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Anatomy 10A
Unit 3: Muscles
For your practicum, you will need to know the muscle name & action. O = origin; I = insertion
Muscles of head and neck:
Muscles of facial expression:
Frontalis
Wrinkles forehead
Elevates eyebrow
O: epicranial aponeurosis
I: skin of eyebrow & bridge of nose
Corrugator supercilii
Draws eyebrow to midline
O: orbital rim of frontal bone near frontonasal suture
Orbicularis oculi
Closes eye
O: medial margin of orbit
Orbicularis oris
Compresses, purses lips
Buccinator
Compresses cheek
Zygomaticus major
Elevates corner of mouth (smiling)
O: inferior surface of zygomatic bone
I: angle of mouth
Risorius
Draws corner of mouth laterally
O: fascia around parotid gland
I: angle of mouth
Mentalis
Elevates & protrudes lower lip (pout)
O: incisive fossa of mandible
I: skin of chin
Platysma
Depresses mandible and tenses neck skin
O: fascia of superior thorax
I: mandible & cheek skin
Muscles of mastication:
Masseter
Elevates mandible & closes jaw
O: zygomatic arch
I: lateral surface & mandibular ramus angle
Temporalis
Elevates mandible & closes jaw
O: temporal lines of skull
I: coronoid process of mandible
Anterior muscles of the neck:
Sternocleidomastoid
Rotates head, flexes neck
I: skin around eyelids
O: maxilla & mandible
I: lips
O: lateral alveolar processes of maxilla & mandible
O: sternal end of clavicle & manubrium
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I: eyebrow
I: orbic. oris fibers
I: mastoid region & sup. nuchal line
Posterior muscles of the neck:
Trapezius
Extends neck, moves scapula
Suprahyoid muscles:
Digastric
Opens mouth, elevates hyoid (larynx)
Mylohyoid
Elevates hyoid and floor of mouth
Geniohyoid
Opens mouth, elevates hyoid (larynx)
Stylohyoid
Elevates hyoid (larynx)
O: styloid process of temporal bone
Infrahyoid muscles:
Sternohyoid
Depresses hyoid (larynx)
O: clavicle & manubrium
Sternothyroid
Depresses thyroid cartilage (larynx)
O: manubrium & 1st costal cartilage
Thyrohyoid
Depresses hyoid bone, elevates larynx
O: thyroid cartilage
*O: occipital bone & ligamentum nuchae
*I: acromion & scapular spine
O: posterior chin & mastoid of temporal bone
O: medial mandible
I: hyoid
I: median CT band (raphe) to hyoid
O: posterior chin
I: hyoid
I: hyoid
I: hyoid
I: thyroid cartilage
I: hyoid
Muscles of the body wall:
Thorax:
External intercostals
Elevates ribs (inspiration)
O: inferior border of rib
I: superior border of next lower rib
Internal intercostals
Depresses ribs (expiration)
O: superior border of rib
I: inferior border of next upper rib
Abdomen:
Rectus abdominis
Flexes vertebral column, compresses abdomen
External oblique
Compresses abdomen, trunk rotation opposite side
Internal oblique
Compresses abdomen, trunk rotation same side
O: thoracolumbar fascia & iliac crest
I: inferior borders ribs 9-12, costal cartilages 8-10, linea alba, pubis
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O: superior pubis
I: inferior rib cartilages & xiphoid
O: inferior borders ribs 5-12 I: linea alba & iliac crest
Transversus abdominis
Compresses abdomen
O: cartilages of ribs 6-12, iliac crest, thoracolumbar fascia
I: linea alba, pubis
Muscles of posterior thorax:
Serratus anterior
Protacts shoulder, rotates scapula up O: anterior borders of ribs 1-8
Levator scapulae
Elevates scapula
Rhomboideus major
Adducts & rotates scapula down
O: spinous processes of T1-T6
I: mid & lower vertebral border
Rhomboideus minor
Adducts & rotates scapula down
O: spinous processes of C7-T1
I: mid vertebral border of scapula
O: transverse processes of C1-C4
I: anterior vertebral border of scapula
I: superior vertebral border of scapula
Trapezius
Elevates, retracts, depresses or rotates scapula up O: spinous processes of T1-T12 I: acromion & scap. spine
(adding to listing in posterior neck)
Muscles that move the arm:
Pectoralis major
Flexes, adducts, and rotates shoulder medially
O: cart. of ribs 2-6, sternum, inferior & medial clavicle
I: greater tubercle & intertubercular groove
Pectoralis minor
Depresses and protracts scapula
Deltoid
Abducts shoulder
Latissimus dorsi
Extends, adducts, and rotates shoulder medially
Teres major
Extends and rotates shoulder medially
O: inferior angle of scapula
I: intertubercular groove
Teres minor
Adducts and rotates shoulder laterally
O: lateral border of scapula
I: greater tubercle of humerus
O: anterior ribs 3-5
I: coracoid process of scapula
O: clavicle & acromion & spine of scapula I: deltoid tuberosity of humerus
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O: spinous processes of lower T, all L, sacrum, ribs 8-12,
and thoracolumbar fascia
I: intertubercular groove
Muscles that move the forearm:
Biceps brachii
Flexes elbow & shoulder
O: coracoid process, supraglenoid tubercle (scapula)
I: radial tuberosity
Brachialis
Flexes elbow
O: distal ½ of anterior humerus
Brachioradialis
Flexes elbow
O: ridge superior to lateral epicondyle of humerus I: lateral styloid process of radius
Pronator teres
Pronates forearm & flexes elbow
Supinator
Supinates forearm
O: lateral epicondyle of humerus & ridge near radial notch of ulna
I: anterolateral surface of radius distal to radial tuberosity
Triceps brachii
Extends elbow
O: superior, lateral margin of humerus, infraglenoid tubercle of scapula, posterior
Humerus
I: olecranon of ulna
I: ulnar tuberosity & coronoid process
O: medial epicondyle of humerus, coronoid process of ulna
I: middle of lateral surface of radius
Muscles that move the hand/fingers:
I: bases of 2nd & 3rd metacarpals
Flexor carpi radialis
Flexes and abducts wrist
O: medial epicondyle of humerus
Flexor carpi ulnaris
Flexes and adducts wrist
O: medial epicondyle of humerus, adjacent medial olecranon & anteromed. ulna
I: pisiform, hamate, and base of 5th metacarpal
Palmaris longus
Flexes wrist
Extensor carpi radialis longus
Extends and abducts wrist
O: lateral supracondylar ridge of humerus
Extensor carpi ulnaris
Extends and adducts wrist
O: lateral epicondyle of humerus, adjacent dorsal surface of ulna
I: base of 5th metacarpal
Extensor digitorum
Extends wrist and digits
O: lateral epicondyle of humerus
O: medial epicondyle of humerus
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I: palmar aponeurosis & flexor retinaculum
I: base of 2nd metacarpal
I: posterior surfaces of phalanges 2-5
Muscles that move the thigh:
Gluteals:
Gluteus maximus
Extends and rotates hip laterally
O: iliac crest, posterior gluteal line, lateral ilium, sacrum, coccyx, and
Thoracolumbar fascia
I: iliotibial tract & gluteal tuberosity femur
Gluteus medius
Abducts and rotates hip medially
O: anterior iliac crest, lateral ilium
Gluteus minimus
Abducts and rotates hip medially
O: lateral ilium
Tensor fasciae latae
Abducts and rotates hip medially, extends & laterally rotates knee, tenses fasciae latae
O: iliac crest & lateral anterior superior iliac spine I: iliotibial tract
I: greater trochanter of femur
I: greater trochanter of femur
Adductors:
Adductor longus
Flexes, adducts, and rotates hip medially
Adductor brevis
Flexes and adducts hip
Adductor magnus
Adducts, flexes and rotates hip medially (anterior), extension of hip (posterior)
O: inferior ramus & ischial tuberosity
I: linea aspera & adductor tubercle femur
O: inferior ramus of pubis
O: inferior ramus of pubis
I: linea aspera of femur
I: linea aspera of femur
Muscles that move the leg:
Knee Flexors =”Hamstrings”:
Gracilis
Flexes & medial rotates knee, adducts & medially rotates hip
Sartorius
Flexes knee and hip, abducts and rotates hip laterally
Biceps femoris
Flexes knee, extends and laterally rotates hip
O: ischial tuberosity, linea aspera
I: head of fibula, lateral condyle of tibia
Semimembranosus
Flexes knee, extends and medially rotates hip
O: ischial tuberosity I: posterior medial condyle of tibia
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O: inferior ramus of pubis
I: medial tibial inferior to medial condyle
O: anterior superior iliac spine
I: medial tibia near tuberosity
Semitendinosus
Flexes knee, extends and medially rotates hip
O: ischial tuberosity I: proximal, medial tibia
Knee Extensors = “Quadriceps”:
Rectus femoris
Extends knee and flexes hip
Vastus medialis
Extends knee
O: linea aspera
Vastus lateralis
Extends knee
O: anterior & inferior to greater trochanter & linea aspera (proximal ½ )
Vastus intermedius
Extends knee
O: anterolateral femur & linea aspera (distal ½)
O: anterior inferior iliac spine & superior acetabular rim
I: tibial tuberosity, patella, and patellar ligament
I: same
I: same
I: same
Muscles that move the foot/toes:
Muscles that move the foot:
Gastrocnemius
Plantar flexes ankle, flexes knee
Soleus
Planter flexes ankle
Peroneus (fibularis) longus
Planter flexes ankle and everts foot
O: head & prox. shaft fibula
Peroneus (fibularis) brevis
Plantar flexes ankle and everts foot
O: midlateral fibula
Peroneus tertius
Dorsiflexes and everts foot
Tibialis anterior
Dorsiflexes ankle, inverts foot
Flexor digitorum longus
Flexes toes 2-5, plantar flexes ankle O: posteromedial tibia
Extensor digitorum longus
Extends toes 2-5, dorsiflexes ankle
O: femoral condyles
I: calcaneus via calcaneal tendon
O: head & prox. shaft fibula and adjacent posteromedial shaft tibia
I: base of 1st metatarsal & cuneiform 1
I: base of 5th metatarsal
O: lateral condyle & prox. shaft tibia
I: base of 1st metatarsal & cuneiform I
I: inferior distal phalanges 2-5
O: lateral condyle tibia, anterior fibula
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I: same
I: superior phalanges 2-5