Upper limb note - Lecture notes 2 PDF

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02.ANATOMY OF THE UPPER LIMB1. SHORT HAND ANATOMY CODES YOU MAY SEE:In Anatomy, the ‘arm’ is considered the area between the shoulder and the elbow. Between the elbow and the hand, we call this region the forearm2. BONES OF THE UPPER LIMB:i. 32 bones in each upper limb – including scapula and clavic...

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02.11.18

ANATOMY OF THE UPPER LIMB 1. SHORT HAND ANATOMY CODES YOU MAY SEE: In Anatomy, the ‘arm’ is considered the area between the shoulder and the elbow. Between the elbow and the hand, we call this region the forearm

2. BONES OF THE UPPER LIMB: i.

32 bones in each upper limb – including scapula and clavicle

ii.

Arm – Glenohumeral joint to elbow

iii.

Forearm – elbow to wrist

iv.

Upper limb – shoulder + arm + forearm + hand

v.

The humerus is a long bone of the upper limb, which extends from the shoulder to the elbow.

vi.

The proximal region of the humerus articulates with the glenoid fossa of the scapula, forming the glenohumeral joint.

vii.

Distally, at the elbow joint, the hunerus articulates with the head of the radius and trochlear notch of the ulna.

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3. BONY PRONINENCES:

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4. MORE ATTACHMENT POINTS/REGIONS OF INTEREST:

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5. THE AXILLA A. Axilla definition i. B.

The area under glenohumeral joint (‘arm pit region’). It is a pyramid shaped space. Axilla function

i. C.

It forms an important passageway for arteries, veins, nerves and lymph vessels as they travel from the root of the neck into the arm. The axilla has an apex, a base, and four walls

6. ARM AND AXILLA i.

Apex (axillary inlet) – clavicle, first rib and scapula

ii.

Base – skin (visible surface of axilla)

iii.

Lateral wall – humerus

iv.

Medial wall – serratus anterior.m and thoracic wall

v.

Anterior wall – pectoralis major.m, pectoralis minor.m and subclavius.m

vi.

Posterior wall – subscapularis.m, teres major.m and latissimus dorsi.m

7. BASIC COMPONENTS OF MUSCLE

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i.

Myofibrils (composed of actin and myosin)

ii.

Bundles of myofibrils make up a muscle fibre

iii.

Bundles of muscle fibres make a fascicle

iv.

Bundles of fascicles make the muscle

A.

Epimysium: v.

Dense collagenous sheath

B.

Perimysium: i.

C.

Loose connective tissue around bundles of muscle fascicles Endomysium

i.

Loose connective tissue around individual muscle fibres



Skeletal muscle is one of the three major muscle types, the others being cardiac muscle and smooth muscle. It is a form of straited muscle tissue which is under the voluntary control of the somatic nervous system. Skeletal muscles are attached to bones by tendons.



A skeletal muscle refers to multiple bundles (fascicles) of cells called muscle fibres. Muscle fibres are in turn composed of myofibrils. The myofibrils are composed of actin and myosin filaments, repeated in units called sarcomeres, which are the basic functional units of the muscle fibre. The sarcomere is responsible for the striated appearance of skeletal muscle and forms the basic machinery necessary for muscle contraction.

8. THE UPPER LIMB muscle groups divided into compartments A. Arm i. B.

anterior and posterior Forearm

i. C.

anterior and posterior (superficial and deep) Wrist and hand

i.

dorsal and palmar

9. THE ARM The ‘arm’ is located between the shoulder joint and elbow joint (the humerus). it contains four muscles. A. Three in the anterior compartment (BBC)

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i.

Biceps brachii,

ii.

Brachialis

iii.

Coracobrachialis

all these muscles are innervated by the musculocutaneous n. B. Two in the posterior compartment i.

Triceps brachii

ii. Anconeus (assists triceps in extending forearm) These are innervated by the radial n. All three heads of the triceps bracii are classically believed to be innervated by the radial nerve. However, a study conducted in 2004 determined that, in 20 cadaveric specimens and 15 surgical dissections on participants, the long head was innervated by a branch of the axillary nerve in all cases.

10.

THE ARM – BICEPTS BRACHII To get started right away, just tap any placeholder text (such as this) and start typing. A. Long head of biceps brachii. m i. B.

C.

Proximal attachment: supraglenoid tubercle Short head of biceps brachii. m

i.

Proximal attachment: coracoid process

ii.

Both heads attach distally onto the radial tuberosity & bicipital aponeurosis. Innervation: Musculocutaneous. n

D. Blood supply: Muscular branches from the brachial artery E. Principle action: Strong supinator and forearm flexor, short head resists dislocation of the shoulder

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11.

THE ARM - BRACHIALIS The brachialis (brachialis anticus) is a muscle in the upper arm that flexes the elbow joint. It lies deeper than the biceps brachii and makes up part of the floor of the region known as the cubital fossa. The brachialis is the prime mover of elbow flexion. A. Brachialis. m i.

Proximal attachment: distal half of the anterior surface of the humerus

ii.

Distal attachment: coranoid process and tuberosity of the ulna

iii.

Innervation: Musculocutaneous. n

iv.

Blood supply: Muscular branches of the brachial artery and the recurrent radial artery

v.

Principle action: Flexes the forearm in all positions

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12.

THE ARM - CORACOBRACHIALIS A. Coracobrachialis. m i.

Proximal attachment: coracoid process of scapula

ii.

Distal attachment: medial surface of the humerus

iii.

Innervation: Musculocutaneous. n

iv.

Blood supply: Muscular branches of the brachial artery

v.

Principal action: Helps to flex and adduct the arm and resist dislocation of shoulder

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13.

THE ARM (POSTERIOR COMPARTMENT) – TRICEPS BRACHII Triceps has three heads: long head, medial head and lateral head A. Proximal attachment: i.

Long head of triceps. m: Infraglenoid tubercle

ii.

Lateral head of triceps. m: post surface of humerus, superior to radial groove

iii.

Medical head of triceps. m: post surface of humerus inferior to radial groove

B.

Distal attachment: Olecranon and forearm fascia

C.

Innvervation: Radial n. and axillary n.

D.

Blood supply: branches of the deep brachial. a

E.

Principle action: Chief extensor of forearm

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14.

THE ARM (POSTERIOR COMPARTMENT) - ANCONEUS A. Anconeus i.

Proximal attachment: Lateral epicondyle of humerus

ii.

Distal attachment: Lateral surface of olecranon and superior part of post surface of ulnar

iii.

Innervation: Radial n.

iv.

Blood supply: branches of the deep brachial. a

v.

Principle action: assists triceps in extending forearm

15.

THE FOREARM The muscles of the forearm are (like the arm) divided into anterior and posterior compartments. However, in the forearm the ant/post compartments are also themselves then divided into superficial and deep. A. Flexors i.

Anterior (ventral) superficial (5 muscles)

ii.

Anterior (ventral) deep (3 muscles)

B.

Extensors i.

Posterior (dorsal) superficial (6 muscles)

ii.

Posterior (dorsal) deep (5 muscles)

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16.

ANTERIOR SUPERFICIAL COMPARTMENT OF THE FOREARM i.

Palmaris longus: flexor retinaculum or palmar aponeurosis. (Median. n)

ii.

Flexor carpi radialis: base of 2nd metacarpal. (Median. n)

iii.

Pronator teres: lateral surface of radius (Median. n)

iv.

Flexor digitorum superficialis: middle phalanx of digits 2-5. (Median. n – ant interosseous branch)

v.

Flexor carpi ulnaris: base of 5th metacarpal, pisiform and hook of hamate (Median. n)

vi.

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Pronator teres also originates from coronoid process

17.

ANTERIOR DEEP COMPARTMENT OF THE FOREARM i.

Flexor digitorum profundus: O: anterior and medial surface of ulnar. I: distal phalanx digits 2-5. Median. n (anterior interosseous branch) and ulnar nerve

ii.

Flexor pollicis longus O: anterior surface of radius and interosseous membrane I: base of distal phalanx of digit 1 (thumb) Median. n (anterior interosseous branch)

iii.

Pronator quadratus Extends between distal surfaces of ulnar and radius. Median. n (anterior interosseous branch) an

iv.

Flexor digitorum profundus, medial part innervated by ulnar nerve. Lateral part innervated by median nerve.

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POSTERIOR SUPERFICIAL COMPARTMENT OF THE FOREARM i. ii. iii. iv.

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In summary. Radial n. does everything down posterior arm and forearm. Musculocuteneous does anterior arm, median nerve supplies everything in ant sup and deep compartment except for flexor carpi ulnaris (which is supplied by ulnar nerve) And flexor digitorum profundus is half supplied by median (lateral side), half by ulnar (medial side)

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POSTERIAL DEEP COMPARTMENT OF THE FOREARM

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MOVEMENTS A. Name suggests function i.

Flexors- flex

ii.

Extensors – extend

iii.

Pronators – pronate

iv.

Supinator's- supinate

v.

Most anterior arm and forearm muscles = flex

vi.

Most posterior arm and forearm muscles = extend

vii.

Think about where muscles are inserting (and what joints they are crossing) and this will help tell you their action.

viii.

Eg. If a flexor muscles tendon crosses the wrist joint to insert in the hand it will flex the wrist.

ix.

21.

If an extensor muscles tendon crosses the wrist joint to insert in the hand it will extend the wrist.

THE BRACIAL PLEXUS A. What is a nerve plexus? i. B.

The 4 main spinal plexuses i.

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Branching network of intersecting nerves composed of afferent and efferent fibres that arise from the merging of the anterior rami of spinal nerves.

Cervical plexus: serves the head, neck and shoulders

ii.

Brachial plexus: serves the chest, shoulders, arms and hands

iii.

Lumbar plexus: serves the back, abdomen, groin, thighs, knees and calves

iv.

Sacral plexus: serves the pelvis, buttocks, genitals, thighs, calves, and feet

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22.

THE BRACHIAL PLEXUS i.

Network of nerve fibres supplying skin and muscles of upper limb.

ii.

Root of neck -> axilla -> upper limb

iii.

Brachial plexus formed by the anterior rami (divisions) of spinal nerves C5, C6, C7, C8 &T1

iv.

The brachial plexus = network of nerve fibres that supplies the skin and muscles of upper limb. Passes from neck through axilla into upper limb. Ulnar nerve C8-T1 Radial nerve C5-T1 Median nerve C6-T1 Axillary nerve C5-C6 Musculocuteneous C5-C7

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23.

HEADING 1 To get started right away, just tap any placeholder text (such as this) and start typing. A. Heading 2 i.

To easily apply any text formatting you see in this outline with just a tap, on the Home tab of the ribbon, check out Styles.

ii.

For example, this paragraph uses Heading 3 style.

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24.

ARTERIAL SUPPLY TO THE UPPER LIMB When the subclavian arteries cross the lateral edge of the 1st rib, they enter the axilla, and are called axillary arteries. Aorta

L Ventricle R Subclavian

L Subclavian

R Axillary

L Axillary

R Brachial

L Brachial

R Radial

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R Ulnar

L Ulnar

L Radial

Superficial Palmar Arch

Deep Palmar Arch

R Digital

L Metacarpal

i.

The arterial supply to the upper limb begins in the chest as the subclavian artery. When the subclavian arteries cross the lateral edge of the 1st rib, they enter the axilla, and are called axillary arteries.

ii.

The axillary artery passes through the axilla, just underneath the pectoralis minor muscle,

iii.

At the level of the humeral surgical neck, the posterior and anterior circumflex humeral arteries arise. They circle around the humerus to supply the shoulder region. The largest branch of the axillary artery also arises here – the subscapular artery.

iv.

The axillary artery becomes the brachial artery at the level of the teres major muscle

v.

Immediately distal to the teres major, the brachial artery gives rise to the deep brachial artery (sometimes called profunda brachii)

vi.

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Brachial artery continues distally until terminally bifurcating in the cubital fossa into the radial and ulnar arteries.

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25.

ARTERIAL SUPPLY OF THE UPPER LIMB The cubital fossa, sometimes referred to as ‘elbow pit’ is the triangular area on the anterior view of the elbow. A. This is where the brachial artery terminally bifurcates into the radial and ulnar artery. i.

Radial a. supplies posterior aspect of the forearm

ii. Ulnar a. supplies the anterior aspect. Anastomose in the hand, by forming two arches, the superficial palmar arch, and the deep palmar arch supplying hand

Brachial a.

Humerus

Cubital fossa Radius Ulnar Radial a.

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Ulnar a.

26.

VENOUS DRAINAGE OF THE UPPER LIMB The venous system of the upper limb drains deoxygenated blood from the arm, forearm and hand and can be subdivided into a superficial system and deep system. A. Superficial system i.

Basillic v. ascends medial aspect of upper limb at border of teres major m. moves deep and combines with the brachial veins to from the axillary vein.

ii.

Cephalic v. ascends anterolateral aspect of upper limb, empties into axillary v.

iii.

At the elbow, the cephalic and basilic veins are connected by the median cubital vein – ‘common site of venepuncture’

iv.

Venepuncture is the practice of obtaining intravenous access. This is usually for the purpose of providing intravenous therapy (e.g. fluids, medications) or for obtaining a blood sample.

v.

The median cubital vein is a common site of venepuncture. It is a superficial vein that is located anteriorly to the cubital fossa region. It is thought to be fixed in place by perforating veins, which arise from the deep venous system and pierce the bicipital aponeurosis.

vi.

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Its ease of access, fixed position and superficial position make the median cubital vein a good site for venepuncture in many individuals.

B. Deep system i.

The deep veins of upper limb lie alongside the arteries.

ii.

Brachial a. pulse assists brachial venous return.

iii.

Radial and ulnar veins drain into brachial v. (joined by basillic v. to drain into axillary v.)

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27.

VENOUS DRAINAGE OF THE UPPER LIMB

28.

LYMPHATIC DAMAGE OF THE UPPER LIMB A. What is lymph? i.

Clear fluid

ii.

Formed from interstitial fluid

iii.

Drains via series of vessels and nodes that collect and filter this fluid before returning it to the venous circulation.

iv.

It forms a vital part of the body’s immune defence

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v.

29.

The lymphatic system functions to drain tissue fluid, plasma proteins and other cellular debris back into the blood stream and is also involved in immune defence. Once this collection of substances enters the lymphatic vessels it is known as lymph; lymph is subsequently filtered by lymph nodes and directed into the venous system

LYMPHATIC DRAINAGE OF THE UPPER LIMB A. Lymphatic vessels i.

Superficial: follow the superficial veins, drain into cubital (supratrochlear) and axillary lymph nodes

ii.

Deep: accompany main vessels, end in axillary lymph nodes

B.

Lymphatic nodes i.

Cubital lymph nodes: lie in elbow (cubital fossa) just above medical epicondyle of humerus

ii. Axillary lymph nodes: arranged into 5 groups The lymphatic system functions to drain tissue fluid, plasma proteins and other cellular debris back into the blood stream and is also involved in immune defence. Once this collection of substances enters the lymphatic vessels it is known as lymph; lymph is subsequently filtered by lymph nodes and directed into the venous system.

30.

LYMPHATICS A. Axillary lymph nodes (arranged in five groups)

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i.

Lateral lymph nodes: lie around distal end of axillary vein, receive drainage from arm, forearm and hand

ii.

Pectoral lymph nodes: lie along lateral thoracic vessels, receive afferents from anterior thoracic wall

iii.

Subscapular lymph nodes: along subscapular vessels receive lymph from nape and scapular region

Efferent’s above 3 groups pass to central lymph node iv.

Central lymph node: lie in fat in axilla, receive drainage fro LN 1, 2, 3 efferent’s pass to apical LN’s

v.

Apical lymph node: lie in apex of axilla along proximal end of axillary vessels. Receive drainage chiefly from central lymph node. Efferent’s form the subclavian trunk. Right subclavian trunk joints right lymphatic duct left subclavian trunk drains into thoracic trunk.

31.

LYMPHATIC DUCTS

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32.

SELF STUDY TEST

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