Week 8

Question 1

Tissue layers of blood vessel

Answer 1

A= endothelium
B= tunica intima: endothelium and internal elastic membrane
C= tunica media: muscle and external elastic membrane
D= tunica adventitia

Question 2

The descending aorta

Answer 2

Commences at end of aortic arch continues down abdomen
Formally ends by bifurcating into left and right common iliac arteries
Thoracic part- commences at sternal angle of Louis (T4-5), ends at aortic hiatus T12, supplies arterial blood to muscles of chest wall and spinal cord
Abdominal part- commences at T12, ends at L4 bifurcating into left and right common iliac arteries,supracistal plane of pelvis, vertebral level umbilicus, T10 dermatome Renal arteries branch off at L1/L2, has two phases: suprarenal segment and infrarenal segment

Question 3

Five major arteries arise from abdominal aorta

Answer 3

Coeliac artery: L1
Superior mesenteric artery: L1
Renal arteries: L1/L2
Inferior mesenteric Artery: L3
Left common iliac artery: L4/5
Right common iliac artery: L4/5
Arteries supplying spinal cord, all vertebral levels L1

Question 4

Arterial tree of lower limb

Answer 4

Common iliac artery: L3/L4, umbilicus, supracristal plane
External iliac artery: L5-S1
-internal iliac artery
Femoral artery : inguinal ligament
-profunda femoris runs through adductor canal
Popliteal artery : adductor canal
Tibial arteries: adductor hiatus
-anterior, posterior : lower border of popliteus
Dorsalis pedis, post tibial artery

Question 5

Femoral artery

Answer 5

Begins at lower border of inguinal ligament
Passes inguinal ligament at mid point
Ends at apex of femoral triangle
Ends by entering adductor canal
The apex of femoral triangle is an opening in adductor Magnus - adductor canal/ subsartorial canal, hunters canal
Then becomes popliteal artery

Question 6

Popliteal artery

Answer 6

Starts at the opening adductor canal and ends at adductor hiatus
Then enters diamond shaped anatomical space at back of thigh- Popliteal fossa
In popliteal fossa it gives off a series of geniculate arteries to supply the knee joint
Popliteal artery ends at lower border of popliteus muscle bifurcating into anterior and posterior tibial artery

Question 7

Anterior tibial artery

Answer 7

Pulses often palpated at its level known as dorsalis pedis
Points of best palpitation are: above the navicular bone, medial to the tendon of extensor hallucis longus

Question 8

Posterior tibial artery

Answer 8

Larger of the terminal branches of the popliteal artery
Descends deep to soleus then becomes superficial in lower third of the leg
Passes behind the medial malleolus between tendons of flexor digitorum longus and flexor hallucis longus
Below the ankle it divides into medial and lateral plantar arteries which constitute principal blood supply to the foot

Question 9

Venous tree of the body

Answer 9

Commences at levels of post capillary venules
Ends when venae cava access the right atrium of the heart

Question 10

Normal drainage venous blood

Answer 10

Longitudinal conduction is that venous blood is conducted from post capillary venules- venules-small veins- larger veins- right atrium
Low pressure system
Has evolved to overcomes an element of the circulatory system where there’s no pump or driving force, tendency of venous blood to pool in lower extremities as a result of gravitational pull

Question 11

Adaptations venous system

Answer 11

One way valves that prevent back flow of blood to promote venous return to heart
Systemic veins with thin walls enabling them to collapse and obliterate the lumen as the veins collapse they passively pump blood past one valve at a time
Musculovenous pump

Question 12

Classes of veins

Answer 12

Superficial veins
Deep veins
Perforating veins
Accompanying veins: vaso vasorum, venae commitante(accompany arteries)
Venous blood flows form superficial to deep veins via perforating veins

Question 13

Sites for venepuncture and saphenous cut down

Answer 13

The great saphenous vein (branch of femoral vein) is accessible through:
A hands breath to the medial edge of patella
In front of medial malleolus

Question 14

Varicose veins

Answer 14

Perforating veins drain venous blood from superficial to deep veins
If incompetence in valves preventing backflow in perforating veins- venae stasis
Resulting in varicose veins, clotting in stagnant venous blood, raising probability DVT

Question 15

Nerve supply to lower limb

Answer 15

Lumbar and sacral spinal segments
Lumbar plexus: L1, L2, L3, half L4
Sacral plexus: half L4, L5, S1,S2, S3 S4
The lumbar contribution to sacral plexus is the lumbosacral trunk

Question 16

The lumbar plexus

Answer 16

Forms behind psoas major
Nerves emerge form medial or lateral border psoas major
Lateral: femoral nerve L2-4, iliohypogastric, ilioinguinal, lateral cutaneous nerve of thigh
Medial: obturator nerve L2-4, lumbosacral trunk half L4, L5

Question 17

The sacral plexus

Answer 17

Plexus forms in pelvis cavity
Lies in relation to piriformis
Composed of lumbosacral trunk half L4 and L5
Sacral spinal segmental outflow
Supplies nerves to pelvic region, gluteal region, perineal region, lower limb via sciatic nerve

Question 18

Sensory supply lower limb

Answer 18

Front limb is supplied largely by lumbar segments
Back limbsuppleid mainly sacral segments
Saddle area is sacral segments
Perineal area is sacral segments

Question 19

Axial lines

Answer 19

Line of junction of two dermatomes supplied from discontinuous spinal levels known as axial line
Limbs have anterior and posterior axial lines
Axial lines mark centre of either pre axial or post axial territories of the limbs
Boundaries between pre axial and post axial compartments are marked out by veins

Question 20

Sensory nerve territories

Answer 20

Sensory divisions of terminal nerves of lumbar plexus supply skin in territorial domains
Not dermatomes

Question 21

Visual assessment of the musculoskeletal system

Answer 21

Appearance of skeletal muscles in the body
Symmetry of muscle bulk between left and right sides
Presentation of the limbs and other muscle systems
Posture
Gait etc

Question 22

Definition of motor unit

Answer 22

Constitutes from the alpha motorneuron and all muscle fibres it supplies
It comprises:
1 alpha-motor neurone
Extrafusal muscle fibres it supplies
Minimal functional unit of the motor system

Question 23

Definition of a reflex

Answer 23

Involuntary, unlearned, repeatable, automatic reaction to a specific stimulus that doesn’t require brain to be intact
Reflex arc:
A receptor
An afferent fibre
Integration centre
Efferent fibre
Effector organ

Question 24

Role the muscle stretch reflex play in neurology

Answer 24

Template neural circuit from which all motor circuits are built
Minimal neural circuit that underlies all movements of muscles of body
Neural circuit that sets all motor tone of the body

Question 25

Muscle Stretch reflex

Answer 25

Stretch activated reflex contraction of skeletal muscle When a muscle is not contracted it relaxes A relaxing muscles is effectively lengthening When muscle length receptors detect stretch they fire action potentials via afferent axons to keep CNS appraised of muscle length at all times

Question 26

How does muscle stretch reflex work

Answer 26

Action potentials from muscle length receptors are sent to: The brain via dorsal column The cerebellum via spino-cerebellar tracts A copy of that signal is also sent directly to spinal motorneurones Results in reflex recruitment of motorneurones

Question 27

Anatomy of stretch reflex

Answer 27

The spinal reflex pathway involves two neurones A stretch receptor afferent Efferent neurone 1 synapse in lamina IX of spinal cord

Question 28

Motor tone

Answer 28

In a normal awake neurological status lower motorneurones tonically supply muscles with background electrical impulses These lead to background minimal contraction of the muscle This minimal contraction gives the muscle a small amount of force called muscle tone/motor tone Motor tone allows us to maintain body posture and hold heads up

Question 29

Muscle tone in babies

Answer 29

Present but low in-utero Suppressed in the new born Returns within months after birth Return of muscle tone in the new baby informs of the absence or presence of birth injury of the brain

Question 30

When is muscle tone inhibited

Answer 30

During deep (REM) sleep in all muscles except: Muscles of breathing Extraocular muscles Urinary sphincter Anal sphincter

Question 31

What happens when muscles generate too little tone

Answer 31

Body becomes limp Body is unable to support its weight Normal body posture is lost This is anything between hypotonia and atonia depending on severity

Question 32

What happens when muscles generate too much tone

Answer 32

Muscles become stiff Reciprocal inhibitory relationships between agonists and antagonists is disrupted Agonists and antagonists become equally as stiff, simultaneously Joints become stiff Normal body posture altered Ability to move affected limb lost Fluidity of movements of joints will be lost Spastic paralysis will results

Question 33

Constellation of Lower motor neurone signs

Answer 33

Flaccid muscle weakness Hypotonia or atonia Hyporeflexia or areflexia Denervation muscle atrophy Fasciculations acute phase Muscle wasting

Question 34

Three types of movement

Answer 34

Involuntary or reflex (simplest) Voluntary (most complex) Rhythmic ( a combination of reflex and voluntary) All require muscle contraction

Question 35

Centre of gravity

Answer 35

Moves with unconscious (reflex) change in posture or with voluntary goal directed movement but must remain within the area bounded by our feet to avoid falling The point at which the whole weight of an object can be considered to act and therefore at which all parts of an object are in balance. The position of the centre of gravity varies according to the shape of the object

Question 36

Postural muscles

Answer 36

Need to maintain tone in order to stay in a constant state of partial contraction and thus counteract gravity Corrective reflexes to maintain stability and position A role for receptors and somatic reflexes

Question 37

Sensory feedback arises from

Answer 37

Visual system Vestibular system- sense of balance and spatial orientation Skin receptors Proprioceptors Skin and proprioceptors—> somatic sensation (somesthesia) Visual and vestibular—> Vestibulo-ocular reflex and optokinetic reflex

Question 38

Muscles spindles

Answer 38

In parallel with muscle fibres, undergo same length change as muscle Measure length Intrafusal muscle fibres lying in parallel within extrafusal muscle fibres, greatest density in small muscles serving fine movement and also deep muscles of neck Innervated by sensory and motor nerves Detect dynamic and static changes in muscle length essential for detection of muscle length and rate of change of length Central region: specialised non contractile fibres, primary and secondary sensory afferent endings Peripheral region: innervated by gamma unmyelinated motor neurones does not contribute to overall force adjusts sensitivity of spindle

Question 39

Golgi tendon organs

Answer 39

In series with muscle fibres measure tension Sensory stretch receptors that are found in tendons near junctions with muscle fibres and respond to tension changes in the muscle they are innervated by myelinated Ib fibres Ib fibres go to ventral horn and activate interneurons which inhibit (glycinergic) alpha motor neurons opposite muscle spindle but with higher threshold than for muscle spindle Stimulation of Golgi sensory neuron fibres causes a reflex inhibition in the efferent signal to skeletal muscle so loss in contraction strength, muscle relaxes Believed to assist in the fine control of muscle length playing a role in the maintenance of posture

Question 40

Proprioceptors

Answer 40

Are sensory receptors found in muscle that are important for reflex control of muscle length and tension

Question 41

Somatic motor reflexes

Answer 41

Stereotypic movements elicited by specific sensory stimuli Characteristic somatotopic organisation and large dendritic tree

Question 42

Afferent innervation muscle spindle

Answer 42

Primary afferents- innervate central region and respond primarily to velocity of lengthening Secondary afferents- innervate ends of central region and respond to static length During a stretch reflex increased firing by the sensory neuron increases signalling by the alpha motor neuron causing the muscle to contract

Question 43

Role of gamma efferents muscle spindle

Answer 43

A passive stretch activates gamma efferents and can initiate corrective reflex If alpha motor axons activated without firing of gamma efferents the spindle loses activity when the muscle contracts - skeletal muscle contracts muscle spindle squashed switched off losing sensitivity of stretch Alpha-gamma coactivation maintains spindle function when muscle contracts, activated independently Gamma motor neurons contract end of muscle spindles

Question 44

What is gait

Answer 44

Walking Jogging Skipping Running Sprinting Children learn to walk between 9-18 months usually 12 months

Question 45

Locomotor unit

Answer 45

11 joints Lumbar spine 2 hip joints 2 knee joints 2 ankle joints 2 subtalar joints 2 metatarsal phalangeal joints

Question 46

Assessment of gait

Answer 46

Assess symmetry Speed: pain slows gait down Top to bottom analysis: - do arms swing naturally -is the lumbar spine hunched or upright and stiff - are pelvis and hips controlled -does hip flex and extend normally -does knee bend normally -assess ankle and foot position -step width -toe out angle- pigeon toe

Question 47

Gait cycle

Answer 47

Stance and swing phases Starts with initial contact- heel strike A complete gait cycle is a single stride from a heel strike to next heel strike of same limb A step is half a stride Stance phase: when the foot that made the heel strike is on the floor Swing phase: the foot that made the initial hell strike is in the air Gait cycle then ends with heel strike of same foot 2 double limb stances in cycle: -beginning and end of stance phase As walking speed increases period in double stance phase decreases until its omitted in running Single support: one foot on the ground bearing body weight

Question 48

Function of the stance phase

Answer 48

Shock absorption Stability Propulsion

Question 49

Function of the swing phase

Answer 49

Ground clearance- need enough hip flexion, knee flexion and ankle Dorsiflexion Step length

Question 50

Sub phases of gait cycle

Answer 50

Swing phase: initial swing, mid swing, terminal swing phase Stance phases: - initial contact heel strike event: hip is flexed, knee extends ankle is neutral -loading response; hip flexes, knee flexes, pelvis dips to absorb shock of impact, ankle plantar flexes then dorsiflexes into midstance -mid stance phase: ankle extends, knee straightens out to allow swing leg to clear ground -terminal stance phase: extended limb is extended further through hip into pre swing as initial contact is made of other side, heel raises and push off occurs -pre swing- toe off

Question 51

Rockers of gait

Answer 51

There are 4 rockers (pivots): - the heel rocker - the ankle rocker - the forefoot rocker -the toe rocker The whole leg rocks over the foot using these pivots in different stages This is called tibial progression When the rockers cease to function properly you can perform physiotherapy to mitigate effect

Question 52

Shock absorption

Answer 52

Important function of stance phase Before heel strike the body is in free fall The shock absorbing response of the foot, ankle, knee and hip reduce intensity of impact Knee flexion is the largest shock absorbing mechanism Weight loss is also benefit joint function as it reduces shock

Question 53

Energy cost gait

Answer 53

Normal walking uses 40% of maximal aerobic capacity Reduce energy expenditure: -selective muscular control is crucial to efficiency of gait -centre of mass control

Question 54

The major determinants of gait

Answer 54

Maintain body centre of mass at constant height above ground to reduce energy expenditure 6 major displacements: - pelvic rotation -pelvic tilt - stance knee flexion - foot and ankle mechanisms -tibiofemoral angle -pelvic lateral displacement

Question 55

Springing pendulum theory of human gait

Answer 55

Pivoting over a stiff stance leg Passive movements of the swing leg Propulsion from the ankle propelling the swing leg Rotation of the hips in axial plane to increase stride length Tilting of the hips in coronal plane to improve balance during stance

Question 56

Muscular anatomy of walking stance phase

Answer 56

Stance phase: Pelvis- stability tensor fascia latae Hip- flexion (iliopsoas, sartorius, rectus femoris) extension (semitendinosus, biceps femoris, gluteus maximus, adductor magnus) Knee- flexion( rectus femoris, vastus lateralis and vastus medialis eccentric contraction), Ankle: plantarflexion (gastrocnemius, soleus), Dorsiflexion( tibialis anterior, extensor digitorum longus, gastrocnemius, soleus)

Question 57

Muscular anatomy of walking swing phase

Answer 57

Pelvis: stabilisation tensor fascia latae Hip: flexion (semitendinosus and biceps femoris) Knee: flexion (sartorius), extension ( rectus femoris, vastus lateralis, vastus medialis) Ankle: Dorsiflexion (tibialis anterior, extensor digitorum longus), plantarflexion (gastrocnemius, soleus)

Question 58

What influences gait

Answer 58

Bony Skeleton Muscle function Other soft tissues Other organ systems Trauma Pain Inflammation Congential abnormality Neurological function Weakness Psychology

Question 59

Antalgic gait

Answer 59

To counteract pain Classic limp There is decreased time spent in stance phase to avoid weight bearing Many causes

Question 60

Circumduction gait

Answer 60

Affected leg excessively abducts in swing phase Cause long or stiff leg

Question 61

Spastic gait

Answer 61

On affected side: Circumduction hip, medial rotation leg, feet are dragged, stiff knee and hip increased swing phase and decrease stance phase Cause: neurological upper motor neurone pathology, stroke or cerebral palsy

Question 62

Ataxic gait

Answer 62

Unstable gait pattern Similar to drunken gait Uncoordinated movement Broad base gait- provides stability Cerebellar

Question 63

Trendelenburg gait

Answer 63

Weak hip abduction Hip is not stabilised in stance phase so pelvis tilts down Persons weight is then used to maintain pelvis position resulting in waddling

Question 64

Toe walking gait

Answer 64

Common Can be habitual

Question 65

Foot drop gait

Answer 65

High step to clear the ground Whole leg being lifted with excessive hip flexion to keep foot clear off the ground in the swing phase Knee also flexes excessively Ankle is usually plantar flexed Cause: polio, spina bifida

Question 66

Parkinsonian gait

Answer 66

Hurry along with short fast steps (shuffling gait) Stooped posture Walking is on forefoot rather than heal Lack of arm swing Cause: Parkinson’s

Question 67

Crouch gait

Answer 67

Occurs with weakness of quadriceps Increased Dorsiflexion of ankle Excessive knee flexion Cause: cerebral palsy

Question 68

Bizarre gait

Answer 68

Psychogenic cause

Question 69

Clumsy gait

Answer 69

Caused: dyspraxia

Question 70

Rapid clinical gait analysis

Answer 70

Is there pain Is there asymmetry Are there clues to a diagnosis Head to toe observation of joint movement

Question 71

Assessing a acutely limping child

Answer 71

Consider broad differential Rule out: infection, tumour, non-accidental injury Be systematic: history, examination, investigations Have a clear diagnosis and plan

Question 72

Red flags in gait assessment of a child

Answer 72

Duration>7 days Unusual story Severe localised pain Change in bowel/bladder Unable to weight bear Nocturnal pain Systemic symptoms Wasting fever Rash Kocher criteria: signs for septic arthritis: - non weight bearing -ESR>40 con -WCC> 12 -Temp>38.5

Question 73

Physical examination gait in child

Answer 73

Musculoskeletal system Systemic exam