Introduction to the Limbs Flashcards
Describe the development of the limbs
It begins at week four of development, Specialised cells migrate from the somites and later plate mesoderm. The limbs will then develop from limb buds.
What are the two types of muscle contraction?
Isometric (muscle tone changes) and isotonic contraction (muscle length changes)
What are the two types of isotonic contraction? and describe them
Concentric (muscle contracts according to the sliding filament mechanism and shortens) and Eccentric (muscle elongates while under tension)
What is a prime mover?
Muscle/s that play the primary role in moving a body part
What is an Agonist?
Muscle/s that act directly to produce the desired movement
What are synergist muscles?
Prevents unwanted movements associated with the action of the prime movers
What are antagonist muscles?
Directly oppose a movement
What are fixating muscles?
Provide necessary support to hold the body in place while movement occurs
What are the features of superficial fascia?
It is found just beneath the skin and contains adipose tissue
What are the features if deep fascia?
Barrier between muscles, encloses muscles and creates compartments of muscles and allows for the attachment of muscles. It allows for the passage for nerves and vessels and holds tendons in place by forming Retinaculae
What is retinaculae?
A band of thickened deep fascia that holds tendons in place
How does deep fascia separate muscles into compartments?
By sending septae between muscles. They also form potential spaces for the passage of nerves and vessels.
What is compartment syndrome?
An injury to a muscle within a tough compartment can cause swelling and increase the pressure which compresses neurovascular bundles.
Describe the fascia of the upper arm
Intermusclar septae divide the arm into an anterior (flexor) and posterior (extensor) compartments
Describe the deep fascia of the forearm
Antebrachial fascia forms interosseous membrane that separates anterior (flexor) and posterior (extensor) compartments. Also forms carpal tunnels
What is deep fascia of the thigh called?
Fascia lata
Describe the deep fascia of the thigh (fascia lata)
- It thickens laterally as the Iliotibial tract
- Sends septae to divide the thigh into anterior (extensor), medial (adductor) and posterior (flexor) compartments
Describe the fascia of the leg (crural fascia)
It fuses with the tibia and forms the interosseous membrane. - It sends septae to divide the leg into anterior (extensor), Two posterior (superficial and deep flexor) and lateral (peroneal) compartments
What is a dermatome?
A strip of skin supplied by one spinal nerve
What is a myotome?
Muscle/group of muscles supplied by one spinal nerve
Why is thumb lateral but bug toe medial
Upper limb rotates laterally, therefore the flexor muscles move to an anterior position but the lower limb rotates medially and so flexor muscles move to a posterior position
What are the branches that come off the brachial plexus
Musculocutaneous, Axillary, Radial, Median and Ulnar
What supplies the lower limbs with nerves
Lumbo-sacral plexus which is within the psoas major.
What are the two main arterial supplies for the upper and lower limbs?
Subclavian and external iliac arteries
What helps venous flow return to the heart?
Muscle pump, arterial pulsation and negative interthoracic pressure
What does the lymphatic system do?
Absorb interstitial fluid via lymph capillaries and transport it to lymph nodes. All lymph will eventually return to the venous flow
What us the largest lymph vessel?
The thoracic duct which opens at the junction between the left subclavian and internal jugular vein
How does in-utero rotation effect dermatomes
It causes the dermatomes too rotate
