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Muscles
Question | Answer |
---|---|
Frontalis | A: With aponuerosis fixed, raised eyebrows; wrinkles forehead skin horizontally |
Occipitalis | A: Fixes aponuerosis and pulls scalp posteriorly |
Temporalis | A: Closes jaw; elevates and retracts mandible; synergist of pterygoids in side-to-side movements; maintains resting position of mandibleO: Temporalis fossaI: Coronoid process of mandible |
Zygomaticus Major | A: Raises lateral corners of mouth upward (smiling muscle)O: Zygomatic boneI: Skin and muscle at corner of mouth |
Zygomaticus Minor | A: Raises lateral corners of mouth upward (smiling muscle) |
Orbicularis Oris | A: Closes mouth; purses and protrudes lips (kissing and whistling muscle) |
Orbicularis Oculi | A: Various parts can be activated individually; closes eyes, produces blinking, squinting, and draws eyebrows inferiorly; protects eyes from intense light and injury |
Masseter | A: Closes jaw and elevates mandibleO: Zygomatic arch and maxillaI: Angle and ramus of mandible |
Risorius | A: Draws corner of lip laterally; tenses lip; synergist of zygomaticus |
Buccinator | A: Draws corner of mouth laterally; compresses cheek (as in whistling and sucking); holds food between teeth during chewing |
Platysma | A: Depresses mandible; pulls lower lip back and down (i.e., produces downward sag of the mouth); tenses skin of neck (e.g., during shaving)Note: This is an unpaired muscle |
Sternocleidomastoid | A: PM of active head flexion; together cause flexion of neck forward (w/ resistance); independently, rotate head toward shoulder on opposite sideO: Manubrium & medial portion of clavicleI: Mastoid process & superior nuchal line of occipital bone |
Scalenes | A: Flex and slightly rotate neck; elevate ribs 1-2 (aid in inspiration)Note: Comprised of anterior, middle, and posterior muscled |
Trapezius | A: Extends head;raises/rotates/retracts (adducts) scapula & stabilizes it; superior fibers elevate scapula & inferior depress itO: Occipital bone; ligamentum nuchae; spines of C7 & all T vertebrae I: Acromion & spinous process; lateral 1/3 of clavicle |
Latissimus Dorsi | A: PM of arm extension; adducts & medially rotates arm; depresses scapula; brings arm down in power strokeO: Indirect at spinous process of lower 6 T vertebrae, lumbar vertebrae, last 3-4 ribs, iliac crest I: Floor of intertubercular sulcus of humerus |
Levator Scapulae | A: Elevates and adducts scapula; with fixed scapula, flexes neck to the same side |
Splenius Group | A: As a group, extend or hyperextend the head; when only one side is active, head is rotated and bent toward the same sideNote: Has two parts, the splenius capitus and spenius cervicis |
Deltoid | A: As a whole, PM of arm abduction;antagonist of pec major/lats that adduct arm; when only specific fibers active, can aid in flexion/extension/rotation of humerusO: Lateral 1/3 of clavicle; acromion & spine of scapula I: Deltoid tuberosity of humerus |
Erector Spinae | A: Prime mover of back extension; extend and bend the vertebral column laterally; provide resistance that helps control action of bending forward at waist and act as powerful extensors to return to erect position; fibers of longissimus also extend head |
Quadratus Lumborum | A: Each flexes vertebral column laterally; together extend the lumbar spine and fix rib 12; maintains upright posture; assists in forced inspiration |
Rhomboid Major | A: Pulls scapula medially (retraction); stabilizes the scapula; rotates glenoid cavity downward |
Rhomboid Minor | A: Pulls scapula medially (retraction); stabilizes the scapula; rotates glenoid cavity downward |
Teres Major | A: Extends, medially rotates, and adducts humerus; synergist of latissimus dorsi |
Teres Minor | A: Same as infraspinatous; lateral rotation of humerus; helps hold head of humerus in glenoid cavity; stabilizes shoulderO: Lateral margin of scapulaI: Greater tubercle of humerus |
Rectus Abdominus | A: Flexes and rotates vertebral column; increases abdominal pressure; fixes and depresses ribs; stabilizes pelvis during walking; used in sit-ups and curls |
Transversus Abdominus | A: Compresses abdominal contents |
External Oblique | A: When pair contracts simultaneously, aid rectus abdominus in flexing vertebral column and in compressing abdominal wall and increasing intra-abdominal pressure; acting individually, aid muscles of back in trunk rotation and lateral flexion |
Internal Oblique | A: When pair contracts simultaneously, aid rectus abdominus in flexing vertebral column and in compressing abdominal wall and increasing intra-abdominal pressure; acting individually, aid muscles of back in trunk rotation and lateral flexion |
External Intercostals | A: Pulls ribs toward one another to elevate rib cage; aids in inspiration; synergist of diaphragm |
Internal Intercostals | A: Draws ribs together to depress rib cage; antagonistic to external intercostals |
Subclavius | A: Helps stabilize and depress pectoral girdle |
Pectoralis Major | A: PM of arm flexion; adducts, medially rotates arm; with arm fixed pulls chest upward (acts in forced inspiration)O: Clavicle, sternum, carilage of ribs 1-6, aponeurosis of external obliqueI: By short tendon into intertubercular sulcus of humerus |
Pectoralis Minor | A: With ribs fixed, draws scapula forward and inferiorly; with scapula fixed draws rib cage superiorly |
Serratus Anterior | A: Prime mover to protract and hold scapula against chest wall; rotates scapula, causing inferior angle to move laterally and upward; raises point of shoulder; abduction and raising of arm ("boxer's muscle") |
Diaphragm | A: Prime mover of inspiration flattens on contraction, increasing vertical dimension of thorax; increases intra-abdominal pressure |
Supraspinatus | A: Assists abduction of humerus; stabilizes shoulder jointO: Supraspinous fossa of scapulaI: Greater tubercle of humerus |
Infraspinatus | A: Lateral rotation of humerus; helps hold head of humerus in glenoid cavity; stabilizes shoulder (part of rotator cuff)O: Infraspinous fossa of the scapulaI: Greater tubercle of humerus |
Subscapularis | A: Chief medial rotator of humerus; assisted by pectoralis major; helps to hold head of humerus in glenoid cavity; stabilizes shoulder jointO: Subscapular fossa of scapulaI: Lesser tubercule of humerus |
Biceps Brachii | A: Powerful flexion of elbow and supination of forearm; weak arm flexorO: Short head - coracoid process of scapula; tendon of long head runs in intertubercular sulcus and within capsule of shoulder jointI: Radial tuberosity |
Brachialis | A: A major flexor of forearmO: Distal portion of anterior humerusI: Coronoid process of ulna |
Brachioradialis | A: Synergist in foream flexion; during rapid flexion and extension, stabilizes elbow |
Coracobrachialis | A: Flexion and adduction of the humerus; syntergist of pectoralis major |
Triceps Brachii | A: Powerful forearm extensor; antagonist of forearm flexorsO: Long head - inferior margin of glenoid cavity; lateral head - posterior humerus; medial head - distal radial groove on posterior humerusI: Olecranon process of ulna |
Palmaris Longus | A: Flexes wrist (weak); tenses skin and fascia of plam; weak synergist for elbow flexion |
Flexor Carpi Ulnaris | A: Powerful flexor of wrist; adducts hand in concert with extensor carpi ulnaris; stabilizes wrist during finger extension |
Flexor Carpi Radialis | A: Powerful flexor of wrist; abducts hand; weak synergist of elbow flexion |
Flexor Digitorum Superficialis | A: Flexes wrist and middle phalanges of fingers 2-5; the important finger flexor when speed and flexion against resistance are required |
Pronator Teres | A: Acts synergystically with pronator quadratus to pronate forearm; weak elbow flexor |
Supinator | A: Assists biceps brachii to forcibly supinate forearm; works alone in slow supination; antagonist of pronator muscles |
Extensor Digitorum | A: Prime mover of finger extension; extends wrist; can flare (abduct) fingers |
Extensor Carpi Radialis Longus | A: Extends wrist in conjuction with extensor carpi ulnaris; abducts wrist in conjuction with flexor carpi radialis |
Extensor Carpi Ulnaris | A: Extends wrist in conjuction with extensor carpi radialis; adducts wrist in conjuction with flexor carpi ulnaris |
Anconeus | A: Abducts ulna during forearm pronation; synergist of triceps brachii in elbow extension |
Iliopsoas | Two closely related muscles: Iliacus and Psoas Major; prime mover for flexing thigh or for flexing trunk on thigh during a bow |
Psoas Major | A: Flex trunk on thigh; flex thigh; lateral flexion of vertebral columnO: Transverse processes, bodies, and discs of T12 and lumbar vertebraeI: On and just below lesser trochanter of femur |
Iliacus | A: Flex trunk on thigh; flex thigh O: Iliac fossa and crest, lateral sacrumI: On and just below lesser trochanter of femur |
Rectus Femoris | A: Extends knee and flexes thigh at hipO: Anterior inferior iliac spine and superior margin of acetabulumI: Tibial tuberosity and patella |
Sartorius | A: Flexes, abducts, and laterally rotates thigh; flexes knee; helps effect cross-legged position ("tailor's muscle")O: Anterior superior iliac spineI: By an aponeurosis into medial aspect of proximal tibia |
Gracilis | A: Adducts thigh; flexes and medially rotates leg, especially during walking |
Vastus Lateralis | A: Extends and stabilizes kneeO: Greater trochanter, intertrochanteric line, and linea asperaI: Tibial tuberosity and patella |
Vastus Medialis | A: Extends knee; stabilizes patellaO: Linea aspera and intertrochanteric lineI: Tibial tuberosity and patella |
Vastus Intermedius | A: Extends kneeO: Anterior and lateral surface of femurI: Tibial tuberosity and patella |
Adductor Longus | A: Adduct and medially rotate and flex thigh |
Adductor Brevis | A: Adduct and medially rotate and flex thigh |
Adductor Magnus | A: Adduct and medially rotate and flex thigh; posterior part is also a synergist of hamstrings in thigh extension |
Tensor Fasciae Latae | A: Flexes, abducts, and medially rotates thigh; steadies trunk |
Biceps Femoris | A: Extends thigh; laterally rotates leg; flexes kneeO: Long head - ischial tuberosity; short head - linea aspera and distal femurI: Tendon passes laterally to insert into head of fibula and lateral condyle of tibia |
Semitendinosus | A: Extends thigh; flexes knee; medially rotates legO: Ischial tuberosityI: Medial aspect of upper tibial shaft |
Semimebranosus | A: Extends thigh; flexes knee; medially rotates legO: Ischial tuberosityI: Medial condyle of tibia; lateral condyle of femur |
Gluteus Maximus | A: Complex, powerful thigh extensor (most effective when thigh is flexed); antagonist of iliopsoas; laterally rotates and abducts thighO: Dorsal ilium, sacrum, and coccyxI: Gluteal tuberosity of femur and iliotibial tract |
Gluteus Minimus | A: Abducts and medially rotates thigh; steadies pelvis |
Gluteus Medius | A: Abducts and medially rotates thigh; steadies pelvis during walkingO: Upper lateral surface of iliumI: Greater trochanter of femur |
Gastrocnemius | A: Plantar flexes foot when knee is extended; crosses knee joint, thus can flex knee (when foot is dorsiflexed)O: By two heads from the medial and lateral condyles of femurI: Calcaneus via calcaneal tendon |
Soleus | A: Plantar flexion; is an important muscle for locomotionO: Proximal portion of tiba and fibula; interosseous membraneI: Calcaneus via calcaneal tendon |
Tibialis Anterior | A: Prime mover of dorsiflexion; inverts foot; supports longitudinal arch of footO: Lateral condyle and upper 2/3 of tibia; interosseous membraneI: By tendon into inferior surface of first cuneiform and metatarsal 1 |
Fibularis Longus | A: Plantar flexes and everts foot; helps keep foot flat on groundO: Head and upper portion of fibulaI: By long tendon under foot to metatarsal 1 and medial cuneiform |
Extensor Digitorum Longus | A: Prime mover of toe extension; dorsiflexes foot |
Hamstrings | Hamstrings are composed of the Biceps Femoris, Semitendinosus, Semimembranosus. Have a common origin site. |
Quadriceps | Quadriceps femoris has four separate heads (Rectus Femoris and Vastus Medialis, Lateralis, and Intermedius). Heads have a common insertion tendon, the quadriceps tendon, inserts into patella and then via the patellar ligament into tibial tuberosity. |
Rotator Cuff | Supraspinatus, Infraspinatus, Teres Minor, Subscapularis (SITS) |
Adductors | Large muscle mass consisting of three muscles (magnus, longus, brevis) |