This is a presentation on muscles of thorax with their Origin, insertion, nerve supply & action. Hope it will help you guys. Thank you.

1. Muscles of Thorax
Origin, Insertion, Nerve supply and Action
Abid Hasan Khan

2. Presented by
Abid Hasan Khan
Roll no: 30
Year: 2nd
Session: 2015-16
Department of Physiotherapy
Bangladesh Health Professions Institute (BHPI),
CRP- Chapain, Savar, Dhaka – 1343.
Abid Hasan Khan

3. Surface Muscles (Anterior)
• Platysma
• Pectoralis major
• Pectoralis minor
• Subclavius
• Serratus anterior
Abid Hasan Khan

4. Platysma
Origin: Skin over lower neck and upper lateral chest.
Insertion: Inferior border of mandible and skin over lower face and
angle of mouth.
Nerve Supply: Cervical branch of
facial nerve (VII)
Action: Depresses and wrinkles skin of
lower face and mouth. Aids forced
depression of mandible
Abid Hasan Khan

5. Pectoralis major
Origin:
Clavicular Head: Anterior surface of the medial half of the clavicle.
Sternal Head: Lateral aspects of the manubrium and
body of the sternum, the upper six costal cartilages
and the aponeurosis of the abdominal oblique.
Insertion:
Clavicular Head: Lateral lip of the bicipital
groove of the humerus and anterior lip of
the deltoid tuberosity.
Abid Hasan Khan

6. Pectoralis major (Conts..)
Sternal Head: Lateral lip of the bicipital groove of the humerus and the
anterior lip of the deltoid tuberosity.
Nerve Supply: Medial pectoral nerve (C7, T1) and lateral pectoral nerve
(C5, 6, 7).
Action: Shoulder flexion, Internal rotation, Adduction.
Abid Hasan Khan

7. Pectoralis minor
Origin: Anterior surfaces of the third to fifth ribs.
Insertion: Via a tendon to the medial aspect of the coracoid process of
the scapula. Part or all of the tendon may
transverse this process and continue into
the coracoacromial ligament.
Nerve supply: Medial pectoral nerve (C7, T1)
Action: Scapula protraction, rotation of the
scapula downwards.
Abid Hasan Khan

8. Subclavius
Origin: From the junction of the first rib and its costal cartilage, just
anterior to the costoclavicular ligament.
Insertion: By muscular fibers to the groove on
the inferior surface of the middle of the clavicle.
Nerve supply: Subclavian branch of brachial plexus
(C5, C6).
Action: Depression of clavicle.
Abid Hasan Khan

9. Serratus anterior
Origin: Fleshy slips from the lateral aspect of the superior eight ribs and
anterior intercostal membranes from the midclavicular line, the lower
four slips interdigitating with external
abdominal oblique.
Insertion: Volar surface of the axillary
border of the scapula, spanning
the superior and inferior angles.
Abid Hasan Khan

10. Serratus anterior (Conts..)
Nerve supply: Long thoracic nerve (C5, 6, 7).
Action: Protracts and stabilizes scapula, assists in upward
rotation.
Abid Hasan Khan

11. Surface Muscles (Posterior)
• Latissimus dorsi
• Trapezius
• Rhomboideus major
• Rhomboideus minor
Abid Hasan Khan

12. Latissimus Dorsi
Origin: Spinous processes of thoracic T7-T12,
9th to 12th ribs, the lumbar and
sacral vertebrae (via the thoracolumbar fascia),
and the posterior third of the external
lip of the iliac crest. Occasionally
by a slip from the posterior surface of
the inferior angle of the scapula.
Abid Hasan Khan

13. Latissimus Dorsi (Cont..)
Insertion: Bottom of intertubercular (bicipital) groove of
humerus.
Nerve supply: Thoracodorsal nerve (C6 – C8).
Action: Extends, adducts, and medially rotates the arm; draws
the shoulder downward and backward; keeps inferior angle of
scapula against the chest wall; accessory muscle of
respiration.
Abid Hasan Khan

14. Trapezius
Origin:
Upper part: External occipital proturberance,
medial third of the superior nuchal line, the
ligamentum nuchae, and the spinous
process of C7.
Medial Part: Spinous processes of T1 to T5.
Lower Part: Spinous processes of T6 to T12.
Abid Hasan Khan

15. Trapezius (Cont..)
Insertion:
Upper Part: Lateral third of the clavicle and the medial aspect of the
acromion process of the scapula.
Middle Part: Medial edge of the superior surface of the acromion
process of the scapula and the superior edge of the scapular spine.
Lower Part: Tubercles of the apex of the scapular spine.
Nerve supply: Spinal Accessory Cranial XI , Ventral Rami C2-C4.
Action:
Upper Part: Upward rotation of the scapula, elevation of the scapula
Middle Part: Retraction of the scapula.
Lower Part: Upper rotation of the scapula, depression of the scapula.
Abid Hasan Khan

16. Rhomboideus major
Origin: Spinous processes of T2 – T5.
Insertion: Vertebral border of the scapula,
from inferior to the scapular spine to
the inferior angle.
Nerve supply: Vertebral border of the scapula,
from inferior to the scapular spine to
the inferior angle.
Action: Retraction of the scapula, downward
rotation of the scapula.
Abid Hasan Khan

17. Rhomboideus minor
Origin: Ligamentum Nuchae and the spinous
processes of C7 and T1.
Insertion: Vertebral border of the scapula,
adjacent to the scapular spine.
Nerve supply: Dorsal scapular nerve C5.
Action: Retraction of the scapula,
downward rotation of the scapula.
Abid Hasan Khan

18. Intercostal Muscles
External Intercostals
Origin: Lower margin of upper eleven ribs.
Insertion: Superior border of rib below
(each muscle fiber runs obliquely and
inserts toward the costal cartilage).
Nerve supply: Intercostal nerves.
Action: Draw ventral part of ribs upward,
increasing the volume of the thoracic cavity
for inspiration.
Abid Hasan Khan

19. Intercostal Muscles (Conts..)
Internal Intercostals
Origin: From the cartilages to the angles of
the upper eleven ribs.
Insertion: Superior border of the rib below
(each muscle fiber runs obliquely and
inserts away from the costal cartilage).
Nerve supply: Intercostal nerves.
Action: Draw ventral part of ribs downward,
decreasing the volume of the thoracic cavity
for expiration.
Abid Hasan Khan

20. Rotator Cuff Muscles
• Supraspinatus
• Infraspinatus
• Teres Minor
• Subscapularis
Abid Hasan Khan

21. Supraspinatus
Origin: Supraspinous fossa of scapula.
Insertion: Superior facet of greater
tubercle of humerus.
Nerve supply: Suprascapular nerve (C5,6).
Action: Abduction of arm and stabilizes
Humerus.
Abid Hasan Khan

22. Infraspinatus
Origin: Infraspinous fossa of the scapula.
Insertion: Middle facet of greater tubercle
of the humerus.
Nerve supply: Suprascapular Nerve (C5, 6).
Action: External rotation of arm, stabilizes
Humerus.
Abid Hasan Khan

23. Teres Minor
Origin: On the dorsal surface of the middle
half of the lateral border of the scapula.
Insertion: The lowest of the three facets of
the greater tubercle of the humerus.
Nerve supply: Axillary nerve (C5,6).
Action: Externally rotates the arm.
Abid Hasan Khan

24. Subscapularis
Origin: Medial two-thirds of volar surface
of the scapula.
Insertion: Lesser tubercle of humerus.
Nerve supply: Upper and Lower Subscapular
Nerve (C5,6).
Action: Internally rotates humerus; Assists
with depression of the humeral head.
Abid Hasan Khan

25. Thank You
Abid Hasan Khan