The pectoral region and the axilla pdf - Upper limb

Basic Anatomy

335

Skin 380

Fascial Compartments of the

Forearm 382

The Region of the Wrist 394

Structures on the Anterior Aspect of

the Wrist 394

Structures on the Posterior Aspect of

the Wrist 396

The Palm of the Hand 397

Skin 397

Deep Fascia 398

The Palmar Aponeurosis 398

The Carpal Tunnel 398

Fibrous Flexor Sheaths 398

Synovial Flexor Sheaths 399

Insertion of the Long Flexor

Tendons 400

Small Muscles of the Hand 400

Short Muscles of the Thumb 400

Short Muscles of the Little Finger 400

Arteries of the Palm 402

Veins of the Palm 403

Lymph Drainage of the Palm 403

Nerves of the Palm 404

Fascial Spaces of the Palm 404

Pulp Space of the Fingers 405

The Dorsum of the Hand 405

Skin 405

Dorsal Venous Arch (or Network) 406

Insertion of the Long Extensor

Tendons 406

The Radial Artery on the Dorsum of the

Hand 406

Joints of the Upper Limb 406

Elbow Joint 406

Proximal Radioulnar Joint 408

Distal Radioulnar Joint 409

Wrist Joint (Radiocarpal Joint) 410

Joints of the Hand and Fingers 411

The Hand as a Functional Unit 412

Radiographic Anatomy 418

Radiographic Appearances of the Upper

Limb 418

Surface Anatomy 418

Anterior Surface of the Chest 418

Suprasternal Notch 418

Sternal Angle (Angle of Louis) 418

Xiphisternal Joint 418

Costal Margin 418

Clavicle 418

Ribs 419

Deltopectoral Triangle 419

Axillary Folds 419

Axilla 419

Posterior Surface of the Chest 425

Spinous Processes of Cervical and

Thoracic Vertebrae 425

Scapula 425

The Breast 425

The Elbow Region 426

The Wrist and Hand 426

Important Structures Lying in Front of

the Wrist 426

Important Structures Lying on the

Lateral Side of the Wrist 426

Important Structures Lying on the Back

of the Wrist 428

Important Structures Lying in the

Palm 428

Important Structures Lying on the

Dorsum of the Hand 428

C H A P T E R

nant cells along the lymph vessels to the lymph nodes in the

importance because of the frequent development of cancer in

The basic anatomy of the breast is of considerable clinical

index finger and the unique ability of the thumb to be drawn across

much function as possible. The pincer action of the thumb and

deserve particular attention because the goal is to preserve as

are commonly seen by the physician. Wrist and hand injuries

Pain, fractures, dislocations, and nerve injuries of the upper limb

O B J E C T I V E S

■

the palm to the other fingers must be preserved at all costs.

■

A physician must be familiar with the nerves, bones, joints,

tendons, and blood and lymphatic vessels and their anatomic

relationships.

■

the glands and the subsequent dissemination of the malig-

armpit.

■

The primary concern of this chapter is to present to the student

the basic anatomy of the upper limb so that as a practicing

medical professional he or she will be able to make an accurate

diagnosis and initiate prompt treatment.

C H A P T E R O U T L I N E

(continued)

natomy

asic

The upper limb is a multijointed lever that is freely

secrete milk (Fig. 9.1). They are present in both sexes. In

The breasts are specialized accessory glands of the skin that

Location and Description

be overemphasized.

is largely into the armpit. Their clinical importance cannot

ral region and their blood supply and lymphatic drainage

cally part of the upper limb; they are situated in the pecto

The breasts, although strictly speaking, are not anatomi

of the trunk with the arm), arm, elbow, forearm, wrist, and

The upper limb is divided into the shoulder (junction

finger.

one to grasp objects between the thumb and index

on the pincer-like action of the thumb, which enables

the hand. Much of the importance of the hand depends

distal end of the upper limb is the important organ,

movable on the trunk at the shoulder joint. At the

hand.

The Pectoral Region and the Axilla

The Breasts

-
-

336

CHAPTER 9

increase in length and branching in the duct system

In the early months of pregnancy, there is a rapid

Early

Pregnancy

The Upper Limb

(Fig. 9.2). The secretory alveoli develop at the ends of the

axillary tail

the superficial fascia. A small part, called the

the midaxillary line. The greater part of the gland lies in

to 6th rib and from the lateral margin of the sternum to

sition of fat. The base of the breast extends from the 2nd

the increased size of the glands is mainly from the depo

the ovarian hormones (Fig. 9.1). The ducts elongate, but

assume their hemispherical shape under the influence of

At puberty in females, the breasts gradually enlarge and

Puberty

extend beyond the margin of the areola.

tem of ducts embedded in connective tissue that does not

The breast tissue consists of a sys

areola.

skin called the

are small and surrounded by a colored area of

nipples

The

males and immature females, they are similar in structure.

of ovarian estrogens and progesterone.

lous. The atrophy after menopause is caused by the absence

The breasts tend to shrink in size and become more pendu

The amount of adipose tissue may increase or decrease.

of the secretory alveoli disappear, leaving behind the ducts.

After the menopause, the breast atrophies (Fig. 9.2). Most

Postmenopause

color.

areola fades, but the area never lightens to its original

nearly to their original size. The pigmentation of the

thickens. The breasts and the nipples shrink and return

of them disappear. The interlobular connective tissue

milk is absorbed, the secretory alveoli shrink, and most

the breasts return to their inactive state. The remaining

Once the baby has been weaned,

Postweaning

colostrum.

with the fluid secretion called

mostly because of the distention of the secretory alveoli

process slows. The breasts, however, continue to enlarge,

During the second half of pregnancy, the growth

Late

active.

epidermis. The areolar glands enlarge and become more

a result of increased deposits of melanin pigment in the

and the areola becomes darker and more extensive as

nourishment for the developing gland. The nipple enlarges,

of the connective tissue also increases to provide adequate

expanding and budding secretory alveoli. The vascularity

smaller ducts, and the connective tissue becomes filled with

(Fig. 9.1), extends upward and laterally, pierces the deep

from a circular base.

In young women, the breasts tend to protrude forward

Young Women

(Fig. 9.1).

retromammary space

breasts is a space filled by loose connective tissue called the

(Fig. 9.1). Behind the

suspensory ligaments

that serve as

The lobes of the gland are separated by fibrous septa

areolar glands.

tubercles on the areola are produced by the underlying

(Fig. 9.1). Tiny

areola

the nipple is surrounded by the

just before its termination. The base of

ampulla

dilated

separately on the summit of the nipple and possesses a

out from the nipple. The main duct from each lobe opens

which radiate

lobes,

Each breast consists of 15 to 20

and enters the axilla.

fascia at the lower border of the pectoralis major muscle,

lactiferous ducts

ampulla

nipple

areola

tubercles

lobes

fibrous septa

adipose tissue

clavicle

rib

pectoralis minor

pectoralis major

retromammary space
filled with loose
areolar tissue

skin

fibrous septa-
suspensory ligaments

adipose tissue

areola

nipple

ampulla

lactiferous duct
of lobe of
mammary gland

axillary tail

FIGURE 9.1

Mature breast in the female.

The axillary tail, which pierces the deep fascia and extends into the axilla.

Sagittal

Anterior view with skin partially removed to show internal structure.

section. C.

Basic Anatomy

uated along the course of the posterior intercostal arter

drain posteriorly into the posterior intercostal nodes (sit

lymph vessels follow the posterior intercostal arteries and

ity along the course of the internal thoracic artery). A few

thoracic group of nodes (situated within the thoracic cav

that pierce the intercostal spaces and enter the internal

muscle). The medial quadrants drain by means of vessels

just posterior to the lower border of the pectoralis major

rior axillary or pectoral group of nodes (Fig. 9.3) (situated

The lateral quadrants of the breast drain into the ante

nodes.

of the malignant cells along the lymph vessels to the lymph

of cancer in the gland and the subsequent dissemination

clinical importance because of the frequent development

The lymph drainage of the mammary gland is of great

Lymph Drainage

The veins correspond to the arteries.

Veins

lateral thoracic and thoracoacromial branches.

arteries. The axillary artery also supplies the gland via its

branches of the internal thoracic artery and the intercostal

The branches to the breasts include the perforating

Arteries

337

Blood Supply

-
-

ies); some vessels communicate with the lymph vessels

abdominal wall.

of the opposite breast and with those of the anterior

female before puberty

female at puberty

young and adult male

female, first half

of menstrual cycle

female, second half

of menstrual cycle

pregnant female

lactating female

female after cessation
of lactation

female after menopause

FIGURE 9.2

eoli in the breasts in both sexes at different stages of

Extent of the development of the ducts and secretory alv

lates with the sternum and 1st costal cartilage medially and

across the root of the neck just beneath the skin. It articu

The clavicle is a long, slender bone that lies horizontally

Clavicle

joint.

which articulate with one another at the acromioclavicular

The shoulder girdle consists of the clavicle and the scapula,

activity.

Bones of the Shoulder Girdle

and Arm

with the acromion process of the scapula laterally (Fig. 9.5).

Witch’s Milk in the Newborn

The condition is resolved spontaneously as the maternal hor

may be expressed from the nipples.

witch’s milk,

fluid, called

in both sexes during the first week of life; in some cases a milky

hormones cross the placental barrier and cause proliferation

While the fetus is in the uterus, the maternal and placental

of the duct epithelium and the surrounding connective tissue.

This proliferation may cause swelling of the mammary glands

mone levels in the child fall.

C L I N I C A L N O T E S

Basic Anatomy

339

permits pathologic examination of the lymph nodes for possible

tasize into the thorax through the small amount of intervening

in the early stages. However, the prognosis is relatively poor

tumor can usually be felt with the flat of the examining hand

Since the amount of breast tissue in the male is small, the

cinomas of the breast. This fact tends to be overlooked when

metastases.

Carcinoma in the Male Breast

Carcinoma in the male breast accounts for about 1% of all car-

examining the male patient.

in the male, because the carcinoma cells can rapidly metas-

tissue.

Development of the Breasts

Unilateral or bilateral enlargement of the male breast occasionally

is recognized as a circular pigmented area of

month, the

At the fifth

which grow into the underlying mesenchyme. Meanwhile, the

becomes slightly depressed, and sends off 15 to 20 solid cords,

small part in the pectoral region. This localized area thickens,

along this ridge. In the human, the ridge disappears except for a

inguinal region. In animals, several mammary glands are formed

which extends from the axilla obliquely to the

In the young embryo, a linear thickening of ectoderm appears

called the milk ridge,

underlying mesenchyme proliferates, and the depressed ecto-

dermal thickening becomes raised to form the nipple.

areola

skin around the future nipple.

Polythelia
Supernumerary nipples occasionally occur along a line corre-

sponding to the position of the milk ridge. They are liable to be

mistaken for moles.

Retracted Nipple or Inverted Nipple
Retracted nipple is a failure in the development of the nipple

during its later stages. It is important clinically, because normal

suckling of an infant cannot take place, and the nipple is prone to

infection (see also page 338).

Micromastia
An excessively small breast on one side occasionally occurs,

resulting from lack of development.

Macromastia
Diffuse hypertrophy of one or both breasts occasionally occurs

at puberty in otherwise normal girls.

Gynecomastia

occurs, usually at puberty. The cause is unknown, but the condi-

tion is probably related to some form of hormonal imbalance.

E M B R Y O L O G I C N O T E S

pectoralis major

apical lymph nodes

pectoralis minor

central
lymph nodes

internal thoracic
lymph nodes

anterior axillary

or pectoral lymph

nodes

FIGURE 9.3

Lymph drainage of the breast.

340

CHAPTER 9

The Upper Limb

skin

glandular tissue supported
by connective tissue

dense
fibrous
septa

nipple

FIGURE 9.4

Mediolateral mammogram showing the glandu

the 7th thoracic vertebra.

subject and marks the level of the 7th rib and the spine of

of the scapula can be palpated easily in the living

rior angle

infe

below (Fig. 9.5). The

infraspinous fossa

above and an

supraspinous fossa

scapula is divided by the spine into the

The posterior surface of the

subscapular fossa.

the shallow

The anterior surface of the scapula is concave and forms

(Fig. 9.7).

suprascapular notch

coracoid process is the

ment for muscles and ligaments. Medial to the base of the

and forward above the glenoid cavity and provides attach

projects upward

coracoid process

the shoulder joint. The

which articulates with the head of the humerus at

fossa,

glenoid cavity,

angle of the scapula forms the pear-shaped

which articulates with the clavicle. The superolateral

mion,

acro

ward. The lateral end of the spine is free and forms the

projects back

spine of the scapula

its posterior surface, the

the posterior chest wall between the 2nd and 7th ribs. On

The scapula is a flat triangular bone (Fig. 9.7) that lies on

in Figure 9.6.

muscles and ligaments attached to the clavicle are shown

and its lateral third is concave forward. The important

The medial two thirds of the clavicle is convex forward

axial skeleton and provides attachment for muscles.

trunk. It also transmits forces from the upper limb to the

The clavicle acts as a strut that holds the arm away from the

lar tissue supported by the connective tissue septa.

Scapula

coracobrachialis and
short head of biceps

supraspinatus

subscapularis

long head of triceps

pectoralis major

latissimus dorsi

teres major

deltoid

coracobrachialis

brachialis

brachioradialis

extensor carpi radialis longus

common flexor tendon

pronator teres

serratus anterior

pectoralis minor

pectoralis major

pectoralis minor

deltoid

teres

minor

common extensor tendon

FIGURE 9.5

vicle, scapula, and humerus.

Muscle attachments to the bones of the thorax, cla

Fractures of the Clavicle

fracture of the bone. This may be the cause of persistent pain

pectoralis major. The medial end is tilted upward by the sterno

move freely on the trunk. Unfortunately, because of its position,

The clavicle is a strut that holds the arm laterally so that it can

it is exposed to trauma and transmits forces from the upper limb

to the trunk. It is the most commonly fractured bone in the body.

The fracture usually occurs as a result of a fall on the shoulder

or outstretched hand. The force is transmitted along the clavicle,

which breaks at its weakest point, the junction of the middle and

outer thirds. After the fracture, the lateral fragment is depressed

by the weight of the arm, and it is pulled medially and forward by

the strong adductor muscles of the shoulder joint, especially the

cleidomastoid muscle.

The close relationship of the supraclavicular nerves to the

clavicle may result in their involvement in callus formation after

over the side of the neck.

Compression of the Brachial Plexus, Subclavian

Artery, and Subclavian Vein by the Clavicle

The interval between the clavicle and the first rib in some patients

may become narrowed and thus is responsible for compression

of nerves and blood vessels. (See discussion of thoracic outlet

syndrome on page 39.)

C L I N I C A L N O T E S

capsule of sternoclavicular joint

trapezius

deltoid

sternocleidomastoid

pectoralis major

capsule of acromioclavicular joint

superior surface

articular surface for acromium

deltoid

subclavius

pectoralis major

coracoclavicular ligament

costoclavicular
ligament

articular surface for
sternum and first costal cartilage

inferior surface

FIGURE 9.6

Important muscular and ligamentous attachments to the right clavicle.

deltoid

acromion

short head of biceps
and coracobrachialis

supraglenoid
tubercle

long head of biceps

glenoid fossa

lateral border

anterior surface

inferior angle

subscapularis

serratus anterior

suprascapular
notch

suprascapular
ligament

superior angle

coracoclavicular ligament

coracoid process

pectoralis minor

articular surface for clavicle

levator scapulae

supraspinatus

supraspinous
fossa

rhomboid minor

rhomboid major

infraspinous fossa

infraspinatus

latissimus dorsi

inferior angle

teres major

lateral border

teres minor

long head of
triceps

capsule of
shoulder joint

glenoid fossa

acromion

coracoid process

coracoacromial ligament

posterior surface

superior angle

trapezius

spine of scapula

deltoid

medial border

infraglenoid tubercle

subscapular fossa

long head of triceps

FIGURE 9.7

Important muscular and ligamentous attachments to the right scapula.

341

342

CHAPTER 9

scapula are shown in Figure 9.7.

The important muscles and ligaments attached to the

The Upper Limb

Fractures of the Scapula

Fractures of the scapula are usually the result of severe

trauma, such as occurs in run-over accident victims or in

occupants of automobiles involved in crashes. Injuries are

usually associated with fractured ribs. Most fractures of

the scapula require little treatment because the muscles

on the anterior and posterior surfaces adequately splint the

serratus anterior. Such imbalance can be detected by careful

as in dropped shoulder, which occurs with paralysis of the tra

fragments.

Dropped Shoulder and Winged Scapula

The position of the scapula on the posterior wall of the thorax

is maintained by the tone and balance of the muscles attached

to it. If one of these muscles is paralyzed, the balance is upset,

pezius, or winged scapula (Fig. 9.8), caused by paralysis of the

physical examination.

C L I N I C A L N O T E S

FIGURE 9.8

Winging of the right scapula.

glenoid cavity of the scapula. Immediately below the head

forms about one third of a sphere and articulates with the

(Fig. 9.9), which

head

upper end of the humerus has a

joint and with the radius and ulna at the elbow joint. The

The humerus articulates with the scapula at the shoulder

Humerus

anatomic neck

supraspinatus

greater tuberosity

surgical neck

bicipital groove

pectoralis major

deltoid tuberosity

deltoid

brachialis

lateral supracondylar ridge

brachioradialis

extensor carpi radialis longus

radial fossa

lateral epicondyle

capitulum

trochlea

capsule of elbow joint

common flexor tendon

medial epicondyle

pronator teres

coronoid fossa

medial
supracondylar ridge

coracobrachialis

teres major

latissimus dorsi

subscapularis

lesser tuberosity

head

capsule of shoulder joint

anterior surface

capsule of

shoulder joint

spiral groove

medial head of triceps

trochlea

anconeus

olecranon fossa

capsule of elbow joint

deltoid

lateral head of triceps

teres minor

infraspinatus

posterior surface

common extensor tendon

FIGURE 9.9

Important muscular and ligamentous attachments to the right humerus.

Basic Anatomy

the upper part of the arm and the side of the chest

The axilla, or armpit, is a pyramid-shaped space between

humerus are shown in Figure 9.9.

The important muscles and ligaments attached to the

elbow joint is extended (Fig. 9.9).

which receives the olecranon process of the ulna when the

olecranon fossa,

ulna. Above the trochlea posteriorly is the

the same movement receives the coronoid process of the

which during

coronoid fossa,

trochlea anteriorly is the

the head of the radius when the elbow is flexed. Above the

which receives

radial fossa,

Above the capitulum is the

articulation with the trochlear notch of the ulna (Fig. 9.9).

for

trochlea

the head of the radius, and the pulley-shaped

for articulation with

capitulum

ligaments, the rounded

for the attachment of muscles and

lateral epicondyles

medial

The lower end of the humerus possesses the

(Fig. 9.9).

which accommodates the radial nerve

spiral groove,

Behind and below the tuberosity

deltoid tuberosity.

lateral aspect of the shaft is a roughened elevation called

About halfway down the

surgical neck.

shaft is a narrow

Where the upper end of the humerus joins the

ital groove.

separated from each other by the

lesser tuberosities,

and

greater

Below the neck are the

anatomic neck.

343

is the

bicip-

the
is a

and

The Axilla

(Fig. 9.11). It forms an important passage for nerves,

pectoralis minor muscles (Figs. 9.12, 9.13, and 9.14)

By the pectoralis major, subclavius, and

Anterior wall:

The walls of the axilla are made up as follows:

Walls of the Axilla

(Fig. 9.11).

the teres major muscle), and medially by the chest wall

lary fold (formed by the tendon of latissimus dorsi and

the pectoralis major muscle), behind by the posterior axil

the anterior axillary fold (formed by the lower border of

is bounded in front by

(Fig. 9.11). The lower end, or

scapula, and medially by the outer border of the first rib

in front by the clavicle, behind by the upper border of the

is directed into the root of the neck and is bounded

apex,

the neck to the upper limb. The upper end of the axilla, or

blood, and lymph vessels as they travel from the root of

base,

■

Fractures of the Proximal End of the Humerus

on the irregular bony surface after the bone fragments are

cess of the fracture (in the callus), or can undergo irritation

forcibly abducted. The ulnar nerve can be injured at the time

medial collateral ligament of the elbow joint if the forearm is

The medial epicondyle (Fig. 9.10) can be avulsed by the

on the brachial artery can occur at the time of the fracture or

occur when the child falls on the outstretched hand with the

Supracondylar fractures (Fig. 9.10) are common in children and

the insertion of the deltoid muscle (Fig. 9.10). When the fracture

The surgical neck of the humerus (Fig. 9.10), which lies immedi

shoulder joint has been reduced. In this situation, open reduction of

in the greater tuberosity remaining displaced posteriorly after the

dislocation, severe tearing of the cuff with the fracture can result

dons form part of the rotator cuff. When associated with a shoulder

natus muscle. The bone fragment will have the attachments of the

trauma, displaced by the glenoid labrum during dislocation of the

The greater tuberosity of the humerus can be fractured by direct

Humeral Head Fractures
Fractures of the humeral head (Fig. 9.10) can occur during the

process of anterior and posterior dislocations of the shoulder

joint. The fibrocartilaginous glenoid labrum of the scapula pro-

duces the fracture, and the labrum can become jammed in the

defect, making reduction of the shoulder joint difficult.

Greater Tuberosity Fractures

shoulder joint, or avulsed by violent contractions of the supraspi-

supraspinatus, teres minor, and infraspinatus muscles, whose ten-

the fracture is necessary to attach the rotator cuff back into place.

Lesser Tuberosity Fractures
Occasionally, a lesser tuberosity fracture accompanies poste-

rior dislocation of the shoulder joint. The bone fragment receives

the insertion of the subscapularis tendon (Fig. 9.10), a part of the

rotator cuff.

Surgical Neck Fractures

ately distal to the lesser tuberosity, can be fractured by a direct

blow on the lateral aspect of the shoulder or in an indirect man-

ner by falling on the outstretched hand.

Fractures of the Shaft of the Humerus

Fractures of the humeral shaft are common; displacement of

the fragments depends on the relation of the site of fracture to

line is proximal to the deltoid insertion, the proximal fragment

is adducted by the pectoralis major, latissimus dorsi, and teres

major muscles; the distal fragment is pulled proximally by the

deltoid, biceps, and triceps. When the fracture is distal to the

deltoid insertion, the proximal fragment is abducted by the del-

toid, and the distal fragment is pulled proximally by the biceps

and triceps. The radial nerve can be damaged where it lies in

the spiral groove on the posterior surface of the humerus under

cover of the triceps muscle.

Fractures of the Distal End of the Humerus

elbow partially flexed. Injuries to the median, radial, and ulnar

nerves are not uncommon, although function usually quickly

returns after reduction of the fracture. Damage to or pressure

from swelling of the surrounding tissues; the circulation to the

forearm may be interfered with, leading to Volkmann’s ischemic

contracture (see page 383).

of the fracture, can become involved later in the repair pro-

reunited.

C L I N I C A L N O T E S

344

CHAPTER 9

The Upper Limb

anatomic neck

head

surgical neck

shaft of humerus

coronoid
fossa

medial
epicondyle

trochlea

lateral epicondyle

radial fossa

deltoid tuberosity

olecranon process

trochlear notch

coronoid process

bicipital tuberosity

shaft of ulna

head

styloid process

shaft of radius

head

greater tuberosity

SUB

capitulum

FIGURE 9.10

among these structures in the axilla is an important nerve

the trunk, down as far as the level of the umbilicus. Lying

from the upper limb and the breast and from the skin of

and lymph vessels and lymph nodes, which drain lymph

and its tributaries, which drain blood from the upper limb;

which supply blood to the upper limb; the axillary vein

The axilla contains the axillary artery and its branches,

Contents of the Axilla

armpit.

and joins the fascial floor of the

ligament of the axilla

suspensory

muscle and then continues downward as the

and 9.14). Below, it splits to enclose the pectoralis minor

tissue that is attached above to the clavicle (Figs. 9.13

The clavipectoral fascia is a strong sheet of connective

Clavipectoral Fascia

divide it into three parts (see page 350).

of nerves. It is used when describing the axillary artery to

ula. It crosses the axillary artery and the brachial plexus

inserted by its apex into the coracoid process of the scap

3rd, 4th, and 5th ribs and runs upward and laterally to be

beneath the pectoralis major (Fig. 9.13). It arises from the

The pectoralis minor is a thin triangular muscle that lies

Pectoralis Minor

Key Muscles in the Axilla

Tables 9.1, 9.2, and 9.3.

muscles forming the walls of the axilla are described in

The origins, insertions, nerve supply, and actions of the

the upper limb and many lymph nodes.

The axilla contains the principal vessels and nerves to

rior and posterior walls (Fig. 9.14).

is formed by the skin stretching between the ante

The

in the bicipital groove of the humerus (Figs. 9.14, 9.15,

By the coracobrachialis and biceps muscles

Lateral wall:

(Figs. 9.14, 9.15, and 9.16)

costal spaces covered by the serratus anterior muscle

By the upper four or five ribs and the inter

Medial wall:

9.14, 9.15, and 9.16)

and teres major muscles from above down (Figs. 9.13,

By the subscapularis, latissimus dorsi,

Posterior wall:

major; CF, pull of common flexure muscles; TR, triceps; SUB, subscapularis.

bony fragments on the site of the fracture line and the pull of the muscles. S, supraspinatus; D, deltoid; PM, pectoralis

Common fractures of the radius and ulna. The displacement of the

Common fractures of the humerus. B.

■

and 9.16)

base

Basic Anatomy

345

superior border of scapula

deltoid

serratus anterior

first rib

clavicle

sternum

inlet from above

pectoralis

major

posterior wall

lateral wall

outlet

inlet

medial wall

anterior wall

subscapularis

teres major

latissimus dorsi

humerus

pectoralis
major

serratus anterior

outlet

walls

fourth rib

scapula

clavicle

stern

rom above

ctoralis

major

posterior wall

lateral wall

outlet

inlet

medial wall

anterior wall

subscapularis

teres major

latissimus dorsi

rus

pectoralis
major

serratus anterior

fourth rib

scapula

FIGURE 9.11

Inlet, walls, and outlet of the right axilla.

346

CHAPTER 9

The Upper Limb

cephalic vein

deltoid

acromium

trapezius

supraclavicular nerves

sternocleidomastoid

external oblique aponeurosis

lateral thoracic artery

long thoracic nerve

serratus anterior

intercostobrachial nerve

teres major

latissimus dorsi

subscapularis

medial cutaneous nerve of arm

axillary vein

axillary artery

long head of triceps

biceps and
coracobrachialis

clavicle

manubrium sterni

body of sternum

pectoralis major

cutaneous branches of
intercostal nerves

xiphoid process

FIGURE 9.12

Pectoral region and axilla.

pectoralis major

musculocutaneous nerve

median nerve

nerves to the triceps

radial nerve

posterior cutaneous nerve of arm

axillary nerve

ulnar nerve

lower subscapular nerve

subscapularis

middle subscapular nerve

latissimus dorsi

long thoracic nerve

lateral thoracic artery

pectoralis minor

clavipectoral fascia

lateral pectoral nerve

manubrium sterni

thoracoacromial
artery

subclavius

cephalic vein

supraclavicular nerves

sternocleidomastoid

trapezius

coracoclavicular ligament

coracoacromial ligament

greater tuberosity

deltoid

coracobrachialis

FIGURE 9.13

Pectoral region and axilla; the pectoralis major muscle has been removed to display the underlying structures.

Basic Anatomy

347

long thoracic nerve

anterior intercostal membrane

levator scapulae

trapezius

dorsal scapular nerve

suprascapular nerve

lateral cord of brachial plexus

musculocutaneous

nerve

radial nerve

axillary nerve

subscapular nerves

thoracodorsal nerve

subscapular artery

subscapularis

serratus anterior

external intercostal muscle

short head of biceps

coraco-brachialis

medial head of triceps

long head of triceps

pectoralis major

deltoid

pectoralis minor

axillary vein

subclavius muscle

C5
6

7
8
T1

nerve to subclavius

FIGURE 9.15

Pectoral region and axilla; the pectoralis major and minor muscles and the clavipectoral fascia have been

removed to display the underlying structures.

clavicle

subclavius

clavipectoral fascia

axillary

artery

pectoralis minor

suspensory

ligament

deep fascia of armpit

anterior wall

subscapularis

latissimus dorsi

teres major

posterior wall

long thoracic nerve

serratus

medial wall

pectoralis minor

pectoralis major

serratus anterior

scapula

teres major

coracobrachialis

biceps

bicipital groove

of humerus

lateral wall

pectoralis

major

FIGURE 9.14

Structures that form the walls of the axilla. The lateral wall is indicated by the arrow.

348

CHAPTER 9

The Upper Limb

Muscles Connecting the Upper Limb to the Thoracic Wall

T A B L E 9 . 1

Muscle

Origin

Insertion

Nerve Supply

Nerve Roots

Action

Pectoralis major

Clavicle, sternum,

and upper six

costal cartilages

Lateral lip of

bicipital groove

of humerus

Medial and lateral

pectoral nerves from

brachial plexus

C5, 6, 7, 8; T1

Adducts arm and rotates

it medially; clavicular

fibers also flex arm

Pectoralis minor

3rd, 4th, and

5th ribs

Coracoid process

of scapula

Medial pectoral nerve

from brachial plexus

C6, 7, 8

Depresses point of

shoulder; if the scapula

is fixed, it elevates the

ribs of origin

Subclavius

1st costal cartilage

Clavicle

Nerve to subclavius

from upper trunk of

brachial plexus

C5, 6

Depresses the clavicle

and steadies this bone

during movements of

the shoulder girdle

Serratus anterior

Upper eight ribs

Medial border

and inferior

angle of

scapula

Long thoracic nerve

C5, 6, 7

Draws the forward

anterior around the

thoracic wall; rotates

scapula

The predominant nerve root supply is indicated by boldface type.

musculocutaneous
nerve

short head
of biceps

long head of biceps

median
nerve

subscapular
artery

subscapularis

latissimus
dorsi

RIGHT SIDE

tendon of pectoralis major (reflected)

tendon of pectoralis minor (cut)

lateral chord of
brachial plexus

coracoid process

clavicle

axillary artery

axillary vein (cut)

subclavius

manubrium
sterni

body of
sternum

lateral thoracic
artery

thoracodorsal
nerve

serratus anterior

external
oblique

FIGURE 9.16

ascia have been

Dissection of the right axilla. The pectoralis major and minor muscles and the clavipectoral f

removed to display the underlying structures.

Basic Anatomy

349

Muscles Connecting the Upper Limb to the Vertebral Column

T A B L E 9 . 2

Transverse processes

Trapezius

Muscle

Origin

Insertion

Nerve Supply

Nerve Roots

Action

Occipital bone,

ligamentum nuchae,

spine of 7th cervical

vertebra, spines of all

thoracic vertebrae

Upper fibers into

lateral third of

clavicle; middle and

lower fibers into

acromion and spine

of scapula

Spinal part of

accessory

nerve (motor)

and C3 and 4

(sensory)

XI cranial

nerve (spinal

part)

Upper fibers elevate

the scapula; middle

fibers pull scapula

medially; lower fibers

pull medial border of

scapula downward

Latissimus

dorsi

Iliac crest, lumbar fascia,

spines of lower six

thoracic vertebrae,

lower three or four

ribs, and inferior angle

of scapula

Floor of bicipital

groove of humerus

Thoracodorsal

nerve

C6, 7, 8,

Extends, adducts, and

medially rotates the

arm

Levator

scapulae

of 1st four cervical

vertebrae

Medial border of

scapula

C3 and 4 and

dorsal

scapular

nerve

C3, 4, 5

Raises medial border of

scapula

Rhomboid

minor

Ligamentum nuchae and

spines of 7th cervical

and 1st thoracic

vertebrae

Medial border of

scapula

Dorsal scapular

nerve

C4, 5

Raises medial border of

scapula upward and

medially

Rhomboid

major

Second to 5th thoracic

spines

Medial border of

scapula

Dorsal scapular

nerve

C4, 5

Raises medial border of

scapula upward and

medially

The predominant nerve root supply is indicated by boldface type.

Muscles Connecting the Scapula to the Humerus

T A B L E 9 . 3

Teres minor

Teres major

Muscle

Origin

Insertion

Nerve Supply

Nerve Roots

Action

Deltoid

Lateral third

of clavicle,

acromion, spine

of scapula

Middle of lateral

surface of shaft

of humerus

Axillary nerve

C5, 6

Abducts arm; anterior fibers

flex and medially rotate

arm; posterior fibers extend

and laterally rotate arm

Supraspinatus

Supraspinous fossa

of scapula

Greater tuberosity

of humerus;

capsule of

shoulder joint

Suprascapular

nerve

C4, 5, 6

Abducts arm and stabilizes

shoulder joint

Infraspinatus

Infraspinous fossa

of scapula

Greater tuberosity

of humerus;

capsule of

shoulder joint

Suprascapular

nerve

(C4), 5, 6

Laterally rotates arm and

stabilizes shoulder joint

Lower third of

lateral border of

scapula

Medial lip of

bicipital groove

of humerus

Lower subscapular

nerve

C6, 7

Medially rotates and adducts

arm and stabilizes shoulder

joint

Upper two thirds of

lateral border of

scapula

Greater tuberosity

of humerus;

capsule of

shoulder joint

Axillary nerve

(C4), C5, 6

Laterally rotates arm and

stabilizes shoulder joint

Subscapularis

Subscapular fossa

Lesser tuberosity of

humerus

Upper and lower

subscapular

nerves

C5, 6, 7

Medially rotates arm and

stabilizes shoulder joint

The predominant nerve root supply is indicated by boldface type.

350

CHAPTER 9

lary artery and divides it into three parts (Figs. 9.13, 9.15,

The pectoralis minor muscle crosses in front of the axil

of the neck, it is seen to be continuous with the prevertebral

If this sheath is traced upward into the root

axillary sheath.

enclosed with them in a connective tissue sheath called the

the cords of the brachial plexus and their branches and is

artery. Throughout its course, the artery is closely related to

the teres major muscle, where it continues as the brachial

the subclavian (Fig. 9.17) and ends at the lower border of

at the lateral border of the 1st rib as a continuation of

The axillary artery (Figs. 9.12, 9.13, 9.15, and 9.16) begins

Axillary Artery

limb. These structures are embedded in fat.

plexus, the brachial plexus, which innervates the upper

The Upper Limb

fascia.

and 9.17).

Absent Pectoralis Major

Occasionally, parts of the pectoralis major muscle may be

absent. The sternocostal origin is the most commonly missing

part, and this causes weakness in adduction and medial rota-

tion of the shoulder joint.

C L I N I C A L N O T E S

First Part of the Axillary Artery

the subscapularis muscle, and the shoulder joint

The posterior cord of the brachial plexus,

Posteriorly:

and the skin (Figs. 9.13 and 9.17)

The pectoralis minor, the pectoralis major,

Anteriorly:

Relations

pectoralis minor muscle (Fig. 9.17).

This lies behind the

Second Part of the Axillary Artery

The axillary vein (Fig. 9.15 and 9.16)

Medially:

The three cords of the brachial plexus (Fig. 9.15)

Laterally:

ratus anterior) (Fig. 9.15)

The long thoracic nerve (nerve to the ser

Posteriorly:

cephalic vein crosses the artery (Figs. 9.13 and 9.15).

The pectoralis major and the skin. The

Anteriorly:

Relations

pectoralis minor (Fig. 9.17).

lateral border of the 1st rib to the upper border of the

This extends from the

■

(Fig. 9.15)

the teres major (Fig. 9.17).

lower border of the pectoralis minor to the lower border of

This extends from the

Third Part of the Axillary Artery

the axillary vein (Figs. 9.15, 9.16, and 9.20)

The medial cord of the brachial plexus and

Medially:

9.13, 9.15, and 9.16)

The lateral cord of the brachial plexus (Figs.

Laterally:

■

second part of axillary artery

third part of axillary artery

anterior and posterior

circumflex humeral

arteries

axillary vein

brachial artery

venae comitantes

of brachial artery

basilic vein

teres major

subscapular artery

lateral thoracic artery

pectoralis minor

thoracoacromial artery

highest thoracic artery

subclavian artery

first rib

first part of axillary artery

FIGURE 9.17

Parts of the axillary artery and its branches. Note the formation of the axillary vein at the lower border of the

teres major muscle.

Basic Anatomy

branches of the axillary artery, and the cephalic vein.

The vein receives tributaries, which correspond to the

subclavian vein.

ends at the lateral border of the 1st rib by becoming the

It runs upward on the medial side of the axillary artery and

tantes of the brachial artery and the basilic vein (Fig. 9.17).

of the teres major muscle by the union of the venae comi

The axillary vein (Fig. 9.12) is formed at the lower border

Axillary Vein

of the humerus, respectively (Fig. 9.17).

wind around the front and the back of the surgical neck

posterior circumflex humeral arter

anterior

The

subscapularis muscle.

runs along the lower border of the

subscapular artery

The

From the third part:

of the pectoralis minor (Fig. 9.17).

runs along the lower border

lateral thoracic artery

The

terminal branches.

immediately divides into

thoracoacromial artery

The

From the second part:

upper border of the pectoralis minor.

is small and runs along the

highest thoracic artery

The

From the first part:

Branches of the Axillary Artery

medial cutaneous nerve of the arm (Fig. 9.13)

The ulnar nerve, the axillary vein, and the

Medially:

culocutaneous nerves also lies on the lateral side (Figs.

humerus. The lateral root of the median and the mus

The coracobrachialis, the biceps, and the

Laterally:

behind the artery (Figs. 9.15 and 9.16).

the teres major. The axillary and radial nerves also lie

The subscapularis, the latissimus dorsi, and

Posteriorly:

the median nerve (Fig. 9.13).

lower down the artery, it is crossed by the medial root of

The pectoralis major for a short distance;

Anteriorly:

Relations

351

■

9.13 and 9.16).

■

and

ies

duce the nerve block. The position of the sheath can be verified

of the sheath. The anesthetic solution is then injected into the

pressure, and a syringe needle is inserted into the proximal part

be obtained. The distal part of the sheath is closed with finger

the brachial plexus, a brachial plexus nerve block can easily

Because the axillary sheath encloses the axillary vessels and

Spontaneous Thrombosis of the Axillary Vein

Spontaneous thrombosis of the axillary vein occasionally

occurs after excessive and unaccustomed movements of the

arm at the shoulder joint.

The Axillary Sheath and a Brachial Plexus Nerve

Block

sheath, and the solution is massaged along the sheath to pro-

by feeling the pulsations of the third part of the axillary artery.

C L I N I C A L N O T E S

Brachial Plexus

the axillary artery (Figs. 9.15 and 9.20). The medial cord

brachial plexus lie above and lateral to the first part of

All three cords of the

Cords of the Brachial Plexus

are enclosed in the axillary sheath.

Here, the brachial plexus and the axillary artery and vein

arranged around the axillary artery in the axilla (Fig. 9.15).

and are fully described on page XXX. The cords become

reside in the lower part of the posterior triangle of the neck

The roots, trunks, and divisions of the brachial plexus

posterior cord.

divisions of all three trunks join to form the

and the posterior

medial cord,

lower trunk continues as the

the anterior division of the

lateral cord,

unite to form the

sions. The anterior divisions of the upper and middle trunks

Each trunk then divides into anterior and posterior divi

lower trunk.

and the roots of C8 and T1 unite to form the

middle trunk,

the root of C7 continues as the

upper trunk,

(Fig. 9.18). The roots of C5 and 6 unite to form the

cords

roots, trunks, divisions,

The plexus can be divided into

the 1st thoracic spinal nerves (Figs. 9.18 and 9.19).

of the anterior rami of the 5th, 6th, 7th, and 8th cervical and

is formed in the posterior triangle of the neck by the union

to the various parts of the upper limb. The brachial plexus

arranged and distributed efficiently in different nerve trunks

ers derived from different segments of the spinal cord to be

This allows the nerve fib

brachial plexus.

plexus called the

At the root of the neck, the nerves form a complicated

secretomotor supply to the sweat glands.

sels by the sympathetic vasomotor nerves; and sympathetic

the muscles; influence over the diameters of the blood ves

deep structures, such as the joints; motor innervation to

important functions: sensory innervation to the skin and

The nerves entering the upper limb provide the following

and

main branches cords

divisions trunks

roots

lateral

upper

posterior

middle

medial

lower

rami

axilla

posterior triangle of neck

FIGURE 9.18

The formation of the main parts of the brachial

plexus. Note the locations of the different parts.

352

CHAPTER 9

of the axillary artery (Fig. 9.20).

the medial cord of the brachial plexus and descends in front

arises from

medial cutaneous nerve of the forearm

The

the skin on the medial side of the arm.

cutaneous branch of the 2nd intercostal nerve). It supplies

9.20) and is joined by the intercostobrachial nerve (lateral

from the medial cord of the brachial plexus (Figs. 9.12 and

(T1) arises

medial cutaneous nerve of the arm

The

muscle, and supplies the pectoralis major muscle (Fig. 9.19).

the brachial plexus, supplies and pierces the pectoralis minor

arises from the medial cord of

medial pectoral nerve

The

no branches in the axilla.

eral side of the axillary artery. The median nerve gives off

median nerve trunk, and this passes downward on the lat

9.13 and 9.19). It is joined by the medial root to form the

tinuation of the lateral cord of the brachial plexus (Figs.

is the direct con

lateral root of the median nerve

The

the musculocutaneous nerve is given in Figure 9.22.

9.13 and 9.20). A summary of the complete distribution of

muscle, and leaves the axilla by piercing that muscle (Figs.

cord of the brachial plexus, supplies the coracobrachialis

arises from the lateral

musculocutaneous nerve

The

cle (Figs. 9.13 and 9.20).

the brachial plexus and supplies the pectoralis major mus

arises from the lateral cord of

lateral pectoral nerve

The

anterior muscle, which it supplies.

and 9.19). It descends over the lateral surface of the serratus

behind the axillary vessels and brachial plexus (Figs. 9.15

axilla by passing down over the lateral border of the 1st rib

roots of the brachial plexus in the neck and enters the

(C5, 6, and 7) arises from the

long thoracic nerve

The

accessory phrenic nerve.

phrenic nerve; this branch, when present, is referred to as

clinically because it may give a contribution (C5) to the

clavius muscle (Figs. 9.15, 9.19, and 9.20). It is important

(C5 and 6) supplies the sub

nerve to the subclavius

The

Branches of the Brachial Plexus Found in the Axilla

are summarized in Table 9.4.

The branches of the brachial plexus and their distribution

Radial nerve

Axillary nerve

Thoracodorsal nerve

Upper and lower subscapular nerves

Posterior cord

Medial root of median nerve

Ulnar nerve

nerve of forearm

Medial cutaneous nerve of arm and medial cutaneous

Medial pectoral nerve

Medial cord

Lateral root of median nerve

Musculocutaneous nerve

Lateral pectoral nerve

Lateral cord

infraspinatus muscles)

Suprascapular nerve (supplies the supraspinatus and

Nerve to subclavius (C5 and 6)

Upper trunk

Long thoracic nerve (C5, 6, and 7)

Dorsal scapular nerve (C5)

Roots

plexus (Figs. 9.19 and 9.21) are as follows:

of the different parts of the brachial

branches

The

artery in its third part (Fig. 9.20).

trunks of the upper limb continue this relationship to the

Most branches of the cords that form the main nerve

cated by their names.

ship to the second part of the axillary artery that is indi

(Fig. 9.20). Thus, the cords of the plexus have the relation

cord lies on the lateral side of the second part of the artery

lies behind the second part of the artery, and the lateral

second part of the artery (Fig. 9.20). The posterior cord

crosses behind the artery to reach the medial side of the

The Upper Limb

-
-

■

the

dorsal scapular nerve

nerve to subclavius

suprascapular nerve

lateral pectoral nerve

thoracodorsal nerve

musculocutaneous nerve

axillary nerve

radial nerve

median nerve

ulnar nerve

medial cutaneous nerve of the forearm

medial cutaneous nerve of the arm

medial pectoral nerve

upper and lower

subscapular nerves

long thoracic nerve

FIGURE 9.19

Roots, trunks, divisions, cords, and terminal branches of the brachial plexus.

Basic Anatomy

posterior cord of the brachial plexus and supply the upper

arise from the

upper and lower subscapular nerves

The

given in Figure 9.22.

gram of the complete distribution of the median nerve is

of the median nerve (Figs. 9.13 and 9.20). A summary dia

the third part of the axillary artery to join the lateral root

medial cord of the brachial plexus and crosses in front of

arises from the

medial root of the median nerve

The

given in Figure 9.23.

mary of the complete distribution of the ulnar nerve is

The ulnar nerve gives off no branches in the axilla. A sum

between the axillary artery and vein (Figs. 9.13 and 9.20).

cord of the brachial plexus and descends in the interval

(C8 and T1) arises from the medial

ulnar nerve

The

353

and lower parts of the subscapularis muscle. In addition,

the lower subscapular nerve supplies the teres muscle
(Figs. 9.15 and 9.19).

and lies behind the axillary artery (Figs. 9.15, 9.19, and 9.20).

is the largest branch of the brachial plexus

radial nerve

The

Figure 9.24.

complete distribution of the axillary nerve is given in

posterior branches (see page 361). A summary of the

branch to the shoulder joint, it divides into anterior and

quadrangular space (see page 361). Having given off a

and 9.19). It turns backward and passes through the

of the posterior cord of the brachial plexus (Figs. 9.15

is one of the terminal branches

axillary nerve

The

latissimus dorsi muscle (Figs. 9.15 and 9.19).

of the brachial plexus and runs downward to supply the

arises from the posterior cord

thoracodorsal nerve

The

medial cutaneous nerve of arm

axillary vein

medial cutaneous nerve of forearm

axillary artery

axillary vein

medial cutaneous nerve of arm

axillary artery

nerve to subclavius

lateral pectoral nerve

suprascapular nerve

dorsal scapular nerve

long thoracic nerve

pectoralis minor

ulnar nerve

radial nerve

median nerve

musculocutaneous nerve

pectoralis major

teres major

ulnar nerve

radial nerve

median nerve

musculocutaneous nerve

coracobrachialis

humerus

bicipital groove

biceps

medial cutaneous nerve
of forearm

FIGURE 9.20

the level of the teres major muscle.

Relations of the brachial plexus and its branches to the axillary artery and vein. B. Section through the axilla at

354

CHAPTER 9

The Upper Limb

Summary of the Branches of the Brachial Plexus and their Distribution

T A B L E 9 . 4

surface of lateral three and a half fingers; articular branches to elbow, wrist,

first two lumbricals (by way of anterior interosseous branch), flexor pollicis

superficialis, abductor pollicis brevis, flexor pollicis brevis, opponens pollicis,

third and fourth lumbricals, interossei, palmaris brevis, skin of medial half of

Flexor carpi ulnaris and medial half of flexor digitorum profundus, flexor digiti

of lateral three and a half fingers; articular branches to elbow, wrist, and

nerve of forearm; skin on lateral side of dorsum of hand and dorsal surface

nerve of arm, posterior cutaneous nerve of arm, and posterior cutaneous

pollicis longus, extensor pollicis brevis; skin, lower lateral cutaneous

extensor digiti minimi, extensor indicis, abductor pollicis longus, extensor

extensor carpi radialis brevis, extensor carpi ulnaris, extensor digitorum,

deep radial nerve branch supplies extensor muscles of forearm: supinator,

Triceps, anconeus, part of brachialis, extensor carpi radialis longus; via

Deltoid and teres minor muscles; upper lateral cutaneous nerve of arm supplies

Coracobrachialis, biceps brachii, brachialis muscles; supplies skin along lateral

Upper Trunk

Rhomboid minor, rhomboid major, levator scapulae muscles

Branches

Distribution

Roots
Dorsal scapular nerve (C5)
Long thoracic nerve (C5, 6, 7)

Serratus anterior muscle

Suprascapular nerve (C5, 6)

Supraspinatus and infraspinatus muscles

Nerve to subclavius (C5, 6)

Subclavius

Lateral Cord
Lateral pectoral nerve (C5, 6, 7)

Pectoralis major muscle

Musculocutaneous nerve (C5, 6, 7)

border of forearm when it becomes the lateral cutaneous nerve of forearm

Lateral root of median nerve (C5, 6, 7)

See medial root of median nerve

Posterior Cord
Upper subscapular nerve (C5, 6)

Subscapularis muscle

Thoracodorsal nerve (C6, 7, 8)

Latissimus dorsi muscle

Lower subscapular nerve (C5, 6)

Subscapularis and teres major muscles

Axillary nerve (C5, 6)

skin over lower half of deltoid muscle

Radial nerve (C5, 6, 7, 8; T1)

hand

Medial Cord
Medial pectoral nerve (C8; T1)

Pectoralis major and minor muscles

Medial cutaneous nerve of arm joined by

intercostal brachial nerve from second

intercostal nerve (C8; T1, 2)

Skin of medial side of arm

Medial cutaneous nerve of forearm (C8; T1)

Skin of medial side of forearm

Ulnar nerve (C8; T1)

minimi, opponens digiti minimi, abductor digiti minimi, adductor pollicis,

dorsum of hand and palm, skin of palmar and dorsal surfaces of medial one

and a half fingers

Medial root of median nerve (with lateral root)

forms median nerve (C5, 6, 7, 8; T1)

Pronator teres, flexor carpi radialis, palmaris longus, flexor digitorum

longus, flexor digitorum profundus (lateral half), pronator quadratus; palmar

cutaneous branch to lateral half of palm and digital branches to palmar

and carpal joints

Basic Anatomy

355

median nerve

deep branch of radial nerve

musculocutaneous nerve

radial nerve

musculocutaneous nerve

radial nerve

ulnar nerve

median nerve

ulnar nerve

median
nerve

ulnar nerve

FIGURE 9.21

ferent fascial compartments of the arm and forearm.

Distribution of the main branches of the brachial plexus to dif

musculocutaneous nerve

median nerve

C5 C6 C7 C8 T1

C5 C6 C7

axilla

coracobrachialis

biceps

upper arm

brachialis
(greater part)

elbow joint

forearm

lateral cutaneous
nerve of forearm

hand

no branches

brachial

plexus

brachial artery

elbow joint

anterior interosseous

nerve

flexor pollicis

longus

flexor digitorum

profundus (lateral half)

pronator quadratus

palmar cutaneous branch

wrist joint

pronator teres

flexor carpi radialis

palmaris longus

flexor digitorum

superficialis

three thenar muscles

first two lumbricals

palmar digital branches

to lateral 3

fingers

FIGURE 9.22

Summary of the main branches of the musculocutaneous and median nerves.

356

CHAPTER 9

abdominal wall above the level of the umbilicus.

the breast and superficial vessels from the anterolateral

nodes receive lymph vessels from the lateral quadrants of

of the pectoralis minor behind the pectoralis major, these

Lying along the lower border

Anterior (pectoral) group:

The lymph nodes are arranged in six groups (Fig. 9.26).

upper limb.

above the level of the umbilicus, and the vessels from the

superficial lymph vessels from the thoracoabdominal walls

lymph vessels from the lateral quadrants of the breast, the

The axillary lymph nodes (20 to 30 in number) drain

Lymph Nodes of the Axilla

described on page 429.

Lesions of the brachial plexus and its branches are

distribution of the radial nerve is given in Figure 9.25.

middle of the back of the arm. A summary of the complete

(Fig. 9.13). The latter branch is distributed to the skin on the

triceps muscle and the posterior cutaneous nerve of the arm

It gives off branches to the long and the medial heads of the

The Upper Limb

■

ulnar nerve

axilla

upper arm

forearm

hand

elbow joint

flexor carpi ulnaris

posterior cutaneous branch

skin of medial side
of dorsum of hand

and medial 1

1/2

fingers

palmar digital

branches to medial

1/2

fingers

palmaris

brevis

no branches

brachial plexus

flexor digitorum

profundus (medial half)

ulnar artery

palmar cutaneous branch

wrist joint

muscles of hypothenar eminence

adductor pollicis

third and fourth lumbricals

interossei

joints of hand

FIGURE 9.23

Summary of the main branches of the ulnar nerve.

axillary nerve

axilla

scapular

region

skin over lower
half of deltoid

deltoid

anterior branch

posterior branch

shoulder joint

brachial plexus

teres minor

upper lateral cutaneous

nerve of arm to skin

over lower half of deltoid

FIGURE 9.24

Summary of the main branches of the axillary

nerve.

Basic Anatomy

large veins at the root of the neck.

tively, the lymph trunks may drain directly into one of the

the right side, it drains into the right lymph trunk. Alterna

On the left side, this trunk drains into the thoracic duct; on

subclavian lymph trunk.

The apical nodes drain into the

lymph vessels from all the other axillary nodes.

eral border of the 1st rib, these nodes receive the efferent

Lying at the apex of the axilla at the lat

Apical group:

vessels from the lateral side of the hand, forearm, and arm.

pectoralis major muscles and receive superficial lymph

the axilla. They lie in the groove between the deltoid and

not strictly axillary nodes because they are located outside

These nodes are

Infraclavicular (deltopectoral) group:

three groups.

axillary fat, these nodes receive lymph from the above

Lying in the center of the axilla in the

Central group:

ing the lateral side—see infraclavicular nodes, below).

of the upper limb (except those superficial vessels drain

lary vein, these nodes receive most of the lymph vessels

Lying along the medial side of the axil

Lateral group:

the iliac crests.

lymph vessels from the back, down as far as the level of

subscapularis muscle, these nodes receive superficial

Lying in front of the

Posterior (subscapular) group:

357

■

lateral 3

fingers

radial nerve

C5 C6 C7 C8 T1

brachial plexus

posterior cutaneous
nerve of arm

axilla

lower lateral

cutaneous nerve
of arm

upper arm

deep branch
of radial nerve

forearm

triceps (long head)

triceps (medial head)
triceps (lateral head)

triceps (medial head)

brachialis (small part)

brachioradialis

extensor carpi
radialis brevis

elbow joint

extensor carpi

supinator

extensor digitorum

extensor digiti minimi

extensor carpi ulnaris

abductor pollicis longus

extensor pollicis longus

extensor pollicis brevis

extensor indicis

posterior cutaneous
nerve of forearm

skin of lateral side of

superficial branch

dorsum of hand and

1/2

FIGURE 9.25

Summary of the main branches of the radial nerve.

infraclavicular group

apical group

axillary
vein

pectoralis
minor

pectoralis major

anterior group

posterior
group

lateral group

central
group

FIGURE 9.26

Different groups of lymph nodes in the axilla.