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Human Anatomy and Physiology of Muscles

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There are approximately 639 skeletal muscles in the human body, all of them attached to the 206 bones that make up the skeleton. By coordinated contractions and relaxations of the various muscles, the skilled movements of the human body are produced.

According to Wikipedia: The gross anatomy of a muscle is the most important indicator of its role in the body. The action a muscle generates is determined by the origin and insertion locations. In most muscles, all the fibers are oriented in the same direction, running in a line from the origin to the insertion.

There are 3 types of muscles: skeletal, smooth, and cardiac. This hub is about skeletal muscles - their origins and terminations, and functions.

(To reinforce your study here on the human anatomy and physiology of muscles, watch the video at the bottom of this article)

courtesy of bodyministries.net

courtesy of bodyministries.net

Muscles of the Neck

courtesy of emedicine.medscape.com

courtesy of emedicine.medscape.com

Muscles of the Neck

Name of MuscleOrigin and TerminationFunction

Omohyoid

Extends from upper border of shoulder blade to hyoid bone in neck

Lowers hyoid bone and floor of mouth.

Sternohyoid

Extends from upper end of breastbone to hyoid bone beneath chin

Pulls hyoid bone downward.

Thyrohyoid

Extends from thyroid cartilage to hyoid bone in neck

Draws hyoid bone downward and thyroid cartilage upward.

Trapezius

A large muscle extending from base of skull and vertebrae in neck to the collarbone, shoulder blade and tip of shoulder.

Raises shoulder and pulls shoulder blade (scapula) backward

Longus capitis

Extends from vertebrae in neck to base of skull

Bends (flexes) head.

Digastric

Extends from lower jaw to hyoid cartilage in neck

Lifts up hyoid bone.

Scalene

Extend from vertebra in neck to first and second ribs

Bend head and neck sideways.

Splenius

Extend from vertebrae in the chest and neck to back of head

Straighten head and spine

Levator scapulae

Extends from spinal column in neck to shoulder blade

Lifts up shoulder

Mylohyoid

Extends from lower jaw to hyoid bone in neck

Lifts floor of mouth

Sternothyroid

Extends from upper end of breastbone to thyroid cartilage

Pulls larynx (voicebox) downward

Shoulder Muscles

courtesy of http://wrathofnino.files.wordpress.com/2009/06/shoulder.jpg

courtesy of http://wrathofnino.files.wordpress.com/2009/06/shoulder.jpg

Shoulder Muscles

Name of MuscleOrigin and TerminationFunction

Deltoid

Extends form collarbone and scapula, over the shoulder, to humerus in upper arm

Lifts upper arm away from body

Subscapularis

Extends from scapula (shoulder blade) to humerus (in upper arm)

Rotates arm inward

Infraspinatus

Extends from shulder blade to upper arm

Rotates arm in an outward direction

Chest Muscles

courtesy of picsdigger.com

courtesy of picsdigger.com

Muscles of the Chest

Name of MuscleOrigin and TerminationFunction

Pectoral

Extend from collarbone, breastbone, and ribs to shoulder blade and humerus of arm

Rotate arm inward, bring shoulder forward and pull arm close to the body

 

 

 

Muscles of the Upper Arm

courtesy of http://www.highfive.me.uk/Resources/Anatomy/UpperArm/All.JPG

courtesy of http://www.highfive.me.uk/Resources/Anatomy/UpperArm/All.JPG

Muscles of the Upper Arm

Name of MuscleOrigin and TerminationFunction

Deltoid

Extends from collar bone and scapula, over the shoulder, to humerus in upper arm

Lifts upper arm away from body

Triceps brachii

Extends from upper end of humerus, in upper arm, to ulna bone in forearm

Straightens elbow

Biceps brachii

Extends from scapula and humeus in upper arm to bones and tissue of forearm

Powerful muscle which flexes upper arm

Anconeus

Extends from humerus in upper arm to ulna in forearm

Straightens elbow joint

Extensor carpi radialis

From humerus bones of wrist

Extends (straightens) wrist

Brachialis

Extends from humerus inupper arm to ulna in forearm

Flexes (bends) elbow joint

Brachioradialis

From humerus in upper arm to radius in the forearm

Flexes (bends) elbow joint

Muscles of the Forearm

courtesy of illpumpyouup.com

courtesy of illpumpyouup.com

Muscles of the Forearm

Name of MuscleOrigin and TerminationFunction

Extensor carpi ulnaris

From humerus in upper arm to bones of wrist

Extends (straightens) wrist

Extensor digitorum

Extends from humerus in upper arm to tendons of fingers on back of hands

Straightens wrist and fingers

Extensor carpi radialis

From humerus to bones of wrist

Extends (straightens) wrist

Extensor digiti minimi

From humerus in upper arm to the base of digit 5 on dorsal side

Extends little finger at all joints

Flexor carpi ulnaris

From humerus and ulna to bones in front of the wrist

Bends wrist

Flexor digitorum

From ulna in forearm to fingers

Flexes (bends) fingers

Abductor pollicis longus

Extends from muscles and tendons of forearm to base of thumb

Straightens (extends) the thumb and pulls it away from other fingers

Extensor pollicis

Extends from radius and ulna bones of forearm to thumb

Straightens thumb and pulls it away (abducts) from other fingers

Flexor pollicis

From radius bone in forearm and bones of wrist to thumb

Flexes thumb

Extensor indicis

From ulna to index finger

Extends index finger and wrist

Abs Muscles

courtesy of luxfitness.com

courtesy of luxfitness.com

Abs Muscles

Name of MuscleOrigin and TerminationFunction

Lattisimus dorsi

Extends from spine and ribs to humerus in upper arm

Brings arm close to body, aids in breathing

Serratus anterior

Extends from spine in chest and lower back to ribs

Elevates ribs and thus aids in breathing

Rectus abdominis

Extends from bottom of breastbone and lower ribs to pubis

Bends spine forward; supports abdominal wall

Oblique

Extends from lower ribs to midline of abdomen and pubis

These muscles support the abdominal wall

External intercostal

Extend from one rib to another

Aid in breathing in and out

For more details on the anatomy and physiology of the human muscles, you may want to avail the latest edition of this book: The Concise Book of Muscles, Fourth Edition

courtesy of kcfac.kilgore.cc.tx.us

courtesy of kcfac.kilgore.cc.tx.us

Thigh Muscles & Gluteus (Buttocks)

Name of MuscleOrigin and TerminationFunction

Psoas major

Extend from vertebrae in lower back to femur in thigh

Flex (bend) trunk and hip

Pectineus

Extends from pubic bone to femur (thighbone)

Pulls thigh toward midline of body and flexes hip

Adductor longus

larger muscle than abductor brevis, arising from the pubic bone and extending to femur

Pulls thigh toward midline (in an inward direction)

Gracilis

From pubic bone down to tibia in leg

Pulls thigh toward midline of body

Sartorius

Extends from hip bone to tibia in leg

Bends knee and hip joints and rotates thigh outward

Vastus

Extend down entire front of thigh to kneecap and tibia in leg

Straighten knee

Iliacus

Extends from pelvis bones to femur in thigh

Flexes hip joint

Tensor fascia latae

Extends from crest of hip, down along outside of thighs, to leg

Draws leg away from body and bends hip joint

Rectus femoris

Extends from hipbone down front of thigh, over knee to upper leg

Straightens knee

Gluteus maximus, medius and minimus (see anatomy chart above)

From bones of pelvis to upper, outer part of femur (thigh bone)

These muscles straighten the hip joint and pull thigh bone away from body

Muscles of the Back

courtesy of luxfitness.com

courtesy of luxfitness.com

Muscles of the Back

Name of muscleOrigin and TerminationFunction

Trapezius (see muscles of the neck capsule)

 

 

Erector spinae - spinalis

Extend from vertebrae in neck, chest and back to other vertebrae in neck, chest and back

Straighten head and spine

Infraspinatus fascia

Extends from shoulder blade to upper arm

Rotates arm in an outward direction

Teres minor

Extends from upper border of scapula to humerus

Rotates arm outward

Teres major

Extends from outer border of scapula to humerus

Rotates arm inward and draws arm toward the body

Lattisimus dorsi (see abs muscles capsule)

 

 

Semispinalis capitis

Extend from vertebrae in neck and upper chest upward to base of skull

Bend head backward and rotate spine in neck region

Splenius

Extend from vertebrae in the chest and neck to back of head

Straighten head and spine

Levator scapulae (see muscles of the neck capsule)

 

 

Rhomboid

Extend from vertebra in neck to scapula near midline

Squares shoulders by drawing shoulder blades backward

Oblique (see abs muscles capsule)

 

 

Supraspinatus

Extends from scapula to humerus

Draws upper arm away from body

Serratus

Extends from spine in chest and lower back to ribs

Elevates ribs and thus aids in breathing

Hamstring Muscles

courtesy of athleticquickness.com

courtesy of athleticquickness.com

Hamstring Muscles - 3 large muscles extending down back of thigh, from ischium to tibia below knee

Name of MuscleOrigin and TerminationFunction

Semitendinosus

Ischium (bone upon which one sits) to tibia in leg

Bends knees and straightens hip

Semimembranosus

-ditto-

-ditto-

Biceps femoris

Extends from femur and ischium to fibula and fibrous tissues below knee

Flexes knee joint and extends (straightens) hip joint

Calf Muscles (See Anatomy Chart above)

Name of MuscleOrigin and TerminationFunction

Gastrocnemius

Extends down leg from femur to heel bone

Bends ankle in a downward direction and helps to flex knee

Soleus

Extends fromtibia and fibula in upper leg to heel (calcaneus)

Bends ankle down

Peroneus

Extends from bones of leg (tibia and fibula) to bones of foot

Bend foot outward, flex and extend ankle

Flexor hallucis longus

From fibula in leg and bones of foot to base of big toe

Flexes big toe