Pectoralis Minor Muscle Anatomy

Pectoralis Minor Location

Pectoralis minor muscle extends from the front side of the upper ribs to the top of the shoulder blade (scapula).

Origin

• Anterior surfaces (near the cartilages) of the ribs 3-5 ^[1]

Insertion

• Coracoid process of the scapula ^[1]

Functions (Actions)

• Draws scapula forward and downward (when the ribs are fixed) ^[1]
• Elevates the rib cage (when the scapula is fixed) and thus assists inhalation ^[1]

Innervation

• Medial pectoral nerve from the spinal roots C8 and T1 ^[1]

Blood Supply

• Pectoral branch of the thoracoacromial trunk

Picture 1. Pectoralis minor origin, insertion and function

Video 1. Pectoralis minor anatomy: origin, insertion, actions,
synergistic and antagonistic muscles,
trigger points locations and causes

Related anatomy: shoulder muscles

Pectoralis Minor Pain

Acute pain in the pectoralis minor can be caused by muscle contusion, strain or tear.

Chronic pain (myofascial pain) in the pectoralis minor can develop after a car accident, using crutches, carrying a heavy backpack, severe coughing, anxiety, poor posture with a bent head and rounded shoulders (Video 1).

Pectoralis Minor Strength Test

Raise an arm sideways by about 120 degrees and then try to move it down toward the opposite hip against the examiner’s resistance (Video 2). Decreased strength of the pectoralis minor (as opposed to the other side) speaks for muscle strain or tear.

Video 2. Pectoralis minor strength test

• References

  1. Pectoralis minor muscle  GetBodySmart
  2. Pectoralis minor  University of Washington, Department of Radiology