SKELETAL MUSCLE PHYSIOLOGY

IT IS A TYPE OF AN EXCITABLE TISSUE

MUSCLES ARE THE MAIN EFFECTOR OF THE BODY.

ALSO KNOWN AS MOBILE TISSUE.

MUSCLES CONVERT DIFFERENT TYPES OF ENERGY IN CHEMICAL ENERGY.

THE MUSCLE FIBERS ARE UNSTABLE AND CAN GENERATE ACTION POTENTIAL.

PROPERTIES OF THE SKELETAL MUSCLE ARE AS BELLOW.

01) VOLUNTARY CONTROL

02) PHASIC MOVEMENTS

03) MULTI-NUCLEATED(NUCLEUS PRESENT ON THE PERIPHERY)

04) CALCIUM COMES FROM SARCOPLASMIC RETICULUM(S.R)

05) RMP IS -90mv.

06) TETANUS, TETANY. TATINIZATION ARE PRESENT.

07) SOMATIC NEVER SUPPLY

08) FATIGUE IS PRESENT

09) AEROBIC GLYCOLYSIS

10) TYPICAL NEUROMUSCULAR JUNCTION

11) CYLANDRICAL

12) A.T.P IS SOURCE OF ENERGY

13) HYPERTROPHY PRESENT

14) TRANSVERSE TUBULES PRESENT

15) SARCOMER PRESENT

PHYSIOLOGICAL ANATOMY OF SKELETAL MUSCLE

ONE FIBER CONTAIN MANY THOUSAND OF MYOFIBRILS

ONE MYOFIBRIL CONTAINS 1500 MYOSIN AND 3000 ACTIN FILAMENTS.

MYOSINS ARE THICK AND DARK COLORED FILAMENTS.

ACTINS ARE THIN AND LIGHT COLOR FILAMENTS.

SARCOMERE IS STRUCTURAL UNIT OF THE SKELETAL MUSCLE.

SARCOMERE CONTAINS MANY PROTION HAVING DIFFERENT COLORS

I-BAND(2 IN NUMBER) PRESENTADJACENT TO THE Z-LINE AND CONTAINS ONLY ACTIN FILAMENTS.

A-BAND(1 IN NUMBER) MAKE A BIG PORTION OF THE SARCOMERE CONTAINS SOME PORTION OF ACTIN AND ALL OF THE MYOSIN FILAMENTS.

IN A-BAND A PORTION WHICH DO NOT HAVE ACTIN FILAMENTS CALLED H-  BAND.

MID LINE WHICH HOLDS THE MYOSIN FILAMENTS CALLED M-LINE.

Z-LINE MAKES THE BOUNDERIES OF THE SARCOMERE.

MYOSIN GIVE RISE TO HOOK LIKE STRUCTURE CALLED "CROSS BRIDGE".

THESE CROSS BRIDGES WORKS FOR THE CONTRACTION BY BINDING THEIR HEADS ON ACTIN.

• "CNS" SEND MESSAGE TO "MOTOR CORTEX" WHICH SEND THE MOTOR IMPULSES IN "SPINAL CORD".
• "SPINAL CORD" DELIVER THE IMPULSE TO "ALPHA MOTOR NEURON" WHICH DELIVER IT TO THE "MOTOR NERVE" OF THE SPECIFIC REGION.
• THROUGH "MOTOR NERVE" IMPULSE REACHES TO THE PRESYNAPTIC MEMBRANE.
• TTHE ACTION POTENTIAL PROPAGATES BY ACTIVATING SODIUM DEPENDENT CHANNELS ALONG THE AXON TOWARD THE SAYNAPTIC CLEFT.
• WHEN THE ACTION POTENTIAL REACHES THE MOTOR NEURON TERMINAL AND CAUSES THE CALCIUM INFLUX THROUGH THE CALCIUM DEPENDENT CHANNELS.
• IN PRESYNAPIC MEMBRANE IT CAUSES THE RELEASE OF THE NEUROTRANSMITTER "ACETYLCOLINE" IN SYNAPTIC CLEFT WHICH BINDS WITH RECEPTORS ON POST SYNAPTICS MEMBRANE.
• AFTER BINDING WITH RECEPTORS THERE IS OPENING OF INTRINSIC SODIUM/POTASSIUM CHANNEL, CAUSING SODIUM INFLUX AND POTASSIUM OUT FLUX WHICH CAUSES THE "ACTION POTENTIAL".
• "ACTION POTENTIAL" THEN TRAVEL THROUGH OUT THE FIBER.
• THIS ACTION POTENTIAL ACTIVATE THE SARCOPLASMIC RETICULUM AND THIS ACTIVATION THUS RESULTS IN RELEASE OF THE CALCIUM IONS.
• CALCIUM BIND WITH TROPONIN-C WHICH PRESENT ON THE ACTIN.THE TROPONIN THEN ALLOSTERICALLY MODULATES THE TROPOMYOSIN. NORMALLY THE TROPOMYOSIN STERICALLY OBSTRUCT BINDING SITE FOR THE MYOSIN ON ACTIN FILAMENT. ONE CALCIUM BINDS TO TROPONIN-C AND CAUSES CHANGE IN THE PROTEIN OF THE TROPONIN THEN TROPONIN-T ALLOWS TROPOMYOSIN TO MOVE WHICH CAUSES THE UNLOCKING THE BINDING SITE.
• MYOSIN BINDS TO UNCOVERED BINDING SITES ON ACTIN FILAMENT.MYOSIN IS NOW STRONGLY BOUND WITH BINDING SITE OF ACTIN.
• THE RELEASE OF ADP & INORGANIC PHOSPHATE ARE STRICTLY COUPLED THE THE POWER STROKE. THIS POWER STROKE WILL PULL THE Z-BANDS TOWARDS EACH OTHER AND THUS CAUSE THE SHORTNING OF THE SARCOMERE.
• ATP WORKS FOR THE DETATCHMENT OF THE CROSS BRIDGES FROM ACTIVE SITE OF ACTIN.
• NOTE IN THE ABSENCE OF ATP THERE WILL BE NO RALAXATION.
• RIGOR MORTIS IS ONE OF THE BEST EXAMPLE OF THAT.

WRIST BIOMECHANICS

ANATOMY OF THE WRIST

There are 8 carpal bones in wrist named as

Scaphoid, Lunate, Triquetrum, Pisiform, Trapezoid,  Trapezium, Capitate and Hamate.

(SHAM LAL TENDAY PAKA TENDAY TERAY CACHY HAIN)

KINAMETICS

Rows

There are two rows of bone in wrist joint are called proximal and distal.

Proximal made up of Scaphoid, Lunate, Triquetrum bone.

Distal row consists Trapezoid, Trapezium, Capitate, Hamate bone.

There are three columns in carpals

Central(flex/ext) column consists Lunate,Capitate,Hamate bone.

Lateral (mobile) is constructed by Scaphoid,Trapezoid,Trapezium bone.

Medial (rotation) made up of only a single bone Triquetrum.

Center of rotation of metacarpals is head of capitate

Radial deviation is a movement in which scaphoid flexes proximal pole goes dorsal “pulling” lunate into palmar flexion. where as in Ulnar deviation scaphoid extends proximal pole goes volar pulling lunate into dorsiflexion.

Triquetrohamate helicoid joint

Ulnar deviation : “low” position distal and dorsiflexed pulling lunate into dorsiflexion

Radial deviation : “high”position proximal and palmar flexed pulling lunate into palmar flexion

Forces Transmission

Principal force transmission is through capitate lunate and proximal pole of scaphoid 75% radius 25% ulna.

Three axes of motion

Flexion 90 degree

Extension 70 degrees

Flex/ext split between radiocarpal & midcarpal

Radial Deviation 20 degrees

Ulnar Deviation 50 degrees

Pronation 90 degree

Supination 90 degrees

Frykman Classification of Distal Radius

Extra Articular Fractures

Type-I : Trans Radial( with in 1 cm)

Type-II : Radius+Ulna+styloid

Treatment is Conservative with bellow elbow casting.

Intra Articular Fractures

Type-III    : RadioCarpal.

Type-IV   : RadioCarpal+UlnoStyloid.

Type-V    : RadioUlnar.

Type-VI   : RadioUlnar+Styloid.

Type-VII  : RadioCarpal,RadioUlnar.

Type-VIII : RadioCarpal,RadioUlnar+ Styloid.

Treatment is Conservative with above elbow casting as well as surgical.

Most Common site of fracture is Scaphoid Due to fall on hands.

Shoulder Biomechanics

SHOUDER JOINT IS A BALL AND SOCKET, ANTEVERTED TYPE OF JOINT.

BONES OF THE SHOULDER JOINT

• SCAPULA

• HUMEROUS

• CLAVICLE

JOINTS AT SHOULDER JOINT

• GLENO-HUMORAL

• ACROMIO-CLAVICULAR

• STERNO-CLAVICULAR

• SCAPULO-THORACIC

LIGAMENTS OF THE SHOULDER JOINT

• SUPERIOR GLENO-HUMORAL LIGAMENT(S.G.H.L)

• MEDIAL GLENO-HUMORAL LIGAMENT(M.G.H.L)

• INFERIOR GLENO-HUMORAL LIGAMENT (I.G.H.L)

( ANTERIOR , POSTERIOR BANDS AND AXILARY APPROCH)

• CORACHOHUMORAL LIGAMENT(C.H.L)

MUSCLES OF THE SHOULDER JOINT

• TRAPEZIUS

• SERATUS ANTEROIR

• ROTATOR CUFF (GALENOHUMORAL)

• SUPRASPINATUS

• INFRASPINATUS

• TERES MINOR

• SUBSCAPULARIS

• LATISMUS DORSI

• PECTORALIS MAJOR

• DELTOID

• BICEPS

• TRICEPS

CARTILAGE

• GLENOID LABRUM

OTHER STRUCTURES

• BRACHIAL PLEAXUS

• BRACHIAL ARTERY

MOVEMENTS AT SHOULDER JOINT

• FLEXON

• EXTENSION

• ADDUCTION(HORIZONTAL)

• ABDUCTION(HORIZONTAL)

• CIRCUMDUCTION

• EXTERNAL ROTATION

• INTERNAL ROTATION

RANGE OF MOVEMENTS AT SHOULDER JOINT

• FLEXON 150-180 DEGREE

• EXTENSION 50-60 DEGREE

• ABDUCTION 150-180 DEGREE

• ADDUCTION 30-40 DEGREE

• EXT. ROTATION 90 DEGREE

• EXT. ROTATION 70-90 DEGREE

LIGAMENTS STABILITY DURING MOVEMENTS

EXT.ROTATION AT “0 DEGREE” S.G.H.L, C.H.L, SUBSCAPULARIS

AT “45 DEGREE” S.G.H.L, M.G.H.L

AT “90 DEGREE” ANTERIOR BAND OF I.G.H.L

INT.ROTATION AT “0 DEGREE” POSTERIOR BAND OF I.G.H.L

AT “45 DEGREE” ANTERIOR AND POSTERIOR BAND OF I.G.H.L

AT “90 DEGREE” ANTERIOR AND POSTERIOR BAND OF I.G.H.L

GAIT TRAINING IN TRANSTIBIAL PROSTHESIS

Definition

It is the process in which the amputee with new prosthetic fitting is trained to adopt a gait which is as close to the normal as the modern technology will allow.

                The importance of proper gait training can not be negotiated. Some of the amputee’s think that there is no need of proper training under the supervision of therapist. It a positive thing but could not be promoted at any cast. The reason is that new amputees are not habitual to use the prosthesis and there is some muscle weakness is present there. And there are also the chances of contracture development which again complicate the prosthetic fitting.

                Amputee, physical therapist and Prosthetist will work as a team to make the rehabilitation as quick and successful as possible. Almost 3 to 9 months are taken by an amputee to gain normal strength of his limb after prosthetic fitting. And there for a proper gait training is vital for the refined movements and for the better control on the prosthesis.

Techniques to Walking

There are a few very important and simple techniques you should know. Then you can trained the amputee so that he/she can safely and naturally walk with prosthesis. It is very important that you take the time to learn these basic fundamentals so that you can develop good gait habits in an amputee.

·         Beginning a step: Each time when amputee stand to walk, he/she needs to always begin by taking a step with his/her prosthesis first.

·         Descending stairs: Prosthetic side should be placed first on stair bellow and followed by sound side.

·         Ascending stairs: Totally opposite to the descending pattern, amputee should lead with his/her sound (good) leg.

 Proper Weight Transfer

·         Another technique which is very important for an amputee to learn is the proper transfer of his/her body-weight on to the prosthesis side.

·         When an amputee put his/her full body weight on the prosthesis he/she should need to shift the body towards the prosthesis confidently; this is called weight transfer.

·         It is emphasized on confidence because for some new amputees it is difficult for them to shift their full weight onto prosthesis because they don’t feel secure with their prosthesis yet.

·         Proper transfer of amputee body weight is important for good walking.

·         The comfort of the prosthesis should never prevent the amputee from putting full weight onto the prosthesis.

·         In case of pain or discomfort that prevents the amputee from fully using the prosthesis he/she should contact their Prosthetist immediately.

  Proper Foot Placement

·         Another fundamental technique is proper foot placement. There are two considerations when an amputee initiating foot placement:

1.    Width of the foot placement (how far apart amputee’s feet are) – The ideal distance (measured heel to heel) is 2-4 inches. As the amputee begin to walk, consider these two conditions

a.     Placing the prosthetic foot wider than 2-4 inches will make the gait more stable, which is sometimes good, but it will increase the energy required to walk. And gait becomes wide base gait and lateral trunk bending may occur.

b.    On the other hand, narrow foot placement, less than 2-4 inches, will make the gait less stable but will decrease the energy required to walk. And heel knocking may occur.

2.    Length of the step (how far you place your front foot in front of you) – This is called step length. Ideal step length is a distance equal to the sound side of the amputee. Basically amputee needs to maintain the equal step length on both sides. If you think about it, it wouldn’t look very natural if amputee took a long step with one leg and a short step with the other leg.

a.     On starting gait training, it is recommend taking “heel to toe” steps.

b.    Place the heel of the prosthetic foot no farther than the toe of the sound side; repeat the same with the next step.

c.     As the confidence builds, amputee will automatically begin to increase the step length. Step length also increases as the walking speed increases.

d.   As faster the walk, as greater the step length.

Troubleshooting

·         Now a day’s advancements in technology have brought a lot of exciting materials to the prosthetic industry.

·         Materials such as acrylic resins, carbon fiber, titanium, silicone and urethane have made prostheses stronger, lighter and more comfortable. Even though callous formation is no longer a common occurrence, fitting problems still occur.

·         While some of the socket fitting problems will require a visit of the Prosthetist.

Some of the common problems and their solutions

Problems	solutions
Pressure on the Anterior distal end of the stump	·         Try adding a one or two ply sock. ·         Recently changed shoes ·         Try one with a lower heel ·         planter flexed foot ·         weight line too far posterior from normal
Pressure on the patellar tendon
Feel like walking down a hill	Dorsiflexion of foot
Pain on the bottom-back of your calf
Feel like walking up a hill	Plantarflexion of  foot
Pressure on the sides of the knee	Medio-lateral dimensions are more

Note

·         Remember, the most common remedy to most socket-fitting problems is adding or removing socks.

·         Prosthetic socks plays an important role in keeping the residual limb comfortably seated within the prosthesis.

·         If the prosthesis is uncomfortable, four out of five times it is because amputees are not wearing the proper amount of prosthetic socks.

·         Vary the sock ply until the prosthesis feels better.

·         If this does not fix the problem, check the measurements other technical faults.