Anatomy Practical 3- Muscles

Masseter

Origin- Zygomatic Arch

Insertion- Angle and Ramus

Action- Elevation and protrusion of mandible (chewing)

Sternocleidomastoid

Origin- Manubrium of Sternum, Clavicle

Insertion- Mastoid Process of Temporal Bone

Action- Abducts, rotates, and flexes head

Temporalis

Origin- Temporal Fossa

Insertion- Coronoid Process and Ramus of Mandible

Action- Elevates (closes) mandible

Trapezius

Origin- Posterior Occipital Bone, Nuchal Ligament, C7-T4

Insertion- Clavicle, Acromion, and Spine of Scapula

Action- Extends and abducts head, rotates and adducts scapula, fixes scapula

Latissimus Dorsi

Origin- T7-12, L1-5, Crest of Ilium, Ribs 10-12

Insertion- Intertubercule Sulcus of Humerus

Action- Extends, adducts and medially rotates humerus, draws shoulder inferiorly

Pectoralis Major

Origin- Clavicle, Sternum, Cartilages of Ribs 1-7

Insertion- Crest of Greater Tubercle of Humerus

Action- Flexes, adducts and medially rotates humerus

Pectoralis Minor

Origin- Ribs 3-5

Insertion- Coracoid Process of Scapula

Action- Depress Glenoid Cavity

Rectus Abdominis

Origin- Pubic Crest and Pubic Symphisis

Insertion- Xiphoid process of Sternum, Coastal Cartilage 5-7

Action- Flexes spine, compress abdominal wall

Zygomaticus Major

Origin- Zygomatic Bone

Insertion- Superolateral angle of mouth and muscles of upper lip

Action- Elevates corner of mouth (smiling and laughing)

Buccinator

Compress cheek

Occipitofrontalis- Frontal belly

Raises eyebrows, draws scalp anteriorly

Occipitofrontalis- Occipital belly

Retracts scalp

Mentalis

Protrude lower lip

Orbicularis Oris

Closes Lips

Orbicularis Oculi

Closes Eyelids

Diaphragm

Inspiration

External Intercoastals

Elevate ribs (increases volume in thorax)

Internal Intercoastals

Elevates and depresses ribs

External Oblique

Compress abdominal wall, laterally rotates waist

Internal Oblique

Compress abdominal wall, laterally rotates waist

Serratus Anterior

Protraction, rotation and stabilization of scapula

Transversus Abdominus

Compress abdominal wall, laterally rotate waist

Zygomaticus Minor

Elevate corners of mouth

Deltoid

Origin- Clavicle, Acromion, Spine of Scapula

Insertion- Deltoid Tuberosity of Humerus

Action- Abducts arm: flexes, extends, medially and laterally rotates humerus

Biceps Brachii

Origin- Long Head: Superior Margin of Glenoid Cavity, Short Head: Coricoid Process of Scapula

Insertion- Radial Tuberosity

Action- Flexes arm and forearm, supinates forearm

Brachioradialis

Origin: Lateral Supercondylar ridge of Humerus

Insertion: Near Styloid Process of Lateral Radius

Action- Flexes forearm

Teres Major

Origin- Inferior angle of Scapula

Insertion- Crest of Lesser Tubercle of Humerus

Action- Extends, medially rotates humerus

Triceps Brachii

Origin- Infraglenoid tubercle of Scapula, Lateral and posterior surface of humerus

Insertion- Olecranon, Tuberosity of Ulna

Action- Extends and adducts arm, extends forearm

Supraspinatus

Origin- Supraspinatus Fossa

Insertion- Greater Tubercle of Humerus

Action- Abducts arm, helps stabilize shoulder joint

Infraspinatus

Origin- Infraspinatus Fossa

Insertion- Greater Tubercle of Humerus

Action- Laterally rotates arm, stabilizes shoulder joint

Teres Minor

Origin- Lateral Border of Scapula

Insertion- Greater Tubercle of Humerus

Action- Laterally rotates and adducts humerus, stabilizes shoulder joint

Subscapularis

Origin- Subscapular Fossa

Insertion- Lesser Tubercle of Humerus

Action- Medially rotates arm, stabilizes shoulder joint

Biceps Femoris

Origin- Ischial Tuberosity, Linea Aspera

Insertion- Head of Fibula

Action- Extends thigh, flexes knee

Semitendinosus

Origin- Ischial Tuberosity

Insertion- Proximal, medial tibia

Action- Extends thigh, flexes knee

Semimembranosus

Origin- Ischial Tuberosity

Insertion- Medial Condyle of Tibia

Action- Extends thigh, flexes knee

Iliacus

Origin- Iliac crest, Iliac fossa, sacrum

Insertion- Lesser Trochanter of Femur

Action- Flex thigh and lumbar vertebrae

Psoas Major

Origin- T12, L1-5

Insertion- Lessor Trochanter of Femur

Action- Flex thigh and lumbar vertebrae

Rectus Femoris

Origin- Anterior inferior iliac spine, margin of acetabulum

Insertion- Patella, Tibial Tuberosity, Lateral and Medial Condyle of Tibia

Action- Flexes thigh, extends leg

Vastus Intermedius

Origin- Proximal Anterior Femur

Insertion- Patella, Tibial Tuberosity, Lateral and Medial Condyle of Tibia

Action- Extends leg

Vastus Lateralis

Origin- Greater Trochanter of Femur, Linea Aspera

Insertion- Patella, Tibial Tuberosity, Lateral and Medial Condyle of Tibia

Action- Extends leg

Vastus Medialis

Origin- Linea Aspera, Medial Spine

Insertion- Patella, Tibial Tuberosity, Lateral and Medial Condyle of Tibia

Action- Extends Leg

Gluteus Maximus

Origin- Outer Iliac Surface, Iliac Crest, Sacrum, Coccyx

Insertion- Gluteal tuberosity of femur, Iliotibial tract of fasciae latae

Action- Extends and Abducts thigh

Gastrocnemius

Origin- Condyles of Femur

Insertion- Calcaneus

Action- Flexes leg, plantar flexion of foot

Tibialis Anterior

Origin- Lateral Condyle and Proximal Tibia

Insertion- First Metatarsal and Medial Cuneiform

Action- Dorsiflexes and Inverts foot

Brachialis

Flexes forearm

Extensor Digitorum

Extends phalanges and hand

Palmaris Longus

Anchors skin and fascia to palmar region

Flexor Carpi Ulnaris

Flexes and adducts wrist

Flexor Carpi Radialis

Flexes and abducts wrist

Pronator Teres

Pronates and flexes forearm

Extensor Carpi Radialis Longus

Extends and abducts wrist

Extensor Carpi Radialis Brevis

Extends and abducts wrist

Piriformis

Laterally rotates extended thigh, abducts flexed thighs

Sartorius

Flexes and laterally rotates thigh, flexes knee

Extensor Digitorum Longus

Extends toes, dorsiflexes foot

Gracilis

Flexes and medially rotates leg

Soleus

Plantar flexes foot

Iliotibial Tract

Stabilization of hip and knee in extension and in partial flexion

Calcaneal Tendon

Plantar flexion, stability of ankle