# Muscles # Musculus rectus abdominis (xlas)
Preview: simple/clean drawings; lots of additional info (+latin names)
*Synonyms: abs; rectus abdominis muscle; straight abdominis muscle; six pack; six-pack; sixpack; rectus* --- ### **Summary** The *Musculus rectus abdominis*, often referred to as "**abs**" (short for "abdominal muscles"), sits in front of your stomach and is visible on trained and **low body fat** people. In fact, there are two individual muscle cords right next to each other (that's why I'll refer to them in plural). Besides being used for **breathing** the muscles also **bend the torso and lift the pelvis forward** - thus the abs are the main antagonist of the back extensor muscles (*M. erector spinae*). There are **tendons that separate the long muscle cords into packs** for better muscle contraction precision. #### **Basics** [![visual introduction.jpg](https://www.anatomyarchive.org/uploads/images/gallery/2025-04/visual-introduction.jpg)](https://www.anatomyarchive.org/uploads/images/gallery/2025-04/visual-introduction.jpg)*general placement of the M. rectus abdominis* *[![visual intro 2 - general tips.jpg](https://www.anatomyarchive.org/uploads/images/gallery/2025-04/scaled-1680-/visual-intro-2-general-tips.jpg)](https://www.anatomyarchive.org/uploads/images/gallery/2025-04/visual-intro-2-general-tips.jpg)some "good to know" things; the size relations are more important than you think* You can read more about "8 packs" in the [advanced](https://www.anatomyarchive.org/link/21#bkmrk-details-%28text-%2B-pict) section below. The 1st row of packs deviates on almost every human being. In general this means, if you draw perfectly aligned abs, they will look less natural. #### **Origin** - Pubic bone (*Os pubis*), more specifically on the **superior pubic ramus** (*Ramus superior*; ramus = branch) - **Pubic symphysis** (*Symphysis pubica*), thats the cartilage between the two pubic bones #### **Insertion** - Cartilage of the **5th, 6th and 7th rib** (there is cartilage at the front tip of each rib) - Some muscle fibers connect to the **breastbone (*Sternum*)** **[![origin and insertion.jpg](https://www.anatomyarchive.org/uploads/images/gallery/2025-04/scaled-1680-/XMJorigin-and-insertion.jpg)](https://www.anatomyarchive.org/uploads/images/gallery/2025-04/XMJorigin-and-insertion.jpg)***origin and insertion; some sources do it the other way round, but it doesn't really matter* #### **Functions** - Bending and crunching the torso forward; the familiar **"sit up" motion** represents this function pretty well - **Lifting/twisting the pelvis forward** - Breathing control; the abs are used mainly for **exhaling** #### **How to draw the muscle** [![viewpoints 1.jpg](https://www.anatomyarchive.org/uploads/images/gallery/2025-04/scaled-1680-/viewpoints-1.jpg)](https://www.anatomyarchive.org/uploads/images/gallery/2025-04/viewpoints-1.jpg)*this shape helps you drawing the abs; it's a little more emphasized on female bodies* [![trained.jpg](https://www.anatomyarchive.org/uploads/images/gallery/2025-04/scaled-1680-/trained.jpg)](https://www.anatomyarchive.org/uploads/images/gallery/2025-04/trained.jpg)*the two main factors are training and body fat percentage; note that women naturally have more subcutaneous fat* ### **Advanced**
Everything beyond the basics The **tendinous intersections** (*Intersectiones tendineae*) determine how many packs you can have. **Most people (around 60%)** have 3 intersections which equals to **6 possible packs**. In some media you see people with 8 packs to empathize their strength. The visual effect works, but in reality more packs don't make you stronger. Only around **20% even have 4 intersections = 8 possible packs**, which means its based on luck (genetics) if you are even able to develop an 8 pack. Chances for 2, 4 or 10 packs are even lower than 20%. [![8 pack.jpg](https://www.anatomyarchive.org/uploads/images/gallery/2025-04/scaled-1680-/8-pack.jpg)](https://www.anatomyarchive.org/uploads/images/gallery/2025-04/8-pack.jpg)*a side by side view for 6 and 8 packs; 10 packs just means that there is another intersection below that*
#### **Reference Pictures (for study only)**
From Wikimedia, Pixabay, Unsplash [![DSC_0013_(5967650617).jpg](https://www.anatomyarchive.org/uploads/images/gallery/2025-05/scaled-1680-/dsc-0013-5967650617.jpg)](https://www.anatomyarchive.org/uploads/images/gallery/2025-05/dsc-0013-5967650617.jpg) *credit to: [JoeInQueens](https://commons.wikimedia.org/wiki/File:DSC_0013_(5967650617).jpg)* *[![adult-1867743_1920.jpg](https://www.anatomyarchive.org/uploads/images/gallery/2025-05/scaled-1680-/adult-1867743-1920.jpg)](https://www.anatomyarchive.org/uploads/images/gallery/2025-05/adult-1867743-1920.jpg)* *credit to: [Pexels](https://pixabay.com/users/pexels-2286921/)* *[![Inder_mohan_Singh_Bodybuilder.jpg](https://www.anatomyarchive.org/uploads/images/gallery/2025-05/scaled-1680-/inder-mohan-singh-bodybuilder.jpg)](https://www.anatomyarchive.org/uploads/images/gallery/2025-05/inder-mohan-singh-bodybuilder.jpg)* *credit to: [Inder Mohan Singh Bodybuilder](https://commons.wikimedia.org/wiki/File:Inder_mohan_Singh_Bodybuilder.jpg)* *[![man-6361657_1280.jpg](https://www.anatomyarchive.org/uploads/images/gallery/2025-05/scaled-1680-/man-6361657-1280.jpg)](https://www.anatomyarchive.org/uploads/images/gallery/2025-05/man-6361657-1280.jpg)* *credit to: [Felipesilvasilva](https://pixabay.com/photos/man-fashion-portrait-model-abs-6361661/)* *[![man-6361661_1280.jpg](https://www.anatomyarchive.org/uploads/images/gallery/2025-05/scaled-1680-/man-6361661-1280.jpg)](https://www.anatomyarchive.org/uploads/images/gallery/2025-05/man-6361661-1280.jpg)* *credit to: [Felipesilvasilva](https://pixabay.com/photos/man-fashion-portrait-model-abs-6361661/)* *[![Annual_Northern_Japan_Bodybuilding_Championships_in_1999.JPEG](https://www.anatomyarchive.org/uploads/images/gallery/2025-05/scaled-1680-/annual-northern-japan-bodybuilding-championships-in-1999.JPEG)](https://www.anatomyarchive.org/uploads/images/gallery/2025-05/annual-northern-japan-bodybuilding-championships-in-1999.JPEG)* *credit to: [SSGT Milo E. Ware, Jr.](https://commons.wikimedia.org/wiki/File:Annual_Northern_Japan_Bodybuilding_Championships_in_1999.JPEG)* *[![aliya-amangeldi-vQtyDXOyb0Y-unsplash.jpg](https://www.anatomyarchive.org/uploads/images/gallery/2025-05/scaled-1680-/aliya-amangeldi-vqtydxoyb0y-unsplash.jpg)](https://www.anatomyarchive.org/uploads/images/gallery/2025-05/aliya-amangeldi-vqtydxoyb0y-unsplash.jpg)* *credit to: [Aliya Amangeldi (@aliyaamangeldi\_photography)](https://unsplash.com/de/fotos/eine-frau-in-blauem-top-und-schwarzen-shorts-vQtyDXOyb0Y)* *[![fitness-7124954_1280.jpg](https://www.anatomyarchive.org/uploads/images/gallery/2025-05/scaled-1680-/fitness-7124954-1280.jpg)](https://www.anatomyarchive.org/uploads/images/gallery/2025-05/fitness-7124954-1280.jpg)* *credit to: [Maxhomefitness](https://pixabay.com/users/maxhomefitness-26533097/)* *[![fitness-1847866_1920.jpg](https://www.anatomyarchive.org/uploads/images/gallery/2025-05/scaled-1680-/fitness-1847866-1920.jpg)](https://www.anatomyarchive.org/uploads/images/gallery/2025-05/fitness-1847866-1920.jpg)* *credit to: [calibra](https://pixabay.com/users/calibra-251645/)* *[![brian-lee--hZu2MbpEzw-unsplash.jpg](https://www.anatomyarchive.org/uploads/images/gallery/2025-05/scaled-1680-/brian-lee-hzu2mbpezw-unsplash.jpg)](https://www.anatomyarchive.org/uploads/images/gallery/2025-05/brian-lee-hzu2mbpezw-unsplash.jpg)* *credit to: [Brian Lee (@sd\_cosplayfit)](https://unsplash.com/de/fotos/frau-in-weissem-sport-bh-und-schwarzen-shorts-mit-schwarzer-hantel--hZu2MbpEzw)* *[![Abdominal_muscles_of_a_woman.jpg](https://www.anatomyarchive.org/uploads/images/gallery/2025-05/scaled-1680-/abdominal-muscles-of-a-woman.jpg)](https://www.anatomyarchive.org/uploads/images/gallery/2025-05/abdominal-muscles-of-a-woman.jpg)* *credit to: [Russ Anderson](https://commons.wikimedia.org/wiki/File:Abdominal_muscles_of_a_woman.jpg)* *[![man-6132513_1920.jpg](https://www.anatomyarchive.org/uploads/images/gallery/2025-05/scaled-1680-/man-6132513-1920.jpg)](https://www.anatomyarchive.org/uploads/images/gallery/2025-05/man-6132513-1920.jpg)* *credit to: [yeye8686](https://pixabay.com/users/yeye8686-20901268/)* *[![sport-1685777_1920.jpg](https://www.anatomyarchive.org/uploads/images/gallery/2025-05/scaled-1680-/sport-1685777-1920.jpg)](https://www.anatomyarchive.org/uploads/images/gallery/2025-05/sport-1685777-1920.jpg)* *credit to: [Keifit](https://pixabay.com/photos/sport-fitness-exercise-pilates-1685777/)* *[![body-6818346_1280.jpg](https://www.anatomyarchive.org/uploads/images/gallery/2025-05/scaled-1680-/body-6818346-1280.jpg)](https://www.anatomyarchive.org/uploads/images/gallery/2025-05/body-6818346-1280.jpg)* *credit to: [Raman\_Spirydonau](https://pixabay.com/users/raman_spirydonau-11910217/)*