Download 19. Classification and action of the lower extremity muscles

Classification
and action of
the lower
extremity
muscles
Key Terms
• agonist: The muscle most directly
involved in bringing about a movement;
also called the prime mover.
• antagonist: A muscle that can slow
down or stop the movement.
Lower limb
musculature
Iliac crest.
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b) Anterior superior iliac spine.
c) Genu of the lateral condyle (femur and
tibia).
d) Tibia.
e) Patella.
f) Tarsal cruciate ligament.
g) Retinaculum musculorum extensorum
inferius.
h) Retinaculum musculorum flexorum.
m. tensor fascia lata.
fascia lata.
m. gluteus medius.
m. gluteus maximus.
m. sartorius.
m. rectus femoris.
m. vastus lateralis.
m. biceps femoris (long head).
m. biceps femoris (short head).
m. tibialis anterior.
m. extensor digitorum (communis)
Aponeuroses of abdominal
muscles
21. External Obliques
22. Rectus Abdominus
23. Sheath of the
straight muscle of the
abdomen
31. Sartorius
32. Rectus Femoris
33. Pectineus
35. Adductor Longus
Psoas Major
Synovial tendon sheath
39. Gastrocnemius
40. Soleous
45. Fibularis Longus
41. Calcaneal Tendon
46. Inferior Retinaculum of the
Extensor Muscles
44. Extensor Digitorum Brevis
What is the Synovial tendon
sheath?
• Where the tendons cross
joints, they are sheathed in
thin membranes known as
synovium, which provide
lubrication to decrease friction
Anatomy Of TheThigh
• The thighs are composed of numerous muscles
including the quadriceps (rectus femoris, rectus
medialis, rectus lateralis, and rectus
intermedialis). These muscles extend the knee
and (rectus femoris only) help to flex the hip.
• The thighs also are made up of the hamstring
muscles (biceps femoris, semitendinosus, and
semimembranosus). These muscles help to flex
the knee joint. Also included in the leg group are
the adductor muscles, the abductor muscles, the
glutes, gracillus, and sartorius.
Hamstrings
• are actually comprised of three separate
muscles: the Biceps Femoris,
Semitendinosus and Semimembranosus.
• These muscles originate just underneath
the Gluteus Maximus on the pelvic bone
and attach on the tibia.
• The Hamstrings are primarily fast-twitch
muscles, responding to low reps and
powerful movements.
• primary functions of the Hamstrings are knee flexion
(bringing the heel towards the buttocks) and hip
extension (moving the leg to the rear).
• Semitendinosus and Semimembranosus: also known as
the medial hamstrings. They cross the hip and the knee
joint and are therefore involved in extending the hip and
flexing the knee. They also assist in turning the knee
inward (medial rotation).
• Biceps Femoris: also known as the leg biceps. Similar to
it's cousin, the biceps brachii, as well as it's name
suggests, the biceps femoris consists of two heads: the
long and the short head. The long head crosses both the
hip and the knee joint and is involved in extending the
hip and flexing the knee. The short head only crosses
the knee joint and is only involved in flexing the knee.
Both heads assist in turning the foot outward (lateral
rotation of the knee)
Posterior Thigh
Leg Curls
Straight Leg Deadlifts
The quadriceps femoris
(quadriceps extensor, or quads)
• includes the four muscles on the front of the thigh. It is the great
extensor muscle of the leg, forming a large fleshy mass which
covers the front and sides of the femur.
It is subdivided into separate portions, which have
distinctive names.
• the middle muscle: is the rectus femoris.
• The other three lie in immediate connection with the
body of the femur, which they cover from the trochanters
to the condyles:
– The muscle on the lateral side of the femur is termed
the vastus lateralis.
– The muscle covering the medial side is termed the
vastus medialis.
– The muscle in front is termed the vastus intermedius.
Figure 11.12a Muscles that Move the
Leg, Part I
• Quadriceps femoris
knee extensors
– Vastus intermedius
muscle
– Vastus lateralis muscle
– Vastus medialis
muscle
– Rectus femoris muscle
The quadriceps main function is to extend
the leg at the knee. This occurs during
activities such as running, jumping, kicking
and walking.
Anterior Thigh
•
Squat
Lunges
Leg Extension
Leg Press
Quadricep stretch
Muscles that Move the Thigh
 Piriformis and obturator muscles
– Lateral rotators
 Psoas major and iliacus
– Merge to form iliopsoas
– Power flexor of hip
 Adductor group adducts hip
– Adductor magnus muscle
– Adductor brevis muscle
– Adductor longus muscle
– Pectineus muscle
– Gracilis muscle
abductor muscles
• a group of four
muscles located in
the buttocks region
on both sides of the
body. Their names
are: 1) Gluteus
Maximus, 2) Gluteus
Medius, 3) Gluteus
Minimus, and 4)
Tensor Fascia Lata
Abductor Function
• to abduct or separate your legs away from the
midline of the body. This occurs during any
athletic movement requiring you to move from
side to side such as playing the infield in
baseball, defense in basketball and football, and
ice skating.
Muscles that Move the Thigh
Figure 11.11a Muscles that Move the
Thigh, Part II
 The iliopsoas
muscle and
the adductors
of the right
hip.
Sartorius/Gracilis
Sartorius is a strap muscle
which runs obliquely across the
front of the thigh. It is the
longest muscle in the body. It
runs from the anterior superior
iliac spine to the medial surface
of the shaft of the tibia
Sartorius flexes both the hip
and knee joints and laterally
rotates the thigh:
when these movements are
carried out simultaneously in
both limbs, a cross-legged
position will result (sartor = a
tailor).
Gracilis is the most superficial
muscle on the medial side of the
thigh. It is thin and flattened, broad
above, narrow and tapering below. It
arises by a thin aponeurosis from
the anterior margins of the lower half
of the symphysis pubis and the
upper half of the pubic arch.
The fibers run vertically downward,
and end in a rounded tendon, which
passes behind the medial condyle of
the femur, curves around the medial
condyle of the tibia, where it
becomes flattened, and is inserted
into the upper part of the medial
surface of the body of the tibia,
below the condyle.
Muscles of the posterior thigh
Figure 11.14e, f Muscles that Move the
Leg, Part III
Lower Leg: Posterior View
Lower Leg: Anterior View
Lower Leg: Medial and Lateral Views
Foot: Dorsal View
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