Question | Answer |
rectus fibers | run parallel to the midline- rectus abdominis |
transverse fibers | run perpendicular to the midline- transverse abdominis |
oblique fibers | run diagonal to the midline- external oblique |
maximus | largest-gluteus maximus |
minimus | smallest-gluteus minimus |
longus | longest-adductor longus |
deltoid | triangular shape-deltoid |
rhomboid | diamond shape-rhomboid majot |
trapezius | trapezoid shape-trapezius |
biceps | two origins-biceps femoris |
triceps | three origins-triceps brachii |
quadriceps | four origins-quadriceps femoris |
occipitofrontalis: frontalis and occipitalis | composite muscle that overlies the cranium; the two muscles are connected by an aponeruosis. Actions: frontalis-raises the eyebrows occipitalis: draws scalp posteriorly |
orbicularis oris | circular muscle that encircles the mouth. Action: puckers the mouth as in kissing |
orbicularis oculi | circular muscle that encircles each eye Action: closes each eye as in blinking |
zygomaticus major | originates on the zygomatic bone and inserts on the skin at the corners of the mouth Action: pulls the corners of the mouth superiorly as in smiling |
platysma | originates on the fascia of the chest and deltoid and inserts on the mandible and skin below the mouth Action: depresses the lower lip and mandible; tenses neck skin |
temporalis | Originates on the temporal bone and inserts on the mandible. Action: elevates and retracts the mandible |
masseter | originates on the maxillae and zygomatic bones and inserts on the mandible Action: elevates and protracts the mandible |
sternocleidomastoid | originates on the sternum and clavicle and inserts on the mastoid process of the temporal bone Action: if one side contracts, the head rotates tot eh opposite side. If both contract, flexion of the head is the result |
rectus abdominis | originates on the pubis and inserts superiorly on the lower ribs and xiphoid process Action: flexes the vertebral column and compresses the abdomen |
external oblique | originates laterally on the lower ribs and inserts medially on the iliac crest and linea alba Action: rotation of the trunk results if one side contracts. if both sides contract together, flexion of the vertebral column and compression of the abdomen |
internal oblique | located deep to the external oblique, the internal oblique originates laterally at the iliac crests and inserts medially at the linea alba and lower ribs Action: the internal oblique has the same action as the external oblique |
transverse abdominis | located deep to the internal oblique, the transverse abdominis originates laterally on the iliac crest and the cartilages of the lower ribs. It inserts medially at the xiphois process and linea alba |
erector spinae: iliocostalis group, longissimus group, spinalis group | composite group of muscles that individually originate on vertebral processes or ribs and insert on superior processes of the vertebral column Action: one side contracts muscles laterally flex and rotate the vertebral column. Both contract muscles extend" |
diaphragm | dome shaped muscle that originates on the lower ribs and lumbar vertebrae and inserts medially at the central tendon Action: during inspiration the diaphragm moves downward in the thoracic cavity increasing the horizontal and vertical dimensions of thorax |
external intercostals | located between the ribs, originate on the inferior border of the superior rib and insert on the inferior rib Action: contraction pulls the ribs upward and together to expand the dimensions of the thorax during forced inspiration |
internal intercostals | between the ribs, originate on the superior border of the inferior rib and insert on the inferior border of the superior rib Action: contraction pulls the ribs down and together to decrease the dimensions of the thorax during forced expiration |
pectoralis minor | anterior muscle of the chest. Originates medially on the upper ribs and inserts laterally on the scapula Action: depresses and protracts the scapula |
levator scapulae | posterior muscle of the upper back. Originates medially at the occipital bone, lower cervical and thoracic vertebra and inserts on the superior portion of the vertebral border of the scapula Action: elevates the scapula |
trapezius | posterior muscle of upper back. Originates medially at occipital bone lower cervical thoracic vertebrae, inserts on clavicle/scapula Action:superior portion elevates scapula and clavicle extends the head; middle adducts scapula; inferior depresses scapula |
rhomboid major | posterior muscle of the upper back that originates on the upper thoracic vertebrae and inserts on the vertebral border of the scapula Action: elevates, adducts and inferiorly rotates the scapula |
rhomboid minor | posterior muscle of the upper back that originates on the lower cervical and upper thoracic vertebrae and inters on the vertebral border of the scapula Action: elevates, adducts and inferiorly rotates the scapula |
pectoralis major | anterior muscle of the trunk that originates on the clavicle, sternum and upper ribs and inserts laterally on the greater tubercle of the humerus Action: flexes, adducts and medially rotates the arm |
latissimus dorsi | posterior muscle of the trunk that originates on the lower thoracic vertebrae and inserts on the anterior proximal humerus Action: adducts, extends, and medially rotates the arm |
deltoid | large shoulder muscle that originates on scapula posteriorly and clavicle anteriorly. Inserts on deltoid tuberosity of humerus Action:medial fibers abduct arm; anterior fibers flex and medially rotate arm; posterior fibers extend and laterally rotate arm |
supraspinatus | originates on the supraspinous fossa of the scapula and inserts on the greater tubercle of the humerus Action: abducts the arm |
infraspinatus | originates on the infraspinous fossa of the scapula and inserts on the greater tubercle of the humerus Action: laterally rotates and adducts the arm |
teres major | originates on the inferior posterior surface of the scapula and inserts on the anterior proximal humerus Action: extends, adducts and medially rotates the arm |
biceps brachii | muscle of the anterior arm with two points of origin on the scapula. Inserts on the radial tuberosity Action: flexes and supinates the forearm; flexes arm |
brachialis | deep to the biceps brachii, the brachialis originates on the anterior distal humerus and inserts on the proximal ulna Action: flexes the forearm |
brachioradialis | originates on the distal humerus and inserts on the styloid process of the radius Action: flexes the forearm |
triceps brachii | muscle of the posterior arm with three points of origin on the scapula and posterior humerus. IT inserts on the olecranon process of the ulna Action: extends the forearm and extends the arm |
flexors | muscles of the anterior forearm that originate on the medial distal humerus and insert on the carpals and metacarpals Action: flex the hand |
extensors | muscles of the posterior forearm that originate on the lateral distal humerus and insert on the metacarpals Action: extend the hand |
iliopsoas: iliacus and psoas major | muscles of the anterior hip. The iliacus originates on the ilium and psoas major originates on the lower vertebrae. Both muscles insert on the proximal femur Action: both muscles act to flex the thigh |
tensor fascial latae | muscle sof the lateral hip and thigh that originates on the iliac crest and inserts on the proximal lateral tibia via the iliotibial tract Action: flexes and abducts the thigh |
gluteus maximus | large, superficial muscle of the posterior hip that originates on the ilium and sacrum and inserts on the gluteal tuberosity of the femur Action: extend and laterally rotates the thigh |
gluteus medius | deep to the gluteus maximus, the gluteus medius originates on the posterior ilium and inserts on the greater trochanter of the femur Action: abducts and medially rotates the thigh |
gluteus minimus | deep to the gluteus medius, the gluteus minimus originates on the posterior ilium and inserts on the greater trochanter of the femur Action: abducts and medially rotates the thigh |
gracilis | muscle of the medial thigh that originates on the pubis and inserts on the medial surface of the proximal tibia Action: adducts the thigh and flexes the leg |
adductor magnus | A deep adductor muscle that originates on the ischium and pubis and inserts on the linea aspera of the femur Action: adducts and medially rotates the thigh |
adductor longus | originates on the pubis and inserts on the linea aspera of the femur Action: adducts, flexes. and medially rotates the thigh |
adductor brevis | originates on the pubis and inserts on the linea aspera of the femur Action: adducts, medially rotates and flexes the thigh |
rectus femoris- quadriceps femoris | muscle of the anterior thigh that originates on the anterior ilium and inserts on the tibial tuberosity via the patellar ligament Action: flexes the thigh and extends the leg |
vastus lateralis- quadriceps femoris | originates on the proximal femur and inserts on the tibial tuberosity Action: extends the leg |
vastus medialis- quadriceps femoris | oiginates on the linea aspera of the femur and inserts on the tibial tuberosity Action: extends the leg |
vastus intermedius | originates on the anterior and lateral surfaces of the body of the femur and inserts on the tibial tuberosity Action: extends the leg |
sartorius | called the "tailor muscle" the sartorius is the longest muscle in the body. Originates on the ilium and inserts on the medial body of the tibia Action: flexes the leg and flexes and laterally rotates the thigh |
Biceps femoris- hamstrings group | lateral muscle of the posterior thigh. Its two heads originate on the ischial tuberosity and linea aspera of the femur and insert on the head of the fibula and lateral condyle of the tibia Action: flexes the leg and extends the thigh |
Semimembranosus- hamstrings group | medial and deep muscle of the hamstrings group that originates on the ischial tuberosity and inserts on the medial condyle of the tibia Action: flexes the leg and extends the thigh |
Semieninosus- hamstrings group | medial and superficial muscle of the hamstrings group that originates on the ischial tuberosity and inserts on the medial side of the body of the tibia Action: flexes the leg and extends the thigh |
grastrocnemius- triceps surae | muscle of the posterior leg, its two head originate on the distal posterior femur and insert on the calcaneus via the achilles tendon Action: plantar flexes the foot and flexes the leg |
soleus- triceps surae | deep to the gastrocnemius, this muscle originates on the head of the fibula and proximal medial tibia and inserts on the calcaneus via the achilles tendon Action: plantar flexes the foot |
tibialis anterior | anterior muscle of the leg that originates on the lateral condyle of the tibia and inserts on the first metatarsal and cuneiform Action: dorsiflexes and inverts the foot |
Tibialis posterior | deep to the soleus, the tibialis posterior originates on the superior portion of the posterior tibia and fibula and inserts medially on the inferior surface of several tarsals and metatarsals Action: inverts and plantar flexes the foot |
fibularis (peroneus) longus | lateral muscle of the leg that originates on the lateral condyle of the tibia and head of the fibula and inserts on the first metatarsal and cuneiform Action: everts and plantar flexes the foot |
fibularis (peroneus) brevis | lateral muscle of the leg that originates on the body of the fibula and inserts on the fifth metatarsal Action: everts and plantar flexes the foot |