Unit Ii Anatomy Lecture 1

Front 1

What are 6 surface landmarks for structures that travel between the neck and arm?

Back 1

1) Clavicle
2) Pectorialis major
3) Sternocleidomastoid
4) Axillary folds
5) Coracoid process
6) Deltopectoral triangle

Front 2

Describe the location of the deltopectoral triangle

Back 2

Depressed area inferolateral to the lateral aspect of the clavicle
The coracoid process is palpable with deep palpation

Front 3

For what two reasons is the deltopectoral triangle an important landmark?

Back 3

1) Performing a brachial plexus block
2) Diagnosing shoulder dislocations

Front 4

What are two other areas used to anesthetize the brachial plexus?

Back 4

1) Interscalene space
2) Supraclavicular space

Front 5

Describe the axilla

Back 5

Triangular-shaped area where the arm and thorax unite
Apex occurs at floor of lateral triangle of neck, but is not considered part of this triangle

Front 6

Describe the axilla fossa

Back 6

Triangle bounded by bony and soft tissues and houses several structures

Front 7

Describe the bony borders of the axilla fossa

Back 7

Anterior- clavicle
Medial- first rib
Posterior- scapula

Front 8

Describe the muscular walls of the axilla fossa

Back 8

Anterior- pectorialis major/minor and subclavius
Medial- serratus anterior and intercostals
Posterior- subscapularis, teres major, and latissimus dorsi

Front 9

What are the primary structures of the axilla fossa?

Back 9

1) Axillary artery and vein
2) Cords of brachial plexus

Front 10

Describe the divisions of the axillary artery

Back 10

It is divided into three major parts by the tendon of the pectoralis minor muscle.
The assigned division number (1-3) correlated with the number of branches present within each division

Front 11

Describe the first division of the axillary artery

Back 11

Occurs between the lateral border of the first rib and the medial border of the pectoralis minor muscle
Has a single branch

Front 12

What is the branch of the first division of the axillary artery?

Back 12

Highest thoracic (superior thoracic artery)- highly variable and runs inferomedially and posterior to axillary vein; supplies several muscles- serratus anterior, subclavius, pectoral muscles, muscles of the first two intercostal spaces

Front 13

Describe the second division of the axillary artery

Back 13

Lies posterior to the pectoralis minor muscle and has two major branches

Front 14

What are the two major branches of the second division of the axillary artery?

Back 14

1) Thoracoacromial artery
2) Lateral thoracic artery

Front 15

Describe the thoracoacromial artery

Back 15

Proximal branch that occurs deep to the pectoralis minor and pierces the costocoracoid membrane (part of clavipectoral fascia)
Lies deep to clavicular head of pectoralis major, where it divides into four primary branches (deltoid, pectoral, clavicular, acromial)

Front 16

Describe the lateral thoracic artery

Back 16

Commonly arises from the thoracodorsal artery but has variable organs
Other sites of origin include thoracoacromial, suprascapular, or subscapular
Usually it is distal branch of this division and descends to lateral border of pectoralis minor to supply both pectoral muscles and serratus anterior
In women, supplies lateral part of each mammary gland

Front 17

Describe the third division of the axillary artery

Back 17

Courses from lateral border of pectoralis minor to inferior border of teres major
Has three branches

Front 18

What are the three branches of the third division of the axillary artery?

Back 18

1) Subscapular artery
2-3) Circumflex humeral arteries

Front 19

Describe the subscapular artery

Back 19

Largest branch of axilla area, descends along lateral border of subscapularis on posterior axillary wall
Divides into two major arteries

Front 20

What are the two major arteries coming from the subscapular artery?

Back 20

1) Circumflex scapular
2) Thoracodorsal

Front 21

Describe the circumflex scapular artery

Back 21

Proximal branch of subscapular, supplies muscles of dorsum of scapula and participates in anastomoses of scapula

Front 22

Describe the thoracodorsal artery

Back 22

Continuation of subscapularis artery distal to branching of circumflex scapular artery
Supplies muscles on dorsum of scapula and participates in anastomoses of scapula
Supplies several muscles of back/shoulder (subscapularis, teres major, serratus anterior, latissimus dorsi=mainly)

Front 23

Describe the circumflex humeral arteries

Back 23

Arise opposite subscapular artery and pass around surgical neck of humerus to anastomose with each other

Front 24

What are the two main branches of the circumflex humeral artery?

Back 24

1) Anterior humeral circumflex artery- occurs deep to biceps brachii and coracobrachialis muscles
2) Posterior humeral circumflex artery- passes through quadrangular space with axillary nerve

Front 25

Describe the lymphoid tissues of the axilla

Back 25

Receive and filter lymph from the upper limb, anterior and posterior aspects of trunks, and areas from the iliac crest and umbilicus

Front 26

Describe the lymphatic nodes of the axilla

Back 26

Embedded in fatty connective tissue of this area and are related to the blood vessels
Number range from 12-36 and form a straggling chain from the base of the axilla to the apex
Usually subdivided into groups relative to drainage patters and location

Front 27

Describe afferent lymphatic drainage from the periphery

Back 27

Received by three main groups of nodes
An exception involves the breast which drain into the pectoral nodes

Front 28

What are the three areas of afferent lymphatic drainage from the axilla?

Back 28

1) Brachial (lateral)- from scapular and back regions
2) Subscapular (posterior)- from anterior walls of thorax and abdomen
3) Pectoral (anterior)- from between clavicle and umbilicus

Front 29

What happens when the primary nodes of drainage become blocked by cancer cells?

Back 29

Alternative routes of flow open up and become routes to carry metastases to nodes outside the usual territory of drainage

Front 30

What can be done for profuse bleeding of the axilla?

Back 30

Compression of the third part of the axillary artery against the humerus
Artery can be pressed against the first rib by exerting downward pressure in the angle between the clavicle and the attachment of the SCM

Front 31

Describe the arterial anastomoses associated with the scapula

Back 31

E.g. dorsal scapula, suprascapular, and subscapular= by circumflex scapular
Significance of collateral circulation created by these vessels becomes apparent when ligation of a lacerated subclavian or axillary artery is necessary or when vascular stenosis or atherosclerotic lesions reduces blood flow and direction of blood flow is reversed, allowing blood to reach the third part of the axillary artery
Reversal allows structures supplied by subscapular artery to receive blood by several other vessels including, suprascapular, transverse cervical, and intercostal arteries

Front 32

Describe an aneurysm of the axillary artery

Back 32

May involve the first part of this artery, which can compress the trunks of the brachial plexus
Can cause pain and anesthesia in the areas of skin supplied by affected nerves
Condition that may be present in athletes

Front 33

Describe the quadrangular and triangular spaces of the axilla

Back 33

Main fxn is to allow free passage of structures from one region of the body to another region without obstruction
Borders consist of both bony and soft tissue

Front 34

What are the borders of the quadrangular space?

Back 34

Surgical neck of humerus, teres minor and major, subscapularis (deeper), long head of triceps brachii

Front 35

What are the contents of the quadrangular space?

Back 35

Axillary nerve and posterior circumflex humeral artery

Front 36

What are the borders of triangular space 1?

Back 36

Lateral border of scapula, teres minor and major, subscapularis, and long head of triceps brachii

Front 37

What are the contents of triangular space 1?

Back 37

Circumflex scapular artery

Front 38

What are the borders of triangular space 2?

Back 38

Medial shaft of humerus, long head of triceps brachii, and teres major

Front 39

What are the contents of triangular space 2?

Back 39

Radial nerve and profunda brachii artery

Front 40

What is the brachial plexus?

Back 40

Network that provides nerve supply to the upper limb (motor and sensory)

Front 41

What are the basic components of the brachial plexus?

Back 41

From medial to lateral: roots, trunks, divisions, cords and branches

Front 42

Describe the roots of the brachial plexus

Back 42

Include five roots (superior and inferior) formed from the ventral rami of C5-T1
Pass between anterior and middle scalene muscles with subclavian artery
Unite to form trunks
Sympathetic fibers are carried by each root and are received from the gray rami of the middle and inferior cervical ganglia

Front 43

What are the levels of the cervical ganglia?

Back 43

Superior: C1-C4
Middle: C5-C6
Inferior: C7-T1

Front 44

Describe the trunks of the cervical ganglia

Back 44

Names based on a spatial-relationship to each other from superior to inferior
Each trunk divides into anterior and posterior divisions as the plexus passes posterior to the clavicle (via cervicoaxillary sheath)

Front 45

Describe the divisions of the trunks of the brachial plexus

Back 45

Superior: forms from union of C5-C6
Middle: continuation of C7
Inferior: forms from union of C8-T1

Front 46

Describe the divisions of the brachial plexus

Back 46

They pass through the cervicoaxillary canal (posterior to clavicle)
Includes three anterior and three posterior parts
Each trunk provides an anterior and posterior division
Anterior divisions supply anterior compartments (flexor) and posterior divisions supply posterior compartments (extensor)
Divisions form three cords

Front 47

Describe the cords of the brachial plexus

Back 47

Both motor and sensory nerve fibers are named based on their relationship to the second portion of the axillary artery

Front 48

Name and describe the three cords of the brachial plexus

Back 48

1) Lateral cord- forms by the union of the anterior divisions of the upper and middle trunks
2) Medial cord- continuation of the anterior division of the lower trunk
3) Posterior cord- forms by the union of the posterior divisions of all three trunks

Front 49

Describe the branches of the brachial plexus

Back 49

Supply nerve fibers that extend from the upper neck to axilla and supply nerve fibers (motor/sensory) to the upper limbs

Front 50

What are the two major branches of the brachial plexus

Back 50

1) Supraclavicular- above the clavicle
2) Infraclavicular- below the clavicle

Front 51

Describe the supraclavicular branch of the brachial plexus

Back 51

Involves four major branches of the brachial plexus that arise via the anterior rami or superior trunks of the brachial plexus
Approachable through the neck

Front 52

What are the four major branches of the supraclavicular branch of the brachial plexus

Back 52

1) Dorsal scapular
2) Long thoracic
3) Nerve to subclavius
4) Suprascapular

Front 53

Describe the dorsal scapular nerve

Back 53

Origin: ventral ramus of C5 with a frequent contribution from C4
Course: pierces scalenus medius, descends deep to levator scapulae, and enters deep surface of rhomboids
Distribution: innervates rhomboids and occasionally supplies levator scapulae

Front 54

Describe the long thoracic nerve

Back 54

Origin: ventral rami of C5-C7
Course: descends posterior to C8 and T1 rami and passes distally on external surface of serratus anterior
Distribution: innervates serratus anterior
Passes through cervicoaxillary canal (posterior to other brachial plexus structures) and its roots from C5-C6 pierce the middle scalene

Front 55

Describe the nerve to subclavius

Back 55

Origin: superior trunk, receiving fibers from C5 and C6 and often C4
Course: descends posterior to clavicle and anterior to brachial plexus and subclavian artery
Distribution: innervates subclavius and sternoclavicular joint

Front 56

Describe the suprascapular nerve

Back 56

Origin: superior trunk, receiving fibers from C5 and C6 and often C4
Course: passes laterally across posterior triangle of neck, through scapular notch under superior transverse scapular ligament
Distribution: innervates supraspinatus, infraspinatus, and glenohumeral (shoulder) joint
Arises from posterior aspect of superior trunk
Artey goes over transverse ligament and the nerve goes under the ligament

Front 57

Describe the infraclavicular branch of the brachial plexus

Back 57

Involves more than a dozen branches of the brachial plexus, which arise from the cords of the brachial plexus
Approachable via the axilla, each cord may divide into one or more terminal branches
Branches are grouped with the appropriate cord(s) that contributes to each nerve of the brachial plexus

Front 58

Describe the lateral cord of the infraclavicular branch of the brachial plexus

Back 58

Arises from C5-C7 spinal nerves and has three main branches

Front 59

What are the three main branches of the lateral cord?

Back 59

1) Lateral pectoral
2) Musculocutaneous
3) Median

Front 60

Describe the lateral pectoral branch of the lateral cord

Back 60

Origin: lateral cord, receiving fibers from C5-C7
Course: pierces clavipectoral fascia to reach deep surface of pectoral muscles
Distribution: primarily supplies pectoralis major but send a loop to medial pectoral nerve that innervates pectoralis minor
Single side branch that may arise from the lateral cord or the anterior divisions of superior and middle trunks (accompanying lateral cord into axilla)

Front 61

Describe the musculocutaneous branch of the lateral cord

Back 61

Origin: lateral cord, receiving fibers from C5-C7
Course: enters deep surface of coracobrachialis and descends between biceps brachii and brachialis
Distribution: innervates coracobrachialis, biceps brachii, and brachialis; continues as lateral antebrachial cutaneous nerve
Terminal branch

Front 62

Describe the median branch of the lateral cord

Back 62

Origin: lateral root is a continuation of lateral cord, receiving fibers from C6 and C7; medial root is a continuation of medial cord receiving fibers from C8 and T1
Course: lateral root joins medial root to form median nerve lateral to axillary artery
Distribution: innervates flexor muscles in forearm (except flexor carpi ulnaris, ulnar half of flexor digitorium profundus) and five hand muscles
Supplies all muscles in the anterior compartment of the arm

Front 63

Describe the medial cord of the infraclavicular branch of the brachial plexus

Back 63

Arises from spinal nerves C8-T1 and has five branches

Front 64

What are the five branches of the medial cord?

Back 64

1) Median nerve
2) Medial pectoral
3) Medial brachial cutaneous
4) Medial antebrachial cutaneous
5) Ulnar

Front 65

Describe the median nerve of the medial cord

Back 65

Origin: lateral root is a continuation of lateral cord, receiving fibers from C6 and C7; medial root is a continuation of medial cord receving fibers from C8 and T1
Course: lateral joins medial root to form median nerve lateral to axillary artery
Distribution: innervates flexor muscles in forearm (except flexor carpi ulnaris, ulnar half of flexor digitorum profundis) and five hand muscles
Formed by contributions of the roots from two cords: lateral root (terminal branch of lateral cord C6-C7) and medial root (terminal branch of medial cord C8-T1)

Front 66

Describe the medial pectoral nerve of the lateral cord

Back 66

Origin: medial cord, receiving fibers from C8 and T1
Course: passes between axillary artery and vein and enters deep surface of pectoralis minor
Distribution: innervates the pectoralis minor and part of pectoralis major
One of three side branches of medial cord, located lateral to lateral pectoral but arises via medial cord

Front 67

Describe the medial brachial cutaneous nerve of the lateral cord

Back 67

Origin: medial cord, reciving fibers from C8 and T1
Course: runs along the medial side of axillary vein and communicates with intercostobrachial nerve
Distribution: supplies skin on medial side of arm
Supplies of skin of the arm and the superior part of the forearm

Front 68

Describe the medial antebrachial cutaneous nerve of the lateral cord

Back 68

Origin: medial cord, receiving fibers from C8 and T1
Course: runs between axillary artery and vein
Distribution: supplies skin over medial side of forearm
Much larger and termed "fools nerve" because it is similar in size and position to ulnar

Front 69

Describe the ulnar nerve of the lateral cord

Back 69

Origin: terminal branch of medial cord, receiving fibers from C8 and T1 and often C7
Couse: passes down medial aspect of arm and runs posterior to medial epicondyle to enter forearm
Distribution: innervates one and one-half flexor muscles in forearm, most small muscles in hand, and skin of hand medial to a line bisecting 4th digit
Arises via C8-T1, transverses the arm and the forearm without branching, innervates most intrinsic muscles of hand
Innervates flexor carpi ulnaris, ulnar half (medial part) of flexor digitorum profundus

Front 70

Describe the intercostalbrachial nerve

Back 70

Lateral cutaneous banch of the 2nd intercostal nerve and supplies the skin, floor, and tissue of the axilla
Also communicates with the medial brachial cutaneous to supply medial and posterior surfaces of arm

Front 71

Describe the posterior cord of the infraclavicular branch of the brachial plexus

Back 71

ULTRA
Arises from C5-T1 spinal nerves and has five branches

Front 72

What are the five branches of the posterior cord?

Back 72

1) Upper subscapular
2) Thoracodorsal
3) Lower subscapular
4) Axillary
5) Radial

Front 73

Describe the upper subscapular nerve of the posterior cord

Back 73

Origin: branch of posterior cord, receiving fibers from C5 and C6
Couse: passes posteriorly and enters subscapularis
Distribution: innervates superior portion of subscapularis
Forms one of three side branches

Front 74

Describe the thoracodorsal nerve of the posterior cord

Back 74

Origin: branch of posterior cord, receiving fibers from C6-C8
Course: arises between upper and lower subscapular nerves and runs inferolaterally along posterior axillary wall to latissimus dorsi
Distribution: innervates latissimus dorsi
Forms one of three side branches

Front 75

Describe the lower subscapular nerve of the posterior cord

Back 75

Origin: branch of posterior cord, receiving fibers from C5 and C6
Course: passes inferolaterally, deep to subscapular artery and vein, to subscapularis and teres major
Distribution: innervates inferior portion of subscapularis and teres major
Forms one of three side branches

Front 76

Describe the axillary nerve of the posterior cord

Back 76

Origin: terminal branch of posterior cord, receiving fibers from C5 and C6
Course: passes to posterior aspect of arm through quadrangular space in company with posterior circumflex humeral artery and then winds around surgical neck of humerus; gives rise to lateral brachial cutaneous nerve
Distribution: innervates teres minor and deltoid, shoulder joint, and skin over inferior part of deltoid

Front 77

Describe the radial nerve of the posterior cord

Back 77

Origin: terminal branch of posterior cord, receiving fibers from C5-C8 and T1
Course: descends posterior to axillary artery; enters radial groove with deep brachial artery to pass between long and medial heads of triceps
Distribution: innverates triceps brachii, anconeus, brachioradialis, and extensor muscles of forearm; supplies skin on posterior aspect of arm and forearm via posterior cutaneous nerves of arm and forearm

Front 78

Describe the general trends of the motor inervation of the arm

Back 78

Anterior compartment- musculocutaneous
Posterior compartment- radial

Front 79

Describe the general trends of the motor innervation of the forearm

Back 79

Anterior compartment- median-ulnar
Posterior compartment- radial

Front 80

Describe the general trends of the motor innervation of the hand

Back 80

Anterior compartment- ulnar-median

Front 81

Describe the myotomes of the upper limb

Back 81

C5- mediates arm abduction at the shoulder
C5 and C6- mediate flexion at the elbow and biceps reflex
C6- mediates wrist extension
C7- mediates elbow extension and triceps reflex

Front 82

List the specific cutaneous nerves of sensory innervation of the arm and forearm

Back 82

1) Supraclavicular
2) Posterior cutaneous nerve of arm
3) Posterior cutaneous nerve of forearm
4) Superior lateral cutaneous nerve of arm
5) Inferior lateral cutaneous nerve of arm
6) Lateral cutaneous nerve of forearm
7) Medial cutaneous nerve of forearm
8) Intercostobrachial nerve
9) Medial cutaneous nerve of forearm

Front 83

What are the specific cutaneous nerves of sensory innervation of the hand?

Back 83

1) Dorsal branch of ulnar
2) Superficial branch of radial
3) Palmar digital branches of ulnar-median
4) Palmar branches of ulnar-median