Neuroscience For Dummies
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It may seem like a jumble of meaningless Latin at first, but muscle names follow a strict convention that names them according to one or more of the following:

  • Function: These muscle names usually have a verb root and end in a suffix (or or eus), followed by the name of the affected structure. Example: levator scapulae (elevates the scapulae).

  • Compounding points of attachment: These muscle names blend the origin and insertion attachment with an adjective suffix (eus or is). Examples: sternocleidomastoideus (sternum, clavicle, and mastoid process) and sternohyoideus (sternum and hyoid).

  • Shape or position: These muscle names usually have descriptive adjectives that may be followed by the names of the locations of the muscles. Examples: rectus (straight) femoris, rectus abdominis, and serratus (sawtooth) anterior.

  • Figurative resemblance: These muscle names are based on the muscles’ resemblance to some objects. Examples: gastrocnemius (resembles the stomach) and trapezius (resembles a trapezoid or kite shape).

Check out the figure and the following table for a rundown of prominent muscles in the body and key points to remember about each one.

[Credit: Illustration by Kathryn Born, MA]
Credit: Illustration by Kathryn Born, MA
Muscles of the Body
Muscle Origin Insertion Action
Head
Frontalis Galea aponeurotica Eyebrow Expression
Occipitalis Occipital bone Galea aponeurotica Moves scalp forward and backward
Buccinator Alveolar processes of mandible and maxillary bone Orbicularis oris and skin at angle of mouth Mastication
Orbicularis oculi Encircles eye Encircles orbit and extends within eyelid Closes eye
Orbicularis oris Encircles mouth Skin surrounding mouth and at angle of mouth Closes mouth
Masseter Zygomatic arch Mandible Mastication
Temporalis Temporal fossa Coronoid process and ramus of mandible Mastication
Zygomaticus Zygomatic bone Corner of mouth Smiling
Neck
Sternocleidomastoid Manubrium of sternum and median portion of clavicle Mastoid process of temporal bone Rotation and flexion of neck vertebrae
Back
Latissimus dorsi Vertebral column Humerus Extends at shoulder joint
Trapezius Occipital bone and vertebral column (7 cervical vertebrae and all thoracic vertebrae) Clavicle and scapula Rotates, elevates, depresses, adducts, and stabilizes scapula
Pectoral girdle
Pectoralis major Sternum, clavicle, upper 6 ribs, and aponeurosis of external oblique muscle Medial margin of tertubercular groove of humerus Flexion, rotation, and adduction of shoulder joint
Shoulder
Deltoid Lateral third of clavicle, acromion process, and spine of scapula Deltoid tuberosity of humerus Abduction, flexion, rotation, and extension of arm, using coordinated fibers: entire muscle (abduction); interior fibers (flexion); medial fibers (rotation); posterior fibers (extension); and lateral fibers (rotation) of arm
Abdominal wall
External abdominal oblique External surface of lower 8 ribs Aponeurosis to linea alba and anterior half of iliac crest Stabilizes, protects, and supports internal viscera, compresses abdominal cavity, assists in flexing and rotating vertebral column
Internal abdominal oblique Inguinal ligament, iliac crest, and lumbodorsal fasciae Linea alba, pubic crest, and last 3 ribs Stabilizes, protects, and supports internal viscera, compresses abdominal cavity, assists in flexing and rotating vertebral column
Transversus abdominis Inguinal ligament, iliac crest, lumbodorsal fasciae, and costal cartilage of last 6 ribs Linea alba and pubic crest Stabilizes, protects, and supports internal viscera, compresses abdominal cavity, assists in flexing and rotating vertebral column
Rectus abdominis Pubic crest and symphysis pubis Xiphoid process of sternum and costal cartilage of ribs 5–7 Stabilizes, protects, and supports internal viscera
Thorax
Diaphragm Xiphoid process of sternum, inner surface of lower 6 ribs, and lumbar vertebrae Central tendon of diaphragm Pulls central tendon downward, increasing size of thoracic cavity and causing inspiration; separates thoracic and abdominal cavities
External intercostals Inferior border of rib above and costal cartilage Superior border of rib below rib of origin Elevates ribs, aiding inspiration
Internal intercostals Superior border of rib below and costal cartilage Inferior border of rib above rib of origin Depresses ribs, aiding inspiration
Arm
Biceps brachii Long head: Tubercle above glenoid fossaShort head: Coracoid process of scapula Tuberosity of radius Flexion at elbow joint
Triceps brachii Long head: Infraglenoid tubercle of scapulaLateral head: Posterior surface of humerus above radial grooveMedial head: Posterior surface of humerus above radial groove Olecranon process of ulna Extension of elbow joint
Flexor carpi radialis Medial epicondyle of humerus 2nd to 3rd metacarpals Flexor of wrist, abducts hand
Flexor carpi ulnaris Medial epicondyle of humerus and olecranon process Pisiform bone and base of 5th metacarpal Flexor of wrist, adducts hand
Supinator Lateral epicondyle of humerus and proximal end of ulna Proximal end of radius Supinates forearm
Extensor carpi ulnaris Lateral epicondyle of humerus Base of 5th metacarpal Extends and adducts wrist
Extensor carpi radialis longus Lateral supracondylar ridge of humerus Base of 2nd metacarpal Extends and abducts wrist
Extensor carpi radialis brevis Lateral epicondyle of humerus Dorsal surface of 3rd metacarpal Extends and abducts wrist, steadies wrist during finger flexion
Thigh, Anterior (Front)
Rectus femoris (part of quadriceps) Acetabulum of coxal bone Tibial tuberosity via patella Extends knee and flexes thigh at hip
Vastus lateralis (part of quadriceps), vastus medialis, vastus intermedialis (part of quadriceps) Femur Tibia Extends knee
Sartorius Anterior superior iliac spine Proximal medial surface of tibia Flexes at knee and laterally rotates thigh
Adductors Pubis Femur Adduction and flexion at hip joint and lateral rotation of thigh
Gracilis Pubis, symphysis pubis, and pubic arch Medial surface of tibia Adduction of thigh and rotation of leg
Thigh, Posterior (Back)
Biceps femoris (part of hamstrings) Long head: Ischial tuberosityShort head: Linea aspera Fibula and lateral condyle of tibia Flexion at knee, extension of thigh
Semimembranosus (part of hamstrings) Ischial tuberosity Medial condyle of tibia Flexion at knee, extension of thigh
Semitendinosus (part of hamstrings) Ischial tuberosity Proximal end of tibia Flexion at knee, extension of thigh
Leg, Posterior
Gastrocnemius Medial and lateral condyles of femur Calcaneus by Achilles (calcaneal) tendon Flexion at knee and plantar flexion
Soleus Posterior third of fibula and middle third of tibia Calcaneus by Achilles tendon Plantar flexion
Hip
Gluteus maximus Dorsal ilium, sacrum, and coccyx Glutual tuberosity of femur Extends thigh and laterally rotates thigh

About This Article

This article is from the book:

About the book author:

Frank Amthor, PhD, is a professor of psychology at the University of Alabama and holds a secondary appointment in the UAB Medical School Department of Neurobiology. He has been an NIH-supported researcher for over 20 years and has published over 100 journal articles and conference abstracts.

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