Pectoralis Major -The ARM MOVERS

The Pectoralis major is a muscle of the pectoral region. This muscle along with the Pectoralis minor, Subclavius and Serratus anterior forms the pectoral region. It is the largest muscle in this region. Morphologically it is thin and fan-shaped. It is characterized by 2 heads, the large Sternocostal head, and the small Clavicular head.

ORIGIN

The Sternocostal head arises from-

Medial parts of 2nd-6th costal cartilages and aponeurosis of the external oblique muscle of the abdomen.
Lateral half of the anterior surface of the sternum up to 6th costal cartilage.

The Clavicular head arises from the medial half of the anterior aspect of the clavicle.

INSERTION

Pectoralis major is inserted by a bilaminar tendon on the lateral lip of the bicipital groove of the humerus. This tendon has an anterior lamina and a posterior lamina.

Anterior lamina is thick, short and is formed by clavicular fibers.
Posterior lamina is thin, long and is formed by sternocostal and aponeurotic fibers.

NERVE SUPPLY

Pectoralis major is supplied by medial (C8 and T1) and lateral pectoral (C5-C7) nerves.

Important fact-The Pectoralis major and Pectoralis minor are the only muscles of the upper limb which are supplied by all 5 spinal segments that form the Brachial plexus.

BLOOD SUPPLY

The Pectoralis major is supplied by the pectoral branch of the Thoracoacromial trunk which is a branch of the second part of the axillary nerve.

ACTIONS

The Clavicular head is responsible for flexing the arm.
The Sternocostal head is involved in adduction and medial rotation of the arm.

CLINICAL ANATOMY

Poland syndrome involves malfunction of the chest which is caused due to the absence of a Pectoralis major on one side.
Congenital anomaly of a part of the Pectoralis major causes difficulty in adduction and medial rotation of the arm.

CLINICAL TESTING
While lifting a heavy load the clavicular head becomes prominent and while depressing the load the Sternocostal head becomes prominent.

-By Varsha Joshi

Comments

What is Anatomical pulley? Example of Anatomical pulley

Understanding the Importance of Anatomical Pulleys in Physiotherapy As a physiotherapy student, it is essential to have a good understanding of the human body's anatomy and how it works. One of the essential structures in the body that plays a significant role in movement and biomechanics is the anatomical pulley. In this article, we will explore what an anatomical pulley is, its types, and its importance in physiotherapy. What is an Anatomical Pulley? A pulley is a simple mechanical machine that consists of a wheel that turns readily on the axle, usually grooved for a rope or a wire cable. In the human body, the pulley is replaced by a bone, cartilage, or ligament, and the cord is replaced by a muscle tendon. The tendon is lubricated by synovial fluid, and the surface of the tendon is covered by a thin visceral synovial membrane. The tendon is lubricated so that it may easily slide over the pulley. Classification of Anatomical Pulleys There are mainly four classes of pulleys

Electrotherapy Simplified by Basanta Kumar Nanda PDF Download

Electrotherapy Simplified by Basanta Kumar Nanda The aim of this book is to focus on the electrotherapy simplified. Electrotherapy is one of the important aspects among the various approaches of patient management available to a physiotherapist. Electrotherapy Simplified has tried to give comprehensive knowledge on electrotherapy and actinotherapy, starting from basic electricity and magnetism to the theoretical and clinical aspects of the different modalities applied by physiotherapists. This book consists of 19 chapters, which include an introduction, inflammation, repair, and role of physical agents, electrical fundamentals, magnetic energy, valves, transistors, and rectifiers, electrical measurement systems and distribution of electricity, electrophysiology of nerve transmission, and muscle contraction, low-frequency currents, electrodiagnosis, medium frequency currents, low-intensity laser therapy, ultraviolet radiation, and traction. About 250 objective question answers have b

Range of Muscle work in Physiotherapy

The degree of the movement done by muscle contraction is known as the Range of muscle work. The range can be measured with the help of a goniometer. Movement is a very complex mechanism, a lot of muscles are working in a group and in synchronized pattern to draw out the perfect desirable movement. As per function we already talked about Agonist, antagonist, Synergist, and fixator muscles.

#stayfitwithanand

Search This Blog