Where is the pectoralis major located in the body?
Pectoralis major muscle (Musculus pectoralis major) The pectoralis major is a paired, superficial muscle located on the anterior surface of the thoracic cage. If you’re a gym lover, you’ll hear these muscles also being referred to as the pecs muscles.
Why does the pectoralis major have a recess at the top?
Due to the different courses of the muscle fibers, the insertion has a recess which is open to the top preventing the muscle from overstretching. The triangular depression between the pectoralis major muscle, deltoid muscle and clavicle is called infraclavicular fossa (Mohrenheim’s fossa).
How many pectoralis muscles do you have?
Rochelle Collins, DO, is a board-certified family medicine doctor currently practicing in Bloomfield, Connecticut. You have two pectoralis majors or "pecs," one on each side of your chest. These large muscles help you move your shoulder.
What is a pectoralis major injury?
You have two pectoralis majors or "pecs," one on each side of your chest. These large muscles help you move your shoulder. These muscles help pull your arm across the front of your body. Injury to the pectoralis major can cause shoulder pain and limit your ability to use your arm fully.
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What type of muscle Fibre is the pectoralis major?
IIB fiber typeThe pectoralis major muscle was totally made up of the IIB fiber type, both in the Padovana chicken and the medium-growing chicken Berlanda strain.
What muscle arrangement is pectoralis major?
The pectoralis major is the superior most and largest muscle of the anterior chest wall. It is a thick, fan-shaped muscle that lies underneath the breast tissue and forms the anterior wall of the axilla.
What is the fascicle arrangement of the pectoralis major?
Anatomy week 1-6QuestionAnswerThe muscle fascicle arrangement for Orbicularis oris is best characterized ascircularThis arrangement of muscle fascicles tends to be triangular in shape. The Pectoralis major is an example of a muscle with this type of muscle fascicle arrangement.convergent15 more rows
What is the arrangement of muscle fibers?
Each bundle of muscle fiber is called a fasciculus and is surrounded by a layer of connective tissue called the perimysium. Within the fasciculus, each individual muscle cell, called a muscle fiber, is surrounded by connective tissue called the endomysium.
What is the origin of the pectoralis major muscle?
Attachments of Pectoralis Major Muscle: Origin & Insertion Sternal head: sternum, upper costal cartilages (1-6), and the aponeurosis of the external oblique.
What muscle fiber arrangement can be seen in the soleus muscle?
bipennate arrangementSoleus muscle exhibits bipennate arrangement on its centro-anterior aspect and the longitudinal parallel muscle fibers on its posterior and lateral margins.
Is pectoralis major a parallel muscle?
Despite this they generate greater tension because they possess a greater amount of muscle fibers than similarly sized parallel muscles. The pectoralis major found in the chest is an example of a convergent muscle, and is responsible for flexing the upper arm.
Which muscle has a circular arrangement of fascicles?
The fascicles may be attached only on one side of the tendon (unipennate) or to both sides (bipennate). A circular pattern of fascicles is characteristic of sphincter muscles that surround openings (e.g., the mouth or the anus). Figure 2. Shapes of skeletal muscles.
What muscles are pennate?
Pennate muscles may be uni-, bi- or multipennate muscles, examples of each being the extensor digitorum longus, rectus femoris and the deltoid, respectively. The biceps brachii muscle is an example of afusiform muscle, which is spindle shaped, with tapered ends and a fatter belly.
Which muscle has a Unipennate arrangement of fascicles?
The extensor digitorum of the forearm is an example of a unipennate muscle. A bipennate muscle has fascicles on both sides of the tendon. In some pennate muscles, the muscle fibers wrap around the tendon, sometimes forming individual fascicles in the process. This arrangement is referred to as multipennate.
Where is the smooth muscle tissue found?
Smooth muscle fibers are located in walls of hollow visceral organs (such as the liver, pancreas, and intestines), except the heart, appear spindle-shaped, and are also under involuntary control. Skeletal muscle fibers occur in muscles which are attached to the skeleton.
Is pec major Multipennate?
The pectoralis major (PM) is a complex, multipennate muscle of the anterior shoulder girdle that is responsible for adduction, internal rotation, and flexion of the humerus.
Where is pectoralis located?
chestpectoralis muscle, any of the muscles that connect the front walls of the chest with the bones of the upper arm and shoulder. There are two such muscles on each side of the sternum (breastbone) in the human body: pectoralis major and pectoralis minor.
Is the pectoralis major muscle anterior or posterior to the subscapularis muscle?
anteriorThe pectoralis major muscle spreads across the front of the chest from the sternum to the upper arm. By virtue of its placement on top of the subscapularis, the pectoralis major is anterior (towards the front of the body) to the subscapularis muscle.
What is the major muscle of the shoulder called?
The primary muscle group that supports the shoulder joint is the rotator cuff muscles. The four rotator cuff muscles include the supraspinatus, infraspinatus, teres minor, and subscapularis.
What type of muscle is the deltoid muscle?
skeletal musclesDeltoid muscles help you move your arms in different directions. They also protect and stabilize your shoulder joint. Like most other muscles in your body, the deltoids are skeletal muscles. Tendons attach them to bones.
Why is the pectoralis major muscle important?
This action is important in activities such as climbing. When acting from the humeral attachment, the pectoralis major muscle also facilitates the act of inspiration. This is particularly important during forced breathing in physical distress.
What are the parts of the pectoralis major?
The pectoralis major has a broad origin, based on which it is divided into three parts: clavicular part, sternocostal part and abdominal part. All three parts converge laterally and insert onto the greater tubercle of humerus. The main function of this chest muscle as a whole is the adduction and internal rotation of the arm on the shoulder joint.
What is the function of the clavicular muscle?
The main function of this chest muscle as a whole is the adduction and internal rotation of the arm on the shoulder joint. Acting independently, the clavicular part helps to flex the extended arm up to 90°, while the sternocostal part facilitates the extension of the flexed arm by pulling it downwards. In this article, we will discuss the anatomy ...
What are the different types of muscles?
The pectoralis major muscle is a fan-shaped muscle that consists of three parts that originate from three different sites: 1 The clavicular part originates from the anterior surface of the medial half of the clavicle. 2 The sternocostal part originates from the anterior surface of sternum and the anterior aspects of the costal cartilages of ribs 1-6. 3 The smallest, abdominal part originates from the anterior layer of the rectus sheath.
What is the deep surface of the pectoralis minor?
In females, it is covered by the breast. The deep surface of the muscle covers the pectoralis minor and serratus anterior muscles and the anterior surface of the upper six ribs.
How long does it take to read a pectoralis major?
Reading time: 5 minutes. Pectoralis major muscle (Musculus pectoralis major) The pectoralis major is a paired, superficial muscle located on the anterior surface of the thoracic cage. If you’re a gym lover, you’ll hear these muscles also being referred to as the pecs muscles. The pectoralis major has a broad origin, ...
What is the triangular depression between the pectoralis and the deltoid muscle?
The triangular depression between the pectoralis major muscle, deltoid muscle and clavicle is called i nfraclavicular fossa (Mohrenheim’s fossa) which serve s as an important landmark in the surgical procedures on the subclavian artery.
Where is the pectoralis major located?
If you place one hand on the front of your shoulder and slide it in toward your breast bone, your pecs reside under the layer of fatty tissue or breast tissue of your chest.
What are the pectoralis majors?
You have two pectoralis majors or "pecs," one on each side of your chest. These large muscles help you move your shoulder. These muscles help pull your arm across the front of your body. Injury to the pectoralis major can cause shoulder pain and limit your ability to use your arm fully.
How to heal a ruptured pectoralis?
Healing from a pectoralis major rupture is different for everyone. Check with your doctor and physical therapist before starting any exercises or stretches for your pec injury. If a pinched nerve is causing your pectoralis major weakness, the first step is to take the pressure off the nerve.
What nerve in the neck can cause paralysis?
A pinched nerve in your neck can injure the nerve that innervates your pectoralis major, causing muscle weakness or paralysis.
What does it feel like to have a ruptured pectoralis major?
Pain in the front of your shoulder. Swelling in the front of your shoulder. Difficulty moving your arm inward or across your body. A visible or palpable divot in the front of your shoulder. Bruising in your chest or upper arm. If you think you've ruptured or torn your pectoralis major, seek immediate medical attention.
What causes a pectoralis to rupture?
While rare, a pectoralis major rupture can happen if the amount of force applied to the muscle overloads the tendon and causes it to tear.
How long does it take for a pectoralis major to heal?
This will give the tendon time to heal. The length of the initial rest period will depend on how severe the injury is, but 3 weeks is about average. 4 .
What are pennate muscles?
in a pennate pattern, the fascicles are short and they attach obliquely to a central tendon that runs the length of the muscle. Pennate muscles come in three forms: 1 Unipennate, in which the fascicles insert into only one side of the tendon, as in the extensor digitorum longus muscle of the leg. 2 Bipennate, in which the fascicles insert into the tendon from opposite sides so the muscle “grain” resembles a feather. The rectus femoris of the thigh is bipennate. 3 Multipennate, which looks like many feathers side by side, with all their quills inserted into one large tendon. The deltoid muscle, which forms the roundness of the shoulder is multipennate.
Which muscle is a fascicle that inserts into only one side of the tendon?
Unipennate, in which the fascicles insert into only one side of the tendon, as in the extensor digitorum longus muscle of the leg.
What is convergent muscle?
A convergent muscle has a broad origin, and its fascicles converge toward a single tendon of insertion. Such a muscle is triangular or fan shaped like the pectoralis major muscle of the anterior thorax.
What factors contribute to muscle force and speed?
A big factor that contributes to muscle force and speed is fascicle arrangements. Other factors such as fiber type, lever systems and load will be discussed in a separate article.
What is the term for the muscles that close by contracting?
Muscles with this arrangement surround external body openings, which they close by contracting. The general term used for these kinds of muscles is “sphincter”.
Which muscle is shaped like a spindle?
In a parallel arrangement, the length of the fascicles runs parallel to the long axis of the muscle. Such muscles are either straplike like the sartorius muscle of the thigh, or spindle shaped with an extended belly, like the biceps brachii muscle of the arm.
What muscle is the roundness of the shoulder?
Multipennate, which looks like many feathers side by side, with all their quills inserted into one large tendon. The deltoid muscle, which forms the roundness of the shoulder is multipennate.
Anatomy
Function
- The pectoralis major helps you pull your arm across the front of your body (adduction). The muscle also works with your rotator cuff(subscapularis) to allow you to rotate your arm in. When your arm is fixed or bearing weight, the pectoralis major works with the latissimus dorsiand other scapular stabilizers to elevate your body. Using your arms to ...
Associated Conditions
- While rare, a pectoralis major rupturecan happen if the amount of force applied to the muscle overloads the tendon and causes it to tear. Pectoralis muscle tears are graded according to severity. 1. Grade I:Simple overstretching of the tendon 2. Grade II:Tendon is overstretched and partially torn 3. Grade III:Full-thickness tear of the pectoralis tendon According to published cas…
Rehabilitation
- If you think you have injured your pecs, you'll need to see your healthcare provider. A correct and timely diagnosis is the first step to treating a pectoralis major injury. If you injure your pectoralis major, you will need to rest and not move your shoulder (immobilization). This will give the tendon time to heal. The length of the initial rest period will depend on how severe the injury is, but 3 we…
A Word from Verywell
- If you've injured your pectoralis major, the first step in treating the injury is to rest. You may also need to have surgery. Once the muscle has had time to heal, working with a physical therapist will help with proper healing, and improve the range of motion and strength in your shoulder, while avoiding further injury.