The function of pectoralis major muscle is:

AIIMS BHOPAL NO- 2018( Shift-2nd)

Applied Anatomy

Easy

Appeared in: AIIMS BHOPAL NO- 2018( Shift-2nd)

Explanation

The pectoralis major is a large, fan-shaped muscle covering the upper part of the chest.
Its primary function as a whole muscle is the adduction (bringing the arm toward the body's midline) and medial rotation of the arm at the glenohumeral (shoulder) joint.
This action is crucial for movements like pulling objects towards the chest or pushing up from a seated position.
While different parts of the muscle can also assist in arm flexion (clavicular head) and extension from a flexed position (sternocostal head), adduction is its main role.

Option A: Flexion of the elbow is incorrect. This movement is primarily performed by the biceps brachii and brachialis muscles, which are located in the anterior compartment of the arm.
Option C: Extension of the elbow is incorrect. This action, which straightens the arm, is the primary function of the triceps brachii muscle, located on the posterior aspect of the arm.
Option D: Abduction of the arm is the opposite of the pectoralis major's primary function. Abduction involves moving the arm away from the body's midline and is primarily carried out by the deltoid muscle.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Function of the pectoralis major muscle as background academic context rather than a clinical decision trigger.
Rupture or tear of the pectoralis major muscle is a significant injury often seen in athletes, particularly during weightlifting (e.g., bench press). It results in sudden pain, bruising, and weakness in arm adduction and internal rotation.
The pectoralis major muscle is an important surgical landmark and is often utilized as a myocutaneous flap in reconstructive surgery for the head, neck, and chest wall due to its reliable blood supply.
What if the patient presents with 'winging' of the scapula (the medial border of the scapula protrudes from the back)? This would not be related to the pectoralis major, but rather indicates paralysis of the serratus anterior muscle, usually due to injury to the long thoracic nerve.

How to Approach the Question

First, identify the key term in the question stem, which is 'pectoralis major muscle'.
Recognize this as a factual recall question from the subject of anatomy.
Mentally access your knowledge about the major muscles of the upper torso and their actions on the shoulder and arm.
Recall that the pectoralis major is a large chest muscle that attaches to the humerus (arm bone). Its main job is to pull the arm towards the chest.
Systematically evaluate each option against this knowledge:
'Flexion of elbow' and 'Extension of elbow' relate to the elbow joint, primarily involving muscles of the upper arm like the biceps and triceps, not the chest.

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