Skeletal Muscles and Actions

Vocabulary flashcards covering the names, locations, and actions of human skeletal muscles as presented in the lecture notes.

Frontalis

Action: Elevates eyebrows; wrinkles skin of forehead horizontally

Origin : Epicranius aponeurosis

Insertion : skin of eyebrows

Nerve : facial nerve

Occipitalis

Action : pulls scalp posteriorly

Origin : occipital bone

Insertion : Epicranial aponeurosis

Epicranius

An aponeurosis connecting the frontalis and occipitalis to form the occipitofrontalis.

Orbicularis oris

Action: Closes and protrudes lips as in kissing

Origin: maxilla and mandible

Insertion: skin and connective tissue of lips

Zygomaticus major

Action: pulls the angle of mouth superiorly and laterally as in smiling

Origin : zygomatic bone

Insertion: lateral muscle fibers of corner / angle of mouth

Buccinator

Action : Presses cheeks against teeth and lips as in whistling, blowing, and sucking.

Origin : molar regions of maxilla and mandible

Insertion : Orbicularis oris muscle and connective tissue of cheek/ lips

Platysma

Action : Draws outer part of lower lip inferiorly and posteriorly as in pouting and depresses mandible

Origin : connective tissue of deltoid and pectoralis major muscles

Insertion : Mandible, skin and connective tissue inferior to mouth

Orbicularis oculi

Action : Closes eye

Origin : orbital portions of the frontal bone and maxilla

Insertion : skin of the orbital area and eyelids

Corrugator supercilii

Action : Draws eyebrow inferiorly and wrinkles skin of forehead vertically as in frowning.

Origin: medial supraorbital margin of frontal bone

Insertion: skin of medial eyebrows

Masseter

Action: Elevates mandible as in closing mouth.

Origin : Zygomatic arch

Insertion: Angle and lateral surface of ramus of mandible

Temporalis

Action : Elevates and retracts mandible

Origin : lateral surface of skull

Insertion: Coronoid process of the mandible

Digastric

Action : Elevates hyoid bone and depresses mandible

Origin : anterior belly, anterior inner margin of the mandible ; posterior belly , into mastoid notch, medial to the mastoid process

Insertion : connective tissue to the hyoid bone

Sternocleidomastoid

Action : Acting together, flex cervical vertebral column and head.

Origin : Manubrium of sternum, medial portion of clavicle

Insertion: Mastoid process of temporal bone

Iliocostalis (lateral) group

Action : Acting together, muscles of each region (cervical, thoracic, and lumbar) extend and maintain erect posture of vertebral column of their respective regions.

Origin: Posterior surfaces of ribs ; portions of sacrum and ilium

Insertion : Transverse processes of inferior cervical vertebrae; posterior surfaces of ribs

Longissimus (intermediate) group

Action : Acting together, longissimus capitis muscles extend head; acting together longissimus cervicis and both longissimus thoracic muscles extend vertebral column of their respective regions.

Origin : transverse process of vertebrae usually several vertebrae inferior to insertions

Insertion: mastoid process; transverse process of vertebrae; medial posterior portions of ribs in thoracic area

Spinalis (medial) group

Action: Acting together muscles of each region (cervical, thoracic and lumbar) extend vertebral column of their respective regions.

Origin : Spinous process of superior lumbar, thoracic, and inferior cervical vertebrae

Insertion : Spinous process of thoracic and cervical vertebrae in skull

Diaphragm

Action: Contraction causes it to flatten and increase size of thoracic cavity resulting in inhalation; relaxation causes it to move superiorly and decrease the size of the thoracic cavity resulting in exhalation.

Origin: Xiphoid process of strenum, lower ribs and costal cartilages , lumbar vertebrae

Insertion: Central tendon of diaphragm

External Intercostals

Action : Contraction causes ribcage to expand and increase the size of the thoracic cavity resulting in inhalation.

Origin: lower edge of rib superior to its insertion

Insertion: upper edge of rib inferior to its origin

Internal Intercostals

Action: Contraction draws adjacent ribs together to decrease the size of the thoracic cavity resulting in exhalation.

Origin: upper edge of rib inferior to its insertion

Insertion: lower edge of ribs, superior to its origin, deep to the insertion of the external intercostals

Rectus abdominis

Action : Flexes vertebral column and compresses abdomen.

Origin: superior aspect of pubic bones

Insertion: Costal cartilages of inferior ribs

External oblique

Action: Acting together, compress abdomen

Origin: inferior eight ribs

Insertion: iliac crest, pubic tubercle , and línea alba

Internal oblique

Action : Acting together, compress abdomen.

Origin: iliac crest and inguinal

Insertion: inferior three to four ribs, línea alba , and pubic bone

Transversus abdominis

Action : Compresses abdomen

Origin : Inferior six costal cartilages, thoracolumbar fascia, iliac crest, and inguinal ligament

Insertion : Linea alba and pubic bone

Pectoralis minor

Action: Fixator of scapula

Origin: Anterior part of ribs 3-5

Insertion: Carcoid process

Serratus anterior

Action: Fixator of scapula prime mover of scapula in protraction; assists in superior rotation of scapula

Origin: first nine ribs

Insertion: Medial border of scapula

Trapezius

Action: Fixator of scapula.

Origin: external occipital, protuberance and cervical vertebrae

Insertion: lateral clavicle

Levator scapulae

Action :Fixator of scapula.

Origin: transverse process of C1/C4

Insertion: Superior angle of scapula

Rhomboid major

Action : Fixator of scapula.

Origin: Spinous processes of T2-T5 major

Insertion: medial border of scapula

Rhomboid minor

Action : Fixator of scapula.

Origin: C7- T1 minor

Insertion: Medial border of scapula

Pectoralis major

Action: adducts and medially rotates arm.

Origin: Medial clavicle, sternum, costal cartilages 1-7

Insertion: Greater tubercle and lateral lip of intertubercular sulcus of humerus

Latissimus dorsi

Action: Extends, adducts and medially rotates arm.

Origin: iliac crest ,spinous processes of lower thoracic and all lumbar vertebrae

Insertion: Floor of inter-tubercular sulcus of the humerus

Deltoid

Action : Abducts arm

Insertion: Acromion and spine of scapula; lateral clavicle

Origin: deltoid tuberosity of humerus

Supraspinatus

Action : Assists deltoid muscle in abducting arm.

Origin: Supraspinous fossa of scapula

Insertion: Greater tubercle of humerus

Infraspinatus

Action: Laterally rotates arm

Origin: Infraspinous fossa of scapula

Insertion: Greater tubercle of humerus

Subscapularis

Action: Medially rotates arm.

Origin: Subscapular fossa of scapula

Insertion: Lesser tubercle of humerus

Biceps brachii

Action : Flexes forearm.

Origin: Supraglenoid tubercle ( long head) and coracoid process (short head)

Insertion: Radial tuberosity

Brachialis

Action: Flexes forearm.

Origin: Distal half of the diaphysis of the anterior humerus

Insertion: Coronoid process of ulna

Brachioradialis

Action: Flexes forearm.

Origin: Ridge proximal to the lateral condlye of the distal humerus

Insertion: Distal radius proximal to the styloid process

Triceps brachii

Action: Extends forearm.

Origin: infraglenoid tubercle ( long head) posterior , proximal diaphysis ( lateral head); most of posterior diaphysis (medial head )

Insertion: Olecranon process

Pronator teres

Action : Pronates forearm.

Origin: media epicondyle of humorous, coronoid process of ulna

Insertion: lateral surface of radius

Supinator

Action: Supinates forearm.

Origin: lateral epicondyle of humorous, area of the radial notch of ulna

Insertion: Anterior / lateral area of proximal third of radius, distal to tuberosity

Palmaris longus

Action : Flexes hand at wrist joint.

Origin: Epicondlye of humerus

Insertion: Flexor retinaculum and surrounding connective tissue in palm of hand

Flexor carpi radialis

Action: Flexes and abducts hand at wrist joint (radial deviation).

Origin: Medial epicondyle of humerus

Insertion: second and third metacarpals

Flexor carpi ulnaris

Action : Flexes and adducts hand at wrist joint (ulnar deviation).

Origin: Medial epicondyle of humerus, medial olecranon process of ulna

Insertion: Pisiform , hamate, fifth metacarpal

Extensor digitorum

Action :Extends hand at wrist joint.

Origin: lateral epicondyle of humorous

Insertion: posterior phalanges of fingers 2-5

Extensor carpi radialis longus

Action :Extends and abducts hand at wrist joint (radial deviation).

Origin: lateral lower diaphysis of humerus

Insertion: Second metacarpal

Extensor carpi ulnaris

Action : Extends and adducts hand at wrist joint (ulnar deviation).

Origin: lateral epicondyle of humerus, lateral proximal ulna

Insertion: Fifth metacarpal

Psoas Major

Action: Part of iliopsoas that flexes thigh.

Origin: lateral side and transverse process of T12 and lumbar vertebrae

Insertion: lesser trochanter of the femur

Iliacus

Action:Part of iliopsoas that flexes thigh.

Origin: iliac fossa

Insertion: lesser trochanter of the femur

Gluteus maximus

Action: Extends thigh.

Origin: posterior and lateral portions of the ilium, sacrum, and coccyx

Insertion: gluteal tuberosity of femur and iliotibial tract

Gluteus medius

Action : Abducts thigh.

Origin : between posterior and interior gluteal lines on the outer surface of ilium

Insertion: greater trochanter a femur

Tensor fascia lata

Action : Abducts thigh.

Origin: Iliac crest and anterior superior iliac spine

Insertion: iliotibial tract, the thickened portion of the fascia lata, which itself insertion into the proximal, lateral tibia

Adductor longus

Action :Adducts thigh.

Origin: body of pubis

Insertion: línea áspera

Adductor magnus

Action :Adducts thigh.

Origin: ischial tuberosity, ischial ramus , inferior ramus of pubis

Insertion: Línea áspera and adductor tubercle of femur

Gracilis

Action : Adducts thigh.

Origin: body and inferior ramus of pubis; ischial ramus

Insertion: medial surface proximal tibia

Quadriceps femoris

Muscle group where all four heads (rectus femoris, vastus lateralis, vastus medialis, vastus intermedius) extend leg. Extends the leg and flexes the thigh

Sartorius

Action: Flexes leg.

Origin: Anterior superior iliac spine

Insertion: proximal portion of medial condlye of the tibia

Hamstrings

Muscle group comprising the biceps femoris, semitendinosus, and semimembranosus that flexes leg. It extends the thigh and flexes the leg

Tibialis anterior

Action : Dorsiflexes foot.

Origin: lateral condlye and proximal diaphysis of the tibia

Insertion: Medial cuneiform bone and first metatarsal

Extensor digitorum longus

Action : Dorsiflexes foot.

Origin: lateral condyle of the tibia and proximal portion of the fibula

Insertion: phalanges and connective tissues of toes 2-5

Tibialis posterior

Action : Plantar flexes foot.

Origin: proximal tibia, fibula, and interosseous membrane

Insertion: Metatarsals 2-4

Fibularis longus

Action: Plantar flexes foot.

Origin: proximal lateral fibula

Insertion: Medial cuneiform bone and first metatarsal

Fibularis brevis

Action :Plantar flexes foot.

Origin: distal fibula

Insertion: fifth metatarsal

Gastrocnemius

Action: Plantar flexes foot.

Origin: medial and lateral condlyes of the femur

Insertion: posterior calcaneus

Soleus

Action: Plantar flexes foot.

Origin: Head of fibula, proximal tibia, and interosseous membrane

Insertion: posterior calcaneus

Flexor Hallucis Longus

Action : Dorsiflexes big toe.

Origin : posterior fibula and interosseous membrane

Insertion: distal phalanx of great toe

Tendons

A tough flexible band fibrous connective tissue that connects skeletal to bone

Patellar tendon

Calcaneal Tendon

IT Band