Muscles: A&P I

Masseter

Origin: Zygomatic arch

Insertion: Mandible

Action: Elevates mandible

Temporalis

Origin: Temporal line

Insertion: Mandible

Action: Elevates mandible

Sternocleidomastoid

Origin: Sternal end of clavicle, manubrium

Insertion: Mastoid of skull

Action: Flexes neck, bends head to shoulder

Pectoralis Major

Origin: Ribs 2-6, sternum and medial clavicle

Insertion: Greater tubercle of humerus

Action: Flexion, adduction, medial (internal) rotation of the shoulder

Buccinator

Origin: Maxilla and mandible

Insertion: Obicularis oris

Action: Compresses cheeks

Obicularis Oris

Origin: Maxilla and mandible

Insertion: Lips

Action: Compresses lips

Pectoralis Minor

Origin: Ribs 3-5

Insertion: Coracoid process of scapula

Action: Tilts scapula anteriorly

Serratus Anterior

Origin: Anterior, superior ribs 1-8

Insertion: Vertebral border of scapula

Action: Protracts shoulder and rotates scapula

External Intercostals

Origin: Inferior border of each rib

Insertion: Superior border of each rib

Action: Elevates ribs

Internal Intercostals

Origin: Superior border of each rib

Insertion: Inferior border of each rib

Action: Depresses ribs

Deltoid

Origin: Clavicle and scapula

Insertion: Deltoid tuberosity of the humerus

Action: Abduct shoulder - anterior (flexion and medial rotation), posterior (extension and lateral rotation)

Supraspinatus

Origin: Supraspinous fossa of scapula

Insertion: Greater tubercle of humerus

Action: Abduct shoulder

Infraspinatus

Origin: Infraspinous fossa of scapula

Insertion: Greater tubercle of humerus

Action: Lateral (external) rotation at shoulder

-Is a rotator cuff muscle (I of SITS)

Teres Minor

Origin: Lateral border of scapula

Insertion: Greater tubercle of humerus

Action: Lateral (external) rotation at shoulder

Subscapularis

Origin: Subscapular fossa of the scapula

Insertion: Lesser tubercle of the humerus

Action: Medial (internal) rotation at shoulder

Rectus Abdominis

Origin: Superior pubis

Insertion: Ribs 5-7, xiphoid process

Action: Depresses ribs, flexes vertebral column, and compresses abdomen

Internal Oblique

Origin: Thoracolumbar fascia and iliac crest

Insertion: Inferior ribs, linea alba, xiphoid process

Action: Compress abdomen, trunk flexion, rotate same side

External Oblique

Origin: Ribs 5-12

Insertion: Linea alba and iliac crest

Action: Compresses abdomen, flexes vertebral column, laterally flex and rotate opposite side

Transversus Abdominus

Origin: Ribs 6-12, iliac crest, thoracolumbar fascia

Insertion: Linea alba, pubis

Action: Compresses abdomen and helps force breathing

Rhomboid Major

Origin: Superior thoracic vertebrae

Insertion: Vertebral border of scapula

Action: Adduct scapula and downward rotation

Rhomboid Minor

Origin: C7-T1

Insertion: Vertebral border of scapula

Action: Adduct scapula and downward rotation

Levator Scapulae

Origin: First 4 cervical vertebrae

Insertion: Vertebral border

Action: Elevates scapula

Trapezius

Origin: Occipital bone, spinous process of thoracic vertebrae, and ligamentum nuchae

Insertion: Clavicle and scapula

Action: Elevates, retracts, depresses, and rotates scapula; elevates clavicle and extends neck

Brachialis

Origin: Distal surface of humerus

Insertion: Ulna

Action: Flexion of elbow

Biceps Brachii

Origin: Coracoid process, supraglenoid tubercle

Insertion: Tuberosity of radius

Action: Flexion of elbow

Obicularis Oculi

Origin: Orbit

Insertion: Eyelids

Action: Closes eyes

Epicranius Frontal Belly

Origin: Epicranial aponeurosis

Insertion: Eyebrows and bridge of nose

Action: Wrinkles forehead and raises eyebrows

Epicranius Occipital Belly

Origin: Occipital bone

Insertion: Epicranial aponeurosis

Action: Tenses scalp

Triceps Brachii

Origin: Lateral head: lateral humerus, Long head: infraglenoid tubercle of scapula, Medial head: posterior of humerus

Insertion: Olecranon

Action: Extension of elbow

Iliopsoas Psoas Major

Origin: Vertebrae T12-L5

Insertion: Iliacus

Action: Flexion of hip

Illiacus

Origin: Ilium

Insertion: Femur (tendon fused with psoas major)

Action: Flexion of hip

Latissimus Dorsi

Origin: Inferior thoracic and lumbar vertebrae, ribs 8-12, thoracolumbar fascia

Insertion: Intertubercular groove of humerus

Action: Extension, adduction, and medial (internal) rotation of shoulder

Teres Major

Origin: Inferior angle of scapula

Insertion: Intertubercular groove of humerus

Action: Extension, medial (internal) rotation, and adduction at shoulder

Erector Spinae

Origin: Iliac crest, sacrum, transverse and spinous processes of vertebrae and supraspinal ligament

Insertion: Angles of the ribs, transverse and spinous processes of the vertebrae, posterior aspect of the skull

Action: Extends and laterally bends the trunk, neck and head

Brachioradialis

Origin: Lateral epicondyle of humerus

Insertion: Radius

Action: Flexion of elbow

Pronator Quadratus

Origin: Distal ulna

Insertion: Distal radius

Action: Pronation (inward rotation)

Pronator Teres

Origin: Coracoid process of ulna and humerus

Insertion: Midlateral radius

Action: Pronation (inward rotation)

Supinator

Origin: Lateral epicondyle of humerus, radial notch of ulna

Insertion: Radial tuberosity

Action: Supination (outward rotation)

Gluteus Maximus

Origin: Iliac crest, lateral ilium, sacrum, coccyx, thoracolubar fascia

Insertion: Femur

Action: Extension and lateral (external) rotation of hip

Gluteus Medius

Origin: Anterior Iliac crest

Insertion: Greater trochanter of femur

Action: Abduction and medial (internal) rotation of hip

Gluteus Minimus

Origin: Lateral ilium

Insertion: Greater trochanter of femur

Action: Abduction and medial (internal) rotation of hip

Tensor Fascia Latae

Origin: Ilium

Insertion: Iliotibial tract (iliotibial band)

Action: Tensing the iliotibial band, supporting the knee

Sartorius

Origin: Anterior superior iliac spine

Insertion: Medial surface of the tibia

Action: Flexes, abducts and laterally rotates thigh; flexes knee

Biceps Femoris

Origin: Linea aspera of femur and ischial tuberosity

Insertion: Lateral condyle of tibia and head of fibula

Action: Flexion of knee, hip extension

Semimembranosus

Origin: Ischial tuberosity

Insertion: Medial condyle of tibia

Action: Flexion of knee

Semitendonosus

Origin: Ischial tuberosity

Insertion: Proximal, medial surface of tibia near gracialis

Action: Flexion of knee

Popliteus

Origin: Lateral condyle of femur

Insertion: Tibial shaft

Action: Medial (internal) rotation of tibia and flexion of knee

Rectus Femoris

Origin: Iliac spine, superior ilium

Insertion: Tibial tuberosity by the patellar ligament (tibiopatellar ligament)

Action: Flexion at hip and extension of knee

Vastus Intermedius

Origin: Anterolateral femur and linea aspera of femur

Insertion: Tibiopatellar ligament

Action: Extension of knee

Vastus Lateralis

Origin: Femur and linea aspera (proximal) of femur

Insertion: Tibiopatellar ligament

Action: Extension of knee

Vastus Medialis

Origin: Entire length of linea aspera of femur

Insertion: Tibiopatellar ligament

Action: Extension of knee

Piriformis

Origin: Sacrum

Insertion: Greater trochanter of femur

Action: Lateral (external) rotation and abduction of hip

Adductor Longus

Origin: Inferior ramus of pubis

Insertion: Linea aspera of femur

Action: Adduct hip

Adductor Magnus

Origin: Inferior ramus of pubis

Insertion: Linea aspera of femur

Action: Adduct hip

Gracillis

Origin: Pubis

Insertion: Tibia

Action: Adduct thigh at the hip

Tibialis Anterior

Origin: Lateral condyle of proximal tibia

Insertion: 1st metatarsal bone, medial cuneiform

Action: Flexion at ankle (inversion and dorsiflexion)

Extensor Digitorum

Origin: Tibia, fibula

Insertion: Digits

Action: Extends the toes

Fibularis Brevis

Origin: Fibula

Insertion: Fifth metatarsal

Action: Plantar flexion, eversion of the foot

Fibularis Longus

Origin: Lateral tibia and proximal fibula

Insertion: 1st metatarsal and medial cuneiform

Action: Plantar flexion, eversion of the foot

Gastrocnemius

Origin: Femoral condyles

Insertion: Calcaneus

Action: Flexion of the knee and plantar flexion

Soleus

Origin: Proximal fibula, posterior medial tibia

Insertion: Calcaneus/tendon to gastrocnemius

Action: Plantar flexion of ankle

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