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Flashcards in MSK 3 Deck (29)
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Insertions of BBC muscles

Brachialis - coronoid process of ulna
Biceps brachii - radial tuberosity
Coracobrachialis - Coracoid process


Attachments of long and short head of biceps brachii
Which tendon is most likely to rupture and what is this called

Short head into Coracoid process
Long head into superglenoid fossa of scapula

Long head most likely to rupture - called Popeyes sign


Names of the heads of triceps brachii - nerve innervation with roots

Medial, short and lateral
Innervated by radial nerve C5-T1 and long head also innervated by Axillary nerve C5 and C6


What nerve root does the triceps tendon hammer reflex test for



Where does the long head of the triceps originate from?

Infraglenoid fossa of the scapula


Borders of the cubital fossa

Superior - imaginary line between the medial and lateral epicondyles
Medial - lateral border of pronator teres
Lateral - medial border of brachioradialis


Contents of the cubital fossa

Tendon of biceps brachii
Brachial artery
Median nerve


2 ways that the glenohmeral joint is made stable

- glenohumeral ligament
- transverse humeral ligament
- coracohumeral ligament
- Coracoacromial ligament

Tonic tone of the SITS muscles

Glenoid labrum making the joint deeper

Fibrous capsule


What are the two bursae of the glenohumeral joint

Sub acromial bursae - between Supraspinatous tendon and acromion
Subscapular bursae - bursae between the subscapular tendon & scapula


Ligaments of the glenohumeral joint. Briefly describe their location and where they span between

1. Transverse humeral ligament.
- across the greater and lesser tubercle of humerus and holds tendon of long head of biceps in place during movement

2. Coracoacromial ligament
- across the Coracoid process and acromion
- ligament plus acromion and Coracoid process form an arch
- Coracoacromial arch - prevents superior displacement of humerus

3. Glenohumeral ligament
- from glenoid fossa to the anatomical neck of humerus

4. Coracohumeral
- from Coracoid process to the anterior surface of greater tubercle


Painful arc - what is it and how is it tested

Subacromial bursitis - inflammation of this bursae. Supraspinatus tendon becomes irritated and degeneration occurs of the tendon

Upon abduction, when the affected portion of the tendon comes into contact with the acromion, it hurts - hence painful arc.


Why are most shoulder dislocations anterior and inferior?
What structures are at risk in these dislocations.
What is it anterior and inferior in relation to?

Location is in relation to infraglenoid fossa.
This dislocation is more common because there are no SITS muscles here to stabilise it and this is the weakest part of the joint capsule.
Axillary nerve runs here as well as anterior and posterior circumflex arteries so these structures are at risk.


Describe the major land marks for the arterial supply of the upper limb

Left hand side
- subclavian artery direct branch off the aortic arch
- becomes the Axillary artery as it passes the lateral border of 1st rib
- Axillary artery passes the into upper limb in the axillary sheath below pec minor
- surgical neck of humerus - anterior and poster Cx artery arise
- lower border of teres major, Axillary becomes brachial artery
- gives off profunda brachii for the posterior supply of the arm
- brachial artery bifurcates into radial and ulna artery as it crosses cubital fossa


Where do the limb buds appear in the foetus? Put timings on it

End of week 4, upper limb buds appear on the ventrolateral body wall.
A few days later the lower limb buds appear too, a bit lower down.


From which embryonic tissues do the limbs generate from

Mesoderm (flexible)


What covers the the distal borders of the limb buds and what structure does this become

Forms the Apical Ectodermal Ridge


What is the function of the AER?

- keeps the adjacent mesenchyme undifferentiated but they proliferate.
- proliferation = growth so the cells get further away from the AER
- AER becomes more distal and loses its effect on the proximal cells
- the more proximal cells then differentiate into cartilage and muscle.


How do fingers and toes form from the hand and foot plates

Cell death occurs which separates them into fingers as we know them


What marks the boundary between dorsal and ventral ectoderm?



What is the zone of polarising activity and what does it do

It is a cluster of cells that is located on the posterior base of the limb bud.
It is responsible for asymmetry of the limb (eg ensures the thumb is lateral in the hand) and ensures an anterior posterior axis.
It also maintains the AER.


Which weeks of the foetal development are the most critical for limb defects?

4 to 6


What is syndactyly

Fusion of digits.
Occurs when the apoptosis in the cartilaginous digital rays fails.
Fusion can be due to skin, connective tissue or even bone.


What is polydactyly

Extra digit (s)


What is Amelia

A complete absence of a limb


What is meromelia

Partial absence of a limb


What is phocomelia

This is a subset of meromelia.
Rudimentary hands and feet are connected to the truth via weak, misshaped bones.


Name a drug that is known to have caused phocomelia.



Explain how in the upper limb, the thumb is lateral and the extensors are posteriorly, but in the lower limb the great toe is medial and the extensors are anterior

Limb rotation occurs
- UL rotates 90 degrees laterally
- LL rotates 90 degrees medially


Name the positions of the muscles in the anterior compartment of the arm, relative to each other

Coracobrachialis - medial and deepest
Biceps brachii - most superficial
Brachialis - deep to biceps and more distal