1. The Muscular System
Part 2:
Identification

2. Objectives
Identify the major skeletal muscle of the human body
Explain each identified skeletal muscle’s function or role

3. Muscles of the head & Face
Occipitofrontalis
Raises the eyebrows
Orbicularis oculi
Closes the eye lid
Zygomaticus minor
Raises the upper lip
Zygomaticus major
Pulls corner of the mouth up & out

4. Muscles of the head & Face
Orbicularis oris
Narrows mouth & purses lips
Buccinator
Pulls back the angle of the mouth & flattens the cheek area
Aids whistling and smiling
In babies it is used to suckle
Masseter
Lifts the lower jaw & closes the mouth

5. Smiling Frowning Requires only 4 muscles Levator labii superioris
Zygomaticus minor
Zygomaticus major
Risorius
Requires 8 muscles!
Occipitofrontalis
Corrugator supercilii
Orbicularis oculi
Dilator naris
Platysma
Depressor anguli oris
Depressor labii inferioris
Mentalis

6. Muscles of the Head & Face
m. occipitofrontalis

8. Muscles of the neck Splenius capitis Moves the head & twists the neck
Levator scapulae
Lifts & twists the shoulder
Sternocleimastoid
Tilts & twists the neck
Sternohyoid
Depresses the larynx

9. Muscles of the neck Scalenus anterior, medius, & posterior
Aid in breathing & neck flexion
The anterior and middle scalene muscles elevate the first rib and rotate the neck to the same side
The posterior scalene elevates the second rib and tilts the neck to the opposite side
Trapezius
Rotates, elevates and retracts the shoulder blade

10. Muscles of the neck m. sternocleimastoid m. sternohyoid
m. scalenus anterior
m. sternohyoid

11. Anterior Muscles of the torso
Deltoid
Raises arm away from the body to front, side, and rear
External intercostals
Elevate the ribs
Pectoralis major
Draws arm toward the body and rotates upper arm inward
Biceps brachii
Flexes forearm at the elbow and turns the palm upward

12. Anterior Muscles of the torso
Serratus anterior
Pulls shoulder blades away from the spine
External oblique abdominal
Flexes and rotates trunk
Rectus abdominis
Flexes spine and draws pelvis forward
Pyramidalis
Tenses the linea alba
It is absent in 20% of normal humans

13. Anterior Muscles of the torso
m. deltoid
m. external intercostals
Linea alba
Anterior Muscles of the torso
m. external oblique abdominal

14. Posterior Muscles of the torso
Infraspinatus
Rotates arm & stabilizes the shoulder
Teres major & teres minor
Lifts & twists arm, stabilizes the shoulder
Triceps brachii
Moves arm down towards the body and contracts to straighten the arm

15. Posterior Muscles of the torso
Latissimus dorsi
Extends, rotates and lowers arm, pulls shoulder back
Largest surface area of any muscle in the body
Gluteus maximus
Raises thigh away from body at the hip, rotates the thigh, and tilts the pelvis when walking

16. Posterior muscles of the torso

17. Anterior Muscles of the arm
Pronator teres
pronates the forearm, turning the hand posteriorly
Brachioradialis
Flexes arm at the elbow
Flexor carpi radialis
Flexes hand at wrist
Flexor digitorum superficialis
Flexes joints of hand and wrist

18. Anterior muscles of the arm

19. Posterior Muscles of the arm
Brachialis
Flexes the elbow
Extensor carpi radialis longus
Extends the wrist at the joint & abducts the hand at the wrist
Is a set of 5 muscles together
Extensor digitorum
Extends all finger joints

20. Posterior muscles of the arm

21. Anterior Muscles of the hand
Abductor pollicis brevis
Pulls thumb in toward the palm
Flexor pollicis brevis
Flexes the thumb at the first metacarpal joint
Abductor digiti minimi
Abducts the little finger
Flexor digiti minimi brevis
Flexes the little finger

22. Anterior muscles of the hand

23. Anterior Muscles of the LEg
Iliopsoas
Flexes the thigh at the hip
Pectineus
Flexes & draws thigh in toward the body
Adductor longus
Rotates and draws the thigh in toward the body
Gracilis
Flexes and rotates the leg

24. Anterior Muscles of the Leg
Sartorius
Flexes thigh at the hip and leg at knee joint, and turns thigh outward
Rectus femoris
Flexes the thigh at the hip and with other muscles extends the knee
Vastus lateralis & vastus medialis
Help to extend the knee
Peroneus brevis
Flexes the foot downward and stops it from turning inward

25. Anterior Muscles of the Leg
Peroneus longus
Flexes the foot downward and turns it outward
Tibialis anterior
Flexes the foot upward and inward, & supports the arch of the foot when running or walking
Extensor hallucis longus
Extends the big toe
Extensor digitorum longus
Extends toes & ankle

26. Anterior muscles of the leg

27. Posterior Muscles of the Leg
Adductor magnus
Rotates, flexes & extends the thigh
Biceps femoris, Semitendinosus, & Semimembranosus
Extends the thigh at the hip, flexes and rotates the leg
All three muscles make up the hamstrings
Plantaris
Assists in knee flexion

28. Posterior Muscles of the Leg
Gastrocnemius
The main calf muscle
It contracts to flex the ankle and pull up the heel, as when standing on tip–toe and flexes your knee
Tibialis posterior
Is the main muscle in turning the foot inward
Fibularis longus & fibularis brevis
Flex and turn the foot outward
Soleus
Flexes the foot and it needed for walking and running

29. Posterior Muscles of the Leg
Achilles (calcaneal) tendon
It serves to attach the plantaris, gastrocnemius, and soleus muscles to the calcaneus (heel) bone

30. Posterior muscles of the leg
Achilles (calcaneal) tendon