Upper Limb Applied Anatomy Flashcards
What two nearby neurovascular structures could be damaged if the surgical neck of the humerus is fractured?
The axillary nerve and posterior circumflex artery
What will axillary nerve (C5, C6) damage cause?
It gives rise to the superior cutaneous nerve of the arm that innervates the skin over the lower deltoid area (regimental badge area) so you’d experience a loss of sensation here. Paralysis of the teres minor and deltoid muscle as it innervates them so patient can’t abduct arm beyond first 15 degrees
Where is the radial groove of the humerus found on the humerus? What lies in it?
It runs diagonally down the posterior surface of the humerus. The radial nerve and the profunda brachii artery lie in the groove.
A mid-shaft humeral fracture will affect which structures? What will this result in?
Radial nerve and profunda brachii artery will be affected. Triceps are not affected as branches from radial nerve to triceps are proximal to radial groove. Extensors of the wrist are paralysed resulting in unopposed flexion if the worst known as wrist drop. Sensory loss over dorsal surface of hand and lateral 3 and half digits dorsally.
What typically causes a supraepicondylar fracture (distal humeral fracture)?
Falling on an outstretched hand causing Hyperextension of the elbow. Most common in children.
What is a serious consequence of a supracondylar fracture?
The direct damage or the swelling resulting from can interfere with the brachial artery. The resulting ischaemia can cause Volkmanns ischaemic contracture- uncontrolled flexion of the hand as flexor muscles become fibrotic and short.
What neurovascular structure could a medial epicondyle fracture damage? What would this lead to?
Could damage the ulnar nerve and cause an ulnar claw. There will be loss of sensation over the medial 1 and half fingers of the hand on both the dorsal and palmar surfaces.
What usually causes axillary nerve damage?
Surgical neck of the humerus fracture
What is the most commonly fractured bone in the body?
The clavicle- results from falls on to the shoulder or on an outstretched hand
What is the function of the clavicle?
To transmit forces from the upper limb to the axial skeleton
What is this? What is a complication of this?
A clavicle fracture- usually occurs at the weakest part of the clavicle which is the mid shaft. Lateral 1/3 is displaced inferiority due to weight of arm laterally and weight of pectoralis major medullary. Medial 2/3 is displaced superiors due to sternocleidomastoid muscle. Suprascapular Nerve travels posterior to clavicle so could be damage. It innervates supraspinatus so abduction of arm could stop and innervates infrasoinatus which are lateral rotators. So could cause waiters tip.
How common are fractures of the scapula?
Very uncommon so indicates that there has been severe chest trauma
What causes a winged scapula?
Serratus anterior paralysis- it originates in the surface of the 1st to 8th ribs and inserts onto medial border of the scapula pulling it forward in internal rotation. Long thoracic nerve supplies this muscle so damage to this nerve can also cause winging of scapula as there isn’t anything to pull it forward.
What usually causes accessory nerve damage? How can you test the accessory nerve? What are the clinical presentations of a damaged accessory nerve?
Iatrogenic- damage during a cervical lymph biopsy or cannulation of the internal jugular vein
You can test it by asking patient to shrug shoulders- as upper fibres of trapezius does that
Muscle wasting, partial paralysis of sternocleiodomastoid and asymmetrical neckline
Where is the subacromial bursa located?
Inferior to acromion, deltoid and coraco-acromion ligament and superior to the supraspinatus tendon.
So separates acromion from rotator cuff (mainly the supraspinatus)
Where is the subscapcular bursa located?
Between the subscapularis tendon and the joint capsule
Which way does the humerus commonly move in a shoulder dislocation? What can it damage?
(Anteriorly and) Inferiorly as this is the weakest point of the joint capsule. The axillary nerve passes between the subscapularis and teres major from the Axilla and can be damaged- causing paralysis of deltoid and loss of sensation over regimental badge area.
What roots make up the brachial plexus? Where are they found?
The anterior rami of C5, C6, C7, C8 and T1- they emerge from between the scalenes anterior and scalenes medius in the neck and enter the base of the neck. This is called the posterior triangle of the neck and is formed by the boundaries of the sternocleidomastoid, clavicle and trapezius.
What commonly causes long thoracic nerve palsy? What does this cause?
Traction (stretch) injuries usually when upper limb is stretched violently.
Causes winging of scapula
How are the trunks of the brachial plexus formed? Where are they found?
Found in the posterior triangle of the neck
Upper trunk- combination of C5 and C6
Middle trunk- continuation of C7
Lower trunk- combination of C8 and T1
What roots does the musculocutaneous nerve arise from? What are it’s sensory and motor functions?
C5-C7
Flexion and supination of the forearm at the elbow
Sensory function of the lateral anterior forearm
What roots does the axillary nerve arise from? What are it’s sensory and motor functions? What course does it take?
It arises from the posterior cord (C5, C6). It passes through the quadrangular space and then curls round the surgical neck of the humerus along with the posterior circumflex artery. It supplies the deltoid (abduction after 15 degrees), teres minor (lateral rotation) and the long head of the triceps brachii. It also gives off the superior lateral cutaneous nerve of the arm with innervates the inferior region of the deltoid-the regimental badge area
What are the dermatomes of the arm?
If there is injury to the brachial plexus and C5, C6 were affected what would result?
Erb-duchenne syndrome as musculotaneous and axillary will be affected
Loss of flexion of the forearm, loss of sensation down lateral side of the arm, limb is pronated- waiters tip position
What are the origins and insertion of the biceps brachii? What is its function?
Long head arises from supragenoid tubercle and leaves the capsule of the shoulder joint by passing along the intertubercular groove beneath the transverse ligament. Short head arises from coracoid process of scapula. Both heads unite and insert onto radial tubersoity. From the medial border of this tendon a bicipital aponeurosis blends into the deep fascia of the forearm forming the roof of the cubical fossa.
Main function is supination of forearm but also causes flexion
What is the muscle in the green? What is its origins, insertion, innervation and function?
Brachialis
Origin- anterior distal half of the humerus and intermuscular septa
Insertion- coronoid process of ulna and ulna tuberosity
Innervation- musculocutaneous nerve with contributions from radial nerve
Function- Main flexor at elbow joint
What is the origin, insertion, innervation, arterial blood supply and function of triceps brachii?
Innervation- radial nerve
Arterial blood supply- profunda brachii artery
What connects with what in the elbow joint?
The capitulum of the humerus articulates with the radial head of the radius. The trochlea of the humerus articulates with the trochlear notch of the ulna.
What neurovascular structure is affected if the humerus fractures at the mid shaft?
Radial nerve as it passes along the radial groove at the back of the humerus.
Patient will be unable to use extensors of wrist and fingers, presenting with wrist drop and inability to extend fingers actively
Patients will always have sensory loss over dorsum of the hand
What type of fracture of the humerus usually results from a fall and commonly occurs in children? What are the complications arising from it?
It is important to examine the brachial pulse at regular intervals to see if fluid build up is compressing the brachial artery or not.
What has usually happened in an elbow dislocation?
Usually the trochlear notch slips backwards- called a posterior elbow dislocation.
What is Saturday night Palsy?
What is this?
Olecranon bursitis- enlarged subcutaneous bursa following repeated trauma of resting elbows on table
What is this?
Olecranon bursitis- enlarged subcutaneous bursa following repeated trauma of resting elbows on table
What is this?
Olecranon fracture- transverse fracture, means that triceps are unable to extend the elbow
What muscle is this? What is its function and innervation?
Brachioradialis
Originally from extensor muscle mass so innervated by radial nerve
Migrated around to front- so is flexor of the elbow
Originates from lateral supracondylar ridge and inserts to distal radius.
What is the green muscle? Outline its origin, insertion, innervation and function.
Flexor Carpi ulnaris
Origin- medial epicondyle, olecranon
Insertion- it’s tendon contains the pisiform bone and inserts into hook of hamate by pisohamate and 5th metacarpal by pisometacarpal ligament
Innervation- ulnar nerve
Function- flex, adducts the wrist
What is this muscle? Describe it.
Palmaris longus- absent in 10-15% people
Origin- medial epicondyle
Travels over flexor retinaculum
Insertion- deep fascia of hand
Innervation- median nerve
Function- flexion of wrist
What are the superficial muscles of the forearm that flex the wrist?
What muscle makes up the intermediate layer of the front of the forearm?
Describe the deep layer of the anterior forearm.
What muscle is this? What nerve is associated with the muscle?
Supinator- two heads arise from lateral epicondyle and posterior surface of ulna and insert into posterior surface of radius
Radial nerve divides into suoerficial and deep branches on supinator, the deep branch passes between the two heads of the supinator where it renamed the posterior interosseus nerve. This nerve supplies all extensor muscles of forearm (extensor Carpi radialis longus is already supplied before this branch is given off though).
Name the superficial and deep muscles of the posterior forearm.
Where can you find the radial pulse?
Near the wrist- between the tendons of the brachioradialis and flexor Carpi radialis
What tendons pass under the flexor retinaculum?
Flexor Carpi radialis (but isn’t in carpal tunnel), flexor digitorum superficialis, flexor digitorum profundus and flexor pollicis longus
What type of fracture is this?
Occurs in children and is an incomplete fracture
Where one side of the bone is broken and the other side is only bent
Describe the Innervation of the hand.
What makes up the wrist joint?
Radius and scaphoid and lunate bones
Describe ulnar claw
A hand in ulnar claw position will have the 4th and 5th fingers extended at the metacarpophalangeal joints and flexed at the interphalangeal joints. The patients with this condition can make a full fist but when they extend their fingers, the hand posture is referred to as claw hand. The ring- and little finger can usually not fully extend at the PIP joint.
