The Pectoralis Major Muscle

Pectoralis Major Muscle

David Keil Anatomy, Torso, Upper Limb 1 Comment

Exploring the pectoralis major muscle

Pectoralis major is one of the muscles that move the humerus at the shoulder joint. It’s a broad, powerful muscle and the larger of the two pectoralis muscles. Everyone is familiar with bodybuilders squeezing their arms in front of their body to show off their big “pecs”! That is the very same pectoralis major muscle we’re talking about here.

We show you some yoga postures below related to this muscle. I’ll also mention that this muscle is what the beginner’s body is after when they try to do a posture such as chaturanga dandasana, but can’t keep their elbows in. Their body is moving their elbows out to take advantage of this larger muscle in its action of horizontal abduction!

What does pectoralis major mean?

The name pectoralis major describes the general location of this muscle.

Pectoralis comes from the Latin word “pectus” meaning breast.

Major comes from Latin and means “greater than”.

Where does the pectoralis major attach?

There are two divisions of pec major – the sternal and clavicular divisions.The Pectoralis Major Muscle

 

Origin

The clavicular portion originates on the medial (inner) half of the clavicle (collar bone).

The sternal portion originates on the sternum and the upper 6 ribs.

Insertion

The two divisions of pectoralis major come together to insert on the lateral (outside) lip of the bicipital groove. The bicipital groove is the groove at the top of the humerus that the biceps tendon passes through.

What actions does the pectoralis major do?

Fiber direction from origin to insertion is important in understanding how this muscle creates its actions.

The origin of pectoralis is broad and its insertion is small. This means that pec major can create opposite actions depending on the circumstances.

It can create a number of actions including:

  • medial rotation
  • flexion
  • horizontal flexion

It assists in adduction.

The lower fibers can create extension from a flexed position if there is a resistance to movement.

Because of this last muscle movement, the pectoralis major could be seen to be an antagonist to itself.

Postures where the pectoralis major muscle contracts:

pectoralis major muscle in upluthih

In utpluthih or tolasana, this muscle will contract and shorten.

pectoralis major muscle in chaturanga dandasana

When we lower down in postures like chaturanga, pectoralis major will work along with the triceps doing an eccentric contraction to control the movement.

Postures where the pectoralis major muscle is lengthened:

pectoralis major muscle in dhanurasana

Dhanurasana (bow pose) moves the shoulder girdle back, internally rotates the humerus, and does a horizontal extension, lengthening pectoralis major

pectoralis major muscle in urdhva dhanurasana

Urdhva dhanurasana (backbend) lengthens the lower fibers of pectoralis major.

Trigger points

Trigger Points in Pectoralis Major

Trigger Points in Pectoralis Major

Trigger Points in Pectoralis Major

Trigger Points in Pectoralis Major

Join thousands of yogis when you sign up to our monthly newsletter

  • This field is for validation purposes and should be left unchanged.
Join thousands of yogis when you sign up to our monthly newsletter
  • This field is for validation purposes and should be left unchanged.

Check out our Online Courses and Workshops

c-yoga-anatomy-course-main
  • Enhance your practice
  • Fine tune your teaching skills
  • Go deeper into anatomy and yoga

Related Posts

The Soleus Muscles

The Soleus Muscles

This month David highlights the soleus muscles. Learn where these lower leg muscles are found, what they do, and what yoga postures use them.

Read More »

Popular Posts

About David Keil

This website is simply about delivering yoga anatomy to the yoga community in a simple and understandable way. It has always been about you, the reader, understanding the complexity and diversity of our own humanness as well as our anatomy.

Follow us on:

Comments 1

  1. Pingback: Slouching and Consequences – Dr. Marr

Leave a Reply