Upper Limb MSK anatomy Flashcards
what is the pectoral girdle/ shoulder girdle?
clavicle, scapula and the muscles attached to these bones
what is the arm?
region between the shoulder and elbow joints
what is the forearm?
region between the elbow and wrist joint
what is the glenohumeral joint?
shoulder joint
synovial ball and socket joint formed by the articulation between the scapula and proximal humerus
what type of joint is the elbow?
synovial hinge joint
which bones articulate at the elbow joint?
distal humerus articulates with the ulna and radius
which joints join the radius and ulna?
radioulnar
what do the radioulnar joints allow?
pronation and supination of the forearm and hand
what is the radiocarpal joint?
wrist joint
synovial joint formed by the articulation between the distal radius and two of the carpal bones
which movements does the radiocarpal joint allow?
flexion, extension, abduction and adduction
anterior movement of the scapula
protraction
posterior movement of the scapula
retraction
name movements that the shoulder joint can make
flexion, extension, abduction, adduction, medial (internal) rotation, lateral (external) rotation, circumduction
what happens to the scapula when we raise our upper limb?
rotates
which movements can the elbow joint make?
flexion and extension
which movements can the radioulnar joints make?
pronation and supination
which movements can the wrist joint make?
flexion and extension, abduction and adduction
which movements can the fingers make?
flexion and extension, abduction and adduction
what is the ridge of bone on the posterior surface of the scapula?
spine
what does the lateral end of the spine of the scapula expand to form?
acromion
what does the acromium articulate with?
lateral end of the clavicle
what is the pectoral girdle?
clavicle, scapula and attached muscles
what is the shallow fossa on the lateral aspect of the scapula?
glenoid fossa
which joint is between the scapula and humerus?
glenohumeral joint
which projection of bone is superior to the glenoid fossa?
supraglenoid tubercle
which projection of bone is inferior to the glenoid fossa?
infraglenoid tubercle
what is the long bone of the arm?
humerus
what is the groove at the head of the humerus?
anatomical neck
name the sites of muscle attachments on the proximal humerus
greater tubercle
lesser tubercle
where is the surgical neck in relation to the tubercles?
just distal
which nerve runs close to the surgical neck and is vulnerable in fractures of the surgical neck or dislocation of the humeral head?
axillary nerve
which groove marks the path of the radial nerve?
radial/ spiral groove
which nerve is vulnerable in mid shaft humeral fractures?
radial
is there any bony articulation between the scapula and the posterior thoracic wall? why?
no
the scapula is surrounded by muscles
name the movements of the scapula?
protraction, retraction, elevation, depression, rotation
what movement does the scapula make when we raise our arms?
rotation
by now many degrees does the scapula rotate for every 2 degree abduction of the shoulder?
1 degree
which muscles comprise the anterior pectoral girdle?
pec major, pec minor, serratus anterior
which muscle protracts the scapula?
serratus anterior
name the two large muscles of the posterior pectoral girdle
trapezius, latissimus dorsi
name the smaller, deeper muscles of the posterior pectoral girdle
levator scapulae
rhomboid major
rhomboid minor
what do the posterior pectoral girdle muscles attach the scapula to (except latissimus dorsi)?
vertebral column
where does latissimus dorsi insert?
humerus
action of trapezius
upper part - elevates
middle parts - retracts
lower part - depresses
rotates scapula
action of latissimus dorsi
extends, adducts and medially rotates humerus
action of levator scapulae
elevates the scapula
action of rhomboid major
retracts the scapula
action of rhomboid minor
retracts the scapula
origin of trapezius
skull, cervical and thoracic vertebrae
insertion of trapezius
clavicle and scapula (spine and acromium)
origin of latissimus dorsi
lower thoracic vertebrae
insertion of latissimus dorsi
humerus - upper anterior
origin of levator scapulae
upper cervical vertebrae
insertion of levator scapulae
medial border of scapula
origin of rhomboid minor
C7 and T1
insertion of rhomboid minor
media border of scapula
origin of rhomboid major
thoracic vertebrae
insertion of rhomboid major
medial border of scapula
innervation of the posterior pectoral region
mostly brachial plexus
which muscle in the posterior pectoral region is not innervated by the brachial plexus?
trapezius
innervation of trapezius
accessory nerve
which branch of the brachial plexus innervated latissimus dorsi?
thoracodorsal nerve
name movements of the shoulder joint
flexion, extension, abduction, adduction, medial rotation, lateral rotation, circumduction
name the scapulohumeral muscles (attach scapula to humerus)
deltoid, supraspinatus, infraspinatus, subscapularis, teres minor, teres major
function of rotator cuff muscles
provide stability to the shoulder joint
name the rotator cuff muscles
supraspinatus, infraspinatus, subscapularis, teres minor
which is the large muscle over the lateral aspect of the shoulder?
deltoid
origin of deltoid from the scapula
spine and acromium (plus clavicle)
what does the deltoid attach?
humerus to lateral part of clavicle and spine of scapula
where do the rotator cuff muscles, deltoid and teres major have their action?
shoulder joint
which bone do the rotator cuff muscles and deltoid and teres major originate from?
scapula
which bone do the rotator cuff muscles, deltoid and teres major insert onto?
humerus
what is the name of the place where the deltoid inserts onto the humerus?
deltoid tuberosity
action of deltoid at the shoulder joint
powerful abductor of the shoulder joint after 20 degrees
anterior and posterior fibres contribute to flexion and extension of the shoulder respectively
can deltoid initiate abduction?
no, another muscle initiates the first 20 degrees before deltoid takes over
which nerve innervates deltoid?
axillary nerve - from brachial plexus
which aspect of the scapula does teres major arise from?
posterior surface of scapula, inferior part of lateral border
which aspect of the humerus does teres major insert onto?
anterior humerus
action of teres major on the shoulder joint?
medial rotator and adduction
where do the rotator cuff muscles attach to the humerus?
tubercles of the humerus
which rotator cuff muscles originate from the posterior surface of the scapula?
supraspinatus, infraspinatus, teres minor
which rotator cuff muscles insert onto the greater tubercle?
supraspinatus, infraspinatus, teres minor
which structures form the boundaries of the quadrilateral space?
teres minor above
teres major below
long head of triceps medially
surgical neck of humerus laterally
which nerve travels through the quadrilateral space?
axillary
what does the axillary nerve innervate?
deltoid and teres minor
which rotator cuff muscle originates from the anterior surface of the scapula?
subscapularis
where does subscapularis insert?
lesser tubercle of the humerus
action of supraspinatus
first 20 degrees of abduction of the shoulder joint
origin of supraspinatus
supraspinous fossa on scapula
insertion of supraspinatus
greater tubercle - superior facet
action of infraspinatus
lateral rotation
origin of infraspinatus
infraspinous fossa
insertion of infraspinatus
greater tubercle - middle facet
action of teres minor
lateral rotation of the shoulder joint
origin of teres minor
lateral border of the scapula
insertion of teres minor
greater tubercle - inferior facet
action of subscapularis
medial rotation of the shoulder joint
origin of subscapularis
subscapular fossa of scapula
insertion of subscapularis
lesser tubercle of humerus
clinical importance of supraspinatus
travels from the supraspinous fossa to the greater tubercle, travels under the acromium
tendon can become inflamed and pinched between he acromium and humerus during movements of the shoulder
called ‘impingement’
presents as a painful arc
why is the shoulder joint easily dislocated?
poor fit of articular surfaces to allow extensive range of movement
loose joint capsule
how do the rotator cuff muscles provide stability?
contraction of the rotator cuff muscles holds the head of the humerus in the shallow glenoid
rotator cuff tendons fuse with the capsule of the shoulder joint
which other features contribute to the stability of the shoulder?
rim of fibrocartilage around the margin of the glenoid fossa deepens the shallow fossa and aids stability - glenoid labrum
capsule is reinforced by ligaments
tendon of biceps brachii, which lies in the anterior arm, also reinforces the joint
what separate the arm into anterior and posterior compartments?
intermuscular septa
which is the only muscle to lie in the posterior compartment of the arm?
triceps brachii
how many muscle bellies/ heads does triceps brachii have?
3
the three heads of triceps brachii converge via a common tendon onto which single insertion point?
olecranon of the ulna
action of triceps brachii
extension of the forearm at the elbow
name the three heads of triceps?
long, lateral and medial head
origin of the long head of triceps
infraglenoid tubercle of the scapula
origin of the lateral head of triceps
posterior humerus, proximal to the radial groove
origin of the medial head of triceps
posterior humerus, distal to the radial groove
innervation of triceps
radial nerve (terminal branch of brachial plexus)
where does the radial nerve run?
posterior aspect of the humerus in the radial (spiral) groove between the medial and lateral heads of triceps
adhesive capsulitis
‘frozen shoulder’
pain and stiffness in the shoulder
capsule of the joint becomes inflamed, stiff and tight
adhesions may develop
rotator cuff injury
by acute trauma or repetitive use
tendons may degenerate with age
tears are usually painful at rest and on movement
if supraspinatus tendon becomes injured and inflamed, it may become impinged between the acromium and humeral head, as the space here is small
first pat of abduction is not painful, but between 60 and 120 degrees of abduction, the inflamed tendon is compressed against the acromium, and this is when patients experience pain
beyond this, pain subsides again
this presentation is called a ‘painful arc’ and is indicative of supraspinatus tendon pathology
an inflamed tendon may ultimately rupture
dislocation of the shoulder
humeral head moves out of glenoid fossa - can injure axillary nerve
more common anteriorly
axillary nerve injury - cause and presentation
close proximity to surgical neck of humerus
injured in fractures to this area of dislocation of the shoulder joint
motor fibres innervate deltoid and teres minor
sensory fibres innervate a patch of skin over the upper lateral arm
injury to the axillary nerve results in weakness or paralysis of deltoid - difficulty abducting shoulder
altered sensation or numbness over the upper lateral arm
radial nerve injury - cause and presentation
runs in the radial groove of the posterior humerus, close to the bone
fractures of humeral shaft can injure the nerve
weakness of nerve downstream of the point where the nerve is injured
weakness of triceps
impaired elbow extension
radian nerve lesion at the level of the mid arm affects wrist movement because the radial nerve innervates all the muscles of the posterior forearm, which extend the wrist
which muscles abduct the shoulder?
Initiated by supraspinatus (first 20 degrees or so)
● Deltoid then takes over
● Rotation of the scapula is required to raise the arm above the head – this
requires the action of trapezius.
describe the movements of the scapula and the humerus during shoulder abduction
Abduction of the arm at the shoulder is initiated by supraspinatus (first 20 degrees or so)
● Deltoid then takes over
● As the arm rises, the humerus laterally rotates – this keeps the articular
surfaces in contact with each other; in full abduction (with the arm above the
head) the humerus has rotated 90 degrees.
● For every 2 of abduction at the shoulder joint the scapula rotates 1 degree Rotation
tilts the glenoid fossa cranially.
Which nerve innervates trapezius? How would you test if the nerve was functioning?
The accessory nerve / cranial nerve XI (11). Specifically, its spinal root.
● The most straightforward way to test the function of the nerve is to ask the
patient to shrug the shoulders (i.e. elevate the scapula). You would be comparing movement on both sides and looking for symmetry.
Which nerve is at risk of injury in shoulder dislocation? What functional deficits would result and how would you examine a patient to test for these deficits?
The axillary nerve (C5-C6 fibres)
● Potential function deficits are weakness / paralysis of deltoid and teres minor
(motor fibres of the nerve) and impaired sensation / numbness over the skin
of the upper lateral shoulder (sensory fibres of the nerve).
● Motor function – tested by asking the patient to abduct the arm; look for
weakness compared with the unaffected arm
● Sensory function – use light touch over the skin of the upper lateral to arm and compare sensation with the opposite side; ask the patient if it feels the same or different to the unaffected side.
What structures stabilise the shoulder joint?
The rotator cuff is the key stabilising factor
● The tendon of the long head of biceps and the glenoid labrum also contribute
to stability.
Which parts of the pectoral girdle and shoulder joint can be palpated on examination?
Clavicle, acromion, spine of the scapula and lateral border of the scapula.
In a patient with a mid-shaft humeral fracture:
a) What movements could you test to try and ascertain whether the radial nerve
had been injured?
The radial nerve innervates triceps (> extends the elbow) and the posterior
compartment of the forearm (> extends the wrist). Therefore assessment should involve asking the patient to extend the elbow and then extend the wrist. The patient is asked to do this against gravity and against resistance. In the latter, the examiner applies a little force against the movement the patient is asked to perform – this tests the strength of the movement and again should be compared to the other side.
● Weakness of elbow extension and / or wrist extension would indicate a radial nerve injury. ‘Wrist-drop’ is the term given to the appearance of the wrist and hand when the forearm extensors are weak / paralysed.
In a patient with a mid-shaft humeral fracture:
b) Why might triceps be weak compared to the unaffected arm, but not paralysed?
Remember that triceps has 3 heads which arise from different regions proximally. When the radial nerve is injured in the mid-humeral region, muscles innervated ‘downstream’ will be affected. However, by the time the nerve is at the mid-humeral level, it has already given off branches to the proximal parts of the muscle – these are unaffected and those parts of the muscle will still function. Therefore triceps will be weak, but not completely paralysed.
Which muscles comprise the rotator cuff, and where do they insert on the humerus?
They are supraspinatus (inserts on the superior facet, greater tubercle), infraspinatus (inserts on the middle facet, greater tubercle), teres minor (inserts on the inferior facet, greater tubercle) and subscapularis (inserts on the lesser tubercle).
boundaries of the axilla
anterior wall - pec major and minor
posterior wall - subscapularis, trees major and latissimus dorsi
lateral wall - upper humerus
medial wall - serrates anterior and chest wall
apex - first rib, clavicle and scapula
base - skin and fascia between the chest wall and arm
contents of the axilla
fat
lymph nodes
axillary artery - major artery of the upper limb
axillary vein - major vein of the upper limb
brachial plexus - specifically cords and branches - innervates upper limb
what do axillary lymph nodes drain?
upper limb, chest, scapular region, abdominal wall as far as umbilicus
how many groups of lymph nodes are there in the axilla?
5
central, pectoral, humeral, sub scapular, apical
which lymph nodes drain lymph from all other lymph noes in the axilla?
apical nodes
which lymph nodes are likely to be involved in the spread of cancer (metastasis)?
apical
which group of lymph nodes are associated with breast cancer?
axillary
which artery is a continuation of the subclavian?
axillary
then brachial
where does the subclavian run?
under the clavicle into the axilla
where does the axillary artery give branches relative to pec minor?
one above pec minor
two behind pec minor
three below pec minor
which artery is the continuation of the axillary artery?
brachial
where does the axillary artery become the brachial artery?
as it crosses the inferior border of trees major
which vein drains the upper limb?
axillary
which vein is the axillary vein continuous with?
subclavian
how can we half bleeding from axillary vessels?
compress them against the humerus
innervation of the upper limb
brachial plexus
which spinal segments form the brachial plexus?
C5, C6, C7, C8 and T1
segments of the brachial plexus
roots, trunks, division, cords, branches
really thirsty drink cold beer
where are the brachial plexus nerve roots found?
neck
where are the brachial plexus trunks found?
neck
name the trunks of the brachial plexus
superior, middle, inferior
which spinal segments form the superior trunk?
C5 and C6
name the trunks of the brachial plexus
superior, middle, inferior
where do the trunks divide, and how?
under the clavicle
each trunk divides into an anterior and posterior division
how are the brachial plexus cords named?
relative to their position around the second part of the axillary artery
name the cords of the brachial plexus
lateral, posterior, medial
what forms the lateral cord of the brachial plexus?
anterior cord of the superior and middle trunks
what forms the posterior cord of the brachial plexus?
posterior divisions of all the trunks
what forms the medial cord of the brachial plexus?
anterior division of the inferior trunk
where are the brachial plexus branches located?
axilla
which branches does the posterior cord give off?
axillary and radial
which branch is a continuation of the posterior cord?
radial
which cord does the axillary branch originate from?
posterior cord
origin of the musculocutanous branch
lateral cord
origin of the axillary branch
posterior cord
origin of the radial branch
posterior cord
origin of the ulnar branch
medial cord
origin of the median branch
lateral and medial cords
what does the axillary nerve innervate?
deltoid and teres minor
small region of skin over the upper lateral arm
which spinal segments does the axillary nerve contain fibres from?
C5 and C6
where does the axillary nerve run?
close to the surgical neck of the humerus
why is the axillary nerve vulnerable?
runs close to the surgical neck of the humerus
vulnerable to injury in fractures of the surgical neck of the humerus or dislocations of the humeral head
innervation of triceps in the posterior arm
radial nerve
innervation of all the muscles in the posterior compartment of the forearm
radial nerve
these muscles are extensors of the wrist and digits
innervation of skin over the arm, forearm and hand
radial nerve
what does the radial nerve innervate?
triceps in the posterior arm
muscles in the posterior compartment of the forearm - extensors of the wrist and digits
regions of skin over the arm, forearm and hand
which spinal segments does the radial nerve contain fibres from?
C5-T1
where does the radial nerve run?
radial (spiral) groove on the posterior surface of the humerus
which nerve is vulnerable in mid shaft fractures of the humerus?
radial
how many muscles does the musculocutanous nerve innervate in the anterior arm?
3
which spinal segments contributes to the musculocutaneous nerve?
C5-C7
what does the musculocutaneous nerve innervate?
region of skin over the forearm
which nerve from the brachial plexus is rarely injured in isolation?
musculocutaneous
do the median and ulnar nerves innervate any arm muscles?
no
where do the median and ulnar nerve innervate?
anterior forearm and hand
which cords form the median nerve?
lateral and medial cords
from which spinal segments does the median nerve receive fibres from?
C6 - T1
what does the median nerve innervate?
most of the muscles of the anterior forearm (these muscles are on the anterior portion of the arm when the body is in the anatomical position)
small muscles of the thumb
skin over the lateral aspect of the palm of the hand and over the lateral digits
function of the anterior forearm muscles
flexors of the wrist and digits
where is the cubital fossa?
anterior aspect of the elbow
anterior aspect of the elbow
cubital fossa
where is the median nerve most vulnerable?
cubital fossa
which spinal segments contribute to the ulnar nerve?
C8-T1
what does the ulnar nerve innervate?
most of the small muscles in the hand
skin over the medial aspect of the hand and medial digits
which nerve is vital for fine movements of the digits?
ulnar nerve
which nerve is vital for flexing the wrist and digits?
median nerve
where is the ulnar nerve vulnerable to injury?
behind the medial epicondyle as it lies in a superficial position here
muscles of the anterior compartment of the arm
biceps brachii, brachialis, coracobrachialis
function of the muscles of the anterior arm
flexion of the forearm
innervation of the muscles of the anterior arm
musculocutaneous nerve
which muscle lies most superficially in the anterior arm?
biceps brachii
how many muscle bellies does biceps brachii have?
two
long and short head
where are both heads of biceps brachii attached proximally?
scapula
where on the scapula are the long and short head of biceps brachii attached?
long head - supraglenoid tubercle
short head - coracoid process
where do the muscle bellies of biceps brachii converge?
radial tuberosity of the radius
the tendon of which head of biceps pierces the capsule of the shoulder joint and helps to stabilise the joint?
long
function of biceps
flexor of the elbow
crosses the elbow so is also a flexor of the shoulder joint
supinates the forearm WHEN the elbow is flexed e.g a screwdriver works better when the elbow is flexed
which muscle lies deep to biceps?
brachialis
attachments of brachialis
anterior aspect of the lower half of the shaft of the humerus
crosses the elbow joint to insert distally upon the ulna tuberosity
does brachialis act on the shoulder joint? why or why not?
no
does not cross the shoulder joint
action of brachialis
powerful flexor of the elbow joint
attachments of coracobrachialis
coracoid process and medial aspect of middle part of humerus
action of coracobrachialis
weak flexor of the shoulder joint
what is the (ante)cubital fossa?
what shape is it and how many borders does it have?
region anterior to the elbow joint
triangular shaped region with three borders
name the borders of the cubital fossa
lateral, medial, superior (or base)
which muscle forms the lateral border of the cubital fossa?
brachoradialis
which muscle forms the medial border of the cubital fossa?
pronator teres
what forms the superior border/ base of the cubital fossa?
imaginary line drawn between the medial and lateral epicondyles of the humerus
contents of the cubital fossa
tendon of biceps brachii
bicipital aponeurosis (fascial extension of the biceps tendon)
brachial artery
terminal branches of the brachial artery (radial and ulnar arteries)
median nerve
radial nerve
superficial veins in the subcutaneous tissue over the cubital fossa
where does the tendon of biceps brachii insert?
radial tuberosity
which tendon is tapped with a tendon hammer to examine the biceps reflex?
biceps
what is the bicipital aponeurosis?
fascial extension of the biceps tendon
separates the superficial veins from the deeper structures in the fossa - the brachial artery and median nerve
where does the brachial artery lie relative to the biceps tendon?
medial
terminal branches of the brachial artery
radial artery
ulnar artery
which artery is vulnerable in venepuncture and cannulation?
brachial
where does the median nerve lie relative to the brachial artery?
medial to the brachial artery
does the median nerve innervate any arm muscles?
no, only anterior forearm and hand
where does the radial nerve lie?
deep to brachioradialis
where are the veins in the cubital fossa?
superficial
in the subcutaneous tissue
why are the superficial veins in the cubital fossa clinically relevant?
venepuncture (taking blood)
intravenous access - placing a cannula for administering fluids or drugs
which structures may accidentally be punctured during venepuncture?
median nerv
brachial artery
probably not radial nerve as it lies deep to brachioradialis
side effects of axillary lymph node removal
fluid accumulation and swelling in the affected upper limb
which nerves are vulnerable when axillary lymph nodes are removed?
long thoracic nerve
thoracodorsal nerve
what does the long thoracic nerve innervate?
serratus anterior (SALT - serratus anterior, long thoracic)
where does the long thoracic nerve lie?
superficially on the surface of serratus anterior in the medial wall of the axilla
consequence of injury to the long thoracic nerve
weakness of serratus anterior
visible sign of injury to the long thoracic nerve
winged scapula
long thoracic innervates serratus anterior
serratus anterior holds the medial border of the scapula flat against the posterior chest wall
if the muscle is paralysed, the medial border lifts off the chest wall and appears to stick out
what does the thoracodorsal nerve innervate?
latissimus dorsi
where does the thoracodorsal nerve lie?
along the subscapularis muscle, which forms the posterior wall of the axilla
where is the ulnar nerve vulnerable? why?
behind the medial epicondyle
it is superficial here
symptoms of an injury to the ulnar nerve at the medial epicondyle
motor impairments of the hand
sensory impairments in the hand (medial side of the hand and medial 1 1/2 fingers)
hitting which nerve results in the ‘funny bone’ sensation
ulnar nerve
what is Erb’s Palsy?
UPPER parts of the brachial plexus are affected
paralysis of the lateral rotators of the shoulder and the extensors of the wrist
affected limb appears medially rotated with the wrist flexed
typically caused by trauma - mechanisms that stretch the head away from the shoulder
caused by trauma
- someone is thrown from a motorbike or horse
- in newborns in the baby’s shoulder becomes stuck during delivery and the neck is excessively stretched
what is Klumpke’s Palsy?
LOWER parts of the brachial plexus are affected
paralysis of the small muscles of the hand
caused by trauma
- mechanisms that forcefully and suddenly pull the arm upwards which stretches the lower nerves of plexus
- may be sustained during delivery if the arm is forcefully pulled
what is Horner’s syndrome?
injury to T1 spinal nerve
T1 spinal nerve carries sympathetic fibres supplying the face
occurs when sympathetic nerve supply to the face is interrupted
triad of
- ptosis (drooping of the eyelid)
- miosis (constricted pupil)
- anhidrosis (lack of sweating)
on one side of the face
brachial plexus block
form of regional anaesthesia for surgery on the upper limb
local anaesthetic is infiltrated around the nerves of the plexus, which anaesthetises the upper limb
under ultrasound guidance
Describe the route of arterial blood from the left ventricle to the right axillary artery and from the left ventricle to the left axillary artery.
Left ventricle to right axillary artery:
Aorta > brachiocephalic trunk > right subclavian > right axillary
Left ventricle to left axillary artery:
Aorta > left subclavian > left axillary
Draw and label a diagram of the brachial plexus showing the roots, trunks, divisions, cords and the five terminal branches.
Refer to the image in your Upper Limb handbook.
● You do not need to be able to add all the small branches to the plexus.
Describe how the cords of the brachial plexus are situated relative to the second part of the axillary artery.
The lateral cord lies laterally, the medial cord medially and the posterior cord
lies posteriorly to the artery
Which regions of the body drain directly to the axillary lymph nodes? Briefly outline the clinical importance of the axillary lymph nodes.
They drain the upper limb, breast, chest wall, scapular region and the abdominal
wall as far as the umbilicus.
● There are five groups of lymph nodes in the axilla; anterior, posterior, lateral,
central and apical.
● The apical nodes receive lymph from all other lymph nodes in the axilla and
therefore are often involved in the spread of cancer (metastasis).
● The axillary lymph nodes are particularly associated with breast cancer. Detection of a lump in the armpit may be the first sign of breast malignancy. The
axillary lymph nodes can also enlarge in response to infection.
● Axillary lymph nodes can be biopsied to assess whether a breast malignancy has metastasized. They can be removed as part of the patient’s treatment. Removal of the nodes can lead to fluid accumulation and swelling in the affected upper
limb.
What key structures are found in the cubital fossa? Where are they located relative to each other?
The biceps tendon, brachial artery and median nerve.
● The brachial artery and median nerve both lie medial to the biceps tendon.
bones of the forearm
radius and ulna
what connects the radius and ulna in real life?
interosseous membrane
how does the ulna articulate with the humerus?
trochlea notch of the ulna articulate with the trochlea of the humerus
how does the radius articulate with the humerus?
radial head articulates with the capitellum of the humerus
movements of the elbow joint
flexion and extension
name of the joint between the radius and ulna
how many of these are there and where are they?
radioulnar
two, one proximal, one distal
what movements do the radioulnar joints allow?
pronation and supination of the forearm and hand
which forearm bone pivots around the other?
the radius pivots around the ulna
joint between the radius and the small bones of the wrist (carpus)
radiocarpal
name the proximal row of carpal bones from lateral to medial
scaphoid, lunate, triquetral, pisiform (which is not a true carpal bone, but rather is a small bone that develops in the tendon of flexor carpi ulnaris)
name the distal row of carpal bones from lateral to medial
trapeziUM (base of the thUMb), trapezoid, Capitate (located Centrally and is the largest carpal bone) and the hamate
why isn’t the pisiform a true carpal bone?
a small bone that develops in the tendon of flexor carpi ulnaris
what does the hamate bear anteriorly?
bony process (the hook) which is palpable
most commonly fractured carpal bone
scaphoid
which bones lie distal to the carpus?
metacarpals
what are the bones of the digits?
phalanges
how many phalanges in each finger?
three
how many phalanges in each thumb?
two
what bounds the cubital fossa laterally?
brachioradialis
what bounds the cubital fossa medially?
pronator teres
name important structures in the cubital fossa
biceps tendon
median nerve
brachial artery which bifurcates into the radial and ulnar arteries
superficial veins
how many muscles in the anterior compartment of the arm?
eight
generalisations of the muscles in the anterior compartment of the arm
arranged in 3 layers - superficial, middle, deep
most act as flexors of the wrist, fingers or thumb
most are innervated by the median nerve
muscles in the superficial layer of the anterior compartment of the arm from lateral to medial
pronator teres
flexor carpi radialis
palmaris longus
flexor carpi ulnaris
where are the muscles in the superficial layer of the anterior compartment of the arm attached to proximally?
medial epicondyle of the humerus (also called the common flexor origin)
action of pronator teres
pronator of the proximal radioulnar joint
action of flexor carpi radialis
flexes and abducts the wrist
insets onto the radial side of the wrist
describe palmaris longus
small muscle belly but long, thin, easily recognised tendon when present
approx 15% of us do not have one
where does the tendon of palmaris longus insert?
fascia of the palm of the hand
function of flexor carpi ulnaris
flexes and adducts the wrist
where does flexor carpi ulnaris insert?
ulnar side of the wrist
innervation of flexor carpi ulnaris
ulnar nerve
which is the only muscle in the middle muscle layer?
flexor digitorum superficialis
function of flexor digitorum superficialis
flexor of the digits
how many tendons does flexor digitorum superficialis give rise to?
four
which digits do the tendons of flexor digitorum superficialis attach to?
digits 2-5
pointer finger
innervation of flexor digitorum superficialis
dual innervation
lateral half of the muscle
- gives rise to tendons that travel to the index and middle fingers
- is innervated by median nerve
medial half
- gives rise to tendons that travel to the ring and little fingers
- is innervated by ulnar nerve
function of flexor pollicis longus
flexes the thumb
‘pollex’ = thumb
deepest forearm muscle
pronator quadratus
function of pronator quadratus
pronates the distal radioulnar joint
which are the only two anterior forearm muscles that are not flexors?
pronator trees and pronator quadratus
which are the only anterior forearm muscles not be innervated by the median nerve?
flexor carpi ulnas
medial half of flexor digitorum superficialis
what is the carpal tunnel?
narrow passageway at the wrist
what forms the floor and sides of the carpal tunnel?
what forms the roof?
carpal bones
fibrous band - flexor retinaculum
which bones is the flexor retinaculum attached to medially and laterally?
medially
- hook of the hamate
- pisiform
laterally
- scaphoid
- trapezium
how many tendons pass through the carpal tunnel?
9
which tendons pass through the carpal tunnel?
flexor digitorum superficialis (4 tendons, to digits 2-5)
flexor digitorum profundus (4 tendons, to digits 2-5)
flexor pollicis longus (1 tendon to the thumb [1st digit])
which nerve travels through the carpal tunnel?
median
what is carpal tunnel syndrome?
compression of the median nerve
presentation of carpal tunnel syndrome
impaired or altered sensation over the skin of the hand supplied by the median nerve
tingling, numbness or pain in the hand
weakness of the hand muscles supplied by the median nerve - particularly the small muscles of the thumb
consequences of untreated carpal tunnel syndrome
small muscles of the thumb atrophy
treatment of carpal tunnel syndrome
divide the flexor retinaculum to alleviate compression
terminal branches of the brachial artery
radial and ulnar artery
which artery can easily be palpated at the wrist?
radial
which artery travels laterally in the forearm?
radial
which artery travels medially in the forearm?
ulnar
where does all venous blood of the upper limb ultimately drain?
axillary vein
two important superficial veins of the upper limb
cephalic vein
basilic vein
which vein courses laterally in the forearm?
cephalic vein
which vein courses medially in the forearm?
basilic
which vein connects the cephalic and basilic veins in the cubital fossa?
median cubital vein
