What is an insertion point in anatomy

When talking about muscular attachments, it’s important to know and understand the difference between the origin and insertion. They are not interchangeable and have totally different meanings, though you can say muscular attachment or attachment site and be talking about either the origin or the insertion.

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What are insertion points of muscles?
What is insertion and origin in anatomy?
What is insertion location?
What is the point of origin in anatomy?

What’s the difference?
When a muscle contracts, the origin pulls the insertion closer. Always! Muscles pull. The origin is the fixed point that doesn’t move during contraction, while the insertion does move. Your bones are the levers and your muscles are the pulley. Basically, we are all super complex puppets on strings. To explore this further, let’s take a look at the rhomboids.

Rhomboids Minor and Major

Firstly, there are two rhomboids and they’re both deep to the multidirectional fibers of the trapezius. Rhomboid minor sits on top of, or superior to, its larger counterpart rhomboid major. Minor originates on the spinous processes of C7 and T1 while major originates on the spinous processes of T2-T5. You can pretty easily feel for T1 on yourself, it’s just at the base of the posterior neck and it bumps out a little bit posteriorly. The transverse processes stick out to the sides while the spinous processes, which we are talking about here, stick out and a bit downward posteriorly. They remind me of a stegosaurus. It’s from these little posterior projections that both rhomboids originate.

Back to rhomboid minor, it inserts on the upper portion of the medial border of the scapula, across from the spine of the scapula. The insertion for levator scapula is right there too and is easily palpable on yourself or someone else. Rhomboid major inserts on the medial border of the scapula as well, basically between the spine of the scapula and the inferior angle of the scapula. The actions of the rhomboids are to retract or adduct the scapula, elevate the scapula and also downwardly rotate the scapula.

WHOA, WAIT.
How does a muscle that elevates the scapula downwardly rotate it as well? If you look at the direction the fibers run, they’re on a bit of a downward angle going from the spine to the scapula. Because of this, when the muscles contract, they have the pulling capacity to draw the shoulder blades closer together. Downward rotation can be a tricky one because the scapula is the only bone in the body to do it, but we’re referring more specifically to the movement of the acromion, which is the flat bony process at the lateral end of the posterior scapula. When the rhomboids contract, they have the ability to tilt the acromion downward. It’s a slight action but it’s there nonetheless. Lastly the rhomboids can also elevate the scapula as a whole. Every time the muscle contracts (concentrically, that is, but that’s another post for another day), the origin says ‘come to me’, and so the insertion does. This is true for all the muscles in the body.

When studying anatomy, learn to look closely at the direction of the muscle fibers, and determine which end is the origin and which end is the insertion. That information will take you a long way in figuring out what actions a muscle can do.

ANOTHER EXAMPLE
Let’s look at a neck muscle- the sternocleidomastoid, or SCM. It has two heads which means it originates in two spots: the top of the manubrium (sternum) and the medial third of the clavicle. Its insertion is up behind the ear on the mastoid process and the outer portion of the occiput. When both the left and right right SCM contract together, the origin (which is down on the clavicle and sternum) pulls the insertion toward it to create neck flexion and also assist to lift the rib cage to make more space for inhalation.

My hope is that this makes sense but if you don’t understand and would like to, please send me an email and I’ll break it down even more! If you’re teaching and get confused about what’s the origin and what’s the insertion, you can simply say attachment. But do trust yourself! If you take a moment to think about how the body moves and works, and you know the origin is fixed and the insertion moves, you can likely figure it out for yourself.

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Access Origin and Insertion

Select a Point

Viewing Points

Return to full model

View Origin and Insertion points as a layer map

Select Points from the model

Access Origin and Insertion

To see a muscle’s attachment points, select the muscle from the model. The Infobox for that structure will appear on the left of the screen. Under the title of the structure you will see the option to view the attachment points for that muscle.

Select a Point

Select the Origin and Insertion icon to view the points associated with the selected muscle. Choose an option from the list which appears below. You will be taken into Isolate Mode to view your selection more clearly.

Viewing Points

Your selected point will be highlighted on the model, and additional information about the selection is displayed in the Infobox. Continue to explore other points by either tapping on the model, or choosing an item in the list.

Return to full model

Tap Back in the top-left of the screen to return to the full model.

View Origin and Insertion points as a layer map

Origin and Insertion points are available as a layer of the Skeletal System, which show a map of all attachment points across the full skeleton. Tap the Skeletal System Icon, and press the Plus button until you come to the Origin and Insertion layer (the fourth layers of the system). To hide the points, tap the Skeletal System icon and press the Minus button.

Select Points from the model

When viewing the layer map, select a point from the model by tapping on it. The model zooms in to show the selected point. Information about the point will appear in the Infobox. To view another point on the model, tap it. To view any point in Isolate Mode, select it from the list in the Infobox.

What are insertion points of muscles?

The insertion muscle definition is the site where bone and muscle are attached and move during contraction. The origin of insertion of muscles is typically the tissues' distal attachment, the one furthest from the torso. As the muscle contracts, the insertion and connected bone move closer to the body.

What is insertion and origin in anatomy?

Origin. Insertion. Origin is relatively the less movable end of the muscle/tendon that is attached to a bone. Insertion is the more flexible end of the muscle that is usually attached to a bone via tendons.

What is insertion location?

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What is the point of origin in anatomy?

The origin is the fixed point that doesn't move during contraction, while the insertion does move. Your bones are the levers and your muscles are the pulley.