Intro To Limbs Flashcards
Why are bones of lower limbs involved more in locomotion than bones and joints of upper limb?
More robust
In what week do limbs start developing?
Week 4
How do limbs start to develop?
Specialised cells migrate from somites and lateral plate mesoderm
What forms to allow arms and legs to develop?
Limb buds
What is the origin of a muscle?
Usually proximal end of muscle
What happens to origin of muscle during muscular contraction?
Remains fixed and stable
Where is the insertion of a muscle?
Distal end
What happens to insertion of muscle during muscular contraction?
Moves
What happens when a muscle is stimulated?
Contracts and shortens (brings two ends of origin and insertion closer)
In which direction do muscles usually shorten?
Insertion -> Origin
However can shorten in both directions under different situations
What are the two types of muscle contraction?
Isomeric contraction
Isotonic contraction
What’s Isometric contraction?
Muscle tone changes not meter
No movement - doesn’t move a load
What’s isotonic contraction?
Muscle length/meter changes not tone
2 types - concentric and eccentric
Movement - moving a load
What happens in concentric contraction?
Muscle shortens
What happens in eccentric contraction?
Muscle elongates while under tension
What causes muscles to elongate in eccentric contraction?
Due to opposing force greater than the force the muscle generates
How does eccentric contraction act to protect from injury?
Braking force in opposition to concentric contraction
What’s the prime mover?
Muscle with primary role moving a body part
What’s agonist?
Direct action of muscle to produce desired movement
WHat’s synergistic muscles?
Muscles which prevent unwanted movements related with prime movers
What are antagonist muscles?
Muscles which directly oppose a movement
What are fixating muscles?
Muscles that provide support to rest of body while movement occurs
Where is superficial fsascia found?
Membrane immediately beneath skin
How many layers in superficial fascia?
2 - attached to each other or separated
Example of 2 superficial fascia layers separated:
Breast tissue between two layers
What does superficial fascia contain?
Adipose tissue
Where is deep (investing) fascia found?
Surrounding structures
Ensheathes muscles
Important properties of deep fascia:
Continuous
Facilitate contraction
Deep fascia and muscles:
Barrier between muscles
Compartments of muscles
What does deep fascia form while forming compartments?
Passages for nerves and vessels
How does deep fascia allow attachment for muscles?
By forming interosseous membranes
How does deep fascia hold tendons in place?
By forming Retinaculae
How does deep fascia form compartments of muscles?
Sends septae between muscles
Why do septae also form potential spaces in compartments?
Passage of nerves and blood vessels
What are potential spaces formed by septae potential tracks for?
Infection spread and blood loss
What’s compartment syndrome?
Injury to muscle within tough compartment
Swelling
Compression of neuro vascular bundles caused by increased pressure
Main bone in arm:
Humerus
What does deep fascia in arm divide muscles into?
Sends intermuscular septae to divide muscles into two compartments
What main bones are in the forearm?
Radius and Ulnar
What membrane is between radius and ulna in forearm?
Interosseous membrane
What forms interosseous membrane in forearm?
Antebrachial fascia
What compartments does the interosseous membrane divide forearm into?
2 compartments
Anterior - flexor muscles
Posterior - extensor muscles
What is in wrist?
Carpal tunnel
What’s in carpal tunnel?
White spaces are tendons
Has deep fascia lid
What is deep fascia like in thigh?
Thicker
Called fascia lata
Why is deep fascia in thigh thicker?
Needs muscles to compress veins
How does the fascia lata thicken in thigh?
Thickens laterally as the Illotibial tract
What compartments does the septae from Illotibial tract divide the thigh into?
3 compartments
Anterior - extensor muscles
Medial - adductor muscles
Posterior - flexor muscles
What does fascia lata become when it continues into leg?
Crural fascia - leg fascia
What does the crural fascia form?
Fuses with tibia
Forms interosseous membrane
What compartments does septae from interosseous membrane divide the leg into?
Anterior - extensor muscles
2 posterior - superficial and deep flexor muscles
Lateral - - perineal muscles
How many compartments in leg?
3 functionally
4 in structure as septae divides posterior compartment into 2
What is a dermatome?
Strip of skin supplied by 1 spinal nerve
What is a myotome?
Skeletal muscle (s) supplied by 1 spinal nerve
What does rotation of limbs effect?
Dermatomes
In development, what are the thumb and hallux initially positioned like?
On cranial side of each limb
Palm and sole face anteriorly
How does upper limb rotate from its in-utero position?
Rotates laterally
Thumb moves from medial to lateral
What happens to flexor and extensor muscles in rotation of upper limb?
Flexor - move to anterior
Extensor - move to posterior
How does lower limb rotate from its in-utero position?
Rotates medially
Hallux moves from lateral to medial
What happens to flexor and extensor muscles in rotation of lower limb?
Flexor - move to posterior
Extensor - move to anterior
What also happens in rotation of limbs?
Dermatomes rotate too
Where do spinal nerves emerge from?
Intervertebral foramina
Where are C1 to C7 spinal nerves found?
Above respective vertebrae
Where is C8 spinal nerve found?
Below C7 vertebra
Where is T1 and all other spinal nerves found?
Below respective vertebrae
What does ventral ramus go on to form?
Plexuses
What’s involved with neural innervation in upper limb?
Brachial plexus, in axilla
What’s brachial plexus derived from?
C5 - C8 and T1 spinal nerves
What’s involved with neural innervation in the lower limb?
Lumbosacral-sacral plexus
Where is lumbo-sacral plexus found?
Within psoas major on posterior abdominal wall
On lateral wall of pelvis
What’s lumbo-sacral plexus derived from?
Ventral rami of L1 - L5 and S1 - S4 spinal nerves
Main source of arterial supply in upper limbs?
Subclavian arteries
Main source of arterial supply in lower limbs?
External iliac arteries
What’s involved with venous drainage of limbs?
Superficial veins in superficial fascia
Have connections with deep veins
What are the main superficial veins in upper limb for venous drainage?
Cephalic and basilic
What do deep veins in upper limb accompany?
Arteries
What are the main superficial veins in lower limb for venous drainage?
Great (long) and small (short) Saphenous veins
How are connections of superficial veins with deeep veins different in lower limbs than upper limbs?
More significant in lower limb
Direction of venous flow in lower limb:
From superficial to deep
Via perforator (veins)
What helps venous return to heart in lower limbs?
Muscle pump
Arterial pulsation
Negative intrathoracic pressure
Valves in veins
Lymph vessels in limbs:
Follow superficial or deep veins
What lymph nodes do lymph vessels drain to?
Axillary (upper limb) and Inguinal (lower limb)
