intercostal space

INTERCOSTAL SPACE

Dr Vandana RAsst prof ,Dept of Anatomy,Navodaya medical college

Raichur

CONTENTS

• DEFINITION• TYPICAL INTERCOSTAL SPACE• BOUNDARIES,PARTS & FEATURE OF SPACE• CONTENTS OF SPACE- MUSCLE,VESSELS &

NERVES.• APPLIED ANATOMY OF SPACE

RIB

Classification of Ribs

• TRUE = Ribs 1 -7– Vertebrosternal

ribs– Connected to

sternum by their costal cartilages

• FALSE = Ribs 8 -12 1. Vertebrochondral - Ribs 8-10

-connected by its costal cart to the cartilage of rib superior to it

2. Floating - Ribs 11-12- Unattached anteriorly

TypicalHave same featuresRibs 3 - 9

Atypical Ribs• Rib 1

– Broadest and most curved– Prominent scalene tubercle

for attachment of scalenus anterior muscle

• Rib 2– Thinner, less curved, longer– Has tuberosity for serratus

anterior• Rib 10

– Articulates w/ T10 vertebra only

• Rib 11 -12– Short, have single facet on

their heads– Have no NECK or TUBERCLE

INTERCOSTAL SPACE

INTERCOSTAL SPACEThe spaces between the ribs are called intercostals spaces. .

11Pairs of spaces,last two open

TYPICAL INTERCOSTAL SPACE

• BETWEEN TYPICAL RIBS AND TRAVERSED BY NERVES & VESSELS WHICH ARE CONFINED TO THORACIC WALL

• 3RD ,4TH ,5TH & 6TH SPACES ARE TYPICAL

BOUNDARIES

PARTS & FEATURES

CONTENTS

• MUSCLES

• VESSELS

• NERVES

INTERCOSTAL MUSCLES

External Intercostal Muscle• Most superficial• Fibers directed downward &

forward• OriginOrigin: from lower border of

the rib above• InsertionInsertion: upper border of

rib below• Extends from the rib

tubercle behind to the costo-chondral junction in front

• Deficient anteriorly & replaced by external external (anterior) intercostal (anterior) intercostal membranemembrane

Internal Intercostal Muscle

• Intermediate layer• Fibers directed

downward & backward• OriginOrigin: from sub7costal

groove of the rib above• InsertionInsertion: upper border

of rib below• Extends from the

sternum in front to the angle of the rib behind

• Deficient posteriorly & replaced by internal internal (posterior) intercostal (posterior) intercostal membranemembrane

S

costochondral junction

CC

V

anterior intercostal membrane &

external intercostal muscle

posterior intercostal membrane &

internal intercostal muscle

Angle of the rib

3. Innermost (Transversus thoracis) muscle

The deepest incomplete layer ,crosses more than one space.. Can be separated into 3 layers sternocostalis , subcostalis intercostalis intima

ACTION

. 1Muscles of respiration.

2. The muscle tone prevents the sucking in or blowing out of the tissues in the intercostals

VESSELS

ARTERIES

• Each intercostal space contains: A single posterior & Two anterior intercostal arteries

• Each artery gives off branches to the muscles, skin, parietal pleura (& breast)

ANTERIOR INTERCOSTAL ARTERIES

POSTERIOR INTERCOSTAL ARTERIES

VENOUS DRAINAGE

NERVES

INTERCOSTAL NERVES

• Twelve pairs• Are the anterior primary rami anterior primary rami of the thoracic thoracic

spinal nerves.spinal nerves.• 1-6 distributed in the intercostal spaces, 7-

11th supply the anterior abdominal wall• Anterior ramus of 1212thth nerve runs forward in

the abdomen as the subcostal nervesubcostal nerve

INTERCOSTAL NERVE

BRANCHES

• COMMUNICATING

• DISTRIBUTING

APPLIED ANATOMY

The Intercostal spaces are important access points for:

Surgical procedures, e.g. resection of (part of) the lung

Percussion and auscultation of underlying structures e.g. heart & lung

To obtain a sample of pleural fluid or drain pus/blood from the pleural cavity. The needle/drain is passed through the intercostal space just above the upper border of the rib to avoid the neurovascular bundle .