Download Lecture Upper Limb I 2010

Upper Limb, part I
Shoulder, Arm, and Axilla.
Objectives:
1. Bones and joints of the shoulder
2. Organization of the shoulder’s muscles
3. Axilla - borders and contents
4. Organization of the brachial plexus
Which joint serves as the only bony attachment of
the upper limb to the axial skeleton?
Sternal clavicular joint
Anterior view
Posterior view
Which of these bones is commonly fractured?
clavicle
ORGANIZATION OF THE SHOULDER: MUSCLES AND INNERVATION
* Muscles (MM) ATTACH HUMERUS TO AXIAL SKELETON:
1. Latissimus Dorsi ( thoracodorsal n. C6-C8 )
2. Pectoralis Major ( lateral pectoral n. C5-C7, medial pectoral n. C8-Th1 )
- attaches to humerus
* MM ATTACH HUMERUS TO THE SCAPULA
}
1. Supraspinatus, Infraspinatus ( suprascapular n. C5-C6 )
2. Subscapularis ( upper C5 and lower C6 subscapular nn. )
3. Teres Minor ( axillary n. C5-C6 )
4. Teres Major ( lower subscapular n. C6 )
5. Deltoid ( axillary n. C5-C6 )
* MM ATTACH SCAPULA TO AXIAL SKELETON
1. Trapezius ( spinal accesory n. XI )
2. Levator Scapulae, Rhomboids ( dorsal scapular n. C5 )
3. Serratus Anterior ( long thoracic n. C5-C7 )
4. Pectoralis Minor ( medial pectoral n. C8-Th1 )
rotator cuff
Supraspinatus
.: Assists the deltoid in the initial abduction
Infraspinatus
.: Powerful lateral rotator of humerus
Teres minor
.: Helps rotate the arm laterally and assists
in adduction (like infraspinatus). HOWEVER,
it is innervated by the axillary nerve, while
the infraspinatus is innervated by the
suprascapular nerve
Subscapularis
.: It is the primary medial rotator (also
adducts it)
.: Innervated by the subscapular nerve
The deltopectoral
triangle is also
known as the
“clavicopectoral
triangle”. These
two names tells me
the exact borders.
What’s in the
triangle?
The cephalic
vein
Which structures lie in the deltopectoral
triangle?
Cephalic vein
The rotator cuff muscles work as a group in holding the head of the
humerus in the glenoid cavity. They give protection and stability to
the shoulder joint.
Rotator cuff
S
I
T
S
subscapularis
Rotator cuff is formed by the tendons of: Supraspinatus , Infraspinatus,
Teres minor and Subscapularis fuses with the joint capsule.
What is the tendonitis of the rotator cuff? inflammation
Axilla (the armpit)
1. Apex – cervicoaxillary canal, the passageway between
the neck and the axilla. Lies between the 1st rib, clavicle
and upper border of the scapula.
2. Base - formed by the skin, subcutaneous tissue and axillary
fascia
3. Four walls:
* anterior wall - pectoralis major and minor mm, pectoral and clavicopectoral
fascia.
Anterior axillary fold -> pectoralis major!
* posterior wall - scapula , subscapularis m., latissimus dorsi m., teres major m.
Posterior axillary fold -> latissimus dorsi and teres major!
* medial wall - thoracic wall and serratus anterior m.
* lateral wall - intertubercular groove of the humerus.
Fun note: Axillary
fossa = armpit
What passes through the cervicoaxillary cannel?
.: Arteries, veins, lymphatics and nerves to
and from the arm
What mainly forms the posterior wall?
.: Scapula
Contents of the axilla:
• axillary artery and its branches
• axillary vein and its tributaries
• brachial plexus
• axillary lymph vessels and lymph nodes
• 3 muscles: long/short head of biceps brachii m.
and coracobrachialis m.
The axillary artery and vein, and the cords of brachial plexus
(neurovascular bundle) are enveloped in the thin fascial
sheath - axillary sheath.
AXILLA
ROOTS AND TRUNKS
CORDS
CLAVICLE
AXILLARY
ARTERY
NEUROVASCULAR BUNDLE
Axillary artery – three parts
First part - one branch
– superior thoracic a.
Second part - two branches
– thoracoacromial a.
– lateral thoracic a.
Third part - three branches
– subscapular a.
– anterior circumflex humeral a.
Screw the lawyer, save the patient
Superior thoracic
Thoracodorsal
Lateral thoracic
Subscapular
Anterior circumflex humeral
Posterior circumflex humeral
– posterior circumflex humeral a.
The thoracoacromial artery will
further branch off in 4 directions,
named after parts of the body.
Mnemonic: Cadavers Are Dead People
Clavicular
Acromial
Deltoid
Pectoral
posterior circumflex
humeral a. (3rd part)
superior thoracic a.
(1st part)
anterior circumflex
humeral a. (3rd part)
thoracoacromial a.
(2nd part)
lateral thoracic a.
(2nd part)
subscapular a.
(3rd part)
circumflex scapular a.
thoracodorsal a.
Arterial anastomoses around the scapula
.: Thoracoacromial artery
-Cadavers are dead people
-1. clavicular
-2. acromial
-3. deltoid
-4. pectoral
thyrocervical
trunk
Humeral loop:
anterior circumflex humeral
posterior circumflex humeral
profunda brachii
subscapular a.
axillary a.
anterior circumflex humeral a.
deep branch of
transverse cervical a.
*(dorsal scapular)
Scapular loop:
Suprascapular
Dorsal scapular
Subscapular
posterior circumflex humeral a.
circumflex scapular a.
profunda brachii a.
Arterial anastomoses form loops
Think about where the loops are located. That’s
where they get the name. The anterior circumflex
humeral, posterior circumflex humeral and profunda
brachii are all wrapping around in the humerus
The same goes for the scapular loop, which contains
the suprascapular, dorsal scapular and subscapular
ateries
Five principal groups:
1. Pectoral( anterior) nodes receive lymph
mainly from anterior thoracic wall and the
breast and abdominal wall.
2. Subscapular (posterior) nodes receives
lymph from posterior thoracic wall and
scapular region.
3. Humeral (lateral) nodes
receive lymph from upper limb.
4. Central nodes (base of axilla)
receive lymph from anterior, posterior and
lateral nodes.
Drain into apical nodes.
5. Apical nodes (apex of axilla)
Receive lymph from all the other nodes.
Drain into the subclavian trunks.
Axillary lymph
nodes
PLAN OF BRACHIAL PLEXUS = Ventral Rami C5 to T1
ROOTS
(5)
TRUNKS
(3)
DIVISIONS
TERMINALS
(5)
MUSCULOCUTANEOUS
(3/3)
CORDS
(3)
C6
SUPERIOR
A
C5
MIDDLE
LATERAL
C7
C8
T1
P
INFERIOR
POSTERIOR
A
RADIAL
MEDIAL
DIVISIONS = ANTERIOR AND POSTERIOR
AXILLARY
MEDIAN
ULNAR
Which spinal nerves form the brachial plexus? C5, C6, C7 C8 and T1
Brachial plexus is formed by the union of the anterior (ventral) primary
rami of C5 – T1 nerves that constitute roots of brachial plexus.
The roots of brachial plexus unite to form three trunks:
* superior trunk (C5-C6)
* middle trunk (C7)
* inferior trunk (C8-T1)
Each trunk divides into anterior and posterior divisions of brachial
plexus.
The divisions of the trunks form three cords of brachial plexus:
* posterior cord - posterior divisions of all three trunks
* lateral cord – anterior divisions of superior and middle trunk
* medial cord – anterior division of the inferior trunk
The cords of brachial plexus give rise to most of the named peripheral
nerves (branches) that result from the plexus formation.
Basic Anatomy of the Brachial Plexus
Musculocutaneous nerve
Axillary nerve
Lateral cord
5
Trunk
7
Radial nerve
Median nerve
Ventral rami
6 or
roots
Posterior cord
8
1
Medial cord
Ulnar nerve
Posterior divisions
Anterior divisions
BRACHIAL PLEXUS
Roots, Trunks and
Cords:
Motor Distribution to
Anterior and Posterior
Shoulder
Terminal Branches:
Motor Distribution to
Arm, Forearm and
Hand
CORDS OF BRACHAL PLEXUS - TERMINAL BRANCHES
I. LATERAL CORD:
1. musculocutaneous n.(C5-C7):
 anterior group of arm (muscles of anterior arm are innervated;
biceps, brachialis and coracobrachialis)
2. lateral root of median n.(C6-C7) :
 anterior group of forearm (except flexor carpi ulnaris,
medial half of flexor digitorum profundum)
 thenar muscles and first two lumbricals
Musculocutaneous
nerve (C5,6,7)
Coracobrachialis muscle
Biceps brachii muscle
Brachialis muscle
Lateral cutaneous nerve
of forearm
Note the name: musculocutaneous
It innervates the muscles in the arm and
the cutaneous layer (skin) of the forearm
What cord does this nerve spring from?
The lateral cord.
This is a pretty good way to remember
what part of the forearm the
musculocutaneous nerve innervates.
Lateral anterior
Lateral cord of brachial
plexus
Ulnar nerve
Cutaneous innervation
( skin of lateral forearm)
CORDS OF BRACHAL PLEXUS - TERMINAL BRANCHES
II. MEDIAL CORD:
1. medial root of median n. (C8-T1):
 anterior group of forearm (except flexor carpi ulnaris,
medial half of flexor digitorum profundum)
 thenar muscles and first two lumbricals
2. ulnar n. (C8-T1):
 flexor carpi ulnaris
 medial half of flexor digitorum profundum
 all the small muscles of the hand (except thenar and two
first lumbricals)
What did the lateral root of the median
nerve innervate?
.: thenar muscles, first two lumbricals,
and anterior group of forearm except for
flexor carpi ulnaris and medial half of
flexor digitorum profundum
Does the medial root of the median nerve
innervate these exceptions?
.: No, in fact it does the same thing as
the lateral root (these cords join together to
form the median nerve
So what does innervate
the flexor carpi ulnaris
and the medial half of
flexor digitorum
profundum?
.: ulnar nerve
Anything else?
.: All the small muscles
of the hand except for
the thenar and the first
two lumbricals, which is
what the median nerve
takes care of.
Note that the median nerve only
cutaneously innervates the anterior part of
the hand, and the back of the fingertips,
not the rest of the back of the hand.
Medial cord of brachial plexus
Median nerve
(C5,6,7,8,T1)
Lateral cord of brachial plexus
The pimp hand is felt with the radial nerve
and the ulnar, I believe.
Muscles of forearm
Flexors of forearm except
fl.carp.ulnaris and medial
flexor dig. profundus
Cutaneous
innervation
Palmar branch of
median nerve
Muscles of hand
(thenar group and two
first lumbricals)
Common &
proper digital
nerves
Note: Only muscles
innervated by ulnar nerve
shown
Ulnar nerve
(C7,8,T1)
Medial epicondyle
Cutaneous
innervation
Flexor dig. profundus (medial
part)
Flexor carpi ulnaris muscle
Dorsal branch of ulnar nerve
Deep & superficial branch of
ulnar nerve
Muscles of the hand
(excluding thenar and
two lumbrical muscles)
Proper palmar digital nerves
CORDS OF BRACHAL PLEXUS - TERMINAL BRANCHES
III. POSTERIOR CORD:
1. axillary n. (C5-C6):
 deltoid,
 teres minor
2. radial n. (C5-T1):
 posterior group of arm and forearm
In what situations
the axillary
nerve may be
damaged (injured)?
Fracture of the surgical neck
Dislocation of the glenohumeral
joint
Compression from the incorrect
use of crutches
Radial nerve(C5,6,7,8)
a
Superficial and deep
branch of radial
nerve
Posterior interosseous
nerve (continuation of
deep branch of Radial
nerve)
Superficial branch of
radial nerve
Dorsal digital nerves
BRACHIAL PLEXUS –
branches of ROOTS,
TRUNKS AND CORDS
DORSAL SCAPULAR C5
RHOMBOID MM AND LEVATOR
SCAPULE
SUPRASCAPULAR C5,6
SUPRASPINATUS M
INFRASPINATUS M
ROOTS
C5
N. TO SUBCLAVIUS C5,6
SUBCLAVIUS
C6
C7
LATERAL PECTORAL C5-C7
PECTORAL MM
ROOTS
TRUNKS
C8
THORACODORSAL C6-C8
T1
LATISSIMUS DORSI M
CORDS
LONG THORACIC C5-C7
SERRATUS ANTERIOR M
MEDIAL PECTORAL C8,T1
SUBSCAPULAR NN C5,6
SUBSCAPULARIS M
TERES MAJOR M
PECTORAL MM
ARM muscles - action on shoulder and elbow
Flexors (anterior compartment):
* biceps brachii (both joints) - supination and flexion of forearm
- flexion of arm
* coracobrachialis (shoulder joint) - flexion and add. of arm
* brachialis (elbow joint) - flexion of forearm in all position
Extensors (posterior compartment):
* triceps brachii (both joints) - extension of forearm
- extension of arm (long h.)
Anterior ( flexor) compartment
Posterior (extensors) compartment
Important spaces of the shoulder region
Deltopectoral triangle – bounded by the clavicle superiorly, deltoid
laterally and the pectoralis major (clavicular head) medially.
Cephalic vein and deltoid branch of thoracoacromial artery.
Quadrangular space – bounded superiorly by the teres minor and
subscapularis, inferiorly by the teres major, medially by the long head
of the triceps and laterally by the surgical neck of the humerus.
Axillary nerve and posterior circumflex humeral artery and vein.
Triangular space – superiorly by the teres minor, inferiorly by the
teres major and laterally by the long head of triceps.
Circumflex scapular vessels.
Triangular interval - between the two heads of the triceps muscle,
inferior to the teres major.
Deep brachial artery and radial nerve.
1 – triangular space, 2 – quadrangular space, 3 – triangular interval
2
1
3
Brachial plexus injuries
Injuries to the brachial plexus affect movements (paralysis) and
cutaneous sensation (anesthesia). Signs and symptoms depend on the
part of the plexus involved.
Erb-Duchenne palsy is a paralysis of the arm caused by injury to the upper group of the
arm's main nerves (specifically, spinal roots C5-C7), almost always occurring during
birth. Depending on the nature of the damage, the paralysis can either resolve on its own
over a period of months, necessitate physical therapy or require surgery.
Dejerine-Klumpke (Klumpkes) palsy refers to paralysis of the lower brachial plexus.
A rare condition where a lower spine lesion causes paralysis of the forearm and hand
muscles. The lesion may occur during birth or as a result of infection, tumor or trauma.
Questions of the day!
1.
Which muscle is the primary supinator of the forearm?
1.
Biceps brachii
2.
Which muscle serves as the prime extensor of the forearm?
1.
Triceps
3.
If a tumor grows into the quadrangular space of the axillary region, which structures would be in
danger? (Axillary nerve, posterior circumflex humeral)
1.
Humeral loop
2.
Brachial plexus
4.
****Which artery may be damaged during the fracture of the shaft of the humerus?
1.
Posterior circumflex humeral artery