Topic 11: Muscular System - Naming of Skeletal Muscles Flashcards
What are 7 ways that muscles are named?
- Action they perform (in anatomical pos)
- Shape
- Origin and inertion
- Location
- Relative size
- Direction of fibers
- Number of origins
Skeletal muscles can be named based on the action they perform in anatomical position. Name the two types of actions performed by muscles
- flexors
- extensors
What are flexors?
- decrease the angle between 2 bones
- ex. flexor carpi radialis
What are extensors?
- increase angle (back to anatomical position after flexion)
- ex. extensor carpi ulnaris
The shape of a muscle can influence how it is named. Give 2 examples of muscles and why they are named that way
- deltoid - triangular shape
- trapezius - trapezoid shape (no 2 sides parallel)
Origin and insertion influences how a muscle is named. Use sternocleidomastoid as an example.
origin - sterno = sternum, and cleido = clavicle
insertion - mastoid - mastoid process of temporal bone
Give an example of how location influences name of muscle
tibialis anterior
Relative size is an example of how muscles can be named. Using GLUTEUS, give 3 examples of their names
- maximus
- medius
- minimus
Direction of fibers can influence how a muscle is named. Use the rectus abdominis and external obliques as an example.
rectus means straight
- i guess fibers are running straight
external obliques
- \ //
The number of origins influences how a muscle is named. Use these examples:
1. Biceps brachii
2. triceps trachii
3. quadriceps femoris
biceps brachii - 2 origins on scapula
triceps brachii - 3 origins on scapula and humerus
quadriceps femoris - 4 origins on os coxa and femur
In the lab, we need to know action, origin + insertion of muscle (bones only, not which part of bone). We can often deduce it based on the name. Try extensor carpi radialis as an example
Action - extends wrist
position - near radius
origin - humerous
insertion - metacarpals
