MSK 1 - Upper Limbs Flashcards
what is the axilla?
Is a pyramidal space below the shoulder joint. It provides a passageway for vessels and nerves going to and from the upper limb
what is the shape of the axilla?
The axilla is roughly pyramidal in shape and has an apex, base, and 4 walls
The anterior wall of axilla is formed by what?
Pectoralis major muscle and Pectoralis minor muscle
The posterior wall of the axilla is formed by what 3 muscles?
subscapularis, Teres major and Latissimus dorsi
Medial wall of the axilla is formed by what?
the thoracic wall and serratus anterior muscle
Lateral wall of the axilla is formed by what?
the intertubercular groove of the humerus
a
Brachial plexus
b
Axillary lymph nodes (apical group on left and central group more lateral on the right)
c
Axillary artery
d
Axillary vein
The axillary artery is the continuation of which artery?
Subclavian artery
At what anatomical point does the axillary artery begin?
Outer boarder of the first rib
The axillary artery continues beyond the axilla as which vessel?
Brachial artery
At what anatomical point does the name of this vessel change
lower border of teres major
CLinical:
The enlargement of ________________ is common in infection of the upper limb, and in malignant processes involving the breast tissue.
The ____________ is a point where vasculature can be _________ (via a tourniquet) in response to profuse bleeding to the upper limb – for example after tissue trauma
axillary lymph nodes
axillary artery
compressed
_______________\_ is the major network of nerves innervating the upper limb. It begins in the cervical region and extends into axilla.
The Brachial Plexus
what ofrms the brachial plexus?
Brachial plexus is formed by the ventral rami of
C 5 to T 1
Which nerve roots form the upper trunk? (of brachial plexus?
C5 and C6
Which roots of the plexus contribute to the lower trunk? (brachial plexus)
C8 and T1
Which root forms the middle trunk? (brachial plexus)
C7
The brachial plexus can be further sub divided into trunks, divisions, cords and terminal branches as it passes down into the arm
what is purple
roots
The brachial plexus can be further sub divided into trunks, divisions, cords and terminal branches as it passes down into the arm
what is oragne
trunks
The brachial plexus can be further sub divided into trunks, divisions, cords and terminal branches as it passes down into the arm
what is yellow
division
The brachial plexus can be further sub divided into trunks, divisions, cords and terminal branches as it passes down into the arm
what is pink
cords
The brachial plexus can be further sub divided into trunks, divisions, cords and terminal branches as it passes down into the arm
what is green
terminals
The division of the trunks form three cords of the brachial plexus in the axilla. The cords are named for their position in relation to the ______________________
axillary artery in the axilla
Clinical: Erb’s
Injury to upper trunk causes Erb’s Palsy, this results in a characteristic ‘waiter’s tip’ appearance of the upper limb - medial rotation of the arm with wrist flexion. This is caused by a hyper-extension injury of the head from the shoulder
Which group of muscles are affected in this condition? They are supplied by the nerve roots C5 -C6 (you should answer this question after studying the relevant regions)
rotator cuff muscles
Clinical: Klumpke’s Palsy
Injury to the lower trunk causes Klumpke’s Palsy
what does this affect
This mainly affects the intrinsic muscles of the hand (typically a claw hand), flexors muscles of the wrist and flexor muscles of the fingers (you will study these muscles later)
Both injuries are most commonly caused by shoulder dystocia at birth or following traumatic injury (e.g. motor vehicle accident)
- _______ nerve from the posterior cord
- ______ nerve from the posterior cord
- ______________ nerve from the lateral cord
- _____ nerve from the medial cord
- ______ nerve from both the lateral and medial cord
Axillary
Radial
Musculocutaneous
Ulnar
Median
https://geekymedics.com/brachial-plexus/
a
Subclavian artery
b
Axillary artery
c
Brachial artery
d
Ulnar artery
e
Radial artery
a
Cephalic vein
b
Basilic vein
c
Median cubital vein
Clinical:
Throughout your medical career you will become very accustomed to finding the superficial veins of the upper arm. They are the most common place for ___________ (taking blood) and _________ (allowing for intra-venous medications and blood transfusions to be delivered)
venepuncture
cannulation
The _______________ is a complex network of veins lying at the distal aspect of the upper limb
All the superficial veins of the upper limb lie in the _______________, just underneath the skin making them easy to access for various procedures
dorsal venous arch
subcutaneous tissue
The _________ vein arises at the lateral end of the dorsal venous arch and _______ vein arises at the medial end of the dorsal venous arch
Cephalic
Basilic
Median cubital vein is a large communicating vein which shunts blood from the ________ vein to the ________ vein
Often the median cubital vein is in a fixed position in the ante-cubital fossa – this is handy as it is the most common site for venepuncture
cephalic
basilic
The ________ vein ascends the arm on its lateral aspect, piercing the clavipectoral fascia draining into the axillary vein
The _______ vein ascends on the medial side of the arm, passing deep at the mid-humeral level and eventually becoming the axillary vein at the lower border of teres minor
cephalic
basilic
________ is more superficial compared to the ______ vein, blood drains deeper
Cephalic
basilic
The area of skin supplied by one spinal segment is called a __________
dermatome
In the upper limb each brachial plexus root (C5 to T1) can be mapped to a specific dermatome
where about are they?
(anterior)
(posteiror)
Clinical:
Following an injury to a ___________ a sensory loss (paraesthesia) will be mapped on the skin corresponding to that specific __________.
Injury to a terminal branch produces sensory loss corresponding to the area of ____________________. This will become clearer through the workbook!
Remember these dermatomes as you require this knowledge to detect peripheral nerve injuries
spinal root
dermatome
distribution of that nerve
Some simple embryology will help to explain their organisation: imagine the limb abducted to 90 degrees, resembling the arrangement in the embryo. The dermatomes are then roughly arranged from upper to lower; C5-T1.
As the limb bud expands the middle levels become squeezed out towards the tip of the limb, to form the adult pattern
Early stages of development in left photo
Later stages of development in right photo
All lymphatic vessels from the upper limb drain into ___________ (lymph nodes are difficult to see in the dissected cadaver)
axillary nodes
Axillary lymph nodes are divided into 4-5 distinct groups, what are they?
- Anterior or pectoral group
- Posterior or subscapular group
- Apical group
- Central group
- Lateral or brachial group
Which group of lymph nodes will be involved if the lymphatic spread of infection/cancer begins in the following areas of the body?
Choose your answer to the below from the following lymph node groups
- *1) Axillary
2) Internal thoracic (internal mammary)
3) Superficial Inguinal**
- Infection of the little finger
- Boil in the scapular region
- Medial part of the breast (close to sternum)
- Lateral part of breast (close to axilla)
- Infection around the umbilicus: This infection can spread to both axillary and superficial inguinal groups of both sides? Why?
a = 1
b = 1
c = 2
d = 1
e = Equidistance between the nodes so top half goes up and bottom half down, due to the amount of blood vessels and lymph around the umbilicus
Clinical:
___________ of the ________ nodes is frequent in malignant disease and infective processes affecting the upper back and shoulder, the front of the chest and mammary gland, upper anterolateral abdominal wall and upper limb
Enlargement
axillary
The pectoral girdle or (shoulder girdle) is the set of bones which connects the upper limb to the axial skeleton on each side
what makes it up?
what is the structure of the clavicle
To attempt to orientate and ‘side’ a clavicle there are a number of features which can help do so
- The lateral aspect of a clavicle is flatter than the medial aspect
- The superior surface is smoother than the inferior surface
- The conoid tubercle – attachment for the conoid ligament – is on the inferior aspect of the lateral portion of the clavicle
diagram which part of the clavicle is weakest and commonly breaks (fractures) during a fall. Why is this?
Middle third of the clavicle is the thinnest and most outermost part and has a lack of support by muscles and ligaments, so its more vulnerable to injury
Junction between middle and lateral thirds of the clavicle due to the weight of the arm
a
Supraspinous fossa
b
Spine of the scapula
c
Infraspinous fossa
d
Superior angle
e
Medial border
f
Subscapular fossa
g
Lateral border
h
Inferior angle
i
Acromion
j
Coracoid process
k
Supraglenoid tubercle
l
Glenoid cavity
m
Infra-glenoid tubercle
What type of synovial joint are the acromioclavicular (AC) and sternoclavicular (SC) joints?
AC joint - Synovial plane
SC joint - Synovial saddle
Clinical:
Movement of the pectoral girdle involves _____________ joints, all moving simultaneously. Functional defects of any one of these joints impair movements of the pectoral girdle. Mobility of the _______ is essential for the freedom of movement of upper limb.
SC, AC and shoulder
scapula
Abduction of the arm occurs in 2 stages: what are they?
The first 30 degrees of abduction is caused by muscles acting at the shoulder joint (gleno-humeral joint).
Beyond 30 degrees, abduction relies on the scapula being pulled upwards (elevated) and laterally rotating on the chest wall (“scapula-thoracic” movement)
This is called the scapulo-humeral rhythm
For every 3 degrees of abduction past the initial 30 degrees – 2 degrees occurs at the gleno-humeral joint, and 1 degree occurs due to “scapula-thoracic” movement (2:1 ratio)
Review the movements of the scapula and therefore the pectoral girdle described below. These are essential in clinical testing of muscle function.
Scapular movement = elevation
what are the main muscles involved?
upper trapezius
levator scapulae
Scapular movement = depression
what are the main muscles involved?
lower trapezius
Scapular movement = Protraction (forward movement)
what are the main muscles involved?
serratus anterior
Scapular movement = Retraction (backward movement)
what are the main muscles involved?
Trapezius (middle fibres) and Rhomboids
Scapular movement = Lateral (upward) rotation: Elevating Glenoid Cavity - Shrugging your shoulders!
what are the main muscles involved?
upper and middle trapezius ??
Scapular movement = Medial (downward) rotation: Depressing Glenoid Cavity
what are the main muscles involved?
- Gravity
- Levator scapulae
- Rhomboid Maj. and Min.
- Pectoralis minor
1
Trapezius
2
Levator scapulae
3
Rhomboideus minor
4
Rhomboideus major
5
Supraspinatus
6
Infraspinatus
7
Teres minor
8
Teres major
9
Latissimus dorsi
The shoulder joint is a synovial ball and socket joint, where the ball is the head of the ________ and socket is the _______ cavity. The rim of cartilage surrounding the socket is the glenoid _______
humerus
glenoid
labrum
What is the function of this cartilage? (glenoid labrum)
Deepens the cavity, increases surface area of shoulder joint
whata re the ligaments like of the shoudler joint?
The joint capsule of the glenohumeral joint is thickened to form definable ligaments, but true ligaments are also present between other bony elements. Together these strengthen and ease movements at the joint
a
The Coracoacromial ligament
b
Coracohumeral ligament
c
Glenohumeral ligaments – strengthen the anterior aspect of the joint capsule
d
The transverse humeral ligament – forms the roof of the bicipital groove
The coracohumeral ligament strengthens _______ aspect of the joint capsule
superior
The coraco-acromial arch is made up of the _______ and ________ process of scapula and ___________ ligament
It prevents __________ displacement of the humeral head
acromion
coracoid
Which part of the shoulder joint capsule is weakest, as it is not protected by muscles or ligaments?
inferior
Bursae Around the Shoulder Joint:
what is their function
Bursae are important as they provide cushioning around joints via. their synovial fluid filled interior – they essentially act as shock absorbers!
The 2 main bursa in the shoulder are what?
where is the subacromial bursa located?
Notice how the subacromial bursa sits between the infra-/supra-spinatus muscles and the deltoid, extending superiorly to lie below the acromion and coracoacromial ligaments
Which bursa communicates with the joint cavity?
Subscapular bursa
What is the role of subacromial bursa?
Sevres as a gliding mechanism between the rotator cuff and coracoacromial arch. Reduce friction in the space under the acromion
What common sporting injury damages the subacromial bursa?
Subacromial bursitis, torn rotator cuff
what muscle is shown, what is its proximal and sital attachment and what movement does it cause at the shoulder joint?
subscapularis
Medial 2/3 of costal aspect of scapula
Lesser tuberosity, shoulder joint capsule, and the front of the upper shaft of the humerus
Adductor and medial rotator of the humerus
what muscle is shown, what is its proximal and sital attachment and what movement does it cause at the shoulder joint?
supraspinatus
Supraspinous fossa of the scapula and from fascia overlying the muscle
Greater tuberosity of humerus
abduction
what muscle is shown, what is its proximal and sital attachment and what movement does it cause at the shoulder joint?
infraspinatus
Infraspinous fossa of scapula
Middle facet of the greater tuberosity of the humerus
Lateral rotator of the humerus
what muscle is shown, what is its proximal and sital attachment and what movement does it cause at the shoulder joint?
teres minor
Upper two thirds of the lateral border of the scapula
Lesser tuberosity of humerus
Adductor and lateral rotator of the humerus
Although the rotator cuff muscles have a role in movement at the glenohumeral joint, what is their primary function?
Stabilise the glenohumeral joint by compressing the humeral head against the glenoid
Clinical:
Rotator cuff injuries are an important (and a potentially career-ending) cause of sport injury. These are caused by what?
repetitive overhead motions, e.g. serving in tennis; or throwing motions, e.g. pitching a baseball. Over time the increased stress on the ligaments and muscles weakens them, making them more likely to tear.
what is the origin and insertion of the dletoid muscle?
It arises from the lateral spine of the scapula, passing across the acromion to the lateral third of the clavicle. Its distal attachment is to the deltoid tuberosity of the humerus
Due to its extensive proximal origin, different parts of the muscle will move the humerus in different directions.
what is the function of the deltoid
Anterior fibres of deltoid flex and internally rotates at the shoulder joint
Middle fibres abductor the arm at the shoulder joint
Posterior fibres extend and laterally rotates at the shoulder joint
What is the nerve supply to deltoid?
Axillary nerve
In what common injury is this nerve often trapped and therefore damaged? (axillary nerve)
Shoulder dislocation (also occurs in fracture of the surgical neck of the humerus as wraps around here)
As this is a mixed nerve, where would you test for loss of sensation to determine if a nerve injury had occurred? (axillary nerve)
C5 and 6, lateral arm, forearm, thumb and index finger
Abducted against resistance at approx. 15 degrees - motor
what is the proximal and distal attachement of the pectoralis major?
The pectoralis major muscle has an extensive origin from the medial third of the clavicle, sternum and costal cartilage of the first 6 ribs and rectus sheath!
The distal attachment of this muscle is to the lateral lip of the bicipital groove of the humerus
what is the action of the pectoralis major?
Its action on the shoulder joint is to adductor the shoulder and internal/medial rotate the humerus at the glenohumeral joint
Pectoralisminor lies deep to the pectoralis major muscle and is important anatomically as it splits the axillary artery into 3 parts. Along with serratusanterior it serves to stabilise the scapula during limb movements by keeping it pulled against the thoracic cage
The latter has an important role in protraction of the scapula
Clinical Case – A Post-Operative Problem…
Mrs Smith is 64 years old and had a left mastectomy with axillary lymph node clearance for breast cancer.
Oddly she’s recently found that she can feel her scapula protruding outwards from her back when she’s been showering, and she is struggling to lift items on her left side.
Why has this occurred, which nerve has been damaged in the procedure?
Long thoracic nerve is vulnerable in breast surgery
Supplies the serratus anterior
1
Trapezius
2
Latissimus dorsi
3
Teres major
4
Deltoid
Trapezius has a long origin meaning that its fibres approach the spine of the scapulae from above, in-line and below it. This results in different movements upon contraction of different parts of the muscle
Superior fibres of trapezius ______ the scapula
Middle fibres of trapezius ______ the scapula (move it back on the thorax)
Inferior fibres of trapezius ________ the scapula
elevate
retracts
depress
Trapezius has an unusual innervation from a cranial nerve – which one?
Which foramen of the skull does this nerve pass through?
Accessory nerve
Jugular foramen
Clinical:
‘Shrugging’ or elevation of the ________ is therefore one of the tests for cranial nerve function
shoulders
shoulder joint movement = Flexion of shoulder (sagittal plane)
what are the shoulder joint muscles causing this?
- anterior fibres of the deltoid
- pectoralis major
- coracobrachialis
- long head of the biceps brachii
shoulder joint movement = Extension of shoulder (sagittal plane)
what are the shoulder joint muscles causing this?
- latissimus dorsi
- teres major
- pectoralis major ?????
- posterior fibres of deltoid
- Long head of triceps brachii
shoulder joint movement = Adduction of shoulder joint
what are the shoulder joint muscles causing this?
- coracobrachialis
- pectoralis major
- latissimus dorsi
- teres major
- subscapularis
shoulder joint movement = Abduction of shoulder joint
what are the shoulder joint muscles causing this?
0 to 90 degrees:
- supraspinatus
- middle fibres of the deltoid
90 to 180 degrees:
- serratus anterior
- trapezius
shoulder joint movement = Medial or internal rotation
what are the shoulder joint muscles causing this?
- Subscapularis
- Latissimus dorsi
- Pectoralis major
- Teres major
- anterior fibres of the deltoid
shoulder joint movement = Lateral or external rotation
what are the shoulder joint muscles causing this?
- posterior fibres of the deltoid
- teres minor
- infraspinatus
