Transcript Muscles and Neurovasculature Of the THORAX

By Chris Sevilla
 Muscles
of the thoracic wall
- Pectorals
- Serratus anterior
- Intercostal muscles
 Mechanism of respiration
 Intercostal veins, arteries and nerves
 VAN bundle
Clavicular head
Most superficial
 Origin:

Clavicular head-anterior medial half
of clavicle
 Sternocostal head- sternum and
upper 6 costal cartilages

Insertion: Lateral lip of
intertubercular sulcus of humerus
 Innervation: Medial AND lateral
pectoral nerves (C5-8, T1)
 Action: Adducts and medially
rotates humerus. CH flexes
humerus, SH extends from flexed
position

Sternocostal
head
 Deep
to Pec major
 Origin: anterior surfaces of
ribs III-V
 Insertion: coracoid process
of the scapula
 Innervation: Medial
pectoral nerves only (C8T1)
 Action: Stabilises scapula
by drawing it anteriorly and
inferiorly.
 Origin:
External surfaces of
ribs 1-8.
 Insertion: Anterior surface of
medial scapula border.
 Innervation: Long thoracic
nerve (C5-C7)
 Action: Protracts scapula
Muscle
Origin
Insertion
Innervation Action
Pectoralis Major
Clavicular headanterior medial
half of clavicle
Sternocostal
head- sternum
and upper 6 costal
cartilages
Lateral lip of
intertubercular
sulcus of humerus
Medial AND
lateral pectoral
nerves (C5-8, T1)
Adducts and
medially rotates
humerus. CH
flexes humerus,
SH extends from
flexed position
Pectoralis
Minor
anterior surfaces
of ribs III-V
coracoid process
of the scapula
Medial pectoral
nerves only (C8T1)
Stabilises scapula
by drawing it
anteriorly and
inferiorly.
Serratus anterior
External surfaces
of ribs 1-8.
Anterior surface
of medial scapula
border.
Long thoracic
nerve (C5-C7)
Protracts scapula
 For
breathing
 Located between ribs
 Innervated by
corresponding thoracic
nerves (T1-T11)
 External
- Anteroinferior direction
- Action: Contract during
forced INSPIRATION and raise
the ribs
 Internal
and innermost
- Posteroinferior direction
- Action: Contract during
forced expiration and lower
the ribs
 Pump
-
handle movement
Increases anteriorposterior dimension.
Sternum moves up and
forwards.
 Bucket
-
handle
movement
Increases transverse
dimension.
Shafts of ribs elevate.
 Anterior
intercostal vv
drain into
internal
thoracic vein.
 Posterior
intercostal vv
drain into
azygos/hemiazygos vein

Internal thoracic
arteries give rise
to anterior
intercostal aa.

Thoracic aorta
and
costocervical
trunks gives rise
to posterior
intercostal aa
Internal thoracic aa and
costocervical trunks are branches of
the subclavian artery
 Dermatome

area of skin
supplied by a
single spinal nerve
 Myotome

the muscles
supplied by a
single spinal nerve
Intercostal aa, vv and nn in the intercostal
space.
 Lies in costal groove of superior rib.
 In between internal and innermost intercostal
muscles.

 Chest
drain/Thoracentesis
 Need to remove blood,
fluid/air from pleural
cavity.
 Insert needle close to
inferior rib to avoid
damaging VAN bundle







The pectoralis major is the largest and most superficial muscle of
the thoracic wall. It is responsible for adducting and medially
rotating the humerus.
The pectoralis minor is a small muscle that allows protraction of
the scapula.
The serratus anterior is innervated by the long thoracic nerve and
is responsible for protracting the scapula.
The intercostal muscles are responsible for respiration by moving
the ribs. These movements are known as the pump and bucket
handle movements.
The external intercostal muscles have fibres that run in the
anteroinferior direction. The other two run in the posteroinferior
direction.
The blood supply of the thoracic wall is from the internal
thoracic aa/vv anteriorly and the aorta/azygos system
posteriorly.
The VAN bundle consists of the intercostal aa/vv/nn running in
the costal groove of the superior rib.
Pectoralis major has 2 heads: a clavicular head and a sternocostal head.
True!
The lateral pectoral nerve innervates pectoralis minor.
False! The MEDIAL pectoral nerve does this!
The pump handle movement increases the A/P diameter of the thorax.
True!
The thoracic aorta provides arterial supply to the anterior thoracic wall.
False! It supplies the posterior thoracic wall!
The VAN bundle lies in the costal groove of the inferior rib.
False! They DO lie in the costal groove, but of the SUPERIOR rib. BEWARE!
Some exam questions ARE this picky!
 Either
Gray’s Anatomy or Moore’s Clinically
Oriented Anatomy.
 An anatomy atlas (e.g. Netter’s, McMinns)
 CAL packages on Moodle
 Aclands Video Atlas of Human Anatomy
(access via UoN library NUSearch)
 Moore,
K., Agur, A., Daley, A.(2011)
Essential Clinical Anatomy.4th Edition.
Chapter 1: Thorax.
 Drake, L. Vogl, W. Gray’s Anatomy for
Students. 2nd Edition. Chapter 3.
 Netter’s
anatomy
 Google images
 Any
questions? Email me at
[email protected]