrocnemius, soleus, and tibialis anterior are crucial for efficient walking and running.
Knowledge of muscle origins (e.g., ischial tuberosity, iliac spine) aids in understanding body movements