Difference Between Origin and Insertion

The key difference between origin and insertion is that origin is the bone attachment at the stationary end of the muscle while insertion is the bone attachment to the mobile end of the muscle.

A muscular tissue mainly comprises of all the contractile tissues of the body including skeletal, cardiac, and smooth muscles. Muscles are a type of connective tissue important for the motions in organisms. The shape of a muscle may change when it moves, but both origin and insertion are special regions in a muscle that do not change their shape during the movement. They are attachment sites of the muscle to a particular bone and are helpful to determine the location and the action of a particular muscle. Not only attachment sites but also the size, direction, and shape of the muscle also determine its action and the range of motion. One muscle may have more than one origin or insertion. The portion of a muscle that is between origin and insertion is called the belly or gaster of the muscle, and it mainly consists of muscle fibres.

CONTENTS

1. Overview and Key Difference
2. What is Origin
3. What is Insertion
4. Similarities Between Origin and Insertion
5. Side by Side Comparison – Origin vs Insertion in Tabular Form
6. Summary

What is Origin?

Origin is the attachment site of the muscle’s tendon to a more stationary bone. In simple words, origin is the site of attachment that is relatively fixed. It has very less movement and normally muscle contracts towards it.

Figure 01: Muscle Contraction and Relaxation

Some muscles have more than one origin; for example, biceps brachii. Usually, origin is at the proximal end of the muscle to the centre of the body.

What is Insertion?

Insertion is the attachment site of the muscle’s tendon to a more movable bone. In simple words, it is the opposite end of the origin.

Figure 02: Origin and Insertion

It has the greatest motion when the muscle contracts and it tends to be more distal to the centre of the body. Therefore, insertion is responsible for the movement of a particular body part.

What are the Similarities Between Origin and Insertion?

• Origin and insertion are two types of attachment points of skeletal muscles.
• They are important for muscle contractions and movements.
• Moreover, they are at the opposite ends of the belly of a muscle.

What is the Difference Between Origin and Insertion?

Origin and insertion are two ends of a muscle that attach to a bone. Origin is the attachment end to the immovable bone while insertion is the attachment end to a more movable bone. So, this is the key difference between origin and insertion. Origin is closer to the centre of the body while insertion is furthest to the centre of the body. Therefore, this is another difference between origin and insertion. Furthermore, insertion has less mass than origin.

Below infographic summarizes the difference between origin and insertion.

Summary – Origin vs Insertion

Origin and insertion are two attachment points. Origin is the attachment to an immovable bone while insertion is the attachment to a movable bone. Therefore, the origin is the end that doesn’t move during the contraction of the muscle while the insertion is the opposite end of the muscle that moves. Usually, insertion is the distal end of the muscle. It is furthest to the centre of the body. On the other hand, origin is the proximal end. Thus, this is the summary of the difference between origin and insertion.

Reference:

1. “Muscle Origin and Insertion: Definition and Actions.” Study.com, Available here.

Image Courtesy:

1. “Animation triceps biceps” By Niwadare – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “Anatomy and physiology of animals Antagonistic muscles, flexion&tension” By Original uploader was Sunshineconnelly at en.wikibooks – Transferred from en.wikibooks; transferred to Commons by User:Adrignola using CommonsHelper (CC BY 3.0) via Commons Wikimedia

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