AXILLA

LEYE OLABIYI

Anatomy Programme

Bowen University

Iwo

OUTLINE

• INTRODUCTION

• BOUNDARIES

• CONTENTS

• APPLIED ANATOMY

• END

INTRODUCTION

• 4-sided pyramidal space

– Lateral to the thoracic wall

– Inferior to the scapulo-humeral (Shoulder)

joint.

• Area of transition for structures to & fro the

upper limb

– Particularly for nerves and vessels.

• Colloquially referred to as the armpit.

• Important structures lie close together.

BOUNDARIES

The axilla is bounded by:

• Four walls

– Anterior

– Posterior

– Medial

– Lateral

It also has

-An Apex

-A Base

ANTERIOR WALL• Formed by Pectorales Ms.

– Pect major covers the whole wall

– Pect. Minor –the intermediate part• Enclosed in clavipectoral fascia

• Wider medially

POSTERIOR WALL• Formed by more muscles

– Above• Subscapularis

– Below• Teres major

• Latissimus dorsi

MEDIAL WALL• Formed by

– Ribs 1-4

– Intercoastal Mles in space 1-3

– Upper part of serratus anterior Mle

• Convex laterally

LATERAL WALL• Formed by-

– Intertubercular groove of humerus

– @ the meeting of the Ant. & Post. Walls

• Quite narrow

APEX• Corresponds to the interval between:

– Outer border of 1st rib- medially– Posterior surface of clavicle- anteriorly– Superior border of scapula -posteriorly

• Termed the Cervico-axillary canal

• Directed upwards into the root of the neck

BASE• Formed by:

– Skin– Subcutaneous tissue– Axillary fascia

• Directed downwards• Broad medially, Narrow laterally• Convex upwards• Forms the concavity of the armpit.

CONTENTS

◼ Vessels⚫ Axillary A. + Branches

⚫ Axillary V. + Tributaries

◼ Nerves⚫ Infraclavicular part of B. plexus +

Braches

◼ Lymph nodes/Vessels

◼ Muscles

◼ Fat

◼ Axillary Sheath

AXILLARY ARTERY

• Continuation of the subclavian artery.

• Begins @ the lateral border of the first rib and ends at the lower boader of the teres major.

• Divided to 3 parts by the Pectoralis minor. – How?

• The first part has one branch,

– Superior thoracic artery, • course down the thoracic wall

• supply

– the first two intercostals spaces

– the highest parts of the serratus anterior.

•

Cont’d…

• The second part has two branches:

– Thoracoacromial artery

• runs over the medial end of the pectoralis minor

• has four branches – Acromial

– Deltoid

– pectoral

– clavicular

– The lateral thoracic .

• Runs vertically along the surface of the serratus anterior.

• Supplies – Pectoralis muscles

– Serratus anterior

– Branches that supply the breast.

CONTD

• The 3RD part has 3 branches.

– The subscapular.

• The largest of the branches

• Runs vertically on the anterior surface of the subscapularis.

• Supplies

– subscapularis, teres major, serratus anterior and latissimus dorsi

• Branches

– Circumflex scapular (supplies the dorsum of the scapula)

– Thoracodorsal (primarily supplies the latissimus dorsi).

– The 2nd and 3rd branches – Anterior circumflex humeral

– Posterior circumflex humeral. » They surround the surgical neck of the humerus.

» The posterior artery runs with the axillary nerve.

Axillary Artery: divided

into three parts

Part 1 (proximal)

one branch

Part 2

(intermediate) two

branches.

Part 3 (distal) three

branches.

Subclavian A.

Brachial A.

Axillary Artery: First Part

From lateral border of 1st rib to

medial border of Pectoralis Major

M.Named Branch:

Supreme Thoracic

A. (to external

thoracic body wall)

Supplies blood to

first and second

intercostal spaces

Axillary Artery: Second part

Deep to the pectoralis minor M.

Thoracoacromial trunk

Branches to:

Clavicular area

Pectoralis region

Acromion of Scapula

Deltoid Muscle.

Lateral Thoracic Artery

Bbr. to Serratus Ant. M.

Axillary Artery: third part

Lateral border of Pectoralis minor M. to

lateral border of Teres major M.

Subscapular A.:

Branches:

Circumflex scapular

A. (to multiple

muscles associated

with the scapula)

1.

Thoracodorsal A.

(to Latissimus

dorsi M.)

2.

Posterior circumflex

humeral A.

Anterior circumflex

humeral A.

How it will look in lab

AXILLARY VEIN◼ Begins @ the lower border of the teres

major

◼ Anterior and medial to the Artery.

◼ Continuation of Brachial Vein

◼ Formed from the union of the brachial veins and the basilic vein.

◼ Ends at lateral border of 1st rib -the subclavian vein

◼ The cephalic vein enters the axillary vein close to its transition to subclavian vein

NERVES• BRACHIAL PLEXUS

– DIVISIONS

• 3 post. 3 ant. @ the

apex.

– CORDS

• Related to 2nd part of

axillary A.

– BRANCHES

• Musculocutaneous

• Radial

• Medial

• Ulnar

LYMPH NODES• Five principal groups.

– Apical, Pectoral (anterior), Humeral (lateral/brachial), Subscapular (posterior) and Central.

• The apical group• is found in the apex.

• Receives lymph from all other groups of axillary lymph nodes.

• The pectoral (anterior) nodes• lie along the medial wall

• Receive lymphatics from the lateral thoracic wall and lateral breast region.

• Drain to the central nodes and eventually to the apical group.

Cont’d…• The humeral (lateral or brachial) nodes

• found in the lateral wall along the distal part of the axillary vein.

• Receive almost all of the lymph from the upper limb

• Drain to the central nodes.

– The subscapular (posterior) nodes• lie along the posterior axillary fold

• drain to the central nodes.

– The central nodes• located in the center of the axilla.

• Receive lymph from the pectoral, subscapular, and humeral groups of the axillary lymph nodes and then pass the collected lymph to the apical group of nodes.

OTHERS

◼ MUSCLES

❑ Short head of biceps

❑ Subclavius

❑ Clavipectoral fascia

◼ FAT

❑ Nodes embedded in it.

◼ AXILLARY SHEATH

❑ Prolongation of the prevertebral layer of cervical fascia

❑ Covers Axillary A, Cords of B. plexus.

APPLIED ANATOMY

• Aneurysm of the Axillary Artery– This can result in compression of the trunks of the brachial plexus,

causing pain and loss of feeling or sensation (anesthesia) in the area supplied by the affected nerves.

• Injuries to the Axillary Vein– The axillary vein is large and is in an exposed position.

– This makes it susceptible to injury when the axilla is injured.

• Enlargement of the Axillary Nodes– When infections of the upper limb occur, the axillary lymph nodes

can become tender.

– Enlargement of the apical group of nodes may obstruct the cephalic vein superior to the pectoralis minor.

Cont’d….• Axillary Lymph Node Dissection

– The excision and pathologic analysis of the axillary lymph nodes is often required for staging and treatment of malignancies such as breast cancer.

– When a dissection of the axillary lymph node is done, the long thoracic nerve and the thoracodorsal nerves are in danger.

• Variations of the Brachial Plexus– Variations in the brachial plexus are common.

• Brachial Plexus Injuries– Affect movements and cutaneous sensations in the upper limb.

– Occur secondary to disease or trauma in the neck or axilla..

APPLIED ANATOMYCONTD.

• Brachial Plexus Block

◼ An injection of an anesthetic solution into the angle between the posterior border of the sternocleidomastoid and the clavicle.

◼ This surrounds the thin axillary sheet that contains the cords of the brachial plexus and axillary vessels.

◼ The anesthetic interrupts nerve impulses and produces anesthesia in the structures supplied by the branches of the cords of the plexus.

◼ This procedure, in combination with an occlusive tourniquet technique, helps surgeons to operate on the upper limb without using general anesthetic.

SCAPULAR ANASTOMOSIS

‘LEYE OLABIYI

ANATOMY DEPARTMENT

CMUL

SCAPULAR ANASTOMOSIS

• The scapular anastomosis is a system

connecting certain subclavian artery and

their corresponding axillary artery, forming

an anastomosis around the scapula. It

allows blood to flow past the joint in case

of occlusion, damage, or pinching of the

scapular arteries.

• transverse cervical artery

• dorsal scapular artery (the anastomosing

branch of the transverse cervical)

• transverse scapular artery

• branches of subscapular artery

• branches of thoracic aorta

• The transverse cervical artery gives off a

branch, the dorsal scapular artery, which

runs down the vertebral border of the

scapula to its medial edge and inferior

angle.

• The dorsal scapular artery anastomoses

with the subscapular artery, providing an

alternate route to the 3rd part of the

axillary artery in the event of a slowly

forming occlusion.

• The suprascapular artery branches off

from the thyrocervical trunk, which in turn

arises from the first part of the subclavian

artery.

• This suprascapular artery crosses over the

suprascapular ligament, passes through

the supraspinous fossa and turns around

the lateral border of the spine of the

scapula and supplies the infraspinous

fossa as far as the inferior angle.

• The subscapular artery branches from

the third part of the axillary and supplies

the subscapularis muscle in the

subscapular fossa as far as the inferior

angle.

• The subscapular artery gives off a

circumflex scapular branch that enters the

infraspinous fossa on the dorsal surface of

the bone, grooving the axillary border.

• These vessels anastamose to connect the

first part of the subclavian with the third

part of the axillary

• Providing a collateral circulation.

• This allows for blood to continue

circulating if the subclavian/axillary is

obstructed.

ARTERIAL SUPPLY OF UPPER LIMB

• Subclavian artery

• Axillary artery

• Brachial artery

• Radial artery

• Ulnar artery

• Superficial arterial arch

• Deep palmar arch

SUBCLAVIAN ARTERY

• Arises From:

– On Right; brachiocephalic trunk.

– On Left; arch of aorta.

• Extends from arch of aorta to lateral

border of first rib.

• Divided to 3 parts by the Scalenus anterior

•

AXILLARY ARTERY• Continuation of subclavian artery from lateral

border of first rib to lower border of teres major

muscle

• Divided to 3 parts by pectoralis minor

• Branches

• 1st part; Superior Thyroid artery

• 2nd part; Thoracoacromial and Lateral thoracic arteries

• 3rd part; Subscapular, Ant & post humeral circumflex

•

BRACHIAL ARTERY

• Continuation of axillary artery, From

inferior border of teres major 2 its

bifurcation in cubital fossa into radial and

ulnar arteries

• Branches

• Profunda brachii, Superior ulnar collateral

artery, Inferior ulnar collateral, Radial

Ulnar

SUPERFICIAL AND DEEP

PALMAR ARCH

• Superficial

• Direct continuation of ulnar artery

• Completed on the lateral side by

superficial palmar branch of radial

• Deep arch

• Direct continuation of radial artery

• Completed on medial side by deep palmar

branch of ulnar

ALLEN TEST

• To check patency of palmar arches

• One of these arteries is compressed after

blood has been forced out of the hand by

clenching it into a fist

• Failure of change of color of the hand

when opened indicates that the artery not

compressed is not patent

Branches

• Internal thoracic artery

• Vertebral artery

• Thyrocervical trunk

• (a) Suprascapular artery; forms

anastomosis around scapula

• (b) Transverse cervical

• (c) Inferior thyroid