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Encyclopedia > Pectoralis major muscle
Pectolaris major
Pectoralis major
Latin Musculus pectoralis major
Gray's subject #122 436
Origin: Kank: anterior surface of the medial half of the clavicle.
Sternocostal head: anterior surface of the sternum, the superior six costal cartilages, and the
Insertion: intertubercular groove of the humerus
Artery: pectoral branch of the thoracoacromial trunk
Nerve: lateral pectoral nerve and medial pectoral nerve
Clavicular head: C5 and C6
Sternocostal head: C7, C8 and T1
Action: Clavicular head: flexes the humerus
Sternocostal head: extends the humerus
As a whole, adducts and medially rotates the humerus. It also draws the scapula anteriorly and inferiorly.
MeSH Pectoralis+Muscles
Dorlands/Elsevier m_22/12550129

The Pectoralis major is a thick, fan-shaped muscle, situated at the upper front (anterior) of the chest wall. It makes up the bulk of the chest muscles in the male and lies under the breast in the female. Image File history File links Pectoralis major muscle Original by sv:Användare:Chrizz, 27 maj 2005 compressed with pngcrush File links The following pages link to this file: Pectoralis major muscle ... For other uses, see Latin (disambiguation). ... A typical adult human skeleton consists of the following 206 bones depending on age, though this number does vary owing to a variety of anatomical variations; for example, a small portion of the human population have an extra rib, or an extra lumbar vertebra. ... Collarbone and collar bone redirect here. ... The sternum (from Greek στέρνον, sternon, chest) or breastbone is a long, flat bone located in the center of the thorax (chest). ... The costal cartilages are bars of hyaline cartilage which serve to prolong the ribs forward and contribute very materially to the elasticity of the walls of the thorax. ... A typical adult human skeleton consists of the following 206 bones depending on age, though this number does vary owing to a variety of anatomical variations; for example, a small portion of the human population have an extra rib, or an extra lumbar vertebra. ... The tubercles of the humerus are separated from each other by a deep groove, the intertubercular groove (bicipital groove, sulcus intertubercular), which lodges the long tendon of the Biceps brachii and transmits a branch of the anterior humeral circumflex artery to the shoulder-joint. ... The humerus is a long bone in the arm or fore-legs (animals) that runs from the shoulder to the elbow. ... Section of an artery For other uses, see Artery (disambiguation). ... The thoracoacromial artery (a. ... Axillary artery and its branches - anterior view of right upper limb and thorax. ... List of human nerves External links List of nerves This is an incomplete list, which may never be able to satisfy certain standards for completeness. ... The Anterior Thoracic Nerves supply the Pectorales major and minor. ... Grays Fig. ... C5 or C-5 may refer to: An inactive complement protein of the complement system. ... C6 or C-6 may refer to: C6, the IATA code for CanJet. ... C7 or C-7 may refer to: The Diemaco C7, a rifle. ... C8 or C-8 may refer to: The Diemaco C8, a rifle. ... Digital Signal 1, originally over a T1 interoffice trunk or Transmission Level 1 telecommunications line in North America and Japan T1 General tax form used in Canada for personal tax returns T1 spinal nerve first thoracic vertebrae The Terminator (movie) T-1 T-1 Jayhawk, a twin-engined jet aircraft... Look up kinesiology in Wiktionary, the free dictionary. ... The term flex, when used by itself, can refer to: Flex Loader FLEX (operating system) Flex lexical analyser Flex machine Flex as colloquial for electrical cable or flexible electronics A flex point on a curve Flex (magazine) Macromedia Flex Flex is the name of a family of automatic test equipment... The humerus is a long bone in the arm or fore-legs (animals) that runs from the shoulder to the elbow. ... Anatomical planes in a human. ... Anatomical planes in a human Adduction is a movement which brings a limb - arm or leg - closer to the body in the sagittal plane. ... Internal rotation (or medial rotation) is rotation towards the center of the body. ... The humerus is a long bone in the arm or fore-legs (animals) that runs from the shoulder to the elbow. ... Left scapula - front view () Left scapula - rear view () In anatomy, the scapula, or shoulder blade, is the bone that connects the humerus (arm bone) with the clavicle (collar bone). ... Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. ... Elseviers logo. ... In zootomy, several terms are used to describe the location of organs and other structures in the body of bilateral animals. ... Male Chest The chest is a part of the anatomy of humans and various other animals. ...

Contents

Origin and insertion

It arises from the anterior surface of the sternal half of the clavicle; from breadth of the half of the anterior surface of the sternum, as low down as the attachment of the cartilage of the sixth or seventh rib; from the cartilages of all the true ribs, with the exception, frequently, of the first or seventh and from the aponeurosis of the abdominal external oblique muscle. Collarbone and collar bone redirect here. ... The sternum (from Greek στέρνον, sternon, chest) or breastbone is a long, flat bone located in the center of the thorax (chest). ... The human rib cage. ... Aponeurosis is the singular of Aponeuroses Grays Anatomy states that Aponeuroses are flattened or ribbon-shaped tendons, of a pearly white color, iridescent, glistening, and similar in structure to the tendons. ... The external oblique muscle (of the abdomen) (also external abdominal oblique muscle) is the largest and the most superficial (outermost) of the three flat muscles of the lateral anterior abdomen. ...


From this extensive origin the fibers converge toward their insertion; those arising from the clavicle pass obliquely downward and outwards (laterally), and are usually separated from the rest by a slight interval; those from the lower part of the sternum, and the cartilages of the lower true ribs, run upward and laterally, while the middle fibers pass horizontally.


They all flat in an end tendon, about 5 cm. in breadth, which is inserted into the crest of the greater tubercle of the humerus.


Laminae

This tendon consists of two laminae, placed one in front of the other, and usually blended together below. This article is about the leaf, a plant organ. ...

  • The anterior lamina, which is thicker, receives the clavicular and the uppermost sternal fibers. They are inserted in the same order as that in which they arise: the most lateral of the clavicular fibers are inserted at the upper part of the anterior lamina; the uppermost sternal fibers pass down to the lower part of the lamina which extends as low as the tendon of the Deltoid and joins with it. Hi from trent
  • The posterior lamina of the tendon receives the attachment of the greater part of the sternal portion and the deep fibers, i. e., those from the costal cartilages.

These deep fibers, and particularly those from the lower costal cartilages, ascend the higher, turning backward successively behind the superficial and upper ones, so that the tendon appears to be twisted. Deltoid can refer to: The deltoid muscle, a muscle in the shoulder A deltoid curve, a three-sided hypocycloid A type of quadrilateral A leaf shape The deltoid tuberosity, a part of the humerus Delta, an article with related definitions. ... The costal cartilages are bars of hyaline cartilage which serve to prolong the ribs forward and contribute very materially to the elasticity of the walls of the thorax. ...


The posterior lamina reaches higher on the humerus than the anterior one, and from it an expansion is given off which covers the intertubercular groove of the humerus and blends with the capsule of the shoulder-joint. The humerus is a long bone in the arm or fore-legs (animals) that runs from the shoulder to the elbow. ...


From the deepest fibers of this lamina at its insertion an expansion is given off which lines the intertubercular groove, while from the lower border of the tendon a third expansion passes downward to the fascia of the arm. hi from zach zastro Fascia is specialized connective tissue layer which surrounds muscles, bones, and joints, providing support and protection and giving structure to the body. ...


Variations

The more frequent variations include greater or less extent of attachment to the ribs and sternum, varying size of the abdominal part or its absence, greater or less extent of separation of sternocostal and clavicular parts, fusion of clavicular part with deltoid, and decussation in front of the sternum. This article is about the bones called ribs. ... The sternum (from Greek στέρνον, sternon, chest) or breastbone is a long, flat bone located in the center of the thorax (chest). ... For the human abdomen, see human abdomen. ... Collarbone and collar bone redirect here. ... Deltoid can refer to: The deltoid muscle, a muscle in the shoulder A deltoid curve, a three-sided hypocycloid A type of quadrilateral A leaf shape The deltoid tuberosity, a part of the humerus Delta, an article with related definitions. ... Decussation is used in biological contexts to describe a crossing. ...


Deficiency or absence of the sternocostal part is not uncommon.


Absence of the clavicular part is less frequent.


Rarely, the whole muscle is missing. This may accompany absence of the breast in females. (See Poland Syndrome). Named after Sir Alfred Poland (ironically not a Pole, but still Polish), Poland anomaly (PA) is described as an underdevelopment or absence of the chest muscle (pectoralis) on one side of the body and webbing of the fingers (cutaneous syndactyly) of the hand on the same side (ipsilateral hand). ...


Training

In addition to being one of the primary pushing muscles of the upper body, the pectoral is a frequent target for bodybuilding. The flat, barbell bench press is the most popular exercise. The pushup is a popular bodyweight exercise targeting the pectoralis major. The muscle is generally worked in compound movements that involve pushing, where the triceps brachii and deltoid muscles are also activated to varying degrees. Exercises that bring the arms together (such as pectoral flies) also work the pectorals, somewhat more selectively. Image File history File links Question_book-3. ... Professional Bodybuilder Gustavo Badell posing Bodybuilding is the process of maximizing muscle hypertrophy through the combination of weight training, sufficient caloric intake, and rest. ... A U.S. Army soldier uses a barbell with Olympic plates (but no collars) to perform a bench press. ... A soldier (lying down) performs a bench press The bench press is a weightlifting exercise which primarily focuses on the development of the pectoralis major muscle as well as other supporting muscles including the the anterior deltoids, serratus anterior, coracobrachialis, and the triceps. ... ... Triceps brachii The triceps brachii muscle is a large three-headed skeletal muscle found in humans. ... Deltoid can refer to: The deltoid muscle, a muscle in the shoulder A deltoid curve, a three-sided hypocycloid A type of quadrilateral A leaf shape The deltoid tuberosity, a part of the humerus Delta, an article with related definitions. ... Fly exercises can work through all three planes of motion. ...


Flat and declining movements generally work the sternal fibers (often called the "lower" or "inner pecs") while inclining movements generally work the clavicular fibers ("upper pecs.") The opposite is true for pushups, where declining (chest below legs) pushups use more clavicular fibers; they are also more difficult than flat or incline pushups due to the increased responsibility of the (smaller) deltoids and the weaker line of pull for pectoralis. The sternum (from Greek στέρνον, sternon, chest) or breastbone is a long, flat bone located in the center of the thorax (chest). ... Collarbone and collar bone redirect here. ...


The following exercises target and work "the pecs:"

Isolation exercises include: A soldier (lying down) performs a bench press The bench press is a weightlifting exercise which primarily focuses on the development of the pectoralis major muscle as well as other supporting muscles including the the anterior deltoids, serratus anterior, coracobrachialis, and the triceps. ... A press up (also push up) is a common strength training exercise performed while lying horizontal and face down, raising and lowering using the arms. ... A dip bar is a piece of fitness equipment that consists of a bar, usually about 1 (2 cm) in diameter, which is suspended slightly above the users head. ...

Fly exercises can work through all three planes of motion. ... The upright row is one exercise that can be performed on the cable machine. ...

Additional images

External links

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant. The University of Washington, founded in 1861, is a public research university in Seattle, Washington. ... A garden sign welcomes residents and visitors to Rogers Park as home of Loyola University Chicago. ... GPnotebook is a British medical database for general practitioners (GPs. ... The public domain comprises the body of all creative works and other knowledge—writing, artwork, music, science, inventions, and others—in which no person or organization has any proprietary interest. ... An illustration from the 1918 edition Henry Grays Anatomy of the Human Body (or Grays Anatomy as it has more commonly become known) is an anatomy textbook widely regarded as a classic work on human anatomy. ...


  Results from FactBites:
 
The Physician and Sportsmedicine: Rupture of the Pectoralis Major Muscle (1945 words)
The patient's MRI revealed extensive tearing of the pectoralis major muscle near the musculotendinous junction, with a large amount of fluid collecting in the tissue planes within the muscle and spreading distally to the tendinous insertion.
An appreciation of the anatomy of the pectoralis major is important for understanding the nature of injuries to this muscle complex (figure A).
Pectoralis major muscle tears can occur in the muscle belly, at the musculotendinous junction, or at or near the distal insertion into the humerus.
eMedicine - Breast, Poland Syndrome : Article Excerpt by: Bradon J Wilhelmi, MD (609 words)
In his original description, titled "Deficiency of the pectoral muscles," he specifically noted absence of the sternocostal portion of the pectoralis major muscle with an intact clavicular origin, absence of the pectoralis minor, and hypoplastic serratus and external oblique muscles.
The absence of the sternal head of the pectoralis major muscle is considered the minimal expression of this syndrome.
Hypoplasia or aplasia of serratus, external oblique, pectoralis minor, latissimus dorsi, infraspinatus, and supraspinatus muscles
  More results at FactBites »

 
 

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