THE MUSCULAR SYSTEM J Deluca 2017

Muscle Types Prime Mover – The muscle that is primarily responsible for causing a specific movement. Antagonist – a muscle that opposes or reverses a movement. The antagonist muscle stretches and relaxes when a prime mover is working. Synergist – A muscle, or group of muscles, that help prime movers by either producing the same kind of motion, or stabilizes nearby joints to allow the prime mover to more efficiently do its job. Fixators – specialized synergists that only stabilize a bone or joint so a prime mover can work, and do nothing else.

Naming Muscles Direction of the muscle fibers Size of the muscle Muscles have fancy names. These names actually have a pattern behind them, and are created from multiple factors. Direction of the muscle fibers Size of the muscle Location of the muscle Number of origins Location of the muscle’s origin and insertion Shape of the muscle Action of the muscle

Naming Muscles Direction – usually named in reference to an imaginary line down the middle of the body. Rectus means “straight”, while oblique means “slanted”. Size – usually used when naming a muscle group that serve a common function, to help differentiate between the muscles. Maximus is the biggest, minimus is the smallest, and medius is between the two.

Naming Muscles Location – some names correspond with the bone they cover, or are attached to. The frontalis covers the frontal lobe, and the temporalis covers the temporal lobe. Number of Origins – the prefix of a muscle name can tell you the number of origins. For example, the bicep has two, while the tricep has 3.

Naming Muscles Origin and Insertion Location – sometimes a muscle is named for where it starts and where it ends. The Sternocleidomastoid starts at the sternum (sterno) and clavicle (cleido) and inserts on the mastoid process. Shape – some muscles are named for their shape, like the deltoid muscle. In the Greek alphabet, Delta is a triangle.

Naming Muscles Muscle Action – some muscles are named simply after what they do. Like the abductor and adductor muscles for the legs. The abductor muscle abducts the legs, the adductor muscle adducts the legs.

MUSCLES OF THE FACE

Muscles of the Face Orbicularis Oris – Circles the mouth Allows you to close the mouth and protrude lips Please stop doing this in pictures, it does NOT look good. Frontalis - Covers the frontal bone Allows you to raise eyebrows and wrinkle forehead Orbicularis Oculi – Circles around the eyes Allows you to close your eyes, squint, blink, and wink

Muscles of the Face Buccinator - Runs across the cheek Allows you to chew and whistle/blow air Zygomaticus– Runs from corner of the mouth to cheekbone Raises the corner of your mouth upward, creating a smile Masseter– Runs from zygomatic process of temporal bone to mandible Allows you to close and open the jaw

Muscles of the Face Temporalis - Covers temporal bone Acts as a synergist to the masseter when closing the jaw Used when you grit your teeth Platysma– Sheet-like muscle covering the front of the neck Pulls the corners of the mouth down, creating a downward sag expression Sternocleidomastoid– Pair of muscles that run down the side of the neck to the center clavicle Aid in neck movement and facial expression

Muscles Of The Trunk The trunk area consists of the area from your neck to your hips, including your arms. We will be looking at both the front (anterior) and back (posterior) muscles.

Muscles Of The Trunk

Muscles Of The Trunk

Muscles Of The Trunk Pectoralis Major - Origin is the shoulder girdle and first 6 ribs. Insertion is the humerus. Used when pushing or during dorsal adduction. Pectoralis Minor – Stabilizes all motions of the Pectoralis Major

Muscles Of The Trunk Intercostals – muscles found between the ribs that allow us to breathe. They are both very helpful, and delicious.

These muscles all work together to keep your upper body upright! Muscles Of The Trunk Rectus Abdominis – superficial paired muscles encased in aponeurosis. Used in flexing the rib cage and forced breathing. Transversus Abdominis – run at a 90-degree to the rectus abdominis, providing them support, and are the muscles you use when you “suck in your gut”. External Oblique – superficial muscles that run on an “angle”, support the rectus abdominis during vertebral flexion, and allow you to “twist” your upper body. Internal Oblique – run at a 90-degree to the external oblique, provide them with support. These muscles all work together to keep your upper body upright!

Muscles Of The Trunk Latissimus Dorsi – Origin on the spine, insertion on the humerus. Both extends and adducts the humerus. Trapezius – Runs from the bottom of the skull to the middle of the back. They help articulate the neck, as well as move and stabilize the scapula.

Muscles Of The Trunk Erector Spinae – Long, thin grouo pf 3 muscles found deep in the back. Responsible for keeping your back straight, and support while lifting things. Deltoid – Thick triangle shaped muscles with origins along the shoulder girdle and insertion on the humerus. Abducts the arms in every direction.

Muscles Of The Trunk The muscles of the rotator cuff work together to rotate, abduct, and adduct the arm. They are the Supraspinatus, Infraspinatus, Teres Minor, and Subscapularis muscles. (SITS)

Muscles Of The Arm Biceps Brachii – both flexes and supinates the forearm. Origin in the shoulder and insertion on the radius. Brachialis – Under the biceps brachii, working with it to flex the arm

Muscles Of The Arm Triceps Brachii – Origin in the shoulder girdle and top of the humerus, inserts in the ulna. Used to straighten the arm out. Brachioradialis – origin in the humerus, insertion on the radius. Aids in flexion of the forearm at the elbow joint.

Muscles Of The Arm Extensor muscle group of forearm is responsible for hand extension, and are all located on the posterior forearm. Flexor muscle group of forearm is responsible for hand flexion, and are all located on the anterior forearm.

Muscles Of The Arm The muscles of the wrist work with the muscles of the hand to articulate the hand and fingers. Extensor groups extend fingers, flexor groups close fingers, adductor and abductor muscles work to spread and close fingers, and move the thumb.

Muscles Of The Lower Limb

Muscles Of The Lower Limb Gluteus Maximus – Extends the thigh, used when climbing stairs, jumping, and standing up from a squatted position. Gluteus Medius – works to steady the pelvis during walking/running, and abducts the leg. Gluteus Minimus – works to help with hip extension and pelvic stabilization.

Muscles Of The Lower Limb Iliopsoas – a group of 3 muscles combined that act as the prime mover of hip flexion. Functions to twist the hips and support the upper body. Sartorious – superficially located muscle that aids in crossing your legs. It is the longest muscle in the body.

Muscles Of The Lower Limb The Hamstring Group Composed of Biceps Femoris, Semitendinosus, and Semimembranosis. They function to raise the heel towards the buttock (flexion), as well as stabilize the leg.

Muscles Of The Lower Limb The Quadriceps Group is made up of 4 muscles: Rectus Femoris, Vastus Lateralis, Vastus Medialis, and Vastus Intermedius. These muscles work together to straighten the leg at the knee, like when you kick. The Vastus Intermedius is under the Rectus Femoris. Rectus Femoris Vastus Lateralis Vastus Medialis

Muscles Of The Lower Limb The Adductor muscle group is made up of 3 muscles: Adductor Brevis, Adductor Longus, and Adductor Magnus. They are responsible for adducting the legs. They have an origin at the pelvis and an insertion along the femur.

Muscles Of The Lower Limb Fibularis Group - 3 muscles that have an origin on the fibula and insertion on the metatarsals. They allow for plantar flexion and eversion of the foot. Extensor Digitorum Longus – Prime mover of toe extension and foot dorsiflexion. Tibialis Anterior – superficial muscle used for dorsiflexion and inversion of the foot. Soleus – Origin on the rear of the tibia, insertion in the metatarsals, used for plantar flexion.

Muscles Of The Lower Limb Gastrocnemius – Prime mover in plantar flexion. Insertion is in the calcaneus by the Achillies tendon. If this tendon is cut, walking becomes nearly impossible, as the heel can no longer be lifted, causing your foot to drag.