The 8 Main Muscles of the Human Body

The 8 Main Muscles of the Human Body

What are the main muscles in the human body? If you’ve ever asked yourself this question, you’re not alone. People ask this all the time, but what makes it so hard to answer? After all, there are only so many muscles in the human body that do things like flex and pull—and those are usually what we mean when we use the word muscle in daily speech.

1) The trapezius

What are the main 12 muscles? The trapezius, also called trap for short, is a muscle that runs from the base of your neck to your shoulders. It helps you shrug, lift things, and turn your head. The latissimus dorsi, or lats for short, is a broad triangular muscle that covers most of the back. It helps you pull objects in front of you and push them away from you. The deltoid is a three-headed muscle that controls arm movements. One of its heads attaches at the shoulder blade; two others attach near the collarbone.

This muscle helps you raise your arms up and over your head as well as turning them out to the sides (as if doing an exercise). It also stabilizes your arm when lifting weights from behind your back. Your pectoralis major is a large chest muscle that is subdivided into clavicular and sternocostal portions. Together, these form the bulk of your chest wall below the armpit. They help stabilize the shoulder joint during any kind of pushing motion like putting on a shirt or rolling something heavy across the floor. Other major muscles include: biceps, triceps, deltoids, gluteus maximus (buttocks), quadriceps femoris (thighs), hamstrings (back thigh), gastrocnemius and soleus (calves), tibialis anterior (lower leg)

2) The deltoids

There are seven muscles that make up the deltoid. The following list summarizes what each muscle does:

- Deltoideus anterior: flexes, abducts, and internally rotates the arm (as in raising an arm to one's mouth); and extends it when acting alone.

- Deltoideus lateralis: extends and internally rotates the arm (as in turning a screwdriver).

- Subscapularis: assists with abduction; also helps with internal rotation.

- Supraspinatus: assists with abduction and external rotation. - Infraspinatus: assists with abduction and external rotation. - Teres minor: assists with abduction.

- Coracobrachialis: adducts the arm; flexes and medially rotates the shoulder joint when acting alone.

- Pectoralis major: adducts, flexes, medially rotates, and raises the arm from abducted position to full extension.

3) The pectoralis major

The pectoralis major is one of the main muscles in our body, and it's often referred to as the chest muscle. It's an anterior (front) muscle that is attached to the sternum, clavicle, and upper ribs. The pectoralis major is a very large and powerful muscle that attaches at the humerus near your shoulder joint. Its main function is to move your arm outwards towards your side. It also helps you take deep breaths by lifting up on your rib cage. There are two different heads of this muscle: the clavicular head and the sternal head. They originate from different places along the breastbone and are therefore used differently during movement. The origins of these heads can be traced back to both your first rib, second rib, third rib, fourth rib and fifth ribs respectively. The origin of the clavicular head lies close to your collarbone whereas the origin for the sternal head lies close to your breast bone.

A strong contraction of the pectoralis major pulls down and together with other muscles compresses your lungs so you can take a deep breath. The iliopsoas: Iliopsoas or hip flexor is located in front of spine and includes three groups: iliacus, psoas major, and psoas minor. Each group has its own tendon attachment points on pelvic bones, lumbar vertebrae, sacrum, or inside femur bone.

4) The latissimus dorsi

The latissimus dorsi are a broad muscle that originates at your back, runs down to your hip and then extends past it. The muscle is attached to the lower spine and can be seen extending down your side when you lean over. It helps with activities like lifting objects off the ground, pulling yourself up on a ladder or even climbing.

What are the main 12 muscles? -Sternocleidomastoid: Sternocleidomastoid is found in the neck region, originating on each clavicle bone and converging into a tendon in front of the mastoid process. There is also a corresponding muscle located in the opposite region called posterior sternocleidomastoid which has an anterior counterpart as well. These muscles help rotate your head towards one side and contract during coughing, vomiting and laughing. They also flex your head forward and backward.

Muscles of facial expression- Frontalis: Frontalis is found just above the eyebrows, running from the frontal bone to the parietal bones. They help control movement for eyebrow elevation, frowning and other expressions such as smiling and raising cheeks during blushing. When contracted they cause forehead wrinkles such as those caused by concentration or worry. Orbicularis oculi: Orbicularis oculi originate near your nose from deep within the temporal bone and fan out around your eye orbitals. Contraction results in things like blinking, closing eyes tightly for a prolonged time period and squinting eyes against bright light or irritation due to windburn for example.

5) The biceps brachii

Muscles are important for a number of reasons. They allow us to move our body and as we age, they can help prevent or lessen the effects of some diseases. The biceps brachii is one such muscle. It is located at the front of your upper arm and is responsible for flexing your elbow and rotating your forearm. In order to work, it relies on another muscle called the triceps brachii. These two muscles work in opposition to one another. For instance, when you lift up an object with your right hand while keeping your left arm still, you use the biceps brachii in this way. However, when you lower that object with your right hand while keeping your left arm still, you use the triceps brachii in this way. If both of these muscles become weakened then lifting objects will be difficult as only one side will be able to provide enough strength to do so alone. As such, it is important to exercise these muscles regularly. One effective method of exercising the biceps brachii is by using resistance bands. First stretch the band out over your shoulder blades before placing it around your wrists and pulling back with both hands until you feel tension in the band. Then slowly release back into starting position whilst trying not to allow any slack between your hands and arms. Be sure to change which hand pulls first after each repetition to ensure even development of both sides!

6) The triceps brachii

The triceps brachii is one of three muscles in the anterior compartment. It has two heads, connected at a long tendinous center called the olecranon. The muscle can be divided into three parts: upper, middle, and lower, each with its own nerve supply. They originate on the back of humerus and inserts on the olecranon process of ulna. Their purpose is to extend and adduct (move towards midline) your arm at an angle. Triceps Brachii are also known as back of the arm muscles. It helps you lift up heavy objects.

7) The abdominals

What are the main 12 muscles? Here's a simple breakdown! -1. Rectus Abdominis: There are two parts to this muscle, and they both start at the pubic bone and go up to the ribs. One attaches to the front of each rib cage. Together, these muscles work with other abdominal muscles to compress the abdomen for actions like pulling in your stomach or rolling over in bed. -2. Transverse Abdominis: It is an internal muscle which wraps around your waist from one side to another and compresses it together when needed for actions like bending forward, coughing or sneezing. -3. Obliques: These muscles run down either side of your spine and help bend the torso sideways to the right or left. They also rotate the torso. -4. Lower Back Muscles: These are located between the lumbar spine (the lower part of your back) and the hip bones and extend outwards to attach onto any part of their hip bone on either side

-5. Quadriceps: The quadriceps' four large thigh muscles all insert into a single kneecap tendon on top of our tibia (shinbone). Their job is straightening out our knees, as well as controlling knee flexion (bending) movements.

8) The erector spinae

The muscles that make up the erector spinae are a group of spinal muscles that assist in supporting and extending your back. The five muscles that make up this group are:

Iliocostalis ilii, which attaches at two vertebrae; longissimus dorsi, which attaches at three vertebrae; iliocostalis cervicis, which attaches at four vertebrae; cervicis capitis and capitis thoracis, both which attach to five vertebrae. These muscles contract when you sit up or extend your back. The psoas major muscle: The psoas major muscle is located deep in the pelvis on either side of the lumbar spine. It attaches at four points along the spine and assists with flexing (bending) and rotating your hip joint. Rectus abdominis: A muscle found on each side of the abdomen, it extends from below rib cage to pubic bone and assists with flexing (bending) as well as bringing food from mouth to stomach during digestion . The following abdominal muscles are also important for our day-to-day activities: External obliques, internal obliques, transverse abdominis. They all work together with the rectus abdominis to help us do tasks such as bending forward and breathing deeply into our lungs. Latissimus Dorsi