The pectoral region is located on the anterior chest wall. Theyre different muscles as stated in the collapsed answers. The shortened, tight muscle can be easily palpated there. In this tutorial we will guide you through the anatomy of the pectoralis major muscle. Identifying the attachments of origin and insertion enhances body awareness, which can increase performance and decrease the risk of injury. Sternocostal headlateral manubrium and sternum, six upper costal cartilages and external oblique aponeurosis. Both the clavicular and sternal heads of the pectoralis major muscle have the same two points of insertion. Patients with injuries at the muscle origin or belly, including contusions and strains, usually are. Fiber direction from origin to insertion is important in understanding how. The pectoralis major muscle is a large muscle in the upper chest, fanning across the chest from the shoulder to the breastbone. The upper fibers clavicular portion are responsible for horizontal adduction towards the opposite shoulder while maintaining slight medial rotation of the humerus. Its origin lies anterior surface of the medial half of the clavicle, the anterior.
There are many ways in which the pectoralis major muscle can be exercised. Pectoralis major function, origin, insertion, innervation. Pectoralis major muscle attachments and actions related to yoga. The pectoralis major is the most superficial muscle in the pectoral region. Part or all of the tendon may transverse this process and continue into the coracoacromial ligament.
Beneath the pectoralis major is the pectoralis minor, a thin, triangular muscle. With the insertion fixed, it may assist in elevating thorax, as in forced. Pectoralis major muscle anatomy anatomyzone youtube. Anterior surface of the medial half of the clavicle insertion. Pectoralis major muscle attachments and actions related to. Clavicular head originates from the anterior surface of the medial clavicle sternocostal head originates from the anterior surface of the sternum, the superior six costal cartilages and the aponeurosis of the external oblique muscle insertion. Via a tendon to the medial aspect of the coracoid process of the scapula.
Every one of the three parts has its own and separate origin, while all its fibers fuse together at the same spot, namely at the upper side of your arm pit. What is the difference between a pectoralis major and a. Anatomy, thorax, pectoralis major major statpearls. There are 2 heads of the pectoralis major, the clavicular and the sternocostal, which reference their area of origin12. The muscle lying over the clavicle will produce a prominent bulge. Its innervated by both medial and lateral pectoral nerves.
To view the pectoralis major, you must cut away a large amount of superficial muscle and connective tissue. The pectoralis minor is triangular in shape and is located under the pectoralis major, and both form the anterior wall of the axilla. May 23, 2017 insertion the two divisions of pectoralis major come together to insert on the lateral outside lip of the bicipital groove. These two points of insertion are both located on the. The clavicular head innervation arises from the spinal segments of c5 and c6, but the sternocostal head innervation arises from c7, c8 and t1. Anatomy, thorax, pectoralis major major statpearls ncbi bookshelf. Us and mr imaging of pectoralis major injuries radiographics. The clavicular head originates from the anterior portion of the medial half of the clavicle. In this episode, leslie samuel talks more about the first of four pectoral muscles, the pectoralis major. Start studying pectoral muscles origin, insertion, action, innervation. Since the pectoralis minor muscle is smaller and located underneath the pectoralis major, this muscle is thought of as the little brother muscle of the chest. Muscle and motion pectoralis major, origin, insertion. The mean maximal thickness at the humeral insertion was 1.
Epidemiology mostly young, physicallyactive males age 2040 years old, although has also reported in elderly women 1 a. The pectoralis major muscle is innervated by the lateral and medial pectoral nerves which are the branches of the brachial plexus. Pectoralis minor with a proximal insertion origin at the superior and ventral surfaces or ribs 35 and a lateral insertion at the coracoid process of the scapula, p. While it is possible to do just by wiggling around the blunt probe and using your fingers, you should be careful not to cut or damage any muscles under the pectoralis.
Learn vocabulary, terms, and more with flashcards, games, and other study tools. Origin insertion action arterial supply innervation i hope you enjoy this. After harvesting the myocutaneous flap, the whole pectoralis major muscle together with the skin paddle is turned upwards to the head and neck region. Insertion medial and upper surface of coracoid process of scapula. With the insertion fixed, it may assist in elevating thorax, as in forced inspiration. The sternocostal head is described as having between 2 to 7 distinct segments. In attaching to the coracoid process, the pectoralis minor forms a bridge structures passing into the upper limb from the thorax will pass directly underneath. It is also located close in relation to the brachial plexus and both the subclavian artery and vein, which all run between the muscle and the rib cage. It makes up the bulk of the chest muscles in the male and lies under the breast in case of the female. The upper and lower fibers of pectoralis major insert to the crest of greater tubercle of the humerus. In humans it is one of two pectoral muscles and it is smaller than pectoralis major but in the cat it is the largest of the four pectoral muscles. The above drawing of the origin and insertion might help visualize this information red is the origin, blue the insertion.
The pectoralis major is composed mainly of two parts the clavicular head and the sternocostal head. It makes up the bulk of the chest muscles and lies under the breast. In crunchwalking or parallelbar work, it will assist in supporting the weight of the body. The pectoralis major muscle consists of clavicular and sternal heads fig 1 and variable contributions from the costal attachments inferior to the sternum, which are sometimes considered to be an abdominal head. The insertion of the pectoralis major is at the lateral lip of the.
With the origin fixed, the pectoralis major adducts and medially rotates the humerus. The medial pectoral nerve pierces the pectoralis minor and the clavipectoral fascia. The pectoralis major from latin pectus, meaning breast is a thick, fanshaped muscle, situated at the chest of the human body. Flexion, adduction and internal rotation of the arm at shoulder innervation. To improve the morbidity of the disorder, an interprofessional team approach is a recommendation. Learn about the anatomy of the pectoralis major muscle, its origin, insertion, and action. In this article, we shall look at the anatomy of the muscles of the pectoral region their attachments, actions and innervation. The flat barbell bench press and the flat dumbbell bench press both involve utilizing the pectoralis major muscle. The mean proximal to distal dimension of the pectoralis major insertion was 72. It consists of a clavicular part and a sternal part, both converging to a flat tendon that inserts on the humerus. Jul 17, 2016 in this tutorial we will guide you through the anatomy of the pectoralis major muscle. Action elevates ribs if scapula fixed, protracts scapula assists serratus anterior nerve medial pectoral nerve c8, t1 from medial cord. Depending on the position of the humerus, the pectoralis major muscle can adduct, flex, and internally rotate the humerus against a stable thorax.
The bicipital groove is the groove at the top of the humerus that the biceps tendon passes through. The muscle anatomy of the pectoralis major origin, insertion, action, innervation and vascular supply. The function of this action is to facilitate overhead upper limb movements such as pulling and throwing. When working in synergy with teres major, latissimus dorsi and pectoralis major, teres minor adducts the arm from the abducted position lowers it. From this extensive origin the fibers converge toward their insertion. Pectoral muscles origin, insertion, action, innervation. From the outside the pectoralis major looks like one muscle. At which of the following points during a bench press is the pectoralis major insertion at greatest risk of rupture. The origin of the pectoralis major includes the clavicle, sternum, the costal cartilage of the upper ribs, and the aponeurosis of the external obliques. Pectoralis major tears are rare injuries, and there may be a delay in the presentation to the emergency department or primary care provider.
It contains four muscles that exert a force on the upper limb. Jan 11, 2017 injuries of the pectoralis major can also be categorized according to their location. Pectoralis minor muscle origin, insertion, action the. Note that the pectoralis major is one of the five muscles in the group we refer to as the muscles that move the arm not including the rotator cuff muscles. If not, take the time to find out with this lesson. Insertional footprint anatomy of the pectoralis major tendon. Pectoralis major muscle an overview sciencedirect topics. Muscles of the pectoral region major minor teachmeanatomy. Pectoralis major muscle origin of pectoralis major clavicular head. Insertion the two divisions of pectoralis major come together to insert on the lateral outside lip of the bicipital groove. Anatomy, thorax, pectoralis major major statpearls ncbi. There are 2 heads of the pectoralis major, the clavicular and the sternocostal, which reference their area of origin 12. Pectoralis major is a thick, fanshaped muscle contributing to the thoracobrachial motion. From a wide sternoclavicular origin the muscle converges on the upper humerus, folding on itself where it forms the anterior axillary wall to become attached to the humerus by means of a trilaminar tendon.
Medial pectoral nerve c8, t1 from medial cord and lateral pectoral nerve c5, c6, c7 from lateral cord. Lateral lip of the bicipital groove of the humerus and anterior lip of the deltoid tuberosity actions. The insertion of the pectoralis major is at the lateral lip of the intertubercular sulcus of the humerus. Pectoralis major tears, also known as pectoralis major ruptures, are an uncommon traumatic injury of the pectoralis major. Pectoralis major is a thick, fanshaped muscle, situated at the chest of the human body. The clavicular head is the most superior unit of the pectoralis major and is a single architectural segment that cannot be further divided. Pectoralis minor is one of the five muscles that are grouped as muscles of the scapula, or sometimes as muscles that moor the scapula. The multiple muscle head origins and crossing pattern of insertion allow the pectoralis major muscle to exert a wide range of actions on the humerus.
Jan 02, 2019 theyre different muscles as stated in the collapsed answers. Both divisions are on the same origininsertion drawing. The biarticulate sternal head of the pectoralis major enters passive insufficiency through the completion of shoulder transverse extension or transverse abducted when the shoulder girdle is more retracted or through the completion of shoulder abduction when the scapula is more rotated upward and elevated. Pectoralis major origin, insertion, actions, innervation.