MD2002- Introduction to Limbs Flashcards
What three points give an overview of the upper limb?
Highly mobile joint
Levers
Enable the hand to be brought to any point in space and keep it steadily
What three points give an overview of the lower limbs?
Supports the body weight
Involved mainly in locomotion
The bones are more robust than those of the upper limbs
At what week does development of the limbs begin?
Week 4
What happens in the beginning of limb development?
Specialized cells migrate from the somites and the lateral plate mesoderm and limb buds form where the arms and legs will develop
When referring to muscles, what is the origin?
The proximal end of the muscle, which remains fixed during muscular contraction
When referring to muscles, what is the insertion?
The distal end of the muscle, which is moveable
When a muscle is stimulated, what happens in regards to the origin and insertion?
They shorten generally in the direction of; insertion -> origin
Some muscles can shorten in both direcions if needed
What are the two types of muscle contraction?
Isometric and Isotonic
What is isometric contraction?
Muscle contracts but does not shorten
What are the two types of isotonic contraction?
Concentric and Eccentric
Define concentric contraction
Muscle contracts according to the sliding filament mechanism and shortens
Define eccentric contraction
The muscle elongates while under tension due to an opposing force greater than the muscle generates
Acts as a braking force to protect from injury
What are the 5 types of muscles?
Prime mover Agonist Synergist Antagonistic Fixating
Describe a prime mover muscle
Muscles that play the primary role in moving a body part
Describe an agonist muscle
Muscles that acts directly to produce a desired movement
Describe a synergist muscle
Muscles which prevent unwanted movements associated with the action of the prime movers
Describe an antagonistic muscle
Muscles which directly oppose a movement
Describe a fixating muscle
Muscles that provide the necessary support to assist in holding the rest of the body in place while the movement occurs
Describe superficial fascia
Just beneath the skin
Contains adipose tissue
Describe deep (investing) fascia
Ensheath muscles but continuous
Facilitates contraction
Barrier between muscles
Passages for nerves and vessels
Attachment for muscles
Hold tendons in place
What is septae?
A thin partition or membrane that divides two cavities or soft masses of tissue
What is the function of septae in muscles?
Deep fascia sends septae between the muscles to separate them into compartments
Forms potential spaces to allow passage of nerves and blood vessels
What is compartment syndrome?
An injury to the muscle within a compartment that may cause swelling and increased pressure that compresses neurovascular bundles
What does the intermuscular septae do in the arm?
Divides the arm into an anterior (flexor) and a posterior (extensor) muscular compartment
What does the anterbrachial fascia form?
It forms the interosseous membrane that separates the anterior and posterior compartments
What is the carpal tunnel?
A narrow passageway on the palm side of your wrist made up of bones and ligaments- contains the median nerve
What is the deep fascia called in the thigh?
Fascia lata
What is the function of the fascia lata?
It thickens laterally as the Iliotibial Tract and sends septae to divide the thigh into anterior (extensor), medial (adductor) and posterior (flexor) compartments
What is the deep fascia called in the leg?
Crural fascia
Describe the crural fascia
Fuses with the tibia
Forms the interosseous membrane
Sends septae to divide the leg into anterior, 2 posterior (superificial and deep flexor) and lateral (peroneal) compartments
Describe a dermatome
A strip of skin supplied by 1 spinal nerve
What is a myotome?
A single or group of skeletal muscles supplied by 1 spinal nerve
Describe the initial position of the thumb, hallux, palm and sole face in a foetus
Thumb and hallux are on the cranial side of each limb
Both the palm and sole face anteriorly
Describe the movement of the upper limb from its in-utero position
Rotates laterally by;
Thumb moves from medial to lateral
Flexor muscle groups move to an anterior position
Extensors move to a posterior position
Describe the movement of the lower limbs from its in-utero position
Rotates medially by;
Hallux moves from lateral to medial
Flexor muscle groups move from an anterior to a posterior position
Extensors move to an anterior position
What do spinal nerves form?
Plexuses
What is the neural innervation of the upper limbs?
Brachial Plexus, in Axilla
Musculocutaneous- C5 Axillary- C6 Radial-C7 Median-C8 Ulnar-T1
What is the neural innervation of the lower limbs?
The Lumbo-Sacral plexus, within the psoas major on the posterior abdominal wall, and on the lateral wall of the pelvis
Derived from the ventral rami of L1 to L5 and S1 to S4
What is phlebotomy?
Removing blood through an incision or puncture
What are the two largests veins in the lower limb?
Great and small Saphenous
What allows the venous flow to go from superficial to deep?
Perforators
Where do the lymph nodes drain to from the limbs?
Axillary (upper limb) Inguinal (lower limb) lymph nodes
