Elbow, forearm and wrist B Flashcards
Describe the articulation of the radius and ulna with the carpal bones.
The distal end of the radius articulates with scaphoid and lunate
The distal end of the ulna does not directly articulate with the carpal bones, it articulates with an articular disc
What is the name given to the joint between the first and second rows of carpal bones?
Midcarpal joint
Which nerves are responsible for: Elbow flexion Elbow extension Wrist flexion Wrist extension
Elbow flexion C56 Elbow extension C78 Write flexion C67 Wrist extension C67
Which muscles are involved in supination?
Supinator
Biceps brachii
(EPL, ECRL)
Which muscles are involved in pronation?
Pronator teres
Pronator quadratus
(FCR, PL, brachioradialis)
Describe how the biceps contribute to supination.
The biceps tendon inserts into the radial tuberosity
When prone, the radial tuberosity is turned posteriorly
So then when the biceps contract, it will pull the tuberosity back around
Which muscles are important for: Flexion of the wrist Extension of the wrist Radial deviation (abduction) Ulnar deviation (adduction)
Flexion of the wrist FCU, FCR (APL, PL) Extension of the wrist ECRL, ECRB, ECU Radial deviation (abduction) ECRL, ECRB, FCR, APL Ulnar deviation (adduction) ECU, FCU
What is an important branch of the ulnar artery?
Common interosseous branch
This splits into the anterior and posterior interosseous arteries . Posterior pierces the interosseous membrane and goes behind
What are the arterial arches of the hand made up of?
Anastomosis of the radial and ulnar arteries
What is the name given to the space anterior to the elbow and what are its boundaries?
Cubital fossa
Superior border – line between the medial and lateral epicondyles of the humerus
Medial border – lateral border of pronator teres
Lateral border – medial border of brachioradialis
What happens to the biceps aponeurosis in this area?
It merges with the fascia of the region
What important vessels and nerves pass through the cubital fossa?
Brachial artery and brachial veins (venae comitantes around brachial arteries)
Median nerve
radial nerve
clinical significance: you put stethoscope here during BP measurement to listen to brachial artery
NB the superficial venous system is considered SUPERFICIAL to cubital fossa so not within it (this incl. basilic, cephalic and median cubital v)
Describe the arrangement of superficial veins in the upper limb.
The cephalic vein (runs laterally) and the basilic vein (runs medially) originate from the dorsal venous arch of the hand
The basilica vein joins venae commitantes (brachial vein) to form the axillary vein in the arm
The cephalic vein joins the axillary vein at the axilla
The axillary vein becomes the subclavian vein at the level of the 1st rib
NOTE: there is normally a median cubital vein joining the cephalic and basilic at the cubital fossa
Describe the deep venous drainage of the upper limb. (arm + forearm)
The deep venous drainage of the upper limb runs in reverse to the arterial supply
What are the two venous arches present on the palmar side of the hand?
Superficial venous palmar arch
Deep venous palmar arch
Where are the main lymph nodes are found in the upper limb?
What does the lymphatic drainage of the upper limbs follow?
Cubital lymph nodes (in cubital fossa)
Axillary lymph nodes also drain from nodes of the distal parts of the upper limb
The lymphatic drainage of the UPPER LIMB can be split into superficial and deep systems too which FOLLOW THE VEINS
Name the difference subsets of axillary lymph nodes.
Pectoral Central Apical Subscapular Humeral
State which spinal nerves roots make up: Musculocutaneous nerve Radial nerve Median nerve Ulnar nerve
Musculocutaneous nerve C567 Radial nerve C5678 T1 Median nerve C678 T1 Ulnar nerve C8 T1
What is the role of the musculocutaneous nerve in the forearm and arm?
It has a lateral cutaneous branch, which provides SENSORY innervation to the lateral part of the forearm
in the arm, it supplies all the muscles in the anterior compartment
Describe the passage of the median nerve through the arm and what muscles does the median nerve supply?
Courses through the anterior compartment of the arm (no significant branches) and lies anterior to the elbow, with the brachial artery ie in cubital fossa (easily damaged!)
Main nerve to the anterior compartment (flexor) muscles of the forearm with the EXCEPTION of flexor carpi ulnaris which is supplied by the ulnar nerve AND half of flexor digitorum profundus (other half supplied by ulnar)
Where can the median nerve be damaged easily?
Elbow and wrist
Why is the ulnar nerve easily damaged? (think of its course)
It goes through the posterior compartment of ARM (doesnt really innervate the arm muscles) and then goes behind the medial epicondyle of the humerus where it can easily be damaged
It can also be damaged at the wrist
Where is the radial nerve easily damaged?
It lies close to the humerus in the radial groove (spiral groove) so fractures of the humerus could damage the radial nerve
It can also be damaged in the axillary region
What two branches does the radial nerve divide into?
Posterior interosseous nerve (motor to extensor compartment of forearm)
Superficial radial nerve (sensory to dorsum/back of hand)
Which muscles of the forearm does the ulnar nerve supply?
FCU
Ulnar half of FDP
What is the role of the flexor retinaculum?
It holds down the long tendons and prevents them from bowing
what are the two joints between the radial and ulnar bones ?
proximal and distal radio-ulnar joints
which ligament is important in the proximal radio-ulnar and what is its function
the annular ligament of the radius
this ligament wraps around the radius and then attaches to the ulna. Its function is to keep the radial head attached to the radial notch of the proximal ulnar bone during pronation
slide 29 picture top right
What are the radial and ulnar notches?
radial notch is a depression on the ulnar bone and ulnar notch is a depression on the radial bone. These notches are important for the proximal and distal radio-ulnar joints. eg the radial notch on the ulnar bone allows the radial bone to attach to the ulnar bone
what is the main nerve of the hand
ulnar nerve
what does the radial nerve supply
ALL muscles in posterior compartment of ARM AND FOREARM
course of the radial nerve?
Axillary region:
The radial nerve lies posterior to the axillary artery in the axilla and enters the posterior compartment of the arm under teres major muscle.
Posterior compartment of arm:
In the posterior compartment of the arm, it winds it way around the spiral groove of the humerus, it then enters the anterior compartment of the ARM. Afterwards, it descends inferiorly and courses anterior to the lateral epicondyle at the level of the elbow joint. It enters the cubital fossa, where it divides into superficial and deep branches.
In the forearm:
The superficial branch courses goes all the way down to the hands and provides sensory innervation to back of hand
The deep branch gives off the posterior interosseous nerve (motor-supplies posterior forearm extensors) which terminates at the level of the wrist joint.
summarise the innervation of the forearm
The Radial Nerve supplies all posterior muscles.
The Ulnar Nerve supplies only FCU and the Ulnar half of FDP .
The Median Nerve supplies all of the remaining anterior muscles.
