A&P Muscles

Trapezius

Large, flat, trapezoid-shaped muscle on back of neck and upper back; origin on occipital bone, C7, and all thoracic vertebrae; inserts on clavicle and scapula; Hyperextends head so as to look at sky; lateral flexion of head; Causes shrugging and medial rotation of shoulders; Helps to maintain spine in extension.

Gluteus Maximus

Largest and most superficial of gluteal muscles; located on posterior surface of buttocks; origin on ilium of coxal bone, sacrum, coccyx, and local aponeurosis; inserts on femur; Forms buttocks; extends and rotates thigh laterally at hip; muscle for sitting and climbing stairs; produces backswing of leg while walking.

Peroneus Longus

Lateral surface of leg; origin on fibula and tibia; inserts on metatarsal and tarsal bones; Plantar flexion and eversion of foot; supports arch.

Gracilis

Located along medial thigh; origin on symphysis pubis; inserts on proximal tibia; Adducts and medially rotates thigh at hip; flexes leg at knee.

Tibialis Anterior

Located on anterior leg; origin on tibia; inserts on tarsal and metatarsal bones; Dorsiflexes and inverts foot.

Liopsoas

Located on anterior surface of groin; origin on ilium and lumbar vertebrae; inserts on femur; Flexes and rotates thigh laterally; antagonist to gluteus maximus.

Rectus Femoris, Vastus Lateralis, Vastus Medialis, Vastus Intermedius

Located on anterior thigh; all insert on tibia; rectus femoris originates on ilium (coxal bone); other "quads" originate on femur; Used to extend leg at the knee (e.g., kicking a football); rectus femoris can flex thigh at hip; vastus lateralis is common site for intramuscular injection in children.

Tensor Fasciae Latae

Located on lateral thigh; origin on ilium; inserts on tibia; Flexes and abducts thigh at hip.

Biceps Femoris, Semitendinosus, Semimembranosus

Located on posterior surface of thigh; as a group, attaches to ischium (origin) to their points of insertion on tibia. Biceps femoris also originates on femur and inserts on both tibia and fibula; As a group, they flex leg at knee, extend thigh at hip; antagonistic to quadriceps femoris.

Pectineus

Located on the medial thigh; origin on pubis; inserts on femur; Adducts and flexes thigh at hip.

Sartorius

Long muscle that crosses obliquely over anterior thigh; origin on ilium; inserts on tibia.

Biceps Brachii

Major muscle on anterior surface of arm; origin on scapula; inserts on radius; Flexes and supinates forearm at elbow and flexes arm at shoulder; muscle used to "MAKE A MUSCLE"; acts synergistically with brachialis and bracchioradialis.

Gastrocnemius

Posterior surface of leg; large two-headed muscle that forms calf; origin on femur; inserts on calcaneus (heel bone) by way of Achilles tendon; Plantar flexion of foot; "TOE DANCER" muscle; flexes leg at knee.

Soleus

Posterior surface of leg; origin on fibula and tibia; inserts on calcaneus; Plantar flexion of foot.

Adductor Longus, Adductor Magnus

As a group, located on anteromedial surface of thigh; Adducts and medially rotates thigh; muscles used by "HORSEBACK RIDERS" to stay on horse.

External Oblique, Internal Oblique, Transverse Abdominis, Rectus Abdominis

As a group, muscles are arranged vertically, horizontally, and obliquely to strengthen abdominal wall; Abdominal wall muscles compress the abdomen, thereby aiding in urination, defecation, childbirth, and forced expiration (breathing); also flex and rotate vertebral column.

Orbicularis Oculi

Circular muscle around eye; Closes eyes; winking, blinking, and squinting.

Masseter

Covers lateral part of lower jaw; origin on maxilla, zygomatic process of the temporal bone; inserts on mandible; Closes jaw; retracts jaw.

Orbicularis Oris

Encircles mouth; Closes, purses lips; "KISSING MUSCLE"..

Sternocleidomastiod

Extends along each side of neck; strong narrow muscles that extend obliquely from sternum and clavicle (origin) upward to mastoid process of temporal bone (insertion); Contraction of both muscles flexes the head at the neck; contraction of one rotates head toward opposite side.

Quadriceps Tendon, Quadriceps Ligament

Extends distally to the tibial tuberosity.

Temporalis

Flat fan-shaped muscle over temporal bone (origin): inserts on mandible; Closes jaw; retracts jaw.

Frontalis

Flat muscle covering forehead; origin on cranial aponeurosis; inserts on skin above eyebrows; Raises eyebrows; "SURPRISED LOOK"; wrinkles forehead.

Linea Alba

Forms a white line midline to the abdominal muscles.

Serratus Anterior

Forms upper side of chest wall; origin on upper ribs; inserts on scapula; Lowers shoulder and moves the arm forward as in pushing a cart.

Infraspinatus, Teres Minor

Group of muscles that attaches humerus (insertion) to scapula (origin); tendons form cuff over proximal humerus; Adduct, extend, and rotate arm at shoulder; the "CUFF" stabilizes shoulder joint.

Buccinator

Horizontal cheek muscle; origin on maxilla and mandible; inserts on orbicularis oris; Flattens cheek; trumpete's muscle; whistling muscle; helps with chewing by positioning food between teeth.

Pectoralis Major

Large muscle that covers upper anterior chest; origin on clavicle, sternum, and cartilages of upper ribs; inserts on anterior humerus; Adducts and medially rotates arm across chest; flexes and extends arm at shoulder.

Latissimus Dosi

Large, broad, flat muscle on mid and lower back; origin on lower vertebral column and lower ribs; inserts on posterior humerus; Adducts and rotates arm medially, behing the back; "SWIMMERS MUSCLE".

Zygomaticus

Origin on cheekbone (zygomatic bone); inserts on corner of mouth; Elevates corner of mouth; smiling muscle.

Brachioradialis

Origin on humerus; flexes on radius; Flexes forearm at elbow.

Brachialis

Origin on humerus; inserts on ulna; Flexes forearm at elbow.

Triceps Brachii

Origin on posterior surface of arm (scapula and humerus); inserts on ulna; Extends forearm at elbow, extends arm at shoulder; "BOXER'S MUSCLE".

Teres Major

Origin on scapula; inserts on humerus; Extends and adducts arm at shoulder; medially rotates arm at shoulder.

Gluteus Medius

Thick muscle partly behind and superior to gluteus maximus; origin on ilium; inserts on femur; Abducts and rotates thigh medially at hip; common site of intramuscular injections.

Deltoid

Thick muscle that covers shoulder joint; origin on clavicle and scapula; inserts on humerus; Abducts arm as in "SCARECROW" position; flexes extends, and rotates arm at shoulder.