Human Anatomy and Physiology of Muscles
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)
Muscles of the Neck
Muscles of the Neck
Name of Muscle | Origin and Termination | Function |
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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
Shoulder Muscles
Name of Muscle | Origin and Termination | Function |
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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
Muscles of the Chest
Name of Muscle | Origin and Termination | Function |
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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 |
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Muscles of the Upper Arm
Muscles of the Upper Arm
Name of Muscle | Origin and Termination | Function |
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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
Muscles of the Forearm
Name of Muscle | Origin and Termination | Function |
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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
Abs Muscles
Name of Muscle | Origin and Termination | Function |
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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
Thigh Muscles & Gluteus (Buttocks)
Name of Muscle | Origin and Termination | Function |
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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
Muscles of the Back
Name of muscle | Origin and Termination | Function |
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Trapezius (see muscles of the neck capsule) |
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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) |
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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) |
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Rhomboid | Extend from vertebra in neck to scapula near midline | Squares shoulders by drawing shoulder blades backward |
Oblique (see abs muscles capsule) |
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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
Hamstring Muscles - 3 large muscles extending down back of thigh, from ischium to tibia below knee
Name of Muscle | Origin and Termination | Function |
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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 Muscle | Origin and Termination | Function |
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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 |