L5.4.4: Naming Skeletal Muscles

• NAMING SKELETAL MUSCLES

  • Direction of the muscle fibers
  • Relative size of the muscle
  • Location of the muscle
  • Number of origins
  • Location of the muscle's origin and insertion
  • Shape of the muscle
  • Action of the muscle
• DIRECTION OF THE MUSCLE FIBERS

  ● Rectus - straight

  ● Its fibers or whole structure run parallel to that imaginary line

  ● Ex: Rectus femoris is the straight muscle of the thigh

  ● Oblique - slant

  ● Muscle fibers run obliquely (at a slant) to the imaginary line
• RELATIVE SIZE OF THE MUSCLE

  ● Maximus - largest

  ● Ex: Gluteus maximus is the largest muscle of the gluteus muscle group

  ● Minimus - smallest

  ● Longus - long
• LOCATION OF THE MUSCLE

  ● Named for the bone with which they are associated

  ● Ex: Temporalis and frontalis muscles overlie the temporal and frontal bones of the skull, respectively
• NUMBER OF ORIGINS

  ● Biceps - 2 origins

  ● Ex: Biceps muscle of the arm has two heads/origins

  ● Triceps - 3 origins

  ● Ex: Tricep muscle has three origins

  ● Quadriceps - 4 origins
• LOCATION OF THE MUSCLE’S ORIGIN AND INSERTION

  ● Named for their attachment sites

  ● Ex: Sternocleidomastoid muscle has its origin on the sternum (sterno) and clavicle (cleido) and inserts on the mastoid process of the temporal bone
• SHAPE OF THE MUSCLE

  ● Some have distinctive shape to identify them

  ● Ex: Deltoid muscle is roughly triangular (deltoid means “triangular”)
• Action of the Muscle

  ○ Flexor and extensor (flexes or extends a bone)