THE MUSCULOSKELETAL SYSTEM

1. Introduction to Musculoskeletal System (Muscle Component)

The musculoskeletal system consists of bones, muscles, joints, tendons, ligaments, and cartilage. The muscular system helps in movement, posture maintenance, breathing, circulation, and organ function.

Functions of Muscles

1. Movement of body parts

2. Maintenance of posture

3. Stabilization of joints

4. Heat production (thermogenesis)

5. Support to organs

6. Circulation of blood

7. Respiration

   
   

2. Types of Muscles

Type	Location	Control	Function
Skeletal muscle	attached to bones	voluntary	movement
Smooth muscle	organs	involuntary	organ function
Cardiac muscle	heart	involuntary	pumping blood

3. Structure of Skeletal Muscle

Part	Function
Muscle fiber	muscle cell
Sarcolemma	muscle cell membrane
Myofibril	contractile unit
Sarcomere	functional unit
Actin	thin filament
Myosin	thick filament

4. Muscle Groups of Body

A. Muscles of Head\

Important Muscles

Muscle	Function
Frontalis	raises eyebrow
Orbicularis oculi	closes eye
Orbicularis oris	closes mouth
Buccinator	chewing
Masseter	jaw movement
Temporalis	mastication

B. Muscles of Neck

Muscle	Function
Sternocleidomastoid	head rotation
Trapezius	shoulder movement
Scalenes	respiration support

C. Muscles of Thorax

Muscle	Function
Intercostal muscles	breathing movement
Diaphragm	respiration

D. Muscles of Abdomen

Muscle	Function
Rectus abdominis	trunk flexion
External oblique	rotation
Internal oblique	support organs
Transversus abdominis	abdominal pressure

E. Pelvic Muscles

Muscle	Function
Levator ani	supports pelvic organs
Coccygeus	pelvic stability

F. Upper Limb Muscles

Muscle	Function
Deltoid	arm abduction
Biceps	elbow flexion
Triceps	elbow extension
Brachialis	flexion

G. Lower Limb Muscles

Muscle	Function
Gluteus maximus	hip extension
Quadriceps	knee extension
Vastus lateralis	leg extension
Hamstrings	knee flexion
Gastrocnemius	walking

5. Principal Muscles (Exam Important)

Muscle	Location	Function
Deltoid	shoulder	arm lifting
Biceps	upper arm	flexion
Triceps	upper arm	extension
Diaphragm	thorax	breathing
Rectus abdominis	abdomen	trunk movement
Pelvic floor muscle	pelvis	organ support
Gluteal muscles	buttock	walking
Vastus lateralis	thigh	knee extension

6. Respiratory Muscles

7. Abdominal Muscles

Functions:

• support organs

• maintain posture

• help defecation

• help childbirth

8. Pelvic Floor Muscles

Functions:

• support bladder

• support uterus

• control urination

• support rectum

9. Gluteal Muscles

Types:

• Gluteus maximus

• Gluteus medius

• Gluteus minimus

Function:

• walking

• running

• standing

10. Vastus Lateralis

Part of quadriceps muscle

Function:

• knee extension

• walking

• standing

11. Major Muscles involved in Nursing Procedures

Nursing activity	muscles involved
Injection (IM)	deltoid, gluteus
Walking patient	quadriceps, gluteus
Deep breathing exercise	diaphragm
Posture support	back muscles
Lifting patient	biceps, triceps
Position change	abdominal muscles
Catheterization position	pelvic muscles
Physiotherapy	limb muscles

12. Clinical Importance in Nursing

Muscle disorders

disorder	description
muscular dystrophy	muscle weakness
myasthenia gravis	muscle fatigue
muscle strain	injury
muscle atrophy	muscle wasting
paralysis	loss of movement