❖ Internal forces :-

🔹Force generated inside the human body as:

1. Forces of ligaments. (tensile force).
2. Muscles, joint capsules.
3.Tendons (musculotendinous junction) (tensile force) .

🔹Muscular contraction :-
Contraction is active shortening of a muscle with the distance between the two muscle attachments.

🔹Muscle produces force in three different muscle-lengthening situations (concentric, isometric, and eccentric).

🔹Concentric (shortening) contraction:

1- The internal forces generated by the muscle are greater than the external force

• في ال concentric ال int.force المتولدة بتكون أكبر من ال External ومثال على دا الـelbow flexion.

2- The muscle produces positive work on the external load.

هنا ال work اللي طالع بيبقى positive ودا عشان ال int.force اتغلبت على ال Ext.force لذلك هنلاقي ان ال movement ضد الجاذبية و في اتجاه ال inner range.

3- Concentric contraction produces the lowest magnitude of the muscular force.

و دا طبقاً للـ Length tension relationship و هي ان فيه علاقه طريه بين ال length و ال tension.

4- Moving the heel closer to the buttocks is an example of a concentric contraction of the hamstring.

🔹Eccentric (lengthening) contraction:

1- The external forces are greater than the internal force.

•زي لما تيجي تعمل Elbow Extension.

2- The external load produces negative work on the muscle.

•ال work المتولد بيكون negative نتيجة تخلى الـ External force على الـ Internal force.

3- Eccentric contraction produces the highest magnitude of the muscular force.

4- Moving the heel away from buttocks is an example of an eccentric contraction of the hamstring.

🔹Isometric contraction:

1- The overall muscle length does not change.

و دا بيحصل أما تيجي تحرك كوعك لفوق او لتحت و تلاقي sudden stop في اي مستوى فـ ميحصلش تغير في الـ muscle length.

2- The internal force generated by the muscle equals the effects of the external
forces.

3- No mechanical work is done as a load is not moved.

بس في Metabolic work بينتج عنه استهلاك ال oxygen اللي موجود في العضلة وبيتكون Lactic acid و يسبب fatigue.

4- Isometric contraction produces intermediate(متوسط )magnitude of the muscular force.

5- No visible change in muscle length in isometric contraction.

6- isometric contraction occurs during :-

- Arm wrestling match when opponents generate equal forces.

- Pushing against a stable wall.

❖ Muscular activity during gait from one point of view :-

➢ During stance :-

• Heel Strike Muscle activity : -

1- Ankle: dorsiflexors isometric to keep ankle neutral position.

• الـ Ant tibial group بيشتغلوا Isometric عشان يحافظوا على ال knee في neutral position.

2- Knee : eccentric knee extensors to allow slight give to flexed knee.

الـ Quardiceps بيعملوا knee extension و في نفس الوقت الـ Hamstring بيكونوا concentric عشان يسمحوا بشوية knee flexion في الـ IC.

3- Hip : isometric hip extensors.
و ال hip بيبقى فيه Isometric.

4- Trunk : erector spinae active.

على مستوى ال trunk ال spinae erector بتكون active.

• Foot Flat Muscle activity (in LR) :

1- Ankle: eccentric contraction of dorsiflexors

At the same time concentric contraction in the calf muscles.

• في ال LR في مستوى ال Ankle ال dorsiflexors بيشتغلو eccentric وفي نفس الوقت ال calf Concentric و دا عشان يحصل ankle plantar flexion بمقدار 15 درجه.

2- Knee: eccentric contraction quadriceps At the same time concentric in the hamstring muscles.

و زي ما حصل على مستوى ال Ankle هيحصل على مستوى ال knee باختلاف العضلات فـ يكون في concentric في ال hamstring و Eccentric في ال quadriceps.

3- Hip: isometric extensor contraction to allow changes to slight concentric, guiding the hip toward extension.

• اما على مستوى ال hip الوضع مختلف شويه لأنه بيحصل Isometric contraction في ال hip extensors عشان يمنع الزياده في ال ROM و بعدين يتحول لـ concentric عشان يخليه يعملExtension.

• Mid-Stance Muscle activity:

1- Ankle: dorsi flexors inactive
while plantar flexors eccentrically contract to control the rate at which the limb moves over the foot .

هنا ال Ankle dorsiflexion بيحصل بس بطريقه مختلفه و هي ان ال proximal ال(Leg) بتتحرك على ال distal ال(dorsum of foot) و يحصل ankle dorsiflexion و دا عن طريق ال forward momentum..و شرط ان يحصل العزم دا :

- inactive dorsiflexors
- Eccentric Plantar flexors.

2- Knee: knee locked in extension, very little contraction needed.

3- Hip: concentric extensors, concentric hip abductors to prevent opposite side of pelvis from dropping in frontal plane.

ال Gluteus Maximus and Medius بيحصلهم concentric contraction عشان يمنعوا الناحية التانية من ال pelvis انه يروح لقدام في ال contra lateral side.

• Terminal-Stance Muscle activity:

1- Ankle : Concentric plantar flexors (push off)
• عشان الرجل تسيب ال ground و يحصل ال push off ال calf بتقصر.

2- Knee : concentric quadriceps (full extension)

ال Quad بتبقى concentric و ال Hamstring بتبقي eccentric عشان ال 1st peak of knee extension فـ يحصل Full Extension.

3- Hip : Isometric extensors, Eccentric hip flexors Isometric

• هيستخدم ال Isometric عشان يمنع الزياده في ال ROM وفي نفس الوقت تكون الـ hip flexors في eccentric عشان يتم ال hip extension.


• Toe Off (PSw) Muscle activity:

1- Ankle : concentric plantar flexion

في ال toes off ببقى متصل بالأرض بال toes بس و دا بيحصل في ال 2nd peak of ankle plantar flexion عشان كدا بتكون ال calf في concentric و ant group في eccentric.

2- Knee : eccentric quadriceps “some degrees of knee flexion” (35:40)

و عشان ال flexion دا يحصل طبيعي هحتاج eccentric quad و concentric hamstring.

3- Hip : concentric hip flexors.

و يقابله طبعا eccentric في ال hip extensors.

➢ During swing :

• Acceleration (ISw) Muscle activity:

1- Ankle : concentric dorsiflexion

• و يقابله eccentric في ال calf.

2- Knee : eccentric quadriceps

و يقابله concentric في ال Hamstring.

3- Hip (Flexion): concentric flexors

• Mid Swing Muscle activity:

1- Ankle : Isometric dorsi-flexion.

ال Isometric هنا معناها اني بحاول اثبت على ال dorsiflexion بدون حدوث تغير.

2- Knee : eccentric quads then quick concentric to initiate acceleration of
the tibia.

الـ MSw فيها الـ 2nd peak of knee flexion، واللي بتتميز بإن ال quad بتبقى في eccentric و بعد كدا يتحول بسرعه لـ (concentric (60:65 و يبدأ ال flexion يقل عشان ال hamstring تعمل full extension في TSw.

🔷️ Determinants of Gait :-

1- Mechanical Factors responsible for minimizing displacement of COG.

2- Various movements occur in the body (not all segments ) including pelvis, knee and ankle to maintain COG in horizontal plane.

❖ Major (Sixth) Determinants :-

1- Pelvic rotation in transverse plane.
2- Lateral Pelvic tilting in frontal plane .
3- Knee flexion in stance phase .
4,5 Knee , ankle ,foot interaction .
6- Physiological valgus of knee.

❖ Minor Determinants:-
1- Neck movement حركة الرقبه
2-Swing arm حركة الدراعين

❖ Function of 6 determinants of gait:
1- prevent excess drop of COG.
2-prevent excess elevation of COG.
3- prevent excess side to side displacement to reach only 2 inches.
4- decrease energy expenditure during normal walking .
5- produce smooth sinusoidal curve.(Prevent over oscillation)
6- minimize vertical and lateral displacement.

❖N.B :-
1- FIRST DETERMINANT :-
- Pelvic rotation in the transverse plane.
- PREVENT DROP OF COG .
2- MIDDLE FOUR DETERMINANT :-
- PREVENT ELEVATION OF COG .
3- SIXTH DETERMINANT:-
PREVENT SIDE TO SIDE DISPLACEMENT .

1- Pelvic rotation in transverse plane أول عامل :
🔹In normal pattern of walking: The pelvis rotates alternatively in transverse plane about the vertical axis .
🔹Forward rotation on the swing side and backward rotation on the stance side

1- The average magnitude of this rotation: equal "8"
degrees. ( four degrees on either side of the central axis )

2- Associated hip movement: Internal and external rotation .

3- Function:
- Prevent drop of COG.
- lengthening of lower extremities.


2- Lateral Pelvic tilting in frontal plane. تاني عامل
🔹In normal pattern of walking: The pelvis tilts downward on swing leg in the frontal plane around sagittal axis.
🔹The maximum tilting is at mid-swing.

1- The average magintude :-five degrees.

2- Associated hip movement:-
- hip adduction in stance
- hip abduction in the swing

3- Function: Prevent elevation of COG.

4- Knee flexion in stance phaseتالت عامل :-
- IC: 15 degrees
- LR: (15-20) degrees.
-MSt: 5 degrees .
-TSt: knee extension (0).
- PSw:(35-40) degrees.

Notice that :- LR is the first peak of knee flexion.

❖ The biomechanical function of LR :
1- Shock absorption.
2- Minimize displacement of COG specially the vertical displacement .
3- Decrease energy expenditure.
- Function: Prevent elevation OF COG.

4-5 Knee , ankle ,foot interaction العامل الرابع و الخامس:-
🔹In normal pattern of walking: movement of knee occur in conjunction with movement of ankle and foot.

1- Early in the stance phase

في البداية اللي كلها حكايات😭 :-
In LR knee flexion: (15-20) degrees ankle plantar flexion 15 degrees foot supination.

2- Late in the stance phase:
In TS

knee extension (0) degree
ankle dorsi flexion (10) degrees
foot pronation.
- Function: Prevent elevation of COG .

❖ Notice that :-

- Foot Supination is :-
- plantar flexion in ankle
- inversion in subtalar joint
- adduction in metatarsals

WHILE

Foot Pronation is :-
- dorsi flexion ankle
- eversion in subtalar joint
- abduction in metatarsal

6- Physiological valgus of the knee:-

- There is natural valgus due to
- femoral and tibial axis form angle medially at knee(180-190) degree.

- Function:
- Prevent\minimize side to side
- displacement of COG (ROBOT
- MOTION).

❖ Tibio-femoral Alignment and Weight-Bearing Forces:-

1- The anatomical axis of femur, is oblique ,directed inferiorly and medially. مائل

2- The anatomical axis of tibia is directed عمودى

3- Consequently, femoral and tibial longitudinal axes form angle medially at knee joint of 180 to 185, creating a slight physiologic (normal) valgus angle at the knee.

4- If medial tibiofemoral angle greater than 185, genu valgum (“knock knees”) exists (Pathological)

5- If medial tibiofemoral angle is 175 or less,genu varum(“bow legs”)exists(Pathological)

6- (Knock knee) (Genu valgum):
Compression over load to the lateral TF compartment.

7- (Bow leg) (Genu varum):
Compression over load to the medial TF compartment.

ادعوا للأدمنز معاكم يشباب الحاله صعبه 😂

أيوة والله يا جماعة الحالة مستعصية 😂🥲

في تلك إجواء الإمتحانات

-لا تنشغل بالنتيجة وأنشغل بالسعي ( فإن سعيك هو نتيجتك ونتيجتك هي قدر الله عليك )

-وأعلم أن من غشنا فليس منا وسلم أمرك لله فإن نتيجتك مقدرها الله لك

-وزاحم الدراسة بالقرآن

-ولا تنسى أن ، ( إنْ قامتْ على أحدِكُم القِيامةُ، وفي يَدِه فَسيلةٌ فَليَغْرِسْها.)♥️

ملخص muscles of the lower limb
#lower
#Anatomy_1

وَأَنْ لَيْسَ لِلْإِنسَانِ إِلَّا مَا سَعَىٰ وَأَنَّ سَعْيَهُ سَوْفَ يُرَىٰ💗💗.

مستوى الامتحان اللي أنا عايزاه :