Joints بالنسبة لفيزياء اولى

single skeletal muscle, such as the triceps muscle, is attached at its
• origin to a large area of bone; in this case, the humerus
• At its other end, the insertion, it tapers into a glistening white tendon which, in this case, is attached to the ulna, one of the bones of the lower arm.
As the triceps contracts, the insertion is pulled toward the origin and the arm is straightened or extended at the elbow. Thus the triceps is an extensor. Because skeletal muscle exerts force only when it contracts, a second muscle — a flexor — is needed to flex or bend the joint. The biceps muscle is the flexor of the lower arm. Together, the biceps and triceps make up an antagonistic pair of muscles. Similar pairs, working antagonistically across other joints, provide for almost all the movement of the skeleton.





Gluteal Musculature

Tensor fascia lata
• Origin:
1. anterior aspect of iliac crest
2. anterior superior iliac spine (ASIS)
• Insertion: anterior aspect of IT band, below greater trochanter
• Action:
1. hip flexion
2. medially rotate & abduct a flexed thigh
tens Gluteus maximus
• Origin:
1. outer rim of ilium (medial aspect)
2. dorsal surface of sacrum and coccyx
3. sacrotuberous ligament
• Insertion:
1. IT band (primary insertion)
2. gluteal tuberosity of femur
3. es IT tract to support femur on the tibia during standing
• Action:
1. powerful extensor of hip
2. laterally rotates thigh
3. upper fibers aid in abduction of thigh
4. fibers of IT band stabilize a fully extended knee
Gluteus medius
• Origin:
1. outer aspect of ilium (between iliac crest and anterior and posterior gluteal lines)
2. upper fascia (AKA gluteal aponeurosis)
• Insertion: superior aspect of greater trochanter
• Action:
1. anterior and lateral fibers abduct and medially rotate the thigh
2. posterior fibers may laterally rotate thigh
3. stabilizes the pelvis and prevents free limb from sagging during gait
Gluteus minimus
• Origin: outer aspect of ilium (between anterior and inferior gluteal lines)
• Insertion:
1. greater trochanter (anterior to medius)
2. articular capsule of hip joint
• Action:
1. abduct and medially rotate the thigh
2. stabilizes the pelvis and prevents free limb from sagging during gait
Piriformis
• Origin: pelvic surface of sacrum (anterior portion)
• Insertion: medial surface of greater trochanter (through greater sciatic foramen)
• Action:
1. lateral rotation of extended thigh
2. abducts a flexed thigh
Superior gemellus
• Origin: ischial spine
• Insertion: medial aspect of greater trochanter via upper tendon of obturator internus
• Action:
1. laterally rotates femur
2. abducts thigh when flexed
Obturator internus
• Origin:
1. internal aspect margins of obturator foramen
2. obturator membrane
• Insertion: medial aspect of greater trochanter (through lesser sciatic foramen)
• Action:
1. laterally rotates femur
2. abducts thigh when flexed
Inferior gemellus
• Origin: ischial tuberosity
• Insertion: medial aspect of greater trochanter via lower tendon of obturator internus
• Action: laterally rotates femur
Quadratus femoris
• Origin: lateral aspect of ischial tuberosity
• Insertion: quadrate line (along posterior aspect of femur and intertrochanteric crest)
• Action: laterally rotates femur


Posterior Thigh Musculature Semitendinosus
• Origin: ischial tuberosity
• Insertion:
1. medial aspect of tibial shaft
2. contributes to the pez anserine
• Action:
1. extends hip
2. flexes knee
3. medially rotates tibia
Semimembranosus
• Origin: ischial tuberosity
• Insertion:
1. posterior medial aspect of medial tibial condyle
2. fibers join to form most of oblique popliteal ligament (& medial meniscus)
• Action:
1. flexes knee
2. extends hip
3. medially rotates tibia
4. pulls medial meniscus posterior during flexion
Biceps femoris
• Origin:
1. long head: ischial tuberosity
2. short head: lateral lip of linea aspera and the lateral intermuscular septum
• Insertion:
1. head of fibula
2. maybe to the lateral tibial condyle
• Action:
1. flexor at the knee (mainly short head)
2. laterally rotates thigh if flexed at the knee
3. extends hip (long head)
Adductor Thigh Musculature
Adductor longus
• Origin: anterior surface of pubis, just inferior to the pubic tubercle
• Insertion: medial lip of linea aspera on middle half of femur
• Action:
1. adducts thigh
2. flexes thigh
3. may laterally rotate thigh at the hip
Adductor brevis
• Origin: body & inferior ramus of pubis
• Insertion: superior portion of linea aspera
• Action:
1. adducts thigh (major)
2. aids in flexion of thigh
3. may laterally rotate thigh at the hip
Adductor magnus
• Origin:
1. anterior fibers: inferior pubic ramus
2. oblique fibers: ischial ramus
3. posterior fibers: ischial tuberosity
• Insertion:
1. proximal 1/3 of linea aspera
2. adductor tubercle
• Action:
1. adducts the thigh
2. posterior fibers also extend and laterally rotate thigh
Gracilis
• Origin: body of pubis & inferior pubic ramus
• Insertion:
1. medial surface of proximal tibia, inferior to tibial condyle
2. contributes to the pez anserine
• Action:
1. adducts thigh
2. flexes knee
3. medially rotates tibia
Obturator externus
• Origin:
1. medial surface of obturator foramen
2. external surface of obturator membrane
• Insertion: trochanteric fossa of femur
• Action:
1. laterally rotates thigh
2. assists in flexion of hip joint
Anterior Thigh Musculature Sartorius
• Origin: anterior superior iliac spine (ASIS)
• Insertion:
1. upper medial surface of body of tibia
2. contributes to pez anserine
• Action:
1. flexes hip and knee
2. laterally rotates thigh if flexed at the hip
Rectus femoris
• Origin:
1. anterior head: anterior inferior iliac spine (AIIS)
2. posterior head: ilium just above the acetabulum
• Insertion:
1. common quadriceps tendon into patella
2. tibial tuberosity via patellar ligament
• Action:
1. extends knee
2. flexes hip
Vastus lateralis