Upper limb 2 Flashcards
What is the brachial plexus?
Network of nerve fibres that supplies the skin and musculature of the upper limb. Initiates in the root of the neck, passes through the axilla, and traverses through the upper extremity. Brachial plexus is divided into five sections: Root, trunks, divisions, cords and branches.
Which spinal nerves the roots of the brachial plexus?
Anterior rami of C5-8 and t1
Where do spinal nerves leave the spinal cord?
Intervertebral foramina of the vertebral column
How many trunks comprise the brachial plexus?
Three
What are the three trunks that form the brachial plexus?
Superior
Middle
Inferior
Which spinal nerves form the superior trunk?
Union of anterior rami of c5 & C6
Which two nerves arise from the superior trunk?
Subclavian nerve,
Suprascapular nerve
Which root forms the middle trunk?
Directly from the anterior rams of C7.
Which roots form the inferior trunk?
Arises from the anterior rami of C8 and T1
What are divisions in terms of the brachial plexus?
Divisions are bifurcations of the trunks, and are the third section of the brachial plexus. Each trunk provides an anterior branch and posterior branch
Where do the divisions leave the posterior triangle?
Pass into the axilla and recombine into the cords
What are the three cords?
Lateral, posterior and medial
what is the lateral cord?
Formed from the union of t the two anterior divisions of the superior and middle trunk
Which nerve is continuous with the lateral cord?
Musculocutaneous nerve
Which nerves arise from the lateral cord?
Lateral pectoral nerve
Musculocutaneous nerve
Which divisions form the posterior cord?
Three posterior divisions
Which nerve branches arises from the posterior cord?
Subscapular, throacodorsal and lower sub scapular nerve
Continues as axillary and radial nerve
AXILLARY AND RADIAL NERVE
Which cord arises as a continuation of the anterior division of the inferior trunk?
Medial cord
What forms the medial cord?
Continuation of the anterior division of the inferior trunk
Which nerves branch from the medial cord?
Medial pectoral, cutaneous nerve of the arm, and the cutaneous nerve of the forearm. Continues as the ulnar nerve.
ULNAR NERVE
What are supraclavicular branches?
From the roots and the trunks (dorsal scapular nerve, long thoracic nerve)
What are infraclavicular branches?
Side branches to pectoral girdle muscle, and the main peripheral nerves (Radial ulnar and median)
Which roots form the musculocutaenous nerve?
C5-7
Terminal branch of the lateral cord
What are the motor functions of the musculocutaneous nerve?
Innervates the brachialis,biceps brachii, and coracobrachialis
What are the sensory functions of the musculocutaneous nerve?
Cutaneous innervation of the lateral forearm, lateral cutaneous nerve of the forearm
Which roots form the ulnar nerve?
C8 & T1, terminal branch of the medial cord, passes posteriorly to the medial epicondyle of the humerus
What are the motor functions of the ulnar nerve?
Innervates the muscles of the hand (excluding the thenar muscles, and two lateral lumbricals), flexor carpi ulnaris, and medial half of flexor digitorum profundus. Enters through the anteromedial aspect of the hand; terminal branches to innervate the hypothenar eminence, two media lumbricals: Palmar interossei, and the dorsal interossei.
What innervates does the ulnar nerve have on the arm?
No innervation of the arm
What cutaneous innervation does the ulnar nerve have on the hand?
Medial cutaneous innervation of the hand (Little finger, medial half of the ring finger)
Which roots form the median nerve?
C6-T1
What are the motor functions of the median nerve?
Innervates majority of flexor muscles in the forearm: Pronator teres, flexor carpi radialis, palmaris longus, and flexor digitorum superficialis.
Where does the media nerve crosses the wrist and enter the hand?
Through the carpal tunnel
Which hand muscles are supplied by the median nerve?
Thenar eminence
Lateral lumbricals
What are the sensory functions of the median nerve?
Palmar cutaneous branch innervates the lateral part of the palm, and the digital cutaneous branch- innervates the lateral 3 ½ fingers on the anterior surface of the hand.
No innervation in the arm.
Which cord does the radial and axillary nerves arise from?
Posterior cord
Which nerve innervates the deltoid muscle?
Axillary nerve
Which nerve innervates the teres minor?
Axillary nerve
Describe the pathway of the axillary nerve?
The axillary nerve traverses laterally posterior the glenohumeral joint to contact the deep surface of the deltoid muscle. Cutaneous branch pierces muscle to innervate associated skin.
What structures are innervated by the radial nerve?
All arm and forearm posterior muscles, NO intrinsic hand muscles
Where does the radial nerve pass distally?
Through the radial groove of the humeral shaft
What are the two branches of the radial nerve?
Superficial and deep branch
Describe the pathway of the radial nerve
Cutaneous branches in arm and forearm. Radial nerve gives branches to triceps muscle, and passes distally through the radial groove of the humeral shaft. Passes anteriorly to the lateral epicondyle of the humerus, divides to provide the superficial and deep branches.
What is the superficial radial nerve branch?
Sensory branch supplies the dorsal, cutaneous to the dorsolateral hand
What is the deep radial nerve branch?
Supplies motor innervation to the posterior forearm muscles
Which nerve supplies the medial 1 1/2 digits?
Ulnar nerve
Which nerve supplies the medial 3 1/2 digits?
Median nerve
Where does the left subclavian artery arise from?
Directly from the arch of the aorta
The arterial supply to the upper limb initiates as the_____ artery
Subclavian artery
Where does the right subclavian artery arise from?
From the brachiocephalic trunk
Where does the subclavian artery travel?
Laterally towards the axilla, divided into the three sections based to the relatively position to the anterior scalene muscles
What is the first part of the subclavian artery?
Origin of the subclavian artery of the medial border of the anterior scalene muscle
Which muscle does the axillary artery lie deep too?
Pectoralis minor
What encloses the axillary artery?
Axillary sheath
What is the axillary sheath?
Fibrous layer that coves the artery, and the three cords of the branchial plexus).
Which artery is a continuation of the axillary artery?
Brachial artery
Where does the brachial artery pass?
Passes the lower border of the teres major
Which artery forms the main blood supply to the arm?
Brachial artery
Which artery arises from the brachial artery?
Profunda brachii
Which nerve travels with the profunda brachii into the radial groove of the humerus?
Radial groove
Which muscles are supplied by the profunda brachii?
Posterior aspect of the upper arm (triceps brachii)
Where does the brachial artery proper descend into?
Cubital fossa, inferior to the bicipital aponeurosis
Where does the brachial artery proper bifurcate?
In the cubital fossa
Which two arteries arises from the bifurcation of the brachial artery?
Radial and ulnar arteries
How the scapular arteries ensure there is efficient constant supply?
Anastomosis
What structures are supplied by the radial artery?
Supplies the posterolateral aspect of the forearm, contributes to anastomotic networks surrounding the elbow joint and carpal bones
What structures are supplied by the ulnar artery?
Supplies the anteromedial aspect of the forearm.
Contributes to the anastomotic network surrounding the elbow joint
Which two main branches arise from the ulnar artery?
Anterior and posterior interosseous arteries
What do the anterior and posterior interosseous arteries supply?
Deep structure in the forearm
Where does the posterior interosseous artery supply?
Pierces the superior region of the interosseous membrane, and passes distally on to its posterior surface
Which artery is a continuation of the subclavian artery?
Axillary artery
Where does the radial artery terminate?
Thenar eminence, forming the deep palmar arch
When do arterial arches form with the hand and wrist?
Arterial arches form when the arteries of the forearm cross the wrist
Which two arteries contribute to the palmar arches?
Radial and ulnar arteries
Superficial and deep palmar arches
Anterior interosseous artery also contributes
Which artery forms the posterior aspect of the hand?
Posterior interosseous artery crosses the wrist and forms the dorsal carpal arch, radial artery contributes
Which parts of the hand do the arches supply?
Branches to the digits, the palmar and dorsal digital arteries
What are the two palmar arches?
Superficial and deep palmar arches
What are deep veins?
Accompanies arteries
What direction is venous flow in?
Distal to proximal
What are deep veins considered as?
Venae comitantes
What are Venae comitantes?
Accompanying veins; multiple veins form a network of relatively smaller arteries which they accompany. Counter-exchange mechanism provides heat exchange (Blood cooled by the extremities can be warmed on return to the trunk) in addition to the artery pulse promoting venous flow (increases venous return).
Interconnections through smaller veins, present an arrangement that is intimately associated.
What are the two main superficial veins of the forearm?
Basilic vein
Cephalic vein
Where do the small vein sin the phalanges drain into?
Into a superficial venous network present on the dorsal of the hand, residing within the subcutaneous tissue of the upper limb,
Where is the superficial venous network located?
Dorsum of the hand
Where does the basilic vein arise?
Originates from the dorsal venous network of the hand, and ascends on the medial aspect of the upper limb.
Where does the basilic vein enter?
Border of teres major, vein traverses deep into the arm forming the venae comitantes and combining with the brachial vein to forth axillary vein
Where does the cephalic vein travel?
Ascends the anterolateral aspect of the upper limb
Where does the cephalic vein enter into the clavipectoral triangle?
Traves between the deltoid and pectorals major muscle as the deltopectoral groove
Where do the basilic and cephalic veins both drain into?
Axillary vein
How are the cephalic and basilic veins connected at the elbow?
Median cubital vein
Where are the cubital vein s located?
Located within the cubital fossa
Which nodes are found within the axillary region?
Axillary nodes
Which nodes are clinically relevant in breast cancer?
Axillary nodes