A & P Practical 2

Epicranius Frontal Belly

Origin: epicranial aponeurosis

Insertion: Skin of eyebrow and root of nose

Action: with aponeurosis fixed it raises eyebrows

Epicranius Occipital Belly

Origin: Occipital and temporal bones

Insertion: epicranial aponeurosis

Function: fixes aponeurosis and pulls scalp posteriorly

orbicularis oculi

Origin: Frontal and maxillary bones

Insertion: Tissue of eyelid

Function: Closes eye, produces blinking, squinting and furrowing

orbicularis oris

Origin: maxilla and mandible

Insertion: Skin and muscles at angles of mouth

Function: Closes lips, purses and protrudes lips (kissing/whistling)

zygomaticus

Origin: zygomatic bone

Insertion: skin and muscle at corners of mouth

action: raises corners of mouth (smiling muscle)

temporalis

Origin: Temporalis fossa

insertion: mandible

action: closes jaw, elevates and retracts mouth

masseter

origin: zygomatic bone

insertion: mandible

action: jaw closer, elevates mandible

latissimus dorsi

origin: lower 6 thoracic vertebrae, lumbar vertebrae, last 3-4 ribs, iliac crest

insertion: sulcus of humerus

function: prime mover of arm extension, adducts and rotates arm, brings arm down in power stroke

pectoralis major

Origin: Clavicle, sternum, cartilage of ribs (true 1-7)

Insertion: sulcus of Humerus

Action: prime mover of arm flexion, adducts, rotates arm, pulls chest upward with arms flexed

Trapezius

origin: occipital bone, spines of c7, all thoracic vertebrae

insertion: scapula and clavicle

function: extends head, raises, rotates and adducts scapula (shrugging shoulder)

deltoid

origin: clavicle and scapula

insertion: tuberosity of humerus

function: prime mover of arm abduction (intramuscular injection site)

Biceps Brachii

origin shorthead: coracoid process of scapula

origin longhead: supraglenoid tubercle of scapula

insertion: radial tuberosity

action: flexion and supination of forearm

triceps brachii

origin longhead: glenoid cavity of scapula

origin Lateral head: humerus

origin Medial head: humerus

insertion: ulna

action: forearm extensor, antagonist of forearm flexors

extensor digitorum (posterior)

origin: humerus

insertion: phalanges II-V

action: prime mover of finger extension, extends hand and can abduct fingers

palmaris longus

origin: humerus

insertion: palmar aponeurosis, skin and fascia of palm

action: flex hand, tenses skin and fascia of palm

flexor carpi ulnaris

origin: humerus

insertion: metacarpal V

action: flexes and adducts hand

flexor digitorum superficialis

origin: humerus

insertion: middle phalanges of II-V

action: flexes hand and middle phalanges of II-V

flexor carpi radialus

origin: humerus

insertion: base of metacarpals II-III

action: powerful flexor and abductor of the hand

gluteus maximus

Origin: dorsal ilium, sacrum and coccyx

insertion: femur tuberosity

action: complex, powerful thigh extensor (most effective when climbing stairs)

quadriceps femoris

Origin: femur

insertion: tibial tuberosity

action: powerful leg extensors (Kick!!)

bicep femoris

origin long head: ischial tuberosity (ilium)

origin short head: distal femur

insertion: lateral head of fibula

action: knee flexion

gastrocnemius

origin: medial + lateral condyles of femur

insertion: calcaneus

action: plantar flexes foot when leg is extended, crosses knee joint thus can flex leg (when foot is dorsiflexed)

tibialis anterior

origin: lateral condyle of tibia

insertion: metatarsal I

action: Prime mover of dorsiflexion, inverts foot, supports longitudinal arch of foot