Lecture 9 Flashcards
Long thoracic, suprascapular, and dorsal scapular nerve all belong to which branches?
supraclavicular branches
Where are the supraclavicular branches largely located?
in the cervical region
Where are the infraclavicular branches primarily located?
axilla/armpit
What branches make up the infraclavicular branches?
Musculocutaneous (C5,6,7)
Axillary (C5/6)
Radial (C5 – T1)
Median (C5 – T1)
Ulnar (C8/T1)
What are the branches of the musculocutaneous nerve?
C5, 6, 7
What are the branches of the axillary nerve?
C5, 6
What are the branches of the radial nerve?
C5-T1
What are the branches of the median nerve?
C5-T1
What are the branches of the ulnar nerve?
C8/T1
Any injury to nerves will be felt __ to the site of injury.
distal
What is the origin of the musculocutaneous nerve?
terminal branch of lateral cord
What are the functions (motor and sensory) of the musculocutaneous nerve?
Motor to anterior arm:
- Coracobrachialis
- Biceps
- Brachialis
Sensory to :
- Skin of anterolateral forearm
Where is the most likely site of injury for musculocutaneous nerve?
in the coracobrachialis muscle belly
What is the pathway of the musculocutaneous nerve?
- Terminal Branch of lateral cord within axilla
- Travels through the coracobrachialis muscle belly
*Most likely site of injury - Innervates muscles of the anterior compartment of the arm
- Continues after passing the cubital fossa as the Lateral. Cutaneous N. of forearm
What is the name of the musculocutaneous nerve after is passes the cubital fossa?
lateral cutaneous nerve of the forearm
What is the origin of the axillary nerve?
terminal branch of posterior cord
What are the functions (motor and sensory) of the axillary nerve?
Motor to lateral shoulder:
- Deltoid
- Teres minor
Sensory to:
- Skin of lateral shoulder
What is the easiest way to assess nerve damage?
strength testing
What is the pathway of the axillary nerve?
- heads posteriorly in axilla
- Travels through the quadrangular axillary space
- Wraps around posterior aspect of humeral neck
- Relationship with the surgical neck of humerus
*Most likely site of injury - Innervates deltoid and Teres minor
Where is the most likely site of injury for the axillary nerve?
surgical neck of humerus due to a fracture
If you injure the axillary nerve, what are the results?
abduction, external rotation, numbness and tingly on skin of lateral shoulder
What does long term nerve damage lead to?
atrophy
What can a long term axillary nerve injury cause?
deltoid atrophy
What is the origin of the radial nerve?
terminal branch of posterior cord
What are the functions (motor and sensory) of the radial nerve?
Motor To:
- Extensor muscles of posterior arm
- Extensor muscles of posterior forearm
- Brachioradialis
- Supinator muscle
Sensory to:
- Skin of posterior arm, forearm and hand
- Dorsal surface of digits 1, 2, 3 and lateral ½ of digit 4 (typically written as lateral 3.5 digits, dorsal surface)
What is the pathway of the radial nerve?
- heads posteriorly in axilla
- Travels posteriorly, inferior to the quadrangular axillary space
wraps around posterior aspect of humeral shaft - Relationship with the radial groove of humerus
*Most likely site of injury - Innervates extensors of arm and forearm and supinator
What is the most likely site of injury of the radial nerve?
radial groove (spiral groove) of humerus
T/F: The Radial nerve has a relationship with the cubital fossa by traveling through it.
True
What are the sensory branches in the posterior arm of the radial nerve?
Post. Cutaneous Nerve of Forearm
Lower lateral cutaneous nerve of arm
Which branch of the radial nerve innervates the muscles in the posterior compartment of the forearm?
deep branch (motor)
Which branch of the radial nerve contributes to the cutaneous innervation of the dorsal hand & fingers?
superficial branch (sensory)
If the radial nerve is injured which functions are affected?
Loss of elbow extension, loss of wrist extension, loss of finger extension, weakness in supination
What nerve is associated with “wrist drop”?
radial nerve
What is the origin of the median nerve?
terminal branch of lateral and medial cords
What are the functions (sensory and motor) of the median nerve?
Motor to Muscles of the anterior forearm and hand:
- Flexors of wrist
- Pronators of forearm
- Flexors of Digits 1, 2, 3
- Lumbricals 1 and 2
- Thenar muscles
Sensory to:
- Palmer surface of digits 1, 2, 3 and lateral ½ of digit 4
(typically written as lateral 3.5 digits, palmer surface)
What is the pathway of the median nerve?
- heads inferiorly from axilla, travelling down antero-medial arm (within layers of muscle)
- crosses anterior elbow within cubital fossa
*likely site of injury - travels down anterior forearm
enters hand via carpal tunnel
*likely site of injury
What are the likely sites of injury of the median nerve?
- cubital fossa
- carpal tunnel
If there is damage of median nerve in the cubital fossa, what occurs?
loss of wrist flexion, digit flexion, pronation, thumb movement, sensory loss in hand
What is carpal tunnel syndrome?
compression of the median nerve as it passes through the carpal tunnel
How does carpal tunnel arise?
- typing
- mechanics
- pregnancy
- obesity
Where is the primary area of impact when there is compression at the wrist?
function of the hand –> thenar muscles
- weakness in thumb movement, and numbness & tingling of 3.5 digits
As the median nerve compression (carpal tunnel) progresses, where can sensory changes radiate to?
forearm & axilla
Which muscles show atrophy quicker if it is not innervated?
smaller muscles
Ape hand deformity is a lesion at which nerve?
median nerve
What is the origin of the ulnar nerve?
terminal branch of medial cord
What are the functions (sensory and motor) of the ulnar nerve?
Motor to medial forearm and hand:
- Medial ½ of flexor digitorum profundus,
- Flexor carpi ulnaris
- Hand intrinsics: Lumbricals 3&4, Hypothenar group, Palmer and Dorsal Interossei
Sensory to:
- Palmer and Dorsal surface of medial ½ of digit 4, And all if digit 5 (typically written as medial 1.5 digits)
What is the pathway of the ulnar nerve?
- heads inferiorly from axilla, travelling down antero-medial arm (protected by muscle)
- passes posterior to medial epicondyle,
*Most likely site of injury - travels down medial forearm
- enters hand external to carpal tunnel
What is the most likely site of injury of the ulnar nerve?
medial epicondyle (funny bone)
If the ulnar nerve is damaged, where will you see
loss of hand function specific to 2, 3, 4, 5, atrophy
What would the fracture of the medial epicondyle of the humerus cause?
ulnar claw hand
What are nerves?
WHITE matter pathways that provide a route for motor and sensory signals to travel between PNS and CNS
Spinal nerves are __ and will carry signals to and from target/receptors on the same side of the body.
ipsilateral
posterior/dorsal root carries __/__ information into CNS.
sensory/afferent
Ventral/anterior root carriers __/__ information out of CNS
motor/efferent
Ventral & dorsal roots come together to form a spinal nerve in the __ __.
intervertebral foramen
What is dermatome?
specific area on the skin innervated by a specific spinal root
What are the 2 test we can do to isolate injury of spinal nerves?
dermatome & myotome
What is myotome?
specific group of muscles innervated by a particular spinal root
What is the myotome and function of the nerve root C5?
myotome: deltoid muscle
function: abduction of arm at the shoulder
What is the myotome and function of the nerve root C6?
myotome: biceps
function: flexion of arm at the elbow
What is the myotome and function of the nerve root C7?
myotome: triceps
function: extension of the arm at the elbow
What is the myotome and function of the nerve root C8?
myotome: small muscles of the hand
function: finger flexion
What is the myotome and function of the the nerve root T1?
myotome: small muscles of hand
function: finger abduction
What is the dermatome and myotome of C5?
Dermatome = sensation of skin of anterior/lateral arm (skin over deltoid)
Myotome = muscle strength of deltoid (arm abduction)
What is the dermatome and myotome of C6?
Dermatome = sensation of anterior skin of thumb
Myotome = muscle strength of biceps (elbow flexion)
What is the dermatome and myotome of C7?
Dermatome = sensation of anterior skin of digits 2 and 3
Myotome = muscle strength of triceps (elbow extension)
What is the dermatome and myotome of C8?
Dermatome = sensation of skin of digits 4 and 5
Myotome = muscle strength of finger flexors
What is the dermatome and myotome of T1?
Dermatome = sensation of skin of antero/medial elbow
Myotome = muscle strength of finger abductors
Why is the reflex arc the simplest of all neural responses?
- automatic
- predictable
- acquired
What are the branches of the arch of aorta?
- left subclavian artery
- left common carotid artery
- brachiocephalic artery
What are the branches of the brachiocephalic arterty?
- right subclavian artery
- right common carotid artery
The subclavian artery goes under the __
clavicle
What is the only source of the blood supply to the upper limb?
subclavian artery
What is the pathway and names of the subclavian artery down the arm?
Subclavian –> under clavicle –> passes axilla –> Axillary artery –> goes to brachial –> brachial artery
Which artery supplies the supraspinatus muscle?
Suprascapular artery
What is the pathway of the suprascapular artery?
goes posteriorly and enters the supraspinous fossa –> passes to infraspinous fossa –> supraspinatus and infraspinatus
Where does the suprascapular artery originate from?
subclavian artery
What does the dorsal scapular artery supply?
levator scapuale, rhomboid major & minor
Axillary artery is the continuation of the ?
subclavian artery
Where does the axillary artery start?
lateral margin of rib 1
When does the axillary artery become the brachial artery?
when it reaches the inferior border of pectoralis major (anterior) or teres major (posterior)
What is the division of the axillary artery based on?
course of pectoralis minor
What is the branch of the 1st part of the axillary artery?
superior thoracic artery
What are the branches of the 2nd part of the axillary artery?
thoraco-acromial artery
lateral thoracic artery
What are the branches of the 3rd part of the axillary artery?
subscapaular
anterior circumflex humeral artery
posterior circumflex humeral artery
What does the thoraco-acromial branch supply?
pectoral and deltoid regions
What does the lateral thoracic artery supply?
lateral thoracic wall (serratus anterior)
What does the subscapaular artery supply?
muscles of the scpaular region
What does the anterior and posterior circumflex humeral arteries supply?
muscles attached to proximal end of humerus
What are the main branches of the brachial artery?
deep brachial (profonda brachii) and muscular branches (2-5)
Where does the deep brachial (profonda brachii) artery travel and supply?
moves posteriorly towards radial groove (accompanying radial nerve) supplying posterior arm compartment
What does the muscular branches of the brachial artery supply?
anterior compartment muscles
What does the brachial artery divide into?
ulnar and radial arteries
T/F: Radial artery is larger than ulnar artery
False, smaller
What does the ulnar artery lie under and what accompanies it?
under flexor carpi ulnaris accompanied by ulnar nerve
What is the pathway of the ulnar artery?
lies under flexor carpi ulnaris and is accompanied by ulnar nerve on its way –> passes on medial side of wrist in front of flexor retinaculum lateral to pisiform –> hand and takes part in formation of palmar arterial arch
What does the ulnar artery supply?
elbow
muscles of anterior compartment on medial side
deep muscles of anterior compartment of forearm
majority of muscles of posterior compartment of wrist joint
Which side does the radial artery supply?
lateral side of forearm
What is the pathway of the radial artery?
descends on the lateral side of the forearm under the cover of the brachioradialis muscle with the superficial branch of the radial nerve –> distal part of the forearm, it passes through the anatomical snuff box –> after passing through the first interosseous space in hand, enters the palm of the hand and takes part in forming the deep palmar arch
What is the major source of blood supply for the dorsal surface of the hand?
radial artery
What do the branches of the radial artery form at the level of the carpal bones?
dorsal arterial arch
Some branches of the radial artery will joint with terminal branches of the ulnar artery for form which structure?
superficial and deep palmar arterial arch
Palmar arches are protected by?
palmar aponeurosis
What do the superficial veins run in (where are they located in the skin)?
superficial fascia
What do the deep veins run with?
arteries
What is the medial branch of the venous arch called?
basilic
What is the lateral branch of the venous arch called?
cephalic
What is the pathway of the basilic vein?
Basilic (basement) –> up on medial side within superficial fascia –> down in the arm pierces deep fascia and goes deep and enters axilla –> axillary vein
What is the pathway of the cephalic vein?
Cephalic (lateral) –> travels lateral side within superficial fascia –> connected w/ basilic vein through median cubital vein (in cubital fossa) –> passes between deltoid and pec major –> drains into axillary vein
From the axillary vein, what is the pathway to the right atrium?
Axillary –> subclavian –> internal jugular vein –> brachiocephalic –> right & left come together to form superior vena cava –> drains into right atrium
What is the cubital fossa?
Triangular impression in front of elbow joint
What is on the lateral and medial side of the cubital fossa?
brachioradialis on lateral side & pronator teres on medial side
What tendon passes through the cubital fossa and divides it into medial and lateral?
tendon of biceps
Which nerves pass through the cubital fossa?
radial and median
What is the axilla? Where is it situated?
a four-sided pyramidal space situated between the upper part of the arm and the chest wall
What is the axilla the transition region for?
between the root of the neck and the upper limb
T/F: most of the structures that enter or leave the upper limb pass through the axilla
True
What forms the anterior wall of the axilla?
pectoral region
What forms the posterior wall of the axilla?
scapular region –> subscapularis mucscle, teres major, latissimus dorsi
What forms the medial wall of the axilla?
the upper 4 ribs and the upper part of he serratus anterior muscle that attaches to these ribs
What forms the lateral wall of the axilla?
narrow and is formed by the upper part of the humerus
What are the contents of the axilla?
Axillary artery and its branches
Axillary vein and its tributaries
Infraclavicular part of the brachial plexus
Axillary Lymph nodes
