MSK/Movement

Question 1

Name every joint in the human body

Answer 1

MCP are knuckles

If theres a distal, there must be a proximal - named relatively

Question 2

Describe nerve and arterial supply to joints

Answer 2

Excellent sensory nerve supply

Sensations detected by the sensory receptors of the joints
-pain, touch, temperature, proprioception

Articular branches of large named arteries nearby supply joints

Periarticular arterial anastomoses are common
-Alternate pathway for blood, movement can block flow in one artery or damage by e.g. dislocation, blood can still flow

The arteries supplying joints can be damaged by dislocations

Nerve supply makes dislocation/arthritis sore
Arthritis infection/inflammation can feel warm

Question 3

What are the different types of joints ?

Answer 3

Different types and subtypes of joints
-Synovial
-Cartilaginous
-Fibrous

Each is a compromise between mobility and stability, each has a different compromise profile
-Increased mobility = decrease stability
-Decreased mobility = increased stability

Question 4

What are fibrous joints ?

Answer 4

Generally limited mobility but quite stable

Types
-Syndesmoses; unites bones with uniting fibrous sheet fibrous membrane e.g. interosseous membranes partially movable
-Sutures; between bones of skull e.g. tightly woven coronal suture highly stable, not much movement

Sutures are more common

Question 5

What are fontanelles ?

Answer 5

Wide sutures in the neonatal skull
-anterior fontanelles
-posterior fontanelles
-lateral fontanelles

Allow the growing frontal, parietal, temporal and occipital bones to ‘slide’ over each other - makes head more flexible so bones can move relative to eachother

Make’s the baby’s head smaller for passage through the birth canal; head can moulding - can have weird head shape at birth due to overlap but usually fixes itself after a couple of days

Refers to gap and also the membrane
Are the widened areas of sutures
Dipped in soft spot can be sign of dehydration, bulged can be signed of raisde intracranical pressure

Question 6

What are cartilagenous joints ?

Answer 6

Fairly limited mobility but relatively stable

Primary cartilaginous/ synchondroses
-bones joined by hyaline cartilage
-ossification and fusion
-e.g. long bone epiphyseal growth plate permit growth in length of bone (before full ossification, long bones can be considered two connected bones, diaphysis and epiphysis)

Secondary cartilaginous / symphyses
-strong
-slightly movable
-fibrocartilage
e.g. intervertebral discs

Both types can ‘slip’
primary – slipped femoral epiphysis
secondary – slipped disc

Pelvic symphyses is secondary carilagenous

Growth plates are joints

Question 7

Visually compare normal synchrose with slipped

Answer 7

Line on left is normal, is not fracture, is epiphyseal growth plate

Right might have line which looks like fracture, but it is slippage of epiyphiseal plate

Line on left but bones are together, line on right but bones have started to move apart and slip relative to eachother

Question 8

Describe secondary cartillagenous joints (sympheses)

Answer 8

Outer fibrous annulus fibrosus
-fibrous ring (fibrocartilage)

Inner soft nucleus pulposus
-‘soft centre’ (90% water in newborns, decreases as you grow)

Sympheses between vertebral bodies

Each disc allows small amounts of movement in all directions, added together to produce considerable movement

A slipped disc can compress the spinal cord, discs usualy slip posteriorly

Question 9

Describe typical features of synovial joints

Answer 9

1) 2 or more bones articulating with each other

2) Articular surfaces are covered in hyaline ‘articular’ cartilage
-provides some shock absorption and a smoother surface for articulation

3) A capsule wraps around the joint
-Outer layer: thick, dense, protective, fibrous
-Inner (synovial) layer; secretes synovial layer

4) Contains a joint cavity with synovial fluid (cushions, nourishes and lubricates so bones can move freely against eachother)

5) Supported by ligaments
-Fibrous structure which connects bone to bone
-Synovial joints usually have many, to support stability

6) Associated with skeletal muscles and their tendons
-They attach around and cross over joint to help move it and also provide some stability
-Tendons are fibrous structure which connects muscle to bone

7) Associated with bursae
-prevent friction around joint; lets bones, tendon, ligaments move
-extensions of joint cavity or closed sacs separate from the joint cavity

8) Often have special/atypical features
-unique features found in different synovial joints e.g. fibroarticular articular disc in TMJ joint

Patella, seen, articulates with femur but not tibia

synovial fluid is secreted

Question 10

What are the subtypes of synovial joints ?

Answer 10

Plane
-Minimal movement in one plane
Pivot
->45^o of “shaking the head” rotation (c1 and c2 in neck, also forearm supination/pronation in radioulnar joints)
Hinge
-Reasonable range of movement in one plane, like elbow and knee
Ball & Socket
-Good ranges of multi-axial movement e.g. circumduction
Biaxial
-reasonable range of movment in one plane and less in another

Question 11

What controls the direction of movement in joints ?

Answer 11

Shape of articular surface determines possible movement (how much movement and in which axis/direction)

-Left is ball and socket, not much preventing movement

-Trochlear notch (ulna) fits trochlea of humerous, quite tightly fit together so only a bit of movement in one direction between them (hinge joint)

Question 12

What are subluxation and dislocation ?

Answer 12

-Ligament injury and/or slipped disc, but articular surfaces still in normal anatomical relationship to each other
-Subluxation: reduced area of contact between articular surfaces
-Dislocation: complete loss of contact between articular surfaces

Intervertebral disc must tear completelt for vertebral dislocation

Question 13

What are common dislocations ?

Answer 13

Acromioclavicular joints, where clavicle and scapula join, clavicle dislocation here aka shoulder seperation injury

-Hip dislocations and hip replacements make it easier for further dislocations.

-Shoulder more prone to repeated dislocation than hip.

-Joint replacements more likely to dislocate

-Very common for ligaments to be stretchef or torn in a dislocation

Question 14

What are the temperomandibular joints (TMJ)

Answer 14

R/L are the synovial articulation between the mandibular fossa & the articular tubercle of the temporal bone superiorly and the head of the condylar process of the mandible inferiorly

-Often dislocates anteriorly so sits under tubercule, needs manipulation to pull down and under back into place, so cant fix itself. TMJ dislocation can be bi or monolateral

Question 15

What is skeletal muscle ?

Answer 15

-Skeletal muscles produce movement (at joints)

-Skeletal muscles usually found deep to deep fascia

-Tough fibrous connective tissue covering

-Usually found deep to deep fascia

Question 16

What are the different types of skeletal muscle ?

Answer 16

Many different types

Longer muscle fibres:
-Have a greater potential range of shortening
-Have greater potential range of movement produced at joint

Circular forms around lips and anus etc
Fusiform has like a belly and thins out on either end
Pennate has feather like arrangement, looks feather like as in spreading/fanning out from middle part
Quadrate has four sides

When a muscle contracts can shorten by up to 70%

Question 17

How are skeletal muscles usually named?

Answer 17

Usually named according to combination of:
shape – Latin/Greek name
location – body region
size – relative size e.g. major / minor
main bony attachment
main action/movement

Muscle name profundus means deep, profound=deep, meaningful

Question 18

Describe skeletal muscle attachement

Answer 18

Usually at least 2 points of attachment to bone via tendons

The function of a skeletal muscle: move the attachments closer together during contraction

During contraction, muscle fibres shorten along the long axis between the attachments

Only function of skeletal muscle in terms of locomotion is to contract and bring attachement points closer together
They shorten along long axis

Question 19

How are muscles attached to bone ?

Answer 19

Tendons attach the muscle (usually) to bone
-found at either end of the muscle
-non-contractile

An aponeurosis is a flattened tendon
-most commonly associated with flat muscles (e.g. attach oblique muscles and cover rectus abdominus on anterior abdominal wall)
-attach muscle to soft tissue rather than bone

Tendons transmit force from muscle to bone to pull bone

Question 20

What controls direction of movement ?

Answer 20

Depends on which side of the joint the muscle spans

e.g. biceps brachii
-Spans the shoulder joint anteriorly, therefore it flexes the arm at the shoulder joint
-spans the elbow joint anteriorly therefore it flexes the forearm at the elbow joint
-Spans the proximal radioulnar joint anteriorly producing supination of the forearm

The action(s) of any given muscle can be worked out with:
-which joint is spanned
-the long axis of the muscle fibres
-the aspect of the joint that is spanned
-the shapes of the articular surfaces of the joint

Question 21

Describe direction of movement of the deltoids

Answer 21

A muscle can move a bone in different direction depending on the orientation of its fibres
Deltoid has multiple different fibers

1) Attaches to posterior arm
2) Attaches to middle arm
3) Attches to anterior arm

Question 22

What is the key info of bicep bachii

Answer 22

Name: Biceps brachii
Attachments: from scapula to radius
Main Actions: flexion of shoulder joint, flexion of elbow joint, supination of radioulnar joints
Nerve Supply: musculocutaneous nerve
How to clinically test it: biceps jerk reflex

Know general attachement points for each muscle if they’ve been discueed e.g. from scapula to radius, dont need much more detail than that

Question 23

Describe purpose and methods of clinical examination of skeletal muscles

Answer 23

Testing
-ability to move and power (response to great/weak) of movement
-muscle itself and the nerve(s) supplying it

Can be carried out by asking patient to make movements or by testing reflexes

Question 24

What are the two main types of reflexes involving skeletal muscle ?

Answer 24

Reflexes are protective and automatic
The 2 main reflexes involving skeletal muscles are:
-Stretch reflex
-Flexion withdrawal reflex

Question 25

What are flexion withdrawal reflexes

Answer 25

-Touch something potentially damaging, sudden flexion to withdraw from the danger -Nerve connections are at spinal cord level the brain is not involved As seen, sensation - heat, pain to spinal cord, motor from spinal cord to effectors | Flexes digits, hand, elbow here ## Footnote Involve skeletal muscle

Question 26

What are deep tendon reflexes ?

Answer 26

Aka stretch reflxes -“biceps jerk”, triceps jerk”, “knee jerk” & “ankle jerk” reflexes -A tendon hammer is used to apply a brief, sudden stretch to the muscle via its tendon -Normal reflex response to being stretched is to contract muscles thus tendons -Reflex contraction results in a brief twitch of the muscle belly or a movement in the normal direction -Reflexes are protective against overstretching

Question 27

Describe stages of a deep tendon reflex ?

Answer 27

1) Sensory nerve from muscle detects the stretch & tells the spinal cord 2) Synapse in the spinal cord between the sensory & motor nerves 3) Motor nerve from spinal cord passes message to muscle to contract 4) The neuromuscular junction is the synapse where the motor nerve communicates with the skeletal muscle 5) The whole route taken by the action potentials is called the reflex arc 6) Brain prevents reflex from being overly brisk ## Footnote Impact on tendon creates stretch on muslce, to counter stretch contraction occurs so it can avoid tearing which it thinks will happen Brain prevents response being too extreme and over extending limb/response - don’t need to kick out too much - reflex happens in spinal cord, brain controls it

Question 28

What functions does a normal stretch reflex indicate are functioning normally ?

Answer 28

1) The muscle 2) Its sensory nerve fibres 3) Its motor nerve fibres 4) The spinal cord connections between the two 5) The neuromuscular junction 6) “descending controls” from the brain ## Footnote A neuromuscular junction (NMJ) is the connection between a motor nerve and a muscle fiber (where muscle contraction is initiated)

Question 29

What are muscle paralysis and spasticity ?

Answer 29

Paralysis: -a muscle without a functioning motor nerve supply is “paralysed” -a paralysed muscle cannot contract -on examination the muscle would have reduced tone (a bit floppy) Spasticity: -the muscle has an intact and functioning motor nerve -the descending controls from the brain are not working -on examination the muscle would have increased tone | Tone = firm, strong

Question 30

What is muscular atrophy ?

Answer 30

Is ‘wasting’ of the muscles Muscle fibres (myocytes) become smaller, reducing the muscle’s bulk Develops as a result of inactivity, due to: -immobilisation after fracture -damage to motor nerve supply (cant contract muscle) -‘couch potato’

Question 31

What is muscular hypertrophy ?

Answer 31

-Opposite to atrophy -Skeletal muscles enlarge -Each individual myocyte enlarges

Question 32

What is the hierarchy of joint types on basis of mobility and stability ?

Answer 32

Question 33

How does the deltoid attach ?

Answer 33