Muscles

Muscles of the human body

”Chest

Pectoralis Major

Pectoralis major is the largest and superficial muscles of the chest of human body. It also known as pec major and consist of two head, one is sternocostal head and other clavicular head. It works on anterior arm.

Origin:

Clavicular head: anterior surface of medial half of the clavicle

Sternocostal head: anterior surface of sternum, 2nd to 6th costal cartilage, aponeurosis of the external oblique.

Insertion:

Lateral lip of bicipital groove (between greater and lesser tubercles) of the Humerus

Nerve supply:

Lateral and medial pectoral nerves

Actions:
  • Pectoralis major is responsible for shoulder joint movement.
  • Clavicular head- flexion of shoulder
  • Sternal head- extension of flexed arm against resistance, climbing
  • Both head acting as a whole- medial rotation and adduct of the shoulder.
  • It assists in deep inspiration
  • In short, pec major acts as shoulder adduction, extension and medial rotation.
Strengthening exercise:

Push up, chest press with resistance band, pec fly with machine, pec fly with resistance band or dumbbells, bench press with a barbell or dumbbell, pull ups, throwing

Incline pec fly, narrow push, modified push up, ball chest press, ball push up, ball pec fly

”Pectoralis

Pectoralis minor muscle is the small muscles of the chest and lie just underneath pectoralis major

Origin:

Anterior surface of the sternal ends of 3, 4, 5 ribs.

Insertion:

Coracoids process of scapula

Nerve supply:

Medial and lateral pectoral nerves

Actions:
  • Draws scapula forward with the help of serratus anterior
  • Depresses the shoulder
  • It assists in forced inspiration
Strengthening exercise:

Chest press with resistance band, pec fly with machine, pec fly with resistance band or dumbbells, bench press with a barbell or dumbbell,

”Subclavius:”

Subclavius is a small muscle of the chest and situated deep to the pectoralis major. It lies between the clavicle and the 1st rib.

Origin:

Junction of 1st rib and costal cartilage

Insertion:

Subclavian groove in Middle third of the clavicle

Nerve supply:

Nerve to subclavius

Actions:

It stabilizes the clavicle during movements of the shoulder girdle. It brings the shoulder down and forward. It assists in forced inspiration by elevating the 1st rib and keeps the shoulder stable

”Serratus

The serratus anterior muscle is mainly responsible for the protraction of the scapula and performs pushing and punching movement. The serratus anterior is functionally very essential as it stabilize the shoulders during weight carrying movement.

Origin:

Anterior surface of upper eight or nine ribs

Insertion:

Medial border of costal surface of the scapula.

Nerve supply:

Long thoracic nerve (C5, C6, C7)

Actions:

Pulls the scapula forward around the chest and acts in pushing and punching movements. Inferior part pull the lower end of the scapula laterally and forward and hence rotates the scapula to elevate arm possible. It assists in respiration. Serratus anterior is called as boxers muscle as it protracts the scapula.

Serratus anterior along with upper and lower fibers of the trapezius plays a vital role in the upward rotation of the scapula while abducting the arm overhead. It stabilizes the scapula by holding it to the chest wall during weight carrying.

In short, serratus anterior protracts (abducts) the scapula and upward rotates it during abducting the arm.

Strengthening exercises:

Push ups

Push ups with resistance band or medicine ball.

Dumbbells pullovers, rope pulls,

Muscles of Shoulder Girdle connecting to the spine

”Trapezius

The trapezius muscle is large and a superficial muscle that runs from the occipital bone to the thoracic vertebrae and spread to the laterally to the scapula. The trapezius muscle is divided into 3 parts:

Upper fibers, middle fibers, lower fibers.

Origin:

Medial third of superior nuchal line, external protuberance of occipital bone, ligamentum nuchae, C7 – T12 spinous process

Insertion:

Upper fibers are inserted into the posterior of clavicle,

Middle fibers are inserted into the acromion and spine of scapula

Lower fibers are inserted into the deltoid tubercle at the medial end of the spine.

Nerve supply:

C3, C4 and accessory cranial nerve (XI).

Action:

Upper fibers (along with levator scapulae): elevate and upward rotation of the scapula, extend neck

Middle fibers (along with rhomboids): retract (adduct) scapula

Lower fibers: depress scapula and assists to upper fibers to upward rotation of scapula

Upper and lower fibers act together: upward rotate scapula. (While levator scapulae and the rhomboids rotate scapula downward)

(Upper and lower fibres along with serratus anterior: rotate the scapula upward in abduction of the arm beyond 90 degree.)

Strengthening exercises:

Shrugging exercises, overhead arms movements, clean and its variation specially hang clean, overhead press,

”Latissimus

The latissimus dorsi is the largest, strong and powerful muscles of the back. The Latissimus dorsi is also known as lats.

Origin:

Outer lip of iliac crest, lumbar fascia, spines of T7-12, lower four ribs, inferior angle of scapula

Insertion:

Floor of intertubercular groove of humerus

Nerve supply:

Thoracodorsal nerve (C6, 7, 8)

Actions:

Adduction, medial rotation and extension of the shoulder,

It also assists during lumbar spine extension and side flexion.

Assists in violent expiration in sneezing and coughing

Synergists:

It also recruits posterior fibres of deltoid, teres major and long head of the triceps brachii.

Lat dorsi and trapezius work together during horizontal pulling movement like rows.

Strengthening exercises:

Lat pull down machine, Lat pull down with resistance band, dumbbell pullover,

(Vertical pulling movement) Pull-downs, pull-ups, chin-ups,

(Horizontal pulling movement) bent-over row, T bar row and other rowing exercises

Pull-overs, deadlift, boxing as it has many punches movement, pull down

Down stroke in swimming the crawl, climbing

”Levator

Levator scapulae is situated either side of neck at the back.

Origin:

Transverse processes of C1-4

Insertion:

Upper part of medial boarder of the scapula

Actions:

It assists in scapula elevation and medially rotates inferior angle (levator scapulae works with rhomboids and pectoralis minor to rotate scapula down)

It stabilize the scapula during arm movement

Rotation and Side flexion of the neck (individual muscles)

Extension of the neck (both muscles work together)

Nerves supply:

Dorsal scapular nerve and anterior primary rami of C3, C4

Strengthening exercises:

Shrugging shoulders and carries heavy weight in hands such as shopping bag

Rhomboideus:

The rhomboideus are two muscles, large muscle is known as rhomboideus major and small muscle is known as rhomboideus minor.

Rhomboideus major:

It is superficial muscles of the upper to middle back and lies deep to the middle trapezius

Origin:

Spinous processes of T2-T5 vertebrae

Supraspinous ligaments

Insertion:

Medial border of the scapula below to the spine of the scapula

Nerve supply:

Dorsal scapular nerve

Action:

It stabilize the scapula

It retracts the scapula

It along with levator scapulae rotate the scapula downward

Strengthening exercises:

Seated row machines, seated row with resistance band, reverse fly with dumbbells and resistance band, seated machines scapular retraction, bent over dumbbell row

”Rhomboideus

Rhomboideus minor is the small muscles of the back that vertebrae column to scapula.

Origin:

Nuchal ligaments and spines processes of C7-T1 vertebrae

Insertion:

Medial border of the scapula at the level of the spine of the scapula

Nerve supply:

Dorsal scapular nerve (C5)

Action:

Rhomboids with Middle fibers of trapezius retract (adduct) the scapula

It rotate the scapula downwards

It stabilize the scapula

Strengthening exercises:

Seated row machines, seated row with resistance band, reverse fly with dumbbells and resistance band, seated machines scapular retraction, bent over dumbbell row

Muscles of the shoulder

”Deltoid:”

The deltoid muscle is the large, most powerful and triangular muscles of the shoulder joint. It gives rounded appearance as it passing over the outer and upper part of the humerus.

The deltoid has three different sets of fibres:

Anterior or clavicular fibres, middle or lateral or acromial fibres and posterior or spinal fibres

Origin:

Anterior is originated from Lateral third of the clavicle,

Middle is originated from acromion and

Posterior fibres is originated from spine of the scapula

Insertion:

The deltoid tuberosity of the humerus

Nerve supply:

Axillary nerve

Action:

Anterior deltoid is flexors and medially rotators of the arm at shoulder

Middle deltoid is the powerful abduction of the arm at the shoulder.

Posterior deltoid is extensors and laterally rotators of the arm at the shoulder.

Strengthening exercises:

Push ups

Front arm lift, side arm lift with dumbbell or resistance band

Upright row with resistance band and barbell or dumbbell

Shoulder press machine

Seated back arm shoulder press, dumbbell shoulder press

Seated dumbbell press, seated lateral raise

Face pulls, behind neck barbell press, bent over laterals, cable side laterals,

Seated military press, dumbbell side laterals, bent over laterals raises, upright rows, smith machine overhead press, standing military press

Hang clean and press, upright barbell rows, overhead squat

Bent over row, one arm row- posterior deltoid

”Infraspinatus:”

Infraspinatus is one of the four rotator cuff muscles. The rotator cuff is a group of four muscles and tendons that are very essential for shoulder movement and maintain shoulder joint stability. The rotator cuff connects the scapula with upper arm.

Origin:

Infraspinous fossa of scapula

Insertion:

Middle part of Greater tubercle of the humerus

Nerve supply:

Suprascapular nerve (C5, C6)

Actions:

External rotator of arm at shoulder joint

It stabilizes the shoulder joint by holding the head of the humerus in glenoid fossa of scapula.

Daily activities:

Brushing hair

Strengthening exercises:

Lateral raises with dumbbell or resistance band

External rotation of shoulder with dumbbell

”Subscapularis:”

Subscapularis is one of the four rotator cuff muscles. The rotator cuff is a group of four muscles and tendons that are very essential for shoulder movement and maintain shoulder joint stability. The rotator cuff connects the scapula with upper arm.

Origin:

Subscapular fossa of the scapula

Insertion:

Lesser tuberosity of the humerus

Nerve supply:

Upper and lower subscapular nerves

Actions:

Internal rotators of arms

Weak Adductors of arms

It stabilizes the shoulder joint by holding the head of the humerus in glenoid fossa of scapula.

Strengthening exercises:

Internal rotation of shoulder with dumbbell or other weight

Muscles of the front arm

”Coracobrachialis:”

Origin:

Coracoids process of the scapula

Insertion:

Middle of medial border of the humerus

Nerve supply:

Musculocutaneous nerve

Actions:

Flexes the arm at shoulder

Weak adductor of arm

”Brachialis:”

Origin:

Lower half of anterior surface of humerus

Insertion:

Coronoid process of the ulna

Tuberosity of ulna

Nerve supply:

Musculocutaneous nerve (C5, C6).

Small Lateral part supplied by Radial nerve (C7)

Actions:

It is flexor of elbow with the forearm either prone or supine.

The brachialis is not attached to the radius, which cannot pronate and supinate the forearm. It purely flexes the elbow joint.

Strengthening exercises:

Biceps curl with weight and Chin ups

The back of upper arm muscles

”Triceps

The triceps has three heads and hence called as three headed muscle. It is large muscle of the back of the upper arm.

Origin:

Long head of triceps: infraglenoid tubercle of the scapula

Lateral head of triceps: posterior surface of humerus, above radial (spiral) groove

Medial head of triceps: posterior surface of humerus, below radial groove

Insertion:

Posterior part of proximal end of Olecranon process of the ulna

Nerve supply:

Radial nerve (C5, 6, 7, 8, T1)

Action:

Chief extensor of the forearm

Long head of triceps adducts the shoulder joints

It assists in shoulder extension

Long head steadies head of humerus while abducting the arm at shoulder joint

Strengthening exercises:

Triceps extension with dumbbell or resistance band

Triceps dips, triceps kick backs with dumbbell and bench press with a dumbbell

”Muscles

They are divided into superficial muscles and deep muscles.

Superficial muscles of the front of forearm:

1) Pronator teres

2) The flexor carpi radialis

3) The Palmaris longus

4) The flexor carpi ulnaris

5) The flexor digitorum superficialis also known as sublimus

”Pronator

It has two head: humeral head and ulnar head.

Origin:

Humeral head: medial epicondyle of the humerus

Ulnar head: medial side of the coronoid process of the ulna

Insertion:

Middle of lateral surface of the body of the radius

Nerve supply:

Median nerve

Actions:

Pronator of the forearm

Flexor of the forearm at elbow joint

Strengthening exercises:

Pronation with weight such as dumbbell or resistance band

”Palmaris

Palmaris longus is absent in around 10-14% of population and this absence does not affect the strength of grip. It is a very popular for use in tendon grafts.

Origin:

Medial epicondyle of the humerus

Insertion:

Distal ½ of Flexor retinaculum and palmar aponeurosis

Nerve supply:

Median nerve

Actions:

Flexors of the hand at wrist

Tightens the palmar aponeurosis

”Flexor

It is the largest and deepest muscles of the superficial muscles of the front of forearm. It has two head: humeroulnar head and radial head.

Origin:

humeroulnar head: medial epicondyle of the humerus and medial coronoid process of the ulna

Radial head: anterior surface of the radius

Insertion:

The muscle splits into 4 tendons and inserted to middle phalanges of the 2-5 (index, middle, ring and little fingers) fingers

Nerve supply:

Median nerve

Actions:

It is a strong flexor of the fingers at the proximal interphalangeal joints

It also Flexors of the metacarpophalangeal joints and wrist

Strengthening exercises:

Wrist flexion with dumbbell or resistance band

Deep muscles of the anterior forearm:

1) Flexor digitorum profundus

2) The flexor pollicis longus

3) The pronator quadratus

”Flexor

Origin:

Anterior surface of the radius and adjacent part of interosseous membrane, coronoid process of ulna

Insertion:

Palmar Base of distal phalanx of the thumb

Nerve supply:

Anterior interosseous nerve

Actions:

Flexor of the interphalangeal joint of thumb

It assists with flexion of wrist

”Muscles

The muscles are devided into superficial and deep muscles.

Superficial muscles of the back of forearms:

There are 7 muscles on back of forearm:

1) Anconeus

2) Brachioradialis

3) Extensor carpi radialis longus

4) Extensor carpi radialis bravis

5) Extensor digitorum

6) Extensor digiti minimi

7) Extensor carpi ulnaris

”Brachioradialis:”

Origin:

Proximal two third of lateral supracondylar ridge of the humerus

Insertion:

Lateral side of radius superior to the styloid process

Nerve supply:

Radial nerve

Actions:

Elbow flexion in midprone position of forearm

Pronation of forearm

Supination of forearm

Strengthening exercises:

Biceps curls in mid prone position with dumbbell or resistance band

Chin ups

”Extensor

Origin:

Lateral epicondyle of the humerus

Insertion:

Dorsal base of 2nd and 3rd metacarpal

Nerve supply:

Radial nerve

Actions:

Extensor of the wrist

Abduction (radial deviation) of the wrist

Daily use:

Typing

Strengthening exercises;

Wrist roller exercise

Wrist extension (reverse wrist curls) with dumbbell or resistance band

”Extensor

Origin:

Lateral epicondyle of the humerus

Insertion:

Dorsal base of the middle and distal phalanx of the little (5th) finger

Nerve supply:

Posterior interosseus branch of radial nerve

Actions:

Extensor of the little finger at the interphalangeal and metacarpophalangeal joint

It also assists in wrist extension

”Supinator:”

Origin:

Lateral epicondyle of humerus, annular and radial collateral ligament, posterior part of ulna

Insertion:

Lateral, anterior and posterior surface of upper third of the radius

Nerve supply:

Posterior interosseus nerve

Actions:

Supinator of the forearm

”Extensor

Origin:

Middle third of Posterior surface of the ulna and interosseous membrane

Insertion:

Dorsal base of the distal phalanx of the thumb

Nerve supply:

Posterior interosseous nerve

Actions:

Extensor of the distal phalanx

It assists with extensor of thumb at metacarpophalangeal and carpometacarapal joint

It assists with Extensor and abductor of the wrist

”Extensor

Origin:

Lower posterior surface of ulna and interosseous membrane

Insertion:

Ulnar side of the extensor digitorum at index finger

Nerve supply:

Posterior interosseous nerve

Actions:

Extensor of the index finger

It assists with extensor of wrist

List of Muscles acting on upper limb joints movement:

Shoulder joints
Shoulder movement Prime movers Synergistic muscles
flexion Clavicular head of pectoralis major Biceps brachii
Anterior deltoid coracobrachialis
extension Posterior deltoid Teres major
Latissimus dorsi Triceps (long head)
Pectoralis major
adduction Pectoralis major Teres major/teres minor
Latissimus dorsi Coracobrachialis
Biceps (short head)
Triceps(long head)
abduction Middle deltoid
Supraspinatus (0-15 degree)
Serratus anterior (above 90 degree)
Trapezius (upper and lower fibers) (above 90 degree)
Medial (internal) rotation Pectoralis major subscapularis
Anterior deltoid
Latissimus dorsi
Teres major
Lateral (external) rotation Posterior deltoid
Infraspinatus
Teres minor
Horizontal adduction Anterior deltoid
Pectoralis major
coracobrachialis
Horizontal abduction Latissimus dorsi Teres minor
Posterior deltoid infraspinatus
Muscles acting on scapular motion
Scapular actions muscles
Scapular retraction (scapular adduction) Rhomboideus major
Rhomboideus minor
Middle Trapezius
Scapular protraction (scapular abduction) Serratus anterior
Pectoralis minor (synergistic )
Pectoralis major (synergistic)
Scapular elevation Levator scapulae
Upper fibres of trapezius
Scapular depression Pectoralis minor
Lowe fibres of trapezius
subclavius
Latissimus dorsi
Scapular upward rotation Upper trapezius
Lower trapezius
Serratus anterior
Scapular downward rotation Pectoralis minor
Levator scapula
Rhomboidus major
Rhomboidus minor
Latissimus dorsi
Muscles acting on elbow joint
Elbow movement Prime movers Synergistic muscles
Elbow flexion Brachialis Pronator teres
Biceps brachii
brachioradialis
Elbow extension triceps anconeus
Muscles acting on radio-ulnar joints
Wrist movement Prime movers Synergistic muscles
flexion Flexor carpi radialis Flexor digitorum superficialis
Flexor carpi ulnaris Flexor digitorum profundus
Palmais longus Flexor pollicis longus
Abductor pollicis longus
Extensor Extensor carpi radialis longus Extensor digitorum
Extensor carpi radialis brevis Extensor indicis
Extensor carpi ulnaris Extensor pollicis longus
Extensor digiti minimi
Radial deviation (abduction) Flexor carpi radialis Extensor pollicis brevis
Extensor carpi radialis longus Abductor pollicis longus
Extensor carpi radialis brevis
Ulnar deviation (adduction) Flexor carpi ulnaris
Extensor carpi ulnaris

List of the muscles of lower limb

”Muscles

Iliacus:

The iliacus muscle lies in the iliac fossa.

Origin:

Iliac fossa of pelvis, iliac crest, anterior inferior iliac spine, base of sacrum

Insertion:

Lesser trochanter of the femur

Nerve supply:

Femoral nerve

Actions:

Powerful flexor of the thigh at hip joint

Bend trunk forward- from supine to sit up position

”Muscles

Sertorius:

Sartorius is the longest muscle of human body. It is thing and ribbon like thing muscle. It is very essential for tailors sit used in their work as cross legged position. it is known as tailor’s muscles where place the heel on the opposite knee. It is two joint muscles as it moves both knee and hip joint.

Origin:

Anterior superior iliac spine (ASIP) of hip bone and part of notch below ASIP

Insertion:

It runs obliquely down the thigh and reaches medial side of knee, and inserted at upper part of tibia, medial to the tibial tuberosity

Nerve supply:

Femoral nerve

Actions:

Abductor, flexor and lateral rotator of the thigh at hip joint

Flexors of the leg at knee joint

Assists with medial rotation of knee joint when the knee is flexed

”Vastus

Origin:

Upper intertrochanteric line, greater trochanter, lateral side of gluteal tuberosity, lateral linea aspera

Insertion:

Lateral Base of patella via ligamentum patellae

Nerve supply:

Femoral nerve

Actions:

Extensor of the leg at knee joint

”Vastus

Origin:

Anterior and lateral surface of femur

Insertion:

Base of patella via ligamentum patellae

Nerve supply:

Femoral nerve

Actions:

Extensor of the knee

Muscles of the medial thigh

”Adductor

Origin:

Superior aspect of pubis below pubic crest

Insertion:

Medial lip of linea aspera of femur

Nerve supply:

Obturator nerve

Actions:

Powerful Adductor of the hip

Assist with flexion and lateral rotation of the thigh

Strengthening exercises:

Hip adduction with weight

”Gracilis:”

Origin:

Pubic symphysis, infterior ramus of pubis and ischium

Insertion:

Upper medial surface of the tibia

Nerve supply:

Obturator nerve

Action:

Flexor of the thigh at hip joint

Medial rotator of the hip when knee is flexed

Assist with Flexor of the legs at knee joint

Weak adductor of the thigh at hip joint

Muscles of the Gluteal region:

”Gluteus

It is large and superficial muscles of the three gluteal muscles. It is a very vital during sitting to standing movement and maintains erect posture after sudden stopping.

Origin:

Posterior iliac crest, posterior lower sacrum, side of coccyx, posterior part of sacrotuberuous ligament

Insertion:

Gluteal tuberosity and iliotibial tract

Nerve supply:

Inferior gluteal nerve

Actions:

Main and powerful extensor of the thigh

Abductor and lateral rotator of the thigh

Stabilize the extended knee through the tighten iliotibial tract

Strengthening exercises:

Squat, lunges, hip thrust, deadlift, quadruped hip extension, step ups, four way hip extensions, hip extension with weight

”Gluteus

Gluteus medius and gluteus minimus maintain body balance when opposite foot is off the floor during walking and running activities. These both muscles prevent the opposite pelvis to drop down towards the floor. Weakness of these muscles can cause a trendelenburg gait that is abnormal gait where opposite hips fall down when weakness side foot on planted

Origin:

Outer surface of the ilium between anterior and inferior gluteal lines

Insertion:

Greater tronchanter of the femur

Nerve supply:

Superior gluteal nerve

Actions:

Abductors of the thigh at hip joint

Medially rotator of the thigh

”Gemellus

Origin:

Posterior ischial spine

Insertion:

Medial surface of greater trochanter

Nerve supply:

Nerve to obturator internus

Actions

Lateral rotator of the thigh at hip joint

Assists in Abductor of flexed thigh

Stabilize the hip joint and work as postural muscles

”Obturator

Origin:

Inner surface of the obturator membrane, body of ischium, ischial tuberosity, ischiopubic rami

Insertion:

Medial aspect of greater trochanter

Nerve supply:

Nerve to obturator internus

Actions:

Lateral rotator of the hip

Abduct the flexed thigh at hip joint

Stabilize the hip joint and work as postural muscle

”Obturator

Origin:

Lateral surface of obturator membrane and obturator foramen

Insertion:

Trochanteric fossa of gluteal region

Nerve supply:

Posterior division of obturator nerve

Actions:

Lateral rotator of the hip

Assists in adductor of the thigh

Muscles of the back of thigh

Back of the muscles are known as hamstring muscles. There are semitendinosus, semimembranosus, the long head of the biceps femoris and the ischial head of the adductor magnus

”Semitendinosus:”

It is known as one of hamstring muscles in the human body.

Origin:

The Ischial tuberosity

Insertion:

Upper medial surface of the tibia

Nerve supply:

Tibial part of sciatic nerve

Actions:

Main and powerful flexor of the knee

Weak extensor of the hip

Medial rotator of the leg when the knee is semiflexed

Medial rotator of the thigh when the hip is extended

”Biceps

Origin:

Long head: ischial tuberosity and sacrotuberous ligament

Short head: lateral lip of linea aspera of femur and upper lateral supracondylar ridge

Insertion:

Head of fibula (styloid process)

Lateral condyle of the tibia

Nerve supply:

Long head: tibial part of sciatic nerve

Short head: common peroneal part of the sciatic nerve

Actions:

Main and powerful flexor of the knee

Weak extensor of the hip

Lateral rotator of the leg when the knee is semiflexed

Lateral rotator of the thigh when the hip is extended

Muscles of the front of the leg

There are four muscles lies in front of the leg: the tibialis anterior, the extensor hallucis longus, the extensor digitorum longus, and the peroneus tertius

”The

Origin:

Lateral condyle of the tibia,

Superior half or more of lateral shaft of the tibia

Insertion:

Medial cuneiform and base of 1st metatarsal

Nerve supply:

Deep peroneal nerve

Actions:

Dorsiflexor and invertor of the foot at the ankle joint

Strengthening exercises:

Walking, toe raises

”Extensor

Origin:

Lateral tibial condyle

Upper three fourth of anterior surface of fibula

Interosseous membrane

Insertion:

Dorsal Base of middle and distal phalanges of toes 2-5

Nerve supply:

Deep peroneal nerve

Actions:

Dorsi flexor of the foot at the ankle joint

Extensor of 2-5 toes

Strengthening exercises:

Toe raises

”Peroneus

Origin:

Lower quater of medial shaft of fibula and interosseous membrane

Insertion:

Dorsal base of 5th metatarsal

Nerve supply:

Deep peroneal nerve

Action:

Dorsiflexor and evertor of the foot

Muscles of the lateral side of the leg

”Peroneus

Origin:

Head of fibula

Proximal half to two third of lateral shaft of the fibula

Intermuscular septa and few fibres from lateral condyle of tibia

Insertion:

Lateral base of the 1st metatarsal, medial cuneiform

Nerve supply:

Superficial peroneal nerve

Actions:

Evertor of the foot

It helps to support the transverse and longitudinal arches of the foot

Helps to maintain the stability of leg upon the foot, especially when standing on one leg

Assists in planter flexion of foot

Muscles of the back of the leg

Back of muscles are divided into superficial and deep muscles.

Superficial muscles of back leg: gastrocnemius, soleus and plantaris

Deep muscles of back of leg: popliteus, flexor digitorum longus, flexor hallucis longus and tibialis posterior

Superficial muscles of the back of leg:

”Gastrocnemius:”

It is very important in standing, walking, running and jumping activities.

The gastrocnemius is the largest, powerful and most superficial muscles of the back leg. It has two heads: medial and lateral head.

Origin:

Medial head: medial femoral condyle and knee joint capsule

Popliteal surface of femur superior to medial condyle

Lateral head: lateral femoral condyle and area above it and knee joint capsule

Insertion:

Posterior calcaneum via Achilles tendon

Nerve supply:

Tibial nerve

Actions:

Main and powerful planter flexors of the foot at the ankle joint

Flexor of the knee joint

Strengthening exercises:

Calf raises

”Plantaris:”

Origin:

Inferior lateral supracondylar line of femur and Popliteal surface superior to lateral condyle of femur

Insertion:

Posterior calcaneum

Nerve supply:

Tibial nerve

Actions:

Assists the gastrocnemius functions such as planter flexion of foot and knee flexion

Deep muscles of the back of leg:

”Popliteus:”

The popliteus is an unlocking muscle of the knee as it unlocks the knee during walking. It unlock by lateral rotating the femur upon tibia and medial rotating the tibia upon femur.

Lateral condyle of the femur, arcuate popliteal ligament and lateral meniscus

Insertion:

Posterior surface of tibia superior to soleal line

Nerve supply:

Tibial nerve

Actions:

Lateral rotator of the femur on the tibia during the initial stages knee flexion and unlock the knee joint

Medial rotator of the tibia when the knee is flexed

Flexor of the knee joint

Draw lateral meniscus back during knee flexion and hence prevent the meniscus from being crushed between condyles of the femur and the tibia

”Flexor

Origin:

Lower two third posterior surface of the fibula

The interosseus membrane

Insertion:

Plantar surface of Base of the distal phalanx of the big toe

Nerve supply:

Tibial nerve

Actions:

Planter flexor of the big toe

Assists in planter flexion of ankle joint

Stabilize the big toe while walking

Maintain medial longitudinal arch of foot

Weak invertor of the foot

List of Muscles acting on lower limbs joints movement:

Muscles acting on Hip Joint’s movement
Movement Prime movers Synergistic muscles
flexion Psoas major Pectineus
Iliacus Rectus femoris
Sartorius
Adductor longus
Adductor brevis
gracilis
Tensor fascia latae
extension Gluteus maximus
Semitendinosus
Semimembranosus
Biceps femoris
adduction Adductor longus Pectinus
Adductor brevis Gracilis
Adductor magnus
Abduction Gluteus medius Sartorius
Gluteus minimus Tensor fascia lata
Piriformis (with hip flexion)
Medial rotation Tensor fascia lata Part of adductor magnus
Anterior fibres of gluteus medius Semitendinosus
gluteus minimus Semimembranosus
Lateral rotaion Quadratus femoris Piriformis (with hip extension)
Gemellus inferior Biceps femoris
Gemellus superior Gluteus maximus
Obturator externus sartorius
Obturator internus
Muscles acting on knee joint
Movement Prime movers Synergistic muscles
flexion Biceps femoris Gracilis
Semitendinosus Sartorius
semimembranosus Popliteus
gastrocnemius
extension Quadriceps femoris:- Tensor fascia lata
Rectus femoris
Vastus medialis
Vastus lateralis
Vastus intermedius
Medial rotation in knee flexed Semimembranosus
Semitendinosus Gracilis
semimembranosus sartorius
popliteus
Lateral rotation in knee flexed Biceps femoris
Muscle acting on the ankle joint
muscles Prime movers Synergistic muscles
Dorsiflexion Tibialis anterior Extensor digitorum longus
Extensor hallucis longus
Peroneus tertius
Plantar flexion Gastrocnemius Plantaris
soleus Tibialis posterior
Flexor digitorum longus
Flexor hallucis longus
Inversion or adduction Tibialis anterior
Tibialis posterior
Eversion or abduction Peroneus longus
Peroneus brevis
Peroneus tertius

Muscle of the abdomen

”External

Origin:

External surface and lower border of the lower eight ribs

Insertion:

Upper fibers: The xiphoid process, linea Alba, anterior superior iliac spine, pubic symphysis and pubic crest, Lower fibers: external iliac crest

Nerve supply:

Ventral branches of lower six thoracic nerve (T7-T12)

Actions:

Bend the trunk forward and bring chest downwards, thus compress the abdomen and supports the abdominal viscera

Lateral flexion (side bend) of the trunk when one side of oblique muscle work (same side internal and external oblique)

Rotation of the trunk to opposite side with the help of opposite internal oblique

In short external oblique muscles bend the trunk same side and rotate it to opposite side.

Strengthening exercises:

Twisting crunches, twisting exercises in sitting, standing with weight

”Transversus

Origin:

Lateral third of inguinal ligament

Anterior internal iliac crest

Thoracolumbar fascia and lower six costal cartilages

Insertion:

Xiphoid process, Pubic crest, pectineal line, and linea Alba

Nerve supply:

Ventral branches of lower six thoracic nerve (T7-T12) and 1st lumbar nerve

Actions:

Compress the abdominal viscera and helps to obliques for forceful expulsive movement such as defecation and micturition.

The muscle stabilizes the core, pelvis and low back and thus it helps in maintenance of posture.

TrA plays the most important role in stabilizing core and the lower back before the extremities move. It stands for stability.

Strengthening exercises:

Plank,

Muscles of the posterior abdominal wall

”Quadratus

Origin:

Internal lip of iliac crest, L5 transverse process, and iliolumbar ligament

Insertion:

Transverse processes of the L1-L4, and lower part of 12 rib

Nerve supply:

Ventral rami of spinal nerve T12-L4

Actions:

Lateral flexor of trunk when pelvis if fixed

Extensor of the trunk when working both sides together

Assist in breath in (inspiration) by fixing the last rib

”Psoas

Origin:

Bodies and intervertebral disc of T12-L1 vertebrae and

Insertion:

Pectin pubis and iliopubic eminence

Nerve supply:

Branch of L1 spinal nerve

Actions:

Weak flexor of the trunk

Iliacus: see at lower limb muscles

Muscles of the face:

”Scalp

Occipitofrontalis:

It draws the scalp backward, and assists in raises the eyebrows and skin over nose, form wrinkles over the forehead. It also gives facial expression such as surprise, fear and horror.

Muscles around ears:

auricularis anterior, auricularis superior, auricularis posterior

Muscles around eyes:

Orbicularis oculi:

It is an important facial expression muscle of the face. It comprises of three parts: orbital part, palpebral part, and lacrimal part. Orbital part of orbicularis oculi close the eyelid tightly, palpebral part closes the eyelid gently, and lacrimal part helps in passing and draining of tears

Corrugators supercilii:

It draws the eyebrow medially and downward, forming vertical wrinkles of the forehead and producing frowning facial expression. It closes the eyelid tightly and show winking facial expression that protect lid from bright light.

Levator palpebrae superioris:

It opens the eyelid by elevating the upper eyelid

It retracts the upper eyelid

Nose muscles:

Procerus: it draw medial end of eyebrow downward and form transverse wrinkles over the nose. It aids in nostrils flaring and show angle expression of face.

Compressor naris, dilator naris, depressor septii

Muscles around the mounth:

orbicularis oris: it closes and purses the lips of mouth. It also whistling and aids in speech and mastication functions

Risorius: it retracts the angle of the mouth to produce grinning facial expression. It is known as laughing muscles

Zygomaticus major: it is facial expression muscle and bring angle of the mouth up and back to produce smile facial expression.

Levator labii superioris alaequae nasi: It dilates nostrils of the nose and elevates and everts the upper lips

Levator labii superioris: It elevates and everts the upper lip

Levator anguli oris: It elevates the angle of mouth

Depressor anguli oris: It depress angle of mouth laterally and aids in frowning facial expression.

Depressor labii inferioris: It depresses the lower lip down and laterally. It aids in sadness facial expression

Mentalis: It elevates and protrudes the lower lip and produce wrinkles at the chin and shows doubt facial expression.

Buccinators: It is the muscle of the cheek. It aids in mastication by flattening/compressiong the cheek against teeth. It also aids in puffing, blowing, whistling and sucking actions of the mouth

”Muscles

Surprise: frontalis

Smiling and laughing: zygomaticus major

Sadness: levator labii supeioris and lavatory anguli oris

Grief: depressor anguli oris

Anger: dilator naris and depressor septii

Frowning: corrugators supercilii and procerus

Horror, terror and fright: platysma

Doubt: mentalis

Grinning: risorius

Contempt: zygomaticus minor

Closes lids tightly, winking: orbicularis oculi

Closes and purses the mouth, whistling, : orbicularis oris

Frowning: corrugator supercilli

Side of the neck muscle:

“Sternocleidomastoid muscle (SCM):”

It is superficial muscle of the neck.
Origin:
Sternal head: proximal front of the manubrium sterni
Clavicular head: medial third of clavicle
Insertion:
Lateral part of mastoid process and lateral half of upper nuchal line (occipital bone)
Nerve supply:
Spinal accessory nerve
Action:
It laterally flexes the neck to the same side and rotates to the opposite side when working one side of muscle
It flexes (raise the head from a pillow) and extends (in forced inspiration0 the neck when working both sides of muscles together

Suboccipital muscles
The suboccipital muscles are situated below the occipital region.
Rectus capitis posterior major:
Origin:
Spine of the axis (C2) vertebrae
Insertion:
Outer part of inferior nuchal line of occipital bone and below the nuchal line
Nerve supply:
Suboccipital nerve
Actions:
Extend the head by working both side muscles together and rotates the face to same side by working one side muscle alone.

Rectus capitis posterior major:
Origin:
Posterior tubercle of the atlas (C1) vertebrae
Insertion:
Inner part of inferior nuchal line of occipital bone and below the nuchal line
Nerve supply:
Suboccipital bone
Actions:
Extend the head
Obliquus capitis superior:
Origin:
Transverse process of the atlas
Insertion:
Between superior and inferior nuchal line of occipital bone
Nerve supply:
Suboccipital bone
Actions:
Extend the head and bend the head

Obliquus capitis inferior
Origin:
Spinous process and lamina of the axis vertebrae
Insertion:
Transverse process of the atlas
Nerve supply:
Suboccipital nerve
Actions:
Rotates the face to the same side

Major muscles of the back

Erector spinae
It is muscles of the back and known as sacrospinalis muscles
Origin:
Crest of sacrum, spinous processes of the T11-L5, supraspinous ligament, posterior and medial lip of iliac crest
Insertion:
All ribs, transverse processes of the C1-T12 (all vertebrae)
Nerve supply:
Dorsal rami of C1-L5 (cervical, thoracic and lumbar) spinal nerve
Actions:
Extension of the spine
Side flexion of the spine
Strengthening exercises:
Back extension on a stability ball, bent over row, deadlift, hyperextension, good morning, pull up, rowing, squat, bridge

Multifidus
Multifidus is powerful muscle of the back that helps to supports to the spine. it helps to pressure off the intervetebral disc and equally distribute the weight on whole spine. this is the muscle that get contracted before any other muscle activate and protect spine
Origin:
Posterior sacrum, posterior superior iliac spine, mamillary processes (lumbar vertebrae), transverse processes of all thoracic vertebrae, articular processes C4-C7 vertebrae
Insertion:
Spinous process of C2-C4 vertebrae superior to its origin
Nerve supply:
Dorsal rami of spinal nerves
Actions:
Extension of the spine
Lateral flexion and rotation of the spine