Muscle Mastery: A Comprehensive Guide to Caring for Your Body's Powerhouses

what is Muscle?

Muscles are specialized types of tissue composed of fibers that can contract, causing and allowing movement of the parts and organs of the body.

Muscles are the body's workhorses, responsible for movement, posture, and heat production.

There are three main types of muscles: skeletal, smooth, and cardiac.

1. Skeletal Muscles:

• Location: Attached to bones by tendons.
• Voluntary Control: Under conscious control.
• Function: Responsible for body movement, such as walking and picking up objects.
• Appearance: Striated or striped appearance under a microscope.

2. Smooth Muscles:

• Location: Found in the walls of internal organs (e.g., stomach, intestines, blood vessels).
• Involuntary Control: Not under conscious control.
• Function: Regulate the size of organs, and propel substances through internal passageways.
• Appearance: Not striated.

3. Cardiac Muscles:

• Location: Found in the heart.
• Involuntary Control: Not under conscious control.
• Function: Pumping blood to the rest of the body.
• Appearance: Striated like skeletal muscles but has a unique branched structure.

On this page...

• what is Muscle?
• what is muscle fiber?
• Muscles of respiration.
• Muscle of mastication.
• Muscle in the floor of the oral cavity.
• Muscle of the tongue.
• Muscle of neck.
• Muscle of the vertebral column.
• Muscles of the arm.
• Muscles of the Forearm.
• Muscles of the Wrist.
• Muscles of the Hand and Fingers.
• Muscle of the abdominal wall.
• Muscles of the thigh that act on the leg.
• Muscle of the leg that moves the ankle, foot, and toes.
• Common Muscle Problems and Causes.
• 13 ways to take care of your muscles.

what is muscle fiber? 

a structural and functional unit of muscle. It consists of a single cell (smooth and skeletal muscle) or multiple cells (cardiac and muscle). The cell of muscle is known as myocyte. The myocyte consists of the contractile component myofibril. Muscle cells are much longer than breadth, therefore they are called fiber.

Or

A muscle fiber, also known as a myocyte, is the basic unit of skeletal muscle. It is a long, cylindrical cell that is highly specialized for contraction. Muscle fibers are typically several centimeters long and only a few micrometers in diameter. They are surrounded by a thin layer of connective tissue called the sarcolemma. 

Muscle fibers are composed of several thousand myofibrils, which are long, thread-like structures that run the length of the fiber. Myofibrils are composed of sarcomeres, the basic contractile units of muscle fibers. Sarcomeric contraction is the result of the interaction of two types of filaments called actin and myosin. 

Muscle fibers are classified into three types based on their speed of contraction and their energy sources:

1. Slow-twitch fibers (type I fibers) are fatigue-resistant and have a high oxidative capacity, meaning they can use oxygen to break down glucose and produce energy. They are used for sustained activities such as running and swimming.

2. Fast-twitch fibers (type II fibers) are fast-twitching and have a high glycolytic capacity, meaning they can break down glycogen (stored glucose) to produce energy without using oxygen. They are used for explosive activities such as sprinting and jumping.

3. Intermediate fibers (type IIa fibers) have characteristics of both slow-twitch and fast-twitch fibers. They are capable of both sustained and explosive activities

• Fasciculi: a bundle of muscle fiber is called fasciculi.

Properties of muscle fiber;

Muscle fibers have several key properties that contribute to their function:

1. Excitability (Irritability): Muscle fibers can respond to stimuli, such as nerve signals, by generating electrical impulses and initiating muscle contraction.

2. Contractility: Muscle fibers can shorten and generate force, allowing them to pull on bones and produce movement.

3. Elasticity: Muscle fibers can return to their original length after contraction, maintaining flexibility and preventing damage.

4. Extensibility: Muscle fibers can be stretched without being damaged, enabling a wide range of motion in the joints.

5. Sarcomere Structure: The repeating sarcomeric units within muscle fibers allow precise muscle contraction and relaxation control.

6. Energy Efficiency: Muscle fibers can efficiently produce ATP (adenosine triphosphate), the energy currency of cells, to fuel the processes of contraction and relaxation.

These properties collectively enable muscle fibers to perform their vital role in movement and force generation in the body.

Muscles of respiration:

The muscles of respiration play a key role in the process of breathing, which involves the inhalation of oxygen and the exhalation of carbon dioxide.

1. Inspiratory Muscles:

• Diaphragm: The diaphragm is the primary muscle of inspiration. It is a dome-shaped muscle located at the base of the thoracic cavity, separating the chest cavity from the abdominal cavity. When the diaphragm contracts, it flattens, increasing the volume of the thoracic cavity and creating a negative pressure that allows air to be drawn into the lungs.
• External Intercostal Muscles: These muscles are located between the ribs. During inhalation, the external intercostal muscles contract, lifting the ribs upward and outward. This action further expands the thoracic cavity, assisting in the inhalation process.
• Accessory Muscles: In certain situations, especially during heavy or labored breathing, accessory muscles such as the sternocleidomastoid, scalene muscles, and pectoralis minor may also contribute to expanding the thoracic cavity and aiding in inspiration.

2. Expiratory Muscles:

• Internal Intercostal Muscles: The internal intercostal muscles are located between the ribs but function differently during expiration. During forced expiration, these muscles contract to pull the ribs downward, decreasing the volume of the thoracic cavity.
• Abdominal Muscles (Rectus Abdominis, External and Internal Obliques, Transverse Abdominis): Contraction of the abdominal muscles increases intra-abdominal pressure, pushing the diaphragm upward. This action assists in the expulsion of air from the lungs during exhalation.
• Internal Abdominal and External Abdominal Obliques: These muscles play a role in forced expiration by compressing the abdominal contents, and pushing the diaphragm upwards.

Muscle of mastication:

The muscles of mastication are the four muscles that are responsible for chewing. They are:

1. Masseter: The masseter is the most powerful muscle of mastication. It is a thick, quadrilateral muscle that lies on the side of the face. The masseter originates from the zygomatic arch and inserts on the ramus of the mandible.
2. Temporalis: The temporalis is a fan-shaped muscle that lies in the temporal fossa. The temporalis originates from the temporal bone and inserts into the coronoid process of the mandible.
3. Medial pterygoid: The medial pterygoid is a thick, rectangular muscle that lies on the inside of the pterygoid fossa. The medial pterygoid originates from the medial pterygoid plate and inserts on the medial aspect of the ramus of the mandible.
4.  Lateral pterygoid: The lateral pterygoid is a two-headed muscle that lies on the outside of the pterygoid fossa. The lateral pterygoid originates from the lateral pterygoid plate and inserts on the condyle of the mandible.

Nerve supply

The muscles of mastication are innervated by the mandibular nerve, which is a branch of the trigeminal nerve (CN V). The mandibular nerve supplies the masseter, temporalis, and medial pterygoid muscles. The lateral pterygoid muscle is innervated by the buccal nerve, which is also a branch of the trigeminal nerve.

Action

The muscles of mastication work together to move the mandible in three directions: up and down, forward and backward, and from side to side.

• Up and down movement: The masseter and temporalis muscles are responsible for elevating the mandible, while the medial pterygoid muscles are responsible for depressing the mandible.
• Forward and backward movement: The lateral pterygoid muscles are responsible for protracting and retracting the mandible.
• Side-to-side movement: The lateral pterygoid muscles are also responsible for the lateral movement of the mandible.

Clinical significance

The muscles of mastication can be affected by a variety of conditions, including temporomandibular joint disorder (TMJ), myofascial pain syndrome, and trigeminal neuralgia. These conditions can cause pain, difficulty chewing, and other problems.

Muscle in the floor of the oral cavity:

The muscles in the floor of the oral cavity are collectively known as the suprahyoid muscles. They are responsible for the following functions:

• Supporting and maintaining the shape of the floor of the mouth
• Assisting in the movement of the tongue during swallowing and speaking
• Elevating the larynx during swallowing

There are four muscles in the suprahyoid group:

1. Mylohyoid: This is the largest and most superficial muscle in the group. It is a thin, fan-shaped muscle that lies on the undersurface of the mandible. The mylohyoid originates from the mylohyoid line of the mandible and inserts on the median raphe of the tongue.

2. Geniohyoid: This muscle is a small, spindle-shaped muscle that lies beneath the mylohyoid muscle. The geniohyoid originates from the mental spine of the mandible and inserts on the hyoid bone.

3. Digastric: This muscle is a two-headed muscle that lies on the side of the neck. The anterior belly of the digastric originates from the mental spine of the mandible and inserts on the hyoid bone. The posterior belly of the digastric originates from the mastoid process of the temporal bone and inserts into the hyoid bone.

4. Stylohyoid: This muscle is a small, slender muscle that lies beneath the digastric muscle. The stylohyoid originates from the styloid process of the temporal bone and is inserted into the hyoid bone.

Nerve supply

The suprahyoid muscles are innervated by three nerves: the hypoglossal nerve (CN XII), the facial nerve (CN VII), and the lingual nerve (CN V3). The hypoglossal nerve innervates the geniohyoid muscle. The facial nerve innervates the digastric muscle. The lingual nerve innervates the mylohyoid muscle.

Action

The suprahyoid muscles work together to elevate the larynx during swallowing. The mylohyoid and geniohyoid muscles also help to support the shape of the floor of the mouth and assist in the movement of the tongue during swallowing and speaking.

Clinical significance

The suprahyoid muscles can be affected by a variety of conditions, including muscle weakness, nerve damage, and inflammation. These conditions can cause difficulty swallowing, speaking, and maintaining the shape of the floor of the mouth.

Muscle of the tongue:

The tongue is a muscular organ in the mouth that plays a vital role in various functions, including speech, swallowing, tasting, and maintaining oral hygiene. It is composed of two types of muscles: intrinsic and extrinsic.

1. Intrinsic muscles: These muscles are entirely located within the tongue and are responsible for its intricate movements, such as curling, bending, and shaping. They are divided into four groups:

• Superior longitudinal muscle: Shortens and widens the tongue, curling it upward (dorsiflexion).
• Inferior longitudinal muscle: Shortens and widens the tongue, curling it downward (retroflection).
• Transverse muscle: Elongates and narrows the tongue.
• Vertical muscle: Flattens the tongue.

1. Extrinsic muscles: These muscles originate outside the tongue and attach to its base, providing overall movement and positioning. They are responsible for protruding, retracting, and elevating the tongue.

• Genioglossus: The largest muscle of the tongue, responsible for protruding it forward.
• Hyoglossus: Retracts and depresses the tongue.
• Styloglossus: Retracts and elevates the lateral margins of the tongue.
• Palatoglossus: Elevates the posterior tongue, closes the oropharyngeal isthmus, aids in the initiation of swallowing, and prevents the spill of saliva from the vestibule into the oropharynx.

All the muscles of the tongue are innervated by the hypoglossal nerve (CN XII), except for the palatoglossus muscle which is supplied by the vagus nerve (CN X). The hypoglossal nerve controls the motor function of the tongue, enabling its movements for speech, swallowing, and manipulation of food in the mouth.

The muscles of the tongue work together in a coordinated manner to perform a wide range of functions, making it an essential organ for communication, nutrition, and oral health.

Muscle of neck:

1. Anterior muscles

The anterior neck muscles are responsible for the flexion of the neck, meaning they bend the neck forward. They include the following muscles:

• Sternocleidomastoid: This is the largest muscle of the neck and it originates from the sternum and clavicle and inserts into the mastoid process of the temporal bone.
• Thyrohyoid: This muscle originates from the thyroid cartilage and inserts on the hyoid bone.
• Sternothyroid: This muscle originates from the sternum and inserts on the thyroid cartilage.
• Omohyoid: This muscle originates from the scapula and inserts on the hyoid bone.

2. Lateral muscles

The lateral neck muscles are responsible for lateral neck flexion, meaning they bend the neck to the side. They include the following muscles:

• Scalenes: These are three muscles that originate from the cervical vertebrae and are inserted into the first and second ribs.
• Splenius capitis: This muscle originates from the cervical vertebrae and is inserted on the mastoid process of the temporal bone.
• Levator scapulae: This muscle originates from the cervical vertebrae and inserts on the scapula.

3. Posterior muscles

The posterior neck muscles are responsible for the extension of the neck, meaning they straighten the neck. They include the following muscles:

• Semispinalis capitis: This muscle originates from the thoracic vertebrae and inserts into the mastoid process of the temporal bone.
• Trapezius: This is a large muscle that originates from the cervical vertebrae, the thoracic vertebrae, and the scapula and inserts on the clavicle and acromion.

4.Suboccipital muscles

The suboccipital muscles are responsible for fine movements of the head. They include the following muscles:

• Rectus capitis posterior major: This muscle originates from the atlas and inserts on the occipital bone.
• Rectus capitis posterior minor: This muscle originates from the axis and inserts on the occipital bone.
• Obliquus capitis superior: This muscle originates from the atlas and inserts on the occipital bone.
• Obliquus capitis inferior: This muscle originates from the axis and inserts on the occipital bone.

Nerve supply

The muscles of the neck are innervated by the spinal accessory nerve (CN XI) and the cervical nerves (C1-C8). The spinal accessory nerve innervates the sternocleidomastoid and trapezius muscles. The cervical nerves innervate the remaining muscles of the neck.

Function

The muscles of the neck are responsible for a wide range of movements, including flexion, extension, lateral flexion, and rotation of the head. They also play a role in respiration, swallowing, and speech.

Clinical significance

The muscles of the neck can be affected by a variety of conditions, including trauma, infection, and inflammation. These conditions can cause pain, weakness, and loss of range of motion in the neck.

Muscles of the vertebral column and their origin insertion and function:

1.Erector Spinae Group (Spinalis, Longissimus, Iliocostalis):

• Origin: Broadly along the posterior part of the spine, extending from the sacrum to the skull.
• Insertion: Various attachments to the vertebrae, ribs, and the skull.
• Function: Extension of the spine, lateral flexion, and stabilization of the vertebral column.

2. Multifidus:

• Origin: Sacrum, iliac crest, and transverse processes of the vertebrae.
• Insertion: Spinous processes of the vertebrae.
• Function: Stabilization of the vertebral column and facilitation of rotational movements.

3. Rotatores:

• Origin: Transverse processes of the vertebrae.
• Insertion: Spinous processes of the vertebrae.
• Function: Facilitate rotation and stabilize the spine.

4. Semispinalis:

• Origin: Transverse processes of the vertebrae.
• Insertion: Spinous processes of the more superior vertebrae.
• Function: Extension and rotation of the spine.

5.Quadratus Lumborum:

• Origin: Iliac crest and the iliolumbar ligament.
• Insertion: Transverse processes of the lumbar vertebrae and the 12th rib.
• Function: Lateral flexion of the spine, extension of the lumbar spine, and stabilization.

6.Iliopsoas (Psoas Major and Iliacus):

• Origin (Psoas Major): Lumbar vertebrae.
• Origin (Iliacus): Iliac fossa.
• Insertion (Both): Lesser trochanter of the femur.
• Function: Flexion of the hip joint and lumbar spine.

7. Transversospinalis Group (including Semispinalis, Multifidus, and Rotatores):

• Origin: Transverse processes of the vertebrae.
• Insertion: Spinous processes of the more superior vertebrae.
• Function: Stabilization and extension of the spine.

8. Interspinales and Intertransversarii Muscles:

• Function: Stabilization and limited movement between adjacent vertebrae.

The muscles of the vertebral column are innervated by the spinal nerves, which originate from the spinal cord. These nerves provide motor and sensory input to the muscles, allowing them to contract and receive feedback about their position and movement.

The muscles of the vertebral column play a vital role in maintaining posture, supporting the weight of the head and body, and allowing for a wide range of movements, such as bending, twisting, and reaching. They are also essential for activities such as walking, running, and lifting objects.

Dysfunction of the muscles of the vertebral column can lead to a variety of problems, including back pain, muscle spasms, and impaired mobility. Proper exercise, posture, and stretching can help to maintain the strength, flexibility, and function of these important muscles.

Muscles of the arm and their origin insertion and function:

1. Biceps Brachii:

• Origin (Long Head): Supraglenoid tubercle of the scapula.
• Origin (Short Head): Coracoid process of the scapula.
• Insertion: Radial tuberosity and the bicipital aponeurosis into the forearm fascia.
• Function: Flexion at the elbow joint and supination of the forearm.

2. Brachialis:

• Origin: Anterior surface of the distal humerus.
• Insertion: Coronoid process of the ulna.
• Function: Primary flexor of the elbow, especially when the hand is pronated.

3. Brachioradialis:

• Origin: Lateral supracondylar ridge of the humerus.
• Insertion: Styloid process of the radius.
• Function: Flexion at the elbow, especially in a midposition, and assists in pronation and supination.

4. Triceps Brachii:

• Origin (Long Head): Infraglenoid tubercle of the scapula.
• Origin (Lateral Head): Posterior surface of the humerus, above the radial groove.
• Origin (Medial Head): Posterior surface of the humerus, below the radial groove.
• Insertion: Olecranon process of the ulna.
• Function: Extension at the elbow joint.

5. Anconeus:

• Origin: Lateral epicondyle of the humerus.
• Insertion: Lateral surface of the olecranon and upper part of the posterior ulna.
• Function: Assists in extension at the elbow.

6. Deltoid:

• Origin (Anterior Head): Anterior border and the upper surface of the lateral third of the clavicle.
• Origin (Lateral Head): Acromion process.
• Origin (Posterior Head): Spine of the scapula.
• Insertion: Deltoid tuberosity of the humerus.
• Function: Abduction, flexion, and extension of the shoulder joint.

7. Coracobrachialis:

• Origin: Coracoid process of the scapula.
• Insertion: Middle third of the medial surface of the humerus.
• Function: Flexion and adduction of the shoulder.

8.Supraspinatus:

• Origin: Supraspinous fossa of the scapula.
• Insertion: Greater tubercle of the humerus.
• Function: Initiates and assists in abduction of the shoulder.

9.Infraspinatus:

• Origin: Infraspinous fossa of the scapula.
• Insertion: Greater tubercle of the humerus.
• Function: External rotation and stabilization of the shoulder.

10. Teres Major:

• Origin: Posterior surface of the inferior angle of the scapula.
• Insertion: Medial lip of the intertubercular sulcus of the humerus.
• Function: Adduction, medial rotation, and extension of the shoulder.

Muscles of the Forearm and their origin insertion and function:

Anterior Compartment:

1.Flexor Digitorum superficialis (FDS):

• Origin: Medial epicondyle of the humerus, ulnar head of the flexor digitorum superficialis muscle.
• Insertion: Middle phalanges of the four fingers.
• Function: Flexes the middle phalanges of the four fingers at the proximal interphalangeal (PIP) joints.

2.Flexor Digitorum Profundus (FDP):

• Origin: Proximal three-quarters of the anterior and medial surfaces of the ulna and interosseous membrane.
• Insertion: Distal phalanges of the four fingers.
• Function: Flexes the distal interphalangeal (DIP) joints of the four fingers.

3.Flexor Pollicis Longus (FPL):

• Origin: Anterior surface of the radius and interosseous membrane.
• Insertion: Distal phalanx of the thumb (pollicis).
• Function: Flexes the distal phalanx of the thumb at the interphalangeal joint.

4. Pronator Teres:

• Origin: Medial epicondyle of the humerus and coronoid process of the ulna.
• Insertion: Lateral surface of the radius.
• Function: Pronation of the forearm (turning the palm downward).

5.Pronator Quadratus:

• Origin: Distal part of the anterior ulna.
• Insertion: Distal part of the anterior radius.
• Function: Pronation of the forearm.

Posterior Compartment:

1.Extensor Digitorum:

• Origin: Lateral epicondyle of the humerus.
• Insertion: Extensor expansions of the four fingers.
• Function: Extends the fingers at the metacarpophalangeal (MCP), proximal interphalangeal (PIP), and distal interphalangeal (DIP) joints.

2. Extensor Digiti Minimi:

• Origin: Lateral epicondyle of the humerus.
• Insertion: Extensor expansion of the little finger.
• Function: Extends the little finger at the MCP, PIP, and DIP joints.

3.Extensor Carpi Ulnaris (ECU):

• Origin: Lateral epicondyle of the humerus and posterior border of the ulna.
• Insertion: Base of the fifth metacarpal.
• Function: Extends and adducts the wrist.

4. Supinator:

• Origin: Lateral epicondyle of the humerus and radial collateral ligament.
• Insertion: Lateral and posterior surface of the proximal radius.
• Function: Supinates the forearm (turning the palm upward).

5. Abductor Pollicis Longus (APL):

• Origin: Posterior surface of the ulna and radius.
• Insertion: Base of the first metacarpal.
• Function: Abducts and extends the thumb.

6.Extensor Pollicis Brevis (EPB):

• Origin: Posterior surface of the radius and interosseous membrane.
• Insertion: Base of the proximal phalanx of the thumb.
• Function: Extends the proximal phalanx of the thumb.

7.Extensor Pollicis Longus (EPL):

• Origin: Posterior surface of the ulna and interosseous membrane.
• Insertion: Base of the distal phalanx of the thumb.
• Function: Extends the distal phalanx of the thumb.

These muscles are innervated by various branches of the brachial plexus, a network of nerves that originates from the spinal cord and supplies the upper extremity with motor and sensory information.

Muscles of the Wrist:

1.Flexor Carpi Radialis:

• Origin: Medial epicondyle of the humerus.
• Insertion: Base of the second and third metacarpal bones.
• Function: Flexes and abducts the hand at the wrist.

2.Flexor Carpi Ulnaris:

• Origin: Medial epicondyle of the humerus and olecranon of the ulna.
• Insertion: Pisiform, hamate, and base of the fifth metacarpal.
• Function: Flexes and adducts the hand at the wrist.

3. Palmaris Longus:

• Origin: Medial epicondyle of the humerus.
• Insertion: Palmar aponeurosis.
• Function: Weak flexor of the hand at the wrist; not always present in all individuals.

4.Extensor Carpi Radialis Longus:

• Origin: Lateral supracondylar ridge of the humerus.
• Insertion: Base of the second metacarpal.
• Function: Extends and abducts the hand at the wrist.

5.Extensor Carpi Radialis Brevis:

• Origin: Lateral epicondyle of the humerus.
• Insertion: Base of the third metacarpal.
• Function: Extends and abducts the hand at the wrist.

6.Extensor Carpi Ulnaris:

• Origin: Lateral epicondyle of the humerus and posterior border of the ulna.
• Insertion: Base of the fifth metacarpal.
• Function: Extends and adducts the hand at the wrist.

Muscles of the Hand and Fingers:

1. Thenar Muscles: (Abductor Pollicis Brevis, Flexor Pollicis Brevis, Opponents Pollicis):

• Origin and Insertion: Various points in the thumb region.
• Function: Abduction, flexion, and opposition of the thumb.

2. Hypothenar Muscles: (Abductor Digiti Minimi, Flexor Digiti Minimi Brevis, Opponents Digiti Minimi):

• Origin and Insertion: Various points in the little finger region.
• Function: Abduction, flexion, and opposition of the little finger.

3. Interossei Muscles:

• Dorsal Interossei (Abduct): Origin from the metacarpals and inserted into the proximal phalanges.
• Palmar Interossei (Adduct): Origin from the metacarpals and inserted into the proximal phalanges.
• Function: Abduction or adduction of the fingers.

4.Lumbrical Muscles:

• Origin: Tendons of the flexor digitorum profundus.
• Insertion: Extensor hood on the dorsal surface of the fingers.
• Function: Flexion at the metacarpophalangeal joints and extension at the interphalangeal joints.

5.Flexor Digitorum Superficialis (FDS):

• Origin: Medial epicondyle of the humerus, ulnar head.
• Insertion: Middle phalanges of the four fingers.
• Function: Flexes the middle phalanges of the four fingers at the proximal interphalangeal (PIP) joints.

6.Flexor Digitorum Profundus (FDP):

• Origin: Anterior surface of the ulna.
• Insertion: Distal phalanges of the four fingers.
• Function: Flexes the distal interphalangeal (DIP) joints of the four fingers.

7. Adductor Pollicis:

• Origin: Transverse head (anterior metacarpals) and oblique head (capitate and bases of second and third metacarpals).
• Insertion: Base of the proximal phalanx of the thumb.
• Function: Adduction of the thumb.

8. Abductor Pollicis Brevis:

• Origin: Flexor retinaculum and tubercles of the scaphoid and trapezium.
• Insertion: Base of the proximal phalanx of the thumb.
• Function: Abduction of the thumb.

9. Opponents Pollicis:

• Origin: Flexor retinaculum and tubercle of the trapezium.
• Insertion: Lateral surface of the first metacarpal.
• Function: Opposition and rotation of the thumb.

10. Extensor Digitorum Communis (EDC):

• Origin: Lateral epicondyle of the humerus.
• Insertion: Extensor expansions of the four fingers.
• Function: Extends the fingers at the metacarpophalangeal (MCP), proximal interphalangeal (PIP), and distal interphalangeal (DIP) joints.

11. Extensor Indicis:

• Origin: Posterior surface of the ulna and interosseous membrane.
• Insertion: Extensor expansion of the index finger.
• Function: Extends the index finger at the MCP, PIP, and DIP joints.

Muscle of the abdominal wall:

1. Rectus Abdominis:

• Origin: Pubic symphysis and pubic crest.
• Insertion: Costal cartilages of ribs 5-7 and the xiphoid process of the sternum.
• Function: Flexion of the trunk and compression of the abdominal contents. It is divided into segments by fibrous bands called the linea alba and tendinous intersections.

2. External Oblique:

• Origin: External surfaces of the lower eight ribs.
• Insertion: Anterior half of the iliac crest, the pubic tubercle, and the linea alba.
• Function: Flexion, rotation, and lateral flexion of the trunk.

3.Internal Oblique:

• Origin: Inguinal ligament, iliac crest, and thoracolumbar fascia.
• Insertion: Costal cartilages of the last three ribs, the linea alba, and the pubic crest.
• Function: Flexion, rotation, and lateral flexion of the trunk. Works in conjunction with the external oblique.

4.Transversus Abdominis:

• Origin: Internal surfaces of the lower six costal cartilages, thoracolumbar fascia, iliac crest, and inguinal ligament.
• Insertion: Linea alba, pubic crest, and pecten pubis.
• Function: Compression of the abdominal contents and stabilization of the trunk.

5. Pyramidalis:

• Origin: Anterior surface of the pubic symphysis.
• Insertion: Linea alba.
• Function: Tenses the linea alba, but its presence and significance can vary among individuals.

Muscles of the thigh that act on the leg:

 Quadriceps Femoris:

1.Rectus Femoris:

• Origin: Anterior inferior iliac spine.
• Insertion: Tibial tuberosity via the patellar tendon.
• Function: Extends the knee and flexes the hip.

2. Vastus Lateralis:

• Origin: Greater trochanter and lateral lip of the linea aspera.
• Insertion: Tibial tuberosity via the patellar tendon.
• Function: Extends the knee.

3. Vastus Medialis:

• Origin: Intertrochanteric line and medial lip of the linea aspera.
• Insertion: Tibial tuberosity via the patellar tendon.
• Function: Extends the knee.

4.Vastus Intermedius:

• Origin: Anterior and lateral surfaces of the femur.
• Insertion: Tibial tuberosity via the patellar tendon.
• Function: Extends the knee.

 Hamstrings:

1. Biceps Femoris:

a.Long Head:

• Origin: Ischial tuberosity.
• Insertion: Head of the fibula.
• Function: Flexes the knee and extends the hip.

b.Short Head:

• Origin: Linea aspera.
• Insertion: Head of the fibula.
• Function: Flexes the knee and extends the hip.

2.Semimembranosus:

• Origin: Ischial tuberosity.
• Insertion: Medial condyle of the tibia.
• Function: Flexes the knee and extends the hip.

3.Semitendinosus:

• Origin: Ischial tuberosity.
• Insertion: Proximal part of the tibia below the condyle.
• Function: Flexes the knee and extends the hip.

 Adductors:

1. Adductor Magnus:

a.Adductor Part:

• Origin: Inferior ramus of the pubis, ramus of the ischium.
• Insertion: Linea aspera and medial supracondylar line of the femur.
• Function: Adducts and flexes the thigh.

b.Ischiocondylar Part:

• Origin: Ischial tuberosity.
• Insertion: Adductor tubercle of the femur.
• Function: Extends the thigh.

2.Adductor Longus:

• Origin: Pubic body.
• Insertion: Linea aspera.
• Function: Adducts and flexes the thigh.

3. Adductor Brevis:

• Origin: Pubic body and inferior ramus of the pubis.
• Insertion: Linea aspera.
• Function: Adducts and flexes the thigh.

4.Gracilis:

• Origin: Inferior ramus of the pubis and ischial ramus.
• Insertion: Proximal part of the medial surface of the tibia.
• Function: Adducts and flexes the thigh, assists in knee flexion and medial rotation.

Iliopsoas:

1.Iliacus:

• Origin: Iliac fossa and ala of the sacrum.
• Insertion: Lesser trochanter of the femur.
• Function: Flexes the hip joint.

2. Psoas Major:

• Origin: Transverse processes and bodies of lumbar vertebrae.
• Insertion: Lesser trochanter of the femur.
• Function: Flexes the hip joint.

The muscles of the thigh that act on the leg are innervated by the femoral nerve, the sciatic nerve, and the obturator nerve. These nerves provide motor and sensory input to the muscles, allowing them to contract and receive feedback about their position and movement.

The muscles of the thigh play a vital role in walking, running, jumping, and other activities that require movement of the leg. They also help to support the weight of the body and maintain stability when standing or sitting.

Muscle of the leg that moves the ankle, foot, and toes:

Posterior Compartment (Calf Muscles):

1. Gastrocnemius:

• Origin: Medial and lateral condyles of the femur.
• Insertion: Calcaneus (via the Achilles tendon).
• Function: Plantar flexion of the ankle joint and flexion of the knee joint.

2. Soleus:

• Origin: Proximal tibia and fibula.
• Insertion: Calcaneus (via the Achilles tendon).
• Function: Plantar flexion of the ankle joint.

3. Plantaris:

• Origin: Lateral supracondylar ridge of the femur.
• Insertion: Calcaneus (via the Achilles tendon).
• Function: Assists in plantar flexion and knee flexion.

Deep Posterior Compartment:

1.Flexor Digitorum Longus:

• Origin: Posterior surface of the tibia.
• Insertion: Plantar surfaces of the distal phalanges of the four lesser toes.
• Function: Flexion of the four lesser toes at the distal interphalangeal (DIP), proximal interphalangeal (PIP), and metatarsophalangeal (MCP) joints.

2.Flexor Hallucis Longus:

• Origin: Posterior surface of the fibula.
• Insertion: Plantar surface of the distal phalanx of the great toe (hallux).
• Function: Flexion of the great toe at the DIP, PIP, and MCP joints.

3. Tibialis Posterior:

• Origin: Interosseous membrane, posterior surfaces of the tibia and fibula.
• Insertion: Tuberosity of the navicular bone, cuneiforms, and bases of the second, third, and fourth metatarsals.
• Function: Inversion of the foot and plantar flexion of the ankle.

Anterior Compartment:

1. Tibialis Anterior:

• Origin: Lateral condyle and proximal shaft of the tibia.
• Insertion: Medial cuneiform and base of the first metatarsal.
• Function: Dorsiflexion and inversion of the foot.

2.Extensor Digitorum Longus:

• Origin: Lateral condyle of the tibia and anterior shaft.
• Insertion: Middle and distal phalanges of the four lesser toes.
• Function: Extension of the toes at the MCP, PIP, and DIP joints, and dorsiflexion of the foot.

3.Extensor Hallucis Longus:

• Origin: Middle part of the fibula.
• Insertion: Distal phalanx of the great toe (hallux).
• Function: Extension of the great toe at the MCP, PIP, and DIP joints, and dorsiflexion of the foot.

These muscles are innervated by the tibial nerve, the peroneal nerve, and the plantar nerve. These nerves provide motor and sensory input to the muscles, allowing them to contract and receive feedback about their position and movement.

The muscles of the leg that move the ankle, foot, and toes play a vital role in a variety of functions, including:

• Walking and running: These muscles provide the power and stability needed for walking and running.
• Balance and coordination: These muscles help to maintain balance and coordination when standing or moving.
• Foot arch support: These muscles help to support the arch of the foot and prevent it from collapsing.
• Fine foot movements: These muscles allow for fine movements of the foot and toes, such as grabbing and manipulating objects.

Common muscle problems and Causes:

1. Muscle Cramps:

Causes: Dehydration, electrolyte imbalances, overuse of muscles.

2. Muscle Strains:

Cause: Overexertion, improper warm-up, poor flexibility.

3. Delayed Onset Muscle Soreness (DOMS):

Cause: Intense or new exercise, microtrauma to muscle fibers.

4. Tendinitis:

Cause: Overuse, repetitive motion, aging.

5. Muscle Spasms:

Cause: Dehydration, electrolyte imbalances, muscle fatigue.

6. Muscle Fatigue:

Causes: Overtraining, inadequate rest, poor nutrition.

7. Compartment Syndrome:

Causes: Increased pressure within muscle compartments.

13 ways to take care of your muscles:

Keeping your muscles healthy is vital for maintaining good physical health and preventing injuries. Here are some key ways to take care of your muscles:

1. Move your body regularly:

Exercise: Aim for at least 60 minutes of the day in the morning. This can include activities like walking, running, swimming, biking, dancing, or playing sports.

2. Proper Nutrition:

Consume enough protein: Protein is essential for building and repairing muscle tissue. Aim to eat 0.8 grams of protein per kilogram of body weight per day. Good sources of protein include lean meats, fish, poultry, eggs, dairy products, beans, and legumes.

Eat plenty of fruits and vegetables: Fruits and vegetables are rich in vitamins, minerals, and antioxidants that are essential for overall health, including muscle health.

3. Adequate Rest:

• Allow your muscles to rest and recover. Overtraining can lead to fatigue and increase the risk of injuries. Ensure quality sleep to promote muscle repair.

4. Warm-Up and Cool Down:

• Always warm up before exercise to increase blood flow to your muscles and prepare them for activity. Cooling down helps to prevent stiffness and promotes flexibility.

5. Stretching:

• Stretching: Stretch your muscles regularly to improve flexibility and range of motion. Hold each stretch for 30 seconds and repeat 2-3 times per side.

6. Posture Awareness:

• Maintain good posture to reduce strain on muscles. Whether sitting at a desk or standing, be conscious of your posture to avoid unnecessary stress on muscles.

7. Hydration:

• Drink an adequate amount of water to prevent dehydration, which can lead to muscle cramps and fatigue.

8. Listen to Your Body:

• Pay attention to any pain or discomfort. If you experience persistent pain, it's essential to rest and, if needed, consult with a healthcare professional.

9. Massage and Foam Rolling:

• Consider regular massages or foam rollers to relieve muscle tension and improve circulation.

10. Cross-Training:

• Mix up your workouts to prevent overuse of specific muscle groups. Cross-training helps ensure balanced muscle development.

11. Strength Training: 

• Engage in a balanced mix of cardiovascular exercises, strength training, and flexibility exercises. This helps maintain muscle mass, strength, and flexibility.

12. Manage stress: 

• Stress can lead to muscle tension and pain. Find healthy ways to manage stress, such as yoga, meditation, or spending time in nature.

13. Stay Active Throughout the Day:

• Avoid prolonged periods of inactivity. If you have a desk job, take short breaks to stretch and move around.

By incorporating these habits into your lifestyle, you can promote muscle health and reduce the risk of injuries, ensuring your muscles serve you well in the long run.

Note: If you have any muscle problems. Please consult your healthcare provider or physiotherapist due to physical health problems.