1. Chapter 3 Muscle Anatomy and Functions

2. Deep Muscles of the Vertebral Column
The Erector Spinae Group
Spinalis – most medially; along the spine
Longissimus – between spine and iliocostalis
Iliocostalis – most lateral; along the ribs
*Memory tool: “I Long for Spinach

3. Deep Muscles of the Vertebral Column (cont’d)
Function:
Keep the body in an erect/upright position.
Extend spine
Lateral flex spine

4. Muscles of the Thoracic Cage
Affect the rib cage and the process of breathing:
Diaphragm – separates the thoracic and abdominal cavities
Intercostals – “the breathing muscles”, located between each rib
Transverse Thoracic – triangular muscle, acts on the abdominal wall, pulling it inwards.

5. Anterior Abdominal Wall
The “Abs”
Named based on the direction of the fibers
T - Transverse Abdominis
I - Internal Obliques
R - Rectus Abdominis
E - External Obliques
transverse = across oblique = diagonal rectus = vertical

6. Anterior Abdominal Wall
Functions:
Transverse Abdominis
Internal Obliques
External Obliques
Trunk Flexion & Rotation
“ “ “
Rectus Abdominus
Trunk flexion

7. Effective Ab Exercises

8. Muscles of the Shoulder
Pectoralis Major
Deltoid Muscle
(see previous notes)

9. Muscles of the Shoulder (cont’d)
Rotator Cuff Muscles
A group of muscles that stabilize the shoulder and hold it in place.
Eg. When throwing a baseball, the rotator cuff muscles would help to decelerate arm movements
All “SITS” Muscles extend from the scapula and insert on either the greater or lesser tubercle of the humerus
“SITS” Muscles

10. Muscles of the Shoulder (cont’d)
Rotator Cuff Muscles
Clockwise from top:
S – Supraspinatus - abduction
I - Infraspinatus - lateral rotation
T – Teres Minor - lateral rotation
S – Subscapularis - medial rotation
*The subscapularis is the only rotator cuff muscle located on the anterior portion of the scapula.

11. Muscles of the Shoulder (cont’d)
Memory Tool for Rotator Cuff Muscles:
A pro baseball player has injured his rotator cuff muscle. As a result, he “sits” out of the game and gets sent to the “minor leagues”

12. 6 Scapula Movers
(see previous notes)

13. 3 Humerus Movers
(see previous notes)

14. Elbow Flexors 3 “B’s” bend the elbow: Biceps Brachii Brachialis
Brachioradialis

15. Elbow Extension Muscles which straighten the arm:
Triceps brachii – elbow extension
Anconeus – a small triangular muscle which assists the triceps in elbow extension

16. Muscles of the Forearm Anterior group – wrist flexion
Posterior group – wrist extension
(You don’t have to know these in detail)

17. Hip Flexors

18. Hip Flexors
A group of 7 muscles which function to flex the thigh, an action which brings the leg closer to the torso/chest.
All muscles in this group originate on the pelvis and insert somewhere on the femur.

19. The 7 Hip Flexor Muscles:
Anterior Group
Pectineus
Iliopsoas
Rectus Femoris
Sartorius
Adductor Brevis
Adductor Longus
Lateral Group
Tensor Fasciae Latae

20. Iliopsoas The strongest hip flexor Hip Flexion External Rotation
(3 deep muscles that function as one)
Psoas Major
Psoas Minor
iliacus

21. Iliopsoas Iliopsoas (Iliacus and psoas muscles)
Iliopsoas = Hip flexion
Psoas major = Hip flexion + trunk flexion
Psoas minor = weak trunk flexion
The Psoas Minor muscle is present in only 40% of the population!!

22. Pectineus Sometimes considered an extension of the iliopsoas
Upper most muscle of the medial thigh group
Hip Flexion (primary action)
Adduction and
External Rotation

23. Rectus Femoris As mentioned previously, part of the quadriceps group
The only muscle of the quadriceps group that crosses both the hip and the knee joint.
Hip Flexion
Knee Extension
(Eg. Taking forward stride in walking)

24. Sartorius Longest muscle in the body Most superficial thigh muscle
Not very powerful (assists)
Helps to cross the leg
Hip Flexion
Outward rotation at hip
Knee Flexion

26. Hip Extensors

27. Hip Extensors Gluteus Maximus Hamstrings Strongest, most superficial
Bicep Femoris
Semitendinosus
Semimembranosus

28. Gluteus Maximus Gluteus = Greek for “rump”
Used mostly during power movements
Hip Extension
External Rotation

29. Gluteus Maximus
Used more in running than walking because the hip must be extended more than 15 degrees to activate the gluteus.
Doing sprints is an effective way to tone up the gluteus maximus!!
Other power activities which build strength:
Squats, Lunges,

30. Hamstrings
Inability to touch the toes while keeping the knees extended is due to shortened, inflexible hamstring muscles

31. Biceps Femoris Largest Muscle in Hamstring group
Located on lateral side
Hip Extension
Knee Flexion
Outward Rotation
Outward Rotation when knee is in flexed position

32. Semimembranosus and Semitendinosus
Both Located on the medial side of the hamstring group but the semitendinosus lies on top
Hip Extension
Knee Flexion
Internal Rotation of the hip
Internal Rotation of the knee

33. Hip Adductors

34. 5 Hip Adductor Muscles Also known as your “groin” area
The 5 adductor muscles can be categorized in 2 groups: Short Adductors and Long Adductors
The “short adductors” go from the pelvis to the femur bone, while the “long adductors” go from the pelvis to the knee.

35. 5 Adductor Muscles Short Adductors: Long Adductors: Pectineus
The Adductor Longus Muscle is the most commonly injured.
Sprinters, hurdles, football players, soccer players and other athletes involved in sports, which require quick changes in direction, are particularly susceptible to groin strains.
The adductor Magnus is the strongest (and largest) of the adductor muscles
Short Adductors:
Pectineus
Adductor Brevis
Adductor Longus
Long Adductors:
Adductor Magnus
Gracilis

36. 5 Primary Hip Adductors Pectineus Adductor Brevis Adductor Longus
Adduction and hip flexion
Adductor Brevis
Shortest, deepest
Adduction..
Hip Flexion
Adductor Longus

37. 5 Primary Hip Adductors Adductor Magnus Gracilis
The strongest of the adductors
Longest, deepest muscle
Adduction..
Gracilis
The most superficial adductor
Hip Adduction, internal rotation
Knee flexion

38. Hip Abductors

39. Hip Abductors Gluteus Medius Gluteus Minimus Tensor Fasciae Latae
(Lateral Butt muscle)
Abduction, internal rotation
Gluteus Minimus
(Deepest Butt Muscle)
Tensor Fasciae Latae
(Lateral Muscle)

40. Tensor Fasciae Latae Hip Abduction Hip flexion Internal Rotation
Prevents external rotation of the femur when it is in the flexed position. It helps keep the foot placed straight ahead during walking and running.

41. Quadriceps Group Vastus = Large Vastus Lateralis Vastus Medialis
Vastus Intermedius
Rectus Femoris
(see notes)

42. Conclusion Generalized Muscle landmarks in the lower body: Anterior –
Posterior –
Medial –
Lateral – 

43. Practice Quiz
Label #1-11

44. Practice Quiz

45. Practice Quiz

46. Answer Guide Iliopsoas Tensor Fasciae Latae Sartorius Vastus Lateralis
Psoas Major
Pectineus
Adductor Longus
Gracilis
Rectus Femoris
Vastus Medialis
Rectus Femoris Tendon

47. Answer Guide Gluteus Maximus Gluteus Medius Adductor Magnus
Psoas Major
Iliacus
Tensor Fasciae Latae
Adductor Brevis
Adductor Longus
Gracilis
Piriformis
Pectineus