Muscles of head, Muscles of face, Muscles of neck, Muscles of shoulder girdle, Muscles of upper limbs, Muscles of thorax, Diaphragm, Muscles of abdomen, Muscles of back, Muscles of perineum, Muscles of pelvis, Muscles of lower limb, Muscles of leg, Muscles of foot

1. Muscular system
Presented by
Ms.P.Pavithra.,M.Pharm
Assistant Professor,
Dept. of Pharmacology,
SVCP

2. Introduction
 The muscular system consist of a large number of muscles (more than 300).
They bring about various movements in the body.
 Muscles are attached to bones, cartilages, ligaments, skin or other muscles by
fibrous structure called tendons or aponeurosis.
 Tendon is a cord like structure whereas aponeurosis is a thin fibrous sheet.
 Muscles are richly supplied by blood vessels and nerves.
 Each muscle has an origin and an insertion.
 Origin is the end which remains stationary when the muscle contracts.
 The end which moves is called insertion.
 But it is not the same in all cases.
 In some cases, both ends of the muscle may move.

3. Muscles of head, Face and Neck
They are classified into the following main groups:
1. Muscles of scalp : Occipito frontalis is the muscle of the scalp.
It consist of two parts
i. Occipital belley: which is situated under the skin of occipital bone.
ii. Frontal belley: which is situated under the skin of frontal bone.
Contraction of this muscle produces wrinkles in the forehead and raising of eye brows.

4. Muscles of head, Face and Neck……
2. Muscles of facial expressions : They are
i. Orbicularis oculi which are circular muscles around the eye. They produce closing
of the eyes.
ii. Orbicularis oris which is present in the lips. It closes the lips.
iii. Buccinator----the muscles of cheek . It is used in chewing and sucking.

5. 3. Muscles of mastication : They are:
i. Temporal muscles arising from temporal fossa of skull.
ii. Masseter muscle arising from zygomatic arch of temporal bone.
These muscles control the movements of lower jaw. They are involved in chewing.
Muscles of head, Face and Neck……

6. 4. Muscles of neck : They attach the head to trunk.
They are :
i. Platysma which extends from lower jaw to deep fascia of chest. It depresses the jaw.
ii. Sterno- mastoid which extends from sternum and clavicle below to mastoid process of
skull.
iii. Trapezius which arises from occipital bone and spine of all thoracic and cervical
vertebrae. It is inserted in to clavicle and also spine and acromion process of scapula.
iv. Scalene muscles which extend from cervical vertebrae to the first two ribs.
Muscles of head, Face and Neck……

7. Muscles of shoulder girdle
1. Deltoid muscle which is commonly used for intra-muscular injections. It extends
from scapula and clavicle to deltoid tuberosity of humerus. Its action is to abduct the
shoulder.
2. Supraspinatus which extends from supraspinous fossa of scapula to the greater
tuberosity of humerus. Its action is to abduct the humerus.

8. Muscles of shoulder girdle
3. Infraspinatus which extends from infraspinous fossa of scapula to the greater
tuberosity of humerus. It also produces abduction of humerus.
4. Subscapularis muscle which lies in the subscapular fossa. It produces medial
rotation of humerus.

9. Muscles of upper limbs
Muscle of arm: They are:
1. Biceps containing two heads. The long head arises from the
upper part of glenoid cavity. The short head arises from
corocoid process. It is inserted into bicipital tubercle of radius.
Its movement are:
 Supination of forearm
 Flexion of elbow joint
 Forward movement of shoulder joint
2. Brachialis which lies deep to biceps. It runs from humerus
to ulna. It assists biceps in flexing the elbow.
3. Triceps which contains three heads. It passes from scapula
to olecranon fossa of ulna. It extends the elbow joint.

10. Muscles of forearm
 They can be grouped into anterior muscles and posterior muscles.
 Anterior muscles: They are
1. Flexor digitorum sublimus which is a superficial muscle. Its actions
are flexion of
i. Fingers
ii. Wrist joint
iii. Elbow joint
2. Flexor digitorum profundus, a deep muscle. Its actions are flexion of
wrist and fingers.
3. Flexor carpi radialis and flexor carpi ulnaris which extends from
humerus to the wrist bones. These muscles flex the elbow and wrist.
4. Prontor teres, pronator quadratus and brachio radialis which
produce pronation and supination.

11. Muscles of forearm
Posterior muscles: They are
1. Extensor digitorum communis which extends from lateral epicondyle of
humerus to elbow joint. It extends the elbow joint.
2. Extensor muscles of fingers which are attached to the back of the bases of
terminal phalanges.
3. Thenar eminence is a prominence situated at the base of the thumb.
4. Hypothenar eminence is a prominence present at the base of little finger and
ulnar side of hand.

12. Muscles of Thorax
1. Pectoralis major which forms the anterior part of chest and axilla. It arises from the
anterior aspect of sternum, ribs and costal cartilages. It is inserted into the upper end of
humerus.
2. Pectoralis minor which lies deep to pectoralis major. Its origin is similar to pectoralis
major. But it is inserted into corocoid process of scapula.

13. Muscles of Thorax
3. Serratus anterior which extends from ribs to vertebral border of scapula.

14. Muscles of Thorax
4. Intercostal muscles (11 pairs) which extend between the lower and upper border of
two successive ribs. These muscles contain two layers. They are:
 External intercostals which pass downward and forward.
Internal intercostals which pass upward and forward.

15. Diaphragm
 Muscles of Thorax-Diaphragm.
 It is a large, dome-like partition which separates the
abdomen from thorax. It can be divided into three parts:
i. Sternal or front part –attached to lower end of sternum.
ii. Costal or lateral part – attached on either side to lower
six ribs.
iii. Vertebral or posterior part-attached to the first two
lumbar vertebrae.

16. Diaphragm
It has two surfaces. They are
i. An upper surfaces which is related to
Pericardium in the center
Base of lungs on either side
ii. A lower surface which is related to
Liver at the center and on the right side
Fundus of stomach and spleen on the left side
It has three openings which allow the passage of
i. Aorta at the center
ii. Inferior vena cava on the right side
iii. Oesophagus on the left side

17. Muscles of Abdomen
Anterior abdominal wall:
It is composed of
1.) Rectus abdominis which are two muscles lying one on each side. They are
separated in the middle by linea alba which is a thin fibrous tissue. It arises from
xiphoid process and adjacent costal cartilages. It is inserted into the upper border
of pubis.

18. Muscles of Abdomen…...
2.) External oblique which arises from the
lower eight ribs. Its fibres run downwards and
forwards. It is inserted into rectus sheath, spine
of pubis, anterior aspect of iliac crest.
3.) Internal oblique which arises from iliac
crest. Its fibres pass upwards and medially. It is
inserted into rectus sheath, lower ribs.
4.) Transversus abdominis which runs
horizontally across the anterior abdominal
wall.

19. Muscles of Abdomen…...
Posterior abdominal wall:
It is made up of
1.) Quadratus lumborum which extends from iliac crest to the 12th rib.
2.) Iliacus which arises from iliac fossa. It is inserted into the lesser trochanter of femur.
3.) Psoas which arises from lumbar vertebrae. It is inserted with iliacus into the lesser
trochanter of femur.

20. Muscles of the back
1.) Latissimus dorsi muscle which arises from vertebral column and crest of ilium.
It is inserted into humerus.
2.) Levator scapulae muscle which arises from the first four cervical vertebrae. It
is inserted into the scapula.

21. Muscles of the back……
3.) Rhomboids made of rhomboideus major and rhomboideus minor. They extended
from cervical and thoracic vertebrae to scapula.
4.) Sacrospinalis which extends from sacrum to skull.

22. Muscles of Perineum
1.) External anal sphincter which is around the anus.
2.) Sphincter urethrae which surrounds the urethra.
3.) Bulbocavernous, a sphincter at the base of penis in males. It helps in the
erection of penis by preventing venous drainage.
4.) Ischiocavernous in females. It constricts the vaginal orifice.

23. Muscles of pelvis
The pelvic floor is formed mainly by levator ani and coccygeus muscles.
Levator ani is the important muscle of defecation.

24. Muscles of lower limb
Muscles of buttock: They are
• Gluteus maximus
• Gluteus medius
• Gluteus minimus
They arise from the outer surface of ilium and inserted into greater trochanter
of femur.

25. Muscles of thigh:
A.) Anterior muscles:
It includes
i.) Quadriceps femoris made of four muscles: Rectus femoris, vastus medialis,
vastus intermedius, vastus laterlais. Ligamentum patellae is the single tendon formed
by these four muscles. Patellae is embedded within this tendon. It is inserted into the
tuberosity of tibia. Its action is to extend knee joint.
ii.) Sartorius which extends from ilium to the tuberosity of tibia.

26. Muscles of thigh:
B.) Medial muscles:
They include
• Adductor longus
• Adductor brevis
• Adductor magnus
They arise from pubic bone and inserted into linea aspera
of bone.
Action: Adduction of thigh.

27. Muscles of thigh:
C.) Posterior muscles:
They are
• Biceps
• Semitendinosus
• Semimembraneous
These three muscles together are called as hamstring
muscles. They extend from the tuberosity of ischium
to the upper ends of tibia and fibula.
• Action: Extension of hip and flexion of knee.

28. Muscles of leg
A.) Anterior muscles:
They include
• Tibialis anterior which extends from tibia to tarsal bones. Its action is to
dorsiflex the ankle.
• Extensor digitorum longus which arises from the anterior surface of
fibula. It divides into four tendons which are inserted into the metatarso-
phalangeal joints of the lateral four toes. It produces extension of toes.

29. B.) Posterior muscles:
They include
i.) Gastrocnemius which arises from the condyles of femur. Along with the tendon of soleus,
it forms a strong tendon called tendo calcaneus. This tendon is inserted into calcaneum.
ii.) Soleus which arises from the posterior aspects of tibia and fibula. By means of tendoo
calcaneous, it is inserted into calcaneum.
iii.) Tibialis posterior which arises from tibia and fibula. It is inserted into tarsal bones.
iv.) Flexor digitorum longus which arises from posterior surface of fibula, It is inserted into
distal phalanx of big toe.

30. C.) Peroneal or fibrous muscles:
They are peroneus longus and peroneus brevis. They arise from the lateral
surface of fibula. They are inserted into tarsal and metatarsal bones of foot.
Action: Evertion or turning the foot outwards.

31. Muscles of foot
Some leg muscles concerned with the movements of toes are helped by foot
muscles. Flexor digitorum brevis is the flexor of big toe. Flexor hallucis brevis is
the flexor of other toes. In addition, there are a few short muscles of the sole
which are attached to big toe. Interosseus and lumbrical muscles also exist for the
toes.