1. Respiratory Anatomy

2. Muscles of Inspiration
Inspiration is a graded activity
quiet
forced
How does inspiration take place?
All Muscular
Thorax expansion (vertical expansion)-Diaphragm

3. Primary Muscle of Inspiration
Diaphragm:
Completely separates abdominal and thoracic cavities
Large inverted bowl
Attach at inferior boundary of rib cage, xiphoid process & posterior vertebral column
Intermediate region- central tendon (aponeurosis)
Muscle contracts muscle fibers shorten diaphragm pulls central tendon down & forward

4. Diaphragm Sternum Central Tendon Diaphragm Diaphragm Vertebral
Attachment

5. Diaphragm Vertebral Column Sternum Central Tendon Central Tendon
Position when
Contracted

6. Diaphragm Diaphragm Esophageal Hiatus Central Tendon L3 L4 Right Crus
of Vertebral
Attachment
Left Crus
of Vertebral
Attachment

7. Diaphragm (Superficial)

8. Primary Muscle of Inspiration
Diaphragm:
Innervation (nerves):
phrenic nerves (from cervical plexus; C3, C4, C5)
primary control by the autonomic nervous system (no choice)
voluntary control (holding breath)
bilateral innervation

9. Accessory Muscles of Inspiration
Anterior Thoracic
External intercostals
Interchondral portion, internal intercostals
Posterior Thoracic
Levatores costarum (brevis & longis)
Serratus posterior superior
Muscles of Neck
Sternocleidomastoid
Scalenus
Trapezius

10. Accessory Muscles of Inspiration
Muscles of the Thorax, Back, and Upper limb
Pectoralis major
Pectoralis minor
Serratus anterior
Subclavius

11. Accessory: External Intercostals
Run from lower border of one rib to the upper border of the rib below.
Fills the outside of the 11 spaces between the ribs (spareribs)
Pull all lower ribs toward the first rib-elevates rib cage
Second most important muscle of inspiration
Function to increase cavity size
Account for the A-P dimensional change in thorax

12. Accessory: Internal Intercostal (Interchondral Portion)
Mostly muscle of expiration BUT…
Chondral portion (parasternal) active during forced inspiration
Protective barrier for lungs & heart

13. Accessory: External intercostals
Internal Intercostals
External
Intercostals

14. Accessory: External intercostals

15. Accessory: Levator Costarum & Serratus Posterior Superior
Levatores
Costarum
Serratus Posterior
Superior
Latissimus Dorsi

16. Accessory: Levator Costarum
Rib elevators
Series of 12 small muscles
Each insert into rib just below the vertebrae from which it originates
Pulls up on ribs-weak (size, points of insertion gives poor leverage)
Brevis- “brief” originate transverse process of C7-T11 (12 total) (Inserts into next rib down)
Longis- originate transverse process of T7-T11 (by passes next rib down to insert into 2nd rib down from insertion)
Both course obliquely down & out

17. Accessory: Serratus Posterior Superior
Flat muscles, slanting down from neck
Originate from spinous process of C7 & T1-T3 and insert into 2nd-5th ribs
Course down & laterally
Larger than levatores, better angle of insertion
Lifts upper ribs
Stabilizes thorax for pull of external intercostals

18. Accessory: Latissimus Dorsi
Doubted involvement in respiration
Large flat muscle from upper arm to insert into lower back vertebrae
Some fibers insert into lower ribs
humerous movement contracts rib fibers & assists in expanding lower thorax

19. Accessory: Levator Costarum & Serratus Posterior Superior & Inferior

20. Accessory Neck Muscles: Sternocleidomastoid
Broad, thick muscle
Lies superficially in the lateral part of neck
Two head origination: anterior surface of manubrium sternum, sternal end of clavicle
Extends posteriorly & superiorly to insert in skull behind ear (mastoid process & temporal bone)
Function: Balance head & elevate sternum and raise anterior rib cage

21. Accessory: Sternocleidomastoid
Scaleni (Posterior)
Subclavius
Scaleni (Anterior)
Scaleni (Middle)

22. Accessory: Scaleni
Originate from cervical vertebrae & insert into 1st and 2nd ribs
Head balance, major force for raising & stabilizing the upper chest (ribs) of inhalation
Facilitate neck rotation, potential to increase superior-inferior dimensions of thorax

23. Accessory: Upper Arm & Shoulder: Pectoralis Major
Major- Fan-shaped muscle
Originates from 2 heads: sternal head (attached to sternum); Clavicular head (attached to front of clavical)
Inserts into the humerous of the upper arm
When fixed it assists in drawing sternum & ribs upward
Increases transverse dimension of rib cage

24. Accessory: Upper Arm & Shoulder: Pectoralis Minor
Fan shaped
Lies deep to the pectoralis major
Courses superiorly & laterally
Originates from scapula; inserts into 2nd-5th ribs
Function is to elevate the rib cage

25. Accessory: Serratus Anterior
Large; originates from scapula & inserts into the upper nine ribs
Elevates ribs
Serratus= “sawlike”
Coursing upward

26. Accesory: Pectoralis Major
& Minor
Pectoralis
Minor
Pectoralis
Major
Serratus
Anterior

27. Accesory: Pectoralis Major & Minor
Sternocleidomastoid
Pectoralis
Minor

28. Accessory: Serratus Anterior

29. Accessory: Subclavius
Courses under the clavicle obliquely & medially
Originates from inferior margin of the clavicle & inserts into superior surface of the first rib
Small muscle
Elevate first rib during inspiration

30. Accessory: Subclavius

31. Accessory: Trapezius Massive muscle; Upper back & neck
Originating from spinous process of C2 to T12 and insert into scapula and superior surface of clavicle
Function to elongate the neck and head control
Respiratory function; stability & balance for respiratory system

32. Accessory: Trapezius
Trapezius

33. Reading/Assignments Seikel: Ch.3 (Pgs. 80-98)
Dickson: Ch.3 (Pgs )