Musculoskeletal Flashcards

Question

What are 3 main gait disorders, their presentation and origins?

Answer 1

Antalgic Gait: Shortened stance phase, (resulting in a limp). Usually due to pain Cerebellar Ataxia: Slowness of pace and wide stance. Due to loss of balance and coordination. Central neuroplogical problem High Steppage Gait: Weakness of dorsiflexion, so high stepping gait with no heel strike phase. Central neuro, peripheral nerve or muscular problem

Answer 2

Account for 25% of health costs, 1/4 adults affected. | Includes arthritis, osteoporosis, injuries, low back pain, spinal disorder, deformities.

Answer 3

Epiderpis - Stratum Corneum - Stratum lucidum - Stratum granulosum - Stratum spinosum - Stratum germinativum Basal Lamina Dermis - Papillary layer - Reticular layer Subcutaneous Layer/Hypodermis Investing Fascia

Answer 4

The first 3 provide epithelial cells when healing | Also some protection, secretion etc.

Answer 5

The reticular layer of the dermis is key to skin. It contain collagen, with tropocollagens in a quasi-crystalline arrangement to aid tension It also contain elastin, with tropoelastin in a complex arrangement to withstand stretch and relaxation (tension) The two fibres have a 3D basket weave pattern aligned with the skin tension lines (Langer's Lines). This is important for wound healing and hypertrophic scars Therefore, when the fibres are gradually loaded, they extend quickly as they stretch, but stretch little more once straightened, even at higher loads. It works kind of like the laundry rack at home- they stretch out until you can't extend them further

Answer 6

``` Closely packed parallel bundles of collagen, compressed and elongated fibroblasts, sparse capillaries/ Some elastic fibres, more prominent in ligaments. Tendon sheaths (inner epitendineum, outer parietal) allow sliding, with space between containing synovial fluid ```

Answer 7

Normally, they resist tension with minimal (only 2%) elongation, as the collagen fibres are already straightened out. If tension is lost, they are rapidly remodelled. Applying lateral pressure leads to remodelling with formation of fibrocartilage to improve compression resistance. If the pressure is removed they can return to their previous composition

Answer 8

They resist compression very well due to their proteoglycan aggregates. These repel each other. While they only need a small amount of input for maintenance, coompletely unloaded joints rapid, significant loss of PGs. This is prevented by passive movement of unloaded joints

Answer 9

It is very poor at regenerating, resulting in chronic conditions difficult to treat. Rheumatoid arthritis: A.I. disease. Antibodies destroy cartilage, severe inflammation Osteo-arthritis (degenerative arthritis): Assoc. with age, pathological if onset premature. Caused by increased mech. stress to regions with low PG (mainly peripheral)

Answer 10

FC: Resists tension and compressive forces EC: Supports flexible structures, contains elastic fibres with type 2 collagen.

Answer 11

The collagen becomes less regular The tenocytes/fibroblasts become rounded instead of elongated There is increased PG and H2O secretion

Answer 12

The PGs formed are easy to lose, but hard to regain- it takes a long time for a second application of pressure to result in cartilage formation

Answer 13

Most articulating bones, costal area in ribs

Answer 14

- CS and KS GAGs with -ve charges are attached to core proteins, which attach via link proteins to HA. These -ve charges repel - H2O binds to HA between the PGs, which is hard to compress - -ve charges on the GAGs also bind to collagen fibres, making the tissue very stiff

Answer 15

The 2 second creep modulus: When a probe is pushed into cartilage for 2 seconds, how much does it depress? The greater the PG content, the greater the resistance to pressure

Answer 16

There is more PG content in the middle, as the edges of the joint are used less.

Answer 17

Either weightbearing or passive movement of unloaded joints- it only really remodels when weight and movement are removed.

Answer 18

The region of the tendon around the sesamoid part of the ankle is similar to fibrocartilage as it is under pressure. Due to this, it has a high concentration of CS in aggrecan. This is opposed to the low concentration of GAGs in other regions of the tendon, with low levels of DS in decorin PGs

Answer 19

Bone resists tension, pressure and torsion, as its collagen is arranged in lammelae with differing direction, and it has hydroxyapatite in its matrix

Answer 20

The trabeculae are aligned with the direction of force, to transfer these from the middle to the compact outer shell of the bone

Answer 21

It is found more in the articulating edges and shell of the bones, with greater thickness in areas with greater pressure. The osteons are arranged paralled to the direction of compressive forces

Answer 22

Fetuses have fine cancellous bone only, with collagen in a woven pattern Adults have coarse cancellous bone, and compact bone. Their collagen is arranged in lamellae.

Answer 23

- High collagen content - Woven structures, or lamellar sheets - Slight bending in the collagen, to allow straightening - Elongated cells

Answer 24

- High PG content - Retention of H2O - Presence of Hydroxyapatite - Rounded cells

Answer 25

Tension in 1-2 directions (either tendon/ligament or fascia)

Answer 26

Compression

Answer 27

Tension in 3 directions, while allowing recoil

Answer 28

Tension, compression and torsion

Answer 29

Ligaments can have more prominence of elastic fibres, and more PGs

Answer 30

Outermost is the epidural space, containing fat, arteries and veins. It's a good place for local anaesthetic as it is near the main nerves and fairly large The dura mater is very tough The subdural space is a virtual space where some veins cross over, so if shrinkage of the CNS occurs, the veins can burst, causing an hemorrhage. The arachnoid mater is shimmery and weblike The subarachnoid space contains the most CSF of anywhere in the body, and can also hemorrhage The pia mater adheres tightly to the spinal cord and roots themselves. On the edges of the roots, the three combine to form the epineurium, surrounding the nerves themselves

Answer 31

The posterior ramus (smallest) innervates the back muscles The Ramus Communicans connects the spinal cord with the ANS The anterior ramus innervates the front muscles and organs

Answer 32

Conus medularis is the cone shaped ending to the spinal cord proper. The cauda equina descends past this, in a trail of spaghetti-like nerves.

Answer 33

The filium terminale internum is when the pia mater comes together past the conus medularris, and forms a single fiber above the lower limit of the subarachnoid space The Filium terminale externum occurs when the arachnoid mater joins with this fiber and continues down to be attached to the coccyx. It can be identified as it is bluer/whiter and tighter than the other fibres.

Answer 34

It is usually done around L3 as there is little chance of hitting the spinal cord if done after the conus medullaris ends.

Answer 35

There are denticulate ligaments between it and pia/dura, to prevent the expansion and contraction of AM and keep the volume and pressure of CSF constant.

Answer 36

A dense layer of connective tissue surrounding and compartmentalizing the thigh. Superiorly it attaches to the pubic tubercle, pubis and inquinal ligament. Laterally attaches to the iliac crest Posteriorly to sacrum, coccyx and ischial tuberosity. Extends to the knee where it becomes continuous with fascia in the leg 1 Opening: Saphenous to allow the saphenous vein to enter beneath the fascia lata (inf. to inguinal ligament)

Answer 37

Iliotibial Band. | A lateral fusion of the TFL muscle tendon and fascia lata, attaching to the lateral tibia.

Answer 38

``` A space in the superior thigh. Superior border: Inguinal ligament Lateral border: Sartorius Medial border: adductor longus Deep border: Iliopsoas & Pectineus Superficial border: Skin and fascia lata ``` Contains Femoral nerve, artery, vein, and lymph vessels. Femoral sheath contains all but femoral nerve. Subcompartment (femoral canal) contains the lymph, with femoral ring at the proximal end.

Answer 39

Rectus femoris: border between hip and femur, to superior patella Vastus lateralis: greater trochanter to superior patella Vastus medialis: top of femur (dip) to superior patella Vastud intermedius: Along the upper 2/3 of femur to superior patella Sartorius: ASIS to medial tibia (TFL- ASIS to greater trichantor)

Answer 40

All extend the knee, sartorius and rectus femoris also flex the hip Innervated by Femoral nerve Blood supply from Femoral artery Drained by femoral vein & saphenous vein

Answer 41

Adductor Magnus: From Pubis to shaft of femur Adductor Brevis: From Pubis to upper third of femur Adductor Longus: From pubis to middle third of the femur Gracilis: From pubis to superior medial tibia Pectineus: from upper pubis to inferior to lesser trochanter

Answer 42

Adduction of the thigh, although some flex the hip | Supplied by Obdurator nerve, femoral artery, femoral and saphenous veins

Answer 43

From L2-4 in the spinal cord

Answer 44

Levels L2-4 Branches into saphenous nerve Supplies iliopsoas, pectineus, sartorius, vastus and rectus femoris muscles Supplies anterior thigh and medial leg/food (sensation)

Answer 45

Levels 2-4 No branches Supplies obturator externus, abductor and gracilis muscles Supplies medial thigh (sensation)

Answer 46

A gap underneath the middle third of sartorius, allowing the femoral vessels to reach the popliteal fossa to become the popliteal vessels. Inlet is the apex of the femoral triagle, outlet is adductor hiatus in adductor magnus.

Answer 47

- Fem vein = direct line to the heart for cannulation (putting in lines) and taking RHS heart blood pressure and blood samples - Femoral artery good for taking pulses and angiography - Femoral nerve block using femoral artery as a landmark (to relieve pain) - Femoral hernia can occur when digestive tract extends into femoral ring and even through saphenous opening

Answer 48

``` Rapid Expansion (fetal, fracture callus, pathologically induced) Leisurely consolidating/remodelling ```

Answer 49

Fine cancellous bone can be: - Membrane bone, where mesenchymas connective tissue takes on bone-growing properties, with woven collagen fibrils in random orientations - Cartilage bone, where trabeculae forming have a core of calcified cartilage surrounded by woven bone. This is then replaced by adult bone

Answer 50

- Cancellous bone. Lamellar bone in trabeculae with marrow between. Osteocytes in lacunae, no more than .4mm in diameter - Compact bone. Lamellar bone arranged in haversian canals, with vessels and nerves in the middle. Surrounded by fibrous periosteum.

Answer 51

Appositional growth: Osteogenic cells divide, with one becoming an osteoblast. These secrete matrix, which then hardens. Osteocytes linked by canaliculi, with osteogenic cells remaining at the periosteum and endosteum of bones.

Answer 52

Primary: Bone grows appositionally, with ridges forming around the vessel that then fuse together. The peri (now endosteum) grows inwards, surrounding the vessel. Secondary: Osteoclasts dig a cutting cone into the bone, while blood vessels and endosteum follow. Note, the blood vessel loops back out, giving the new canal two vessels in cross section.

Answer 53

Firstly, they secrete acids, causing decalcification and removing hydroxyapatite. Then, they secrete enzymes called acid hydrolases (to work in the acidic conditions). These digest the newly exposed collagen. Any surrounding osteoblasts move out of the way of osteoclasts.

Answer 54

They have a collar attaching them to surrounding bone, preventing their secretions from leaking They also have a ruffled border to increase SA They sit in hoships lacunae.

Answer 55

PTH increases osteoblast and clast activity (but clast to a greater degree) and decreases bone mass Calcitonin decreases osteoclast activity, ruffles, numbers and movement Calcium supplements reduce PTH Hormone therapy, biphosphates, cathepsin K inhibitors decrease osteoclast activity Denosumab inhibits osteoclast formation Sclerostin stops production of bone, so antisclerostin aids bone formation

Answer 56

RANK receptors are on osteoclast precursors RANKL ligands are on osteoblasts When the two link, the osteocyte is encouraged to mature OPG is a ligand that can bind, preventing maturation of osteoclasts

Answer 57

Growth occurs in epiphyseal plate, a hyaline cartilage area in the epiphysis of long bones One side of the plate accumulates cartilage, the other side has cartilage hypertrophing, and then dying. Osteoblasts and blood vessels then migrate in, converting the dead tissue to bone. Until the age of 18, these processes occur in equal amounts, but then the growth stops and resorption continues, closing the plate and stopping further growth.

Answer 58

Osteogenic cells in the broken end of the peri/endosteum divide, producing osteoblasts that turn into chondrocytes due to lack of blood supply. These put down cartilage in a collar around the fracture for support, which is then remodelled into bone when the blood vessels arrive. Internally, secondary osteon formation causes the bone to knit back together.

Answer 59

They can give external support and prevent callus formation, as they hold bits of bone together. However, it takes a longer time for the fracture to heal and the bone formed is weaker.

Answer 60

They provide greater grip between the epidermis and dermis | They give a higher surface area for nutrient diffusion

Answer 61

The collagen weave isn't uniform in all directions, meaning the skin stretches more in some directions than others.

Answer 62

Thermal, abrasive and puncturing wounds | Surgical incisions

Answer 63

Superficial (to the dermis) wounds heal with little to no scarring Deep wounds heal with scarring and sometimes contraction. 1. Hoemostasis and haemotoma 2. Inflammation (redness and oedema) 3. Matrix formation (fibroblasts, collagen and elastin form) 4. Neovascularisation 5. Re-epithelialization 6. Wound contraction and remodelling

Answer 64

Scars are collagen patches intended to aid wound strength. The collagen is aligned along lines of stress, In hypertrophic scars, the collagen is in a random orientation surrounded by oriented bands. It is raised red, itchy and stays within the confines of the wound. They remain indefinitely, and may contract. Keloid scars are also red, itchy and raised, but are invasive. They occur anytime after injury, often recur, do not contract or regress, and commonly occur on the trunk, back, face and earlobes.

Answer 65

These are lines along which the collagen is more tense, with elastic fibres running parallel to these lines. This means that when the skin is cut, the elastic fibres will pull the wound closed rather than stretching it open, aiding scar formation and preventing hypertrophic scars. This is of particular import in joints.

Answer 66

Anterior, lateral, posterior

Answer 67

Anterior: - Tibialus anterior (Superior lateral tibia/IO membrane to superior medial cuneiform and 1st MT) - Extensor digitorum longus (Lateral condyle of tibia, sup. med. tibia and IO membrane to lateral 4 toes) - Extensor halucis longus (Middle ant. fib. and IO membrane to base of distal great to phalanx) - Peroneus Tertius (inf. ant. fibula and IO membrane to base of 5th metatarsal) ``` Lateral: Peroneus Longus (Sup. lat. fibula to inferior medial cuneiform) Peroneus Brevis (inf. Lat. fibula to inf. 5th MT) ```

Answer 68

Ant: - TA: dorsiflexion and inversion - EDL: Dorsiflexion - EHL: Extends big toe - PT: Eversion Lateral: Both eversion.

Answer 69

Anterior compartment: Deep peroneal nerve | Lateral compartment: Superficial peroneal nerve

Answer 70

Anterior compartment: Anterior tibial artery | Lateral compartment: Peroneal artery

Answer 71

Sup. Extensor Retinaculum: From inferior tibia to fibula, sup. to malleoli. Binds ant. compartment tendons Inf. Extensor Retinaculum: Y shaped, from upper calcaneus to medial malleolus and plantar aponeurosis. Sup. peroneal retinaculum: Above lateral malliolus to lateral calcaneus Inf. peroneal retinaculum: Continuous with cruciate crural ligament, attached to lateral surface of calcaneus. Some fibers fixed to peroneal trochlea, making a septum between the lateral tendons These hold the lateral muscle tendons down.

Answer 72

Deep: Wedge between 1st and 2nd toes Superficial: medial superior food

Answer 73

Lateral: Sural nerve Medial: Sup. peroneal nerve 1st and 2nd toes: Deep peroneal nerve Medial: Saphenous nerve

Answer 74

The Dorsalis Pedis artery | This branches off the popliteal artery's anterior tibial artery

Answer 75

Extensor digitorum brevis (inf. Ext. Retinaculum to middle of lateral 4 toes Extensor Hallucis Brevis: Inf. Ext. reticulatum (with the insertion of EDB) to base of great toe.

Answer 76

5 Ps: Pain, Pallor, Pulselessness, Paresthesia and Paralysis | Treat by opening affected and nearby muscle compartments.

Answer 77

The patellofemoral joint (patella and femur) | The tibiofemoral joint (tibia and femur)

Answer 78

The synovial cavity includes the articular surfaces of the three bones, the suprapatellar bursae, and the menisci (medial fused, lateral not) Superficial to this, but within the fibrous joint cavity, are the cruciate ligaments. Superficial to the fibrous membranes are the MCL and LCL, as well as the prepatellar and infrapatellar bursae.

Answer 79

Prepatellar tendon: continuation of quadriceps tendon, from inf. patella to tibial tuberosity. It moves superiorly to inferiorly to extend the leg., MCL and LCL: Medial runs from med. femoral epicondyle to medial tibia. Prevents valgus (tibia moving laterally and femur medially) LCL runs from lat. femoral epicondyle to fibula head. Medial attached to fibrous capsule, lateral discrete. Prevents varus (tibia moving medially and femur laterally) Cruciate ligaments: Anterior goes from ant. tibial spine to lateral condyle. Prevents anterior translation of tibia. Posterior goes from posterior tibial spine to medial epicondyle. Prevents posterior translation of tibia.

Answer 80

The structures on the medial sides are all fused together, so it's more likely that injuries on the medial side will involve multiple structures. The lateral side is more flexible.

Answer 81

Suprapatellar bursa: between quads tendon and femur, continuous with knee joint. Where fluid accumulates during knee joint effusion Prepatellar bursa: Anterior to patella, inflamed with excessive kneeling etc. Infrapatellar bursae: Superficial and deep to patellar ligament, inflamed when kneeling upright.

Answer 82

They are two wedges of fibrocartilage within the tibiofemoral joint, absorbing shock and improving joint articulation. The medial meniscus is more likely to be injured than lateral as it is adherent to the joint capsule and MCL

Answer 83

The knee receives blood superiorly from the femoral, lateral femoral circumflex and popliteal vessals Inferiorly it receives blood from the anterior tibial and circumflex peroneal arteries.

Answer 84

Pes anserinus- insertion of sartorius, gracilis and semitendinosus on med. prox. tibia. They can be used to reconstruct a torn Anterior cruciate ligament Terrible triad is an injury resulting from valgus force. The three structures involved are the MCL, ACL and medial meniscus

Answer 85

Posterior to pelvis, bordered superiorly by iliac crests and inferiorly by gluteal folds The ilium has the ASIS, iliac spine proper and AIIS The Ischium has the ischial tuberosity and ischial spine (which is important for pain relief during childbirth) The pubis has the pubic tubercule.

Answer 86

``` Sacrospinous ligament (sacrum to ischial spine) Spinotuberous ligament (sacrum to ischial tuberosity) These bind the bones of the pelvis together and separate the hold of the pelvis into the greater and leser sciatic foramina. Greater is superior, allowing passage of nerves and vessels TO lower limb, while the inferior lesser allows passage FROM the lower limb. ```

Answer 87

Gluteus maximus: Sacrum and iliac crest to the ITB and lateral femur . Supplied by inferior gluteal nerve. Extensor of the hip and lateral thigh rotator Gluteus medius and minimus: Ilium to greater trochanter. Supplied by superior gluteal nerve. Abducts and internally rotates thigh

Answer 88

- Piriformis: Sacrum to greater trochanter. - Gemellus superior and inferior, Obturator internis: Ischium to greater trochanter - Quadratis femoris: Lateral ischial tuberosity to intertrochanteric crest. All are supplied by sacral plexus, and externally rotate the thigh

Answer 89

- Trochanteric bursa: between GM and greater trochanter - Ischial bursa: between GM and ischial tuberosity - Gluteofemoral bursa: Between ITB and vastus lateralis

Answer 90

- Biceps femoris: Ischial tuberosity (long) and linea aspera (short) to head of fiibula. externally rotates leg - Semitendinosus: ischial tuberosity to sup. med. tibia in pes anserinus. Internally rotates leg - Semimembranosus: Ischial tuberosity to med. condyle of tibia. Internally rotates leg - Adductor magnus: Ischial tuberosity to linea aspera, adductor tubercle, supracondylar ridge. All extend thigh All innervated by tibial nerve

Answer 91

The internal iliac artery branches to give the superior and inferior gluteal nerves, while the sciatic is simply a large nerve. There are plexuses superior and inferior to the piriformis muscle.

Answer 92

Trendelenburg gait- hip drop on affected side due to non-functional hip abductors. Results in leaning and swinging when walking Trochanteric bursitis occurs when the gluteal bursae become inflamed from extra use Hamstring injuries can tear the muscle, or pull off the ischial tuberosity's bone completely Piriformis sydrome occurs due to compression of the sciating nerve against the piriformis, causing numbness, tingling and pain.

Answer 93

It is an excellent place for intra-muscular injections, as it has a large area and can avoid the sciatic nerve on the lateral side.

Answer 94

The pubis, ischium and ilium form a cuplike structure laterally called the acetabulum. It has a lunate surface forming 3/4 of a circle covered in hyaline cartilage, with a transverse acetabular ligament running along the bottom There is an acetabular fossa medially, containing fat, and a ligament that was once an artery This structure is collared by fibrocartilage, called the acetabular labrum, deepening the acetabulum.

Answer 95

Iliofemoral ligament: Provides sup. ant. support, from AIIS to intertrochanteric line, preventing hyperextension Pubofemoral ligament: Provides inferior anterior support, from pubis to joint capsule. Prevents over abduction Ischiofemoral ligament: Posterior reinforcement, from ischial acetabular labrum to greater trochanter. Prevents hyper-extension Ligamentum teres: From acetabular notch to fovea in femoral head.

Answer 96

Flexion: Quads, sartorius and iliopsoas. Supplied by femoral nerve from L2-3 Extension: Hamstrings and Gluteus maximus, supplied by inf. gluteal nerve and tibial nerve from L4-5 Adduction: Adductors, gracilis and pectineus. Supplied by obturator nerve (except pectineus) from L4 Abduction: Gluteus medius and minimus. Supplied by the sup. gluteal nerve from L5-S1

Answer 97

The medial and lateral circumflex femoral arteries (branches off profunda femoris off femoral) anastomose with sup. and inf. gluteal arteries around the neck of femur, running into the capsule of the bone itself around the neck. This means that if the hip is fractured, if this area is not damaged the fracture will heal, whereas if the blood supply is disrupted a replacement will be necessary.

Answer 98

A single alpha motor neuron and the muscle fibres it innervates

Answer 99

Type 1 muscles are slow, whereas type 2 are fast. The size principle states that small oxidative motor units are recruited first, whereas the few largest are recruited last. This allows varying strengths of contraction, and a synchronized contraction between them

Answer 100

The motor end plate is on the muscle fibre, so it is postsynaptic/ On the postsynaptic membrane there are ACh receptors in the crests of the junctional folds, whereas further down in the pits there are voltage gated sodium channels.

Answer 101

- Vesicles are filled with ACh cluster, and then docked at the presynaptic membrane where they are primed and wait until Ca2+ activates them - Action potential reaches nerve terminal - Ca2+ channels are opened, allowing Ca2+ influx - Ach is released by exocytosis, where it diffuses across the cleft and binds to ACh receptors - The ACh is taken up by local release, fast recycling mechanisms, or by slow mechanisms using endosomes.

Answer 102

- ACh binds, causing the opening of voltage-gated AChR channels, causing many Na+ ions to enter and depolarising the cell, propagating an action potential. - This occurs until acetylcholinesterase unbinds the ACh from the membrane, and K+ channels open, allowing the membrane to repolarise.

Answer 103

End plate potential is the total change in membrane potential caused by the AP. End plate current is the direction and strength of the current formed by the influx of ions.

Answer 104

EPC has a shorter amount of buildup to its max, due to the fact that it doesn't have to wait for a change in muscle membrane polarisation. EPP has a relatively longer arc to max depolarisation, as to measure it relies on the whole motor unit being depolarised. Likewise, the EPP also has a longer repolarisation curve

Answer 105

AP reaches nerve terminal Opening of voltage-gated Ca2+ channels Increased Ca2+ triggers exocytosis of ACh ACh binds to post-synaptic channels, which open Influx of Na2+ and efflux of K+ Depolariation of end plate Opening of voltage gated Na+ channels Na+ influx... and so on as it is propagated down the muscle fibre

Answer 106

Diabetes Lambert-Eaton syndrome Some natural toxins These prevent fusion and release of ACh vesicles

Answer 107

``` Myasthenia Gravis- AI disease where antibodies against AChR are produced, so less functional receptors and AP inhibition. Mainly affects facial muscles. Treated with anti-AChE or immunosuppressants. Alpha toxins (snake venom, crurare)- blocks ACh binding sites ```

Answer 108

Enzyme AChE is anchored to collagen in basement membranes Hydrates ACh to form Choline and Acetate Acetate/choline is diffused back into the membrane and reabsorbed

Answer 109

It's a space behind the knee bordered by the hamstrings (superiorly) and the gastrocnemius' two heads (inferiorly) Contains Popliteal artery, popliteal vein, tibial nerve and common peroneal nerve. The artery is the deepest structure in the fossa. This means it is most likely to be injured in a knee dislocation.

Answer 110

Gastrocnemius. Medial head starts at medial condyle of femur, lateral at latera. Both run to the calcaneus via the calcaneal tendon. Plantarflex ankle, flex knee Soleus: Superior 1/3rd fibula to posterior calcaneus via calcaneal tendon. Plantarflex ankle Plantaris: Superior to lateral condyle of femur to medial achilles tendon. Plantarflex ankle

Answer 111

Tibialis posterior: Posterior tibia, fibula and IO membrane to navicular (bones in medial foot). Plantarflex ankle, invert foot Flexor digitorum longus: Middle tibia to distal phalanges. Flex toes, plantarflex ankle Flexor Hallucis longus: Inferior fibula and IO membrane to distal gt. toe. Flexes gt. toe, plantarflexes ankle Popliteus: Lat condyle and meniscus of femur to post. sup. tibia. Medially rotates tibia.

Answer 112

Supplied by posterior tibial artery (which then bifurcates into medial and lateral plantar arteries) Innervated by tibial nerve (which bifurcates into the medial and lateral plantar nerves)

Answer 113

The tendons and blood vessels of the deep post. compartment wind around it in this order (anterior to posterior): Tibialis posterior tendon, flexor digitorum longus tendon, posterior tibial artery, vein, tibial nerve, flexor hallucis longus tendon. Remember using mnemonic: Tom, Dick, And Very Naughty Harry

Answer 114

At MTJ, tendon itself, or its attachment to the calcaneus. Results in an inability to push off.

Answer 115

At the cervical area flex/extension is 40 dgrees, lateral flexion is 40 and rotation is 40 Thoracic: f/e is 40, lat. f is 20 and rotation is 40 Lumbar: f/e is 40, lat. f. is 20 and rot. is less that 5. The vertebral column is much more stiff as it approaches the pelvis compared to the superior aspect

Answer 116

The cervical, thoracic, lumbar and sacral curvature. An increased thoracic curvature = kyphosis An increased lumbar curvature= lordosis A lateral curve in the AP plane of the spine = scoliosis When we are born, our spines are fairly straight. As we begin walking, our lumbar cure develops

Answer 117

Vertebral body: most ant. structure with posterior depression for spinal cord. Contains central rough area of early cartilage/collagen Vertebral arch: C shaped bone surrounding spinal cord. Separated into pedicels (anterior) and laminae (posterior) by the superior/inferior articular processes Spinous process: A-P oriented prominence on the posterior-most curve of the arch The arch forms the vertebral foramen, to contain the spinal cord.

Answer 118

They sit between vertebral bodies. Formed by sheats of collagen inserted into the bone adjoining it. The collagen forms concentric layers. In the middle there is a pulpy, HA and PG rich mass called the nucleus pulposus, which functions as a ball-bearing.

Answer 119

A slipped disc happens when there is a crack in the annulus fibrosus- the nucleus pulposus leaks out and onto the nerve roots for the lower limb, causing back pain. As we age: collagen gets stiffer, our nucleus pulposus gets less watery, and our cartilage endplates on the articular surfaces of the bones becomes calcified.

Answer 120

Anterior longitudinal (covers whole spinal cord anteriorly) Posterior longitudinal (underneath anterior longitudinal but thinner) Supraspinous: placed behind the spinal cord, runs the length Ligamentum flavum: Goes between the arch to superior and inferior processes. Coloured yellow due to elastin to help maintain posture Interspinous ligaments: From spinal process to process

Answer 121

Superficial: Latissimus dorsi- from processes to limbs, assoc. with limb movement Intermediate: Serratus Posterior Inferior- processes to lower ribs, assoc. with deep ventilation

Answer 122

Iliocostalis- long muscle from ilium to ribs Longissimus- prom processes to ribs Spinalis- from upper back to processes (These form the erector spinae- important for remaining upright) Multifidus: transverse, linking the processes

Answer 123

Nerves and vessels to the discs only enter in the superficial third, so much of it has no nerve or blood supply There are up to 3 levels of overlap between vertebtrae nerves, so it's difficult to find the source of any pain etc.

Answer 124

Thoracic axises are in the vertebral body, while lumbar is on the process. As the vertebrae themselves aren't able to move out of alignment- rather the muscles- the lumbar has less rotation.

Answer 125

The pelvic girdle is made of 3 bones fused together, attached to the axis by incredibly strong ligaments The pectoral girdle is made of 2 non-fused bones with synovial joints, and small points of contact with the axis

Answer 126

Retraction and protraction Elevation and depression Superior and inferior rotation (named based on where the glenoid points)

Answer 127

It is a long bone sitting subcutaneously between the sternum and acromion of the scapula. It forms a strut for the transfer of forces from the limb to the axial skeleton, and as a consequence it breaks often. It has multiple attachments for ligaments and muscles, including the deltoid, trapezoid and pectoralis major.

Answer 128

It is a triangular, flat bone, covering the postero-lateral ribs from 2-7. It has 3 angles: superior, inferior and the glenoid fossa (lateral) and 3 borders: superior, medial, lateral). It contains 3 protuberances (the coracoid, acromion and spine), and 3 surfaces: supraspinous fossa, infraspinous fossa, and subscapula fossa

Answer 129

- Sternoclavicular (AC) | - Acromioclavicular (AC)

Answer 130

It is a saddle-shaped synovial joint between the clavicle and the sternum. It contains an intra-articular disc (fibrocartilaginous) between its two joint cavities, which functions like the menisci of the knee- cushions, aids movement, and stabilizes the joint. There are main ligaments stabilizing it: The anterior and posterior sternoclavicular ligaments, of which the p is stronger to prevent backwards dislocation. Additionally, the interclavicular ligament links the two clavicles over the jugular notch, and the costoclavicular ligament braces it to the first rib. The subclavicus muscle runs adjacent to this ligament, where it braces the clavicle and can depress it

Answer 131

A synovial joint between the lateral clavicle and the medial acromion. It also ccontains an intra-articular disc, although it is wedge shaped (like the knee). The joint capsule is fairly loose, and is made up of the sup. and inf. acromioclavicular ligaments. The conical shaped coracoclavicular ligament gives further support. It also receives support from the trapezoid muscle.

Answer 132

- Trapezius muscle: Supplied by accessory nerve, from spinous processes until T12 to spine of the scapula. Retracts scapula. (sup. only elevates, inf. only depresses, mid. only retracts and sup. and mid. cause sup. rotation.

Answer 133

Levator scapulae: Upper cervical spinous processes to sup. angle of scapula. Elevates scapula Rhomboid min./maj. Upper thoracic processes to med. border of scapula. Retracts scapula Both supplied by dorsal scapular nerve

Answer 134

Latissimus dorsi: Iliac crest, sacrum, vertebrae to T7 to ant. humerus. Adducts and internally rotate humerus. Can depress scapula by pulling humerus. Supplied by thoracodorsal nerve.

Answer 135

Pectoralis major: Has 2 heads, running from the clavicle and the sternum/costal cartilage to the lateral intertubercular groove on the anterior humerus. Adducts and internally rotates humerus, can protract the scapula by pulling humerus Supplied by the lat. and med. pectoral nerves

Answer 136

Subclavius: From rib 1 to clavicle. Braces clavicle, innervated by C5 Pectoralis minor: From ribs 3-5 to the coracoid. Depresses scapula, innervated by medial pectoral nerve (NB pectoralis minor overlies the brachial plexus, so compressing it can numb the limb Serratus anterior: Run from ribs 1-8 to medial border of scapula. Protracts scapula, lower fibers superiorly rotate scapula. Works with rhomboids to stabilize the pectoral girdle. Innervated by long thoracic nerve

Answer 137

It happens when the long thoracic nerve is severed, causing the serratus anterior to lo longer hold the scapula tight to the body. Results in scapulae with winged appearances.

Answer 138

- Levator scapulae - Rhomboids - Upper trapezius

Answer 139

``` - Lower serratus anterior Anteriorly: -Subclavius - Pec minor - Lower pec major Posteriorly: - Lower lat dorsi - Lower trapezius ```

Answer 140

- Both pectoralis | - Serratus anterior

Answer 141

- Rhomboids - Middle trapezius - Upper lat dorsi

Answer 142

``` Anterior: - Both pectoralis Posterior: - Levator scapulae - Rhomboids - Lat dorsi ```

Answer 143

- Upper trapezius and lower trapezius | - Serratus anterior

Answer 144

An area in the upper trunk where the major nerve and vascular supply to the limb travel through

Answer 145

Apex: First rib (medially), superior scapula (posterior) and clavicle (anteriorly) Anterior wall: Subclavius, costocoracoid ligament/membrane, pectoralis muscles, suspensory ligament of axilla. Base: Axillary fascia Posterior wall: Lat dorsi, teres major, subscapularis, supraspinatus muscles Medial wall: Serratus anterior muscle Lateral wall: Intertubercular groove of humerus

Answer 146

Most anterior: Vein from upper limb leaves anteriorly to anterior scalene muscle Medial: Artery to upper limb leaves between mid and ant scalene muscles Nerve is posterior to this.

Answer 147

``` Superior trunk (C5/6)- Middle trunk (C7) Inferior trunk (C8/T1) All split into anterior and posterior divisions ```

Answer 148

Lateral cord: Formed from the sup. trunk's ant. division and middle trunk's ant. division Posterior cord: Formed from all 3 trunks' posterior divisons Medial cord: Formed from inferior trunk's anterior division

Answer 149

1. Musculocutaneus: From lateral cord. 2. Median: from lateral and medial cords 3. Axillary: From posterior cord 4. Radial: from posterior cord 5. Ulnar: From medial cord 2 less important: Medial cutaneous nerves of forearm and arm (from medial cord)

Answer 150

Supplies muscles of whole anterior arm, and lateral forearm

Answer 151

Nothing in arm Lateral 3/4 of forearm muscles and lateral hand muscles Thumb and lateral 2.5 fingers of hand

Answer 152

Medial 1/4 of forearm muscles and most hand muscles | Skin on medial 1.5 fingers of hand

Answer 153

Deltoid and teres minor muscles in shoulder | Superior lateral cutaneous arm

Answer 154

All posterior muscles of arm and forearm Cutaneous supply to whole posterior arm and hand apart from: Fingertips, medial back of hand, medial cutaneous nerves of arm and forearm and musculocutaneous nerve areas.

Answer 155

Sweat glands- simple coiled tubular glands Sebaceous glands- branched gland surrounding hair follicle. Often found with arrector pili smooth muscle blocks. PCs look like circular structures with another circle inside it.

Answer 156

1. Zone of resting/reserve cartilage 2. Zone of proliferation (elongation of plate) 3. Zone of maturation/hypertrophy 4. Zone of resorption/ossification

Answer 157

C: Transverse processes form foramina for passage of vertebral arteries. Spinous processes have cleft for neck ligaments to attach to T: Smooth ant. trans. processes for rib articulation, on lat. vertebral bodies for splayed head of rib (2 each side) and sup. inf. processes flat for rotation. Spinous processes long, conical L: No faces, spinous processes broad, short, flat. Inf and sup. processes are curved to prevent rotation

Answer 158

Main artery is the axillary artery (which formed from the subclavian after it passes the first rib). It extends down into the arm, where is becomes the brachial artery after the passing the inferior surface of teres major. It is separated into 3 by the pec minor- proximal, posterior and distal to the muscle. Division 1 has 1 branch: Superior thoracic artery. Supplies superior med. wall of axilla- serratus, subclavius Division 2 has 2 branches: - Thoracoacromial artery: Supplies anterior wall of axilla - Lateral thoracic artery: Supplies lower medial wall of axilla (serratus, some pec. major) Division 3 has 3 branches: - Subscapular artery: Supplies posterior wall of axilla - Anterior and posterior circumflex humeral arteries: Anastomose around the surgical neck of the humerus and supply lateral boundary of humerus

Answer 159

The breast drains into mainly the pectoral nodes, but sometimes the apical nodes first. By finding where the breast is draining to, we can isolate where the cancer may be transferring to.

Answer 160

Deltoid: 3 areas- ant, mid, post. Ant goes from anterior clavicle to deltoid tuberosity. Flexes shoulder, internally rotates arm Mid goes from acromion to deltoid tuberosity. Very strong, abducts arm. Post goes from post. scapula to deltoid tuberosity. Extends shoulder, externally rotates arm All innervated by axillary nerve Teres major: From inf. angle/lat. border of scapula to intertubercular groove. Adducts shoulder, internally rotates arm. Lower subscapular nerve. Coracobrachialis: from coracoid to mid. med. humerus. Adducts arm. Musculocutaneous nerve

Answer 161

- Brachialis: Deepest, from ant. distal humerus to tuberosity of ulna. Flexes elbow. - Biceps brachii: Short head: coracoid. Long head: Inside shoulder joint. Combine to insert on radial tuberosity. Supinate, flex elbow . - And coracobrachialis All supplied by musculocutaneous nerve

Answer 162

Triceps brachii: From intraglenoid tubercle (long), post. humerus (short) and med. humerus (med) to olecranon on ulna. Also anconeus- from lat. epicondyle to ulna. Helps extend elbow. Both innervated by radial nerve

Answer 163

Initially, there is the anterior and posterior compartment, separated by the lateral and medial intermuscular septae. The anterior compartment flexes the elbow and is supplied by the musculocutaneous nerve, while the posterior compartment extends the elbow and is supplied by the radial nerve. Distally, the medial and lateral intermuscular septae split anteroposteriorly, and form 4 compartments of the arm: The ant (flexor) compartment, Post (ext) compartment, as well as the flex/pronator (medial) and ext./sup. compartment (lateral). These contain muscles from the epicondyles of the humerus to the hand, allowing the hand to grip strongly. The med compartment muscles stretch anteriorly and are supplied by the median and ulnar nerves, while the lat compartment stretches posteriorly and is supplied by the radial nerve.

Answer 164

The middle fibres can only abduct once the arm is already about 15 degrees abducted as the axis between its insertion and origin is off. The ant/post fibres can abduct onse the arm is extended as when the arm is adducted the two will continue to adduct the muscle.

Answer 165

It stops superior dislocation of the arm and holds the arm tight to the pectoral girdle

Answer 166

- Synarthroses or fibrous joints. They consist of bones united by fibrous tissue, and can be fused (synostosis- in squamous or serate lines- eg. skull sutures) or unfused (syndesmosis- usually an interosseous membrane- eg. tibiofibular joint) - Synchondroses or cartilaginous joints. Can be primary (bone-cartilage-bone- eg. epiphyseal plate (temporary) or costal cartilage (permanent)) or secondary (bone-cartilage-fibrous tissue-cartilage-bone- eg. intervertebral disc) - Diarthroses or synovial joints. Bone-cartilage-joint space-cartilage-bone. They have a joint space and synovial fluid as well as articular cartilage, a synovial membrane (for fluid production), fibrous capsule (to hold joint in place) and menisci/articular disc.

Answer 167

Surrounded by ligaments (ant and post longitudinal), with annulus fibrosis inserting into cartilage and bone superiorly and inferiorly. The layers of collagen are arranged in lamellae. Towards the inf. and sup. edges, the a.f. becomes fibrocartilage and then hyaline cartilage. In the centre, the nucleus pulposus is soft, supporting movement in all directions. It is gradually compressed during the day and re-inflates during the night. The nucleus pulposus is central in c. and t. vertebrae, but post. in l. vertebrae. Extrusion can occur lateral to the posterior spinal ligament, affecting the nerves the level below. If medial, it affects all levels below. As we age, we lose peripheral cartilage, malleability of n.p. and our cartilage and collagen becomes stiffer (calcified). This can cause osteophytes and vertebral fractures.

Answer 168

If they become inflamed, they over-secrete synovial fluid, forming a large lump in the bursa.

Answer 169

Forming the layer between epitendinium and parietal layers- the tendons sit within these structures like a fist in a balloon.

Answer 170

- Cell membrane is called the sarcolemma - It has infoldings penetrating deep into the myocyte for the condution of action potentials into the cell itself. - Striated appearance is due to the interdigitation of thick and thin filaments within the muscles - The SR borders the t-tubules on either side, and stretches across the sarcomere. It functions as a store for Ca2+. It contains pumps and channels for the release and reuptake oc Ca2+

Answer 171

A-band: thick filaments intertigitated with thin filaments I band: thin filaments only Z disk: middle of I band where different sarcomeres' thin filaments attach H band: Centre of the A band, with thick filaments only (not as dark) M line: centre of H band where opposing myosin filaments attach

Answer 172

Strands composed of myosin, oriented in opposing directions (like golf clubs attached at their handles Bare zone of no heads in the middle Titin acts as a spring, as it stretches from the end of the myosin filament to the z disk, keeping the two somewhat separate

Answer 173

Two strands of actin twisted into a helix. Contains nebulin attaching them to their backbone tropomyosin protein. Has troponin C, I and T, forming a troponin complex C forms the binding site for myosin T positions the complex on the tropomyosin

Answer 174

1. At rest, myosin is attached to actin at a 45 degree angle, with no ATP/ADP/P on it. This is rigor, and is why dead people become stiff 2. ATP binds to myosin, causing it to dissociate from actin 3. ADP is converted to ADP and the myosin weakly binds to actin at a 90 degree angle 4. The phosphate is released, causing the power stroke, where the angle of the head changes to 45 degrees 5. ADP dissociates and the head returns to the rigor state

Answer 175

At rest, tropomyosin blocks the actin's attachment site for myosin, and the TnC already has 2 Ca2+ molecules attached to it. It binds cooperatively, so the extra two it can take become easier to attach. When Ca2+ binds to troponin C, this causes a shift and allows the myosin to bind

Answer 176

A SERCA pump in the SR removes it from the sarcoplasm | Ca2+ is stored in the SR and released from the terminal cisternae

Answer 177

DHP receptors in the T tubules are placed opposite the Ry receptors in the SR terminal cisternae. When the T tubule is depolarised, the DHPRs induce a conformational change in the RyR, enabling it to open and release Ca2+ into the cell. Good as: - Rapid kinetics - No dependence on current - No reliance on diffusion - Excitation can occur regardless of Ca2+ remaining in the sarcoplasm

Answer 178

1. Neuron depolarizes 2. Muscle fiber depolarizes 3. Muscle twitch occurs lasting 10-100msec UNLESS: Summation occurs Summation occurs when a second wave of depolarisation occurs that causes the original force of contraction to increase more, like a buildup. Tetanus occurs when the muscle is held at maximum tension - Unfused is when there are waves reaching max tension, but not frequently enough to result in sustained max. tension (fused tetanus)

Answer 179

- Reduces time to peak tension for fast muscles | - Slow acting muscles reduced

Answer 180

- Isometric: Muscle has no length change, but may need to change its force used - Isotonic- changes in length, but the force it uses remains the same - Concentric: Muscle actively shortens - Eccentric: Muscle actively lengthens - Passive stretch: Muscle passively lengthens

Answer 181

They occur when the force of the weight is greater than the force of the muscle, like when you're lowering weights during bicep curls Due to the stretching involved, not all sarcomeres lengthen equally, resulting in some giving way and producing less force overall. It is associated with delayed onset muscle soreness (DOMS)

Answer 182

The relationship between the stretch of the sarcomere and the force it will generate - When muscle is compressed force is low as there isn't far that it can contract - When about 2.1-2.2 um long it has max contraction due to ability to get a good grip on x bridges and a good deal of contraction - When too stretched, fewer x bridges can be formed, so contraction is weaker

Answer 183

Active is using the cross bridge cycle to generate force | Passive is using the integral elasticity of the muscle to contract (highest when it is stretched)

Answer 184

The max velocity/stress of a muscle occurs when there is no force, and steadily decreases until the contraction changes from concentric to eccentric. The max power/stress occurs at about 30% of maximum force- this is when our muscles are most efficient. Power is the (force x distance contracted) / time. Measured in watts

Answer 185

1st: From creatine phosphate releasing energy to convert ADP to ATP 2nd: Glycolysis 3rd: Aerobic respiration

Answer 186

Type II: fast glycolytic. Use glycolysis predominately. Fast but inefficient Type I: Slow oxidative. Use aerobic respiration. Slow but efficient

Answer 187

Failure to maintain required or expected power output, leading to reduced muscle performance. Not exactly known what causes it, but many potential sites Central fatigue = Decrease in no of motor units recruited, motivational/psychological factors Peripheral fatigue: Decreased Ca2+ in myoplasm Decreased sensitivity of myofilaments to Ca2+ Cross bridges affected

Answer 188

- Accumulation theory states that muscles fatigue to to increased extracellular K+ (decreased excitability), increased inorganic phosphate (Decreased SR cycling, Ca2+ sensitivity and power strokes) or Increased free radicals - Depletion theory states that it is fewer reagents for respiration (ATP, glucose, creatine phosphate, oxygen) that causes fatigue

Answer 189

Dystrophin is missing in the internal cytoskeleton, resulting in muscles that easily tear and rapidly degenerate. Though muscles are normal at birth, they become more permeability, allowing enzymes out and Ca2+ in, which can be damaging. Often causes death by 20 due to failure of resp. muscles X linked mutation

Answer 190

Age related loss of muscle function, where the muscle mass to body mass ratio is decreased. Causes a significant loss of strength, although there is a large range of extremes and it can be prevented by exercise through adulthood Causes increased proportion of type 1 muscles and a decreased capillary to fibre ratio.

Answer 191

Divides from the lateral cord, runs into coracobrachialis and then between biceps and brachialis before passing over the lat. epicondyle of the humerus and becoming the lateral cutaneous nerve for the forearm

Answer 192

Gets contributions from the medial and lateral cords before running down the medial side of the arm, and straight into the medial forearm

Answer 193

Runs from the medial cord down the posterior median arm, before flicking under the medial epicondyle of the humerus and entering the anterior forearm

Answer 194

Comes from the posterior cord. Enters the posterior arm through the triangular interval, before flicking un front of the lateral condyle and back down into the posterior compartment of the forearm.

Answer 195

Leaves the lateral cord, moves posteriorly through the quadrangular space and into the shoulder region

Answer 196

1. Triangular Space: Between teres min and maj, lateral border is long head of triceps. Holds 1 artery 2. Quadrangular space: Lateral border is humerus, between teres min and maj, medial border is long head of triceps. Contains axillary nerve, pst. circum. humeral artery 3. Triangular interval: Superior border teres maj, medial border long head of triceps, lateral border humerus. Contains radial nerve, profunda brachii artery

Answer 197

The axillary artery becomes the brachial artery below the inferior border of teres major. It almost immediately branches laterally to give the profunda brachii artery (supplies post. compt.) Distally, the brachial artery bifurcates into the radial and ulnar arteries

Answer 198

The medial vein is the basilic vein The lateral vein is the cephalic vein In the cubital fossa, the two anastomose in an H shape using the median cubital vein. Proximally, the basilic vein receives tributaries from the brachial veins and profunda brachii veins before becoming the axillary vein and meeting with the cephalic vein.

Answer 199

The glenoid fossa articulates with the head of the humerus. Superoanteriorly is the coracoid, and superoposteriorly is the acromion. The glenoid labrum (a fibrocartilaginous ring, slightly improves articulation. Directly distal to the head of the humerus is the anatomical neck, and posteriorly is the greater tubercle, with the lesser tubercle more anterior, and the intertubercular groove between them. The surgical neck of the femur is seen where the bone shaft begins to narrow.

Answer 200

Articular cartilage covers the articulating surfaces of the glenoid and humerus, with the glenoid labrum sitting around the glenoid itself The long head of biceps in intracapsular, and attaches to the supraglenoid tubercle. There is synovial membrane around the articular cavity with an epitendineum around the biceps tendon. Superficial to this is the fibrous capsule, which reaches from the top to bottom of glenoid. It is fairly loose to allow a lot of range of movement

Answer 201

The only extracapsular ligament is the coracoacromial ligament. This reaches from the acromion to the coracoid, forming a roof over the joint and preventing superior dislocation The three capsular ligaments make up the joint capsule The coracohumeral joint attaches anteriorly from the coracoid to the humerus and helps passively suspend the arm and reinforce the capsule superiorly The transverse humeral ligament spans the tubercles, holding the long head of biceps femoris down The glenohumoral ligaments (3) run from the glenoid to the humerus, but they only provide weak support.

Answer 202

The rotator cuff muscles surround the inferior and anterior joint, while the coracoacromial ligament holds the roof. The inferior aspect has no muscles or bones to support it and so the arm is more likely to dislocate inferiorly

Answer 203

- Subscapular- protects subscapularis from ridge of glenoid fossa - Subacromial- separates coracoacromial arch from supra and infraspinatus tendons - Subdeltoid- lateral continuation of subacromial- protects deltoid

Answer 204

- Subscapularis: From anterior scapula to lesser tubercle. Internally rotates arm. Supplied by upper & lower subscapular nerve - Supraspinatus: From above scapular spine to superior greater tubercle. Abducts arm to first 15 degrees. Supplied by suprascapular nerve - Infraspinatus: from beneath spine of scapular to middle greater tubercle. Externally rotates arm. Supplied by suprascapular nerve - Teres minor: from lateral border of scapula to inferior greater tubercle. Externally rotates arm. Supplied by axillary nerve All of these muscles are responsible for the active stabilisation of the shoulder joint.

Answer 205

- The humerus, ulna and radius - Humero-ulnar joint: The ulnar surface is the olecranon, with the trochlear notch and coronoid process anteriorly. The humeral surface is the trochlea - Humero-radial joint: The radial surface is the superior surface of radius, while the humeral surface is the capitulum - The Superior radio-ulnar joint: The head of the radius articulates with the radial notch on the unla.

Answer 206

1. MCL: Medial epicondyle of humerus to upper medial ulna. Prevents unwanted excessive abduction 2. LCL: Lateral epicondyle to ligament 3. Prevents excessive adduction 3. Anular ligament: Extends around the head of the radius and meets the radial notch, allowing the humerus to attach to the radius without impeding pronation/supination

Answer 207

Supraspinatus | Middle deltoid fibres

Answer 208

``` Pectoralis major Posterior and anterior deltoids Long head of triceps Coracobrachialis Teres major Lat dorsi ```

Answer 209

Anterior deltoid Clavicular Pec major Coracobrachialis Biceps Brachii

Answer 210

``` Long head of triceps Posterior deltoid Teres major Lat dorsi Sternocostal pec major ```

Answer 211

``` Pec major Anterior deltoid Subscapularis Lat dorsi Teres major ```

Answer 212

Posterior deltoid Infraspinatus Teres minor

Answer 213

Between radial notch and head of radius superiorly Down the bone shafts, there is an IO membrane with fibres arranged obliquely. The IO membrane is flexible, so acts as a hinge, as well as a site for muscle attachment. It also allows transmission of forces as when you lean down, it puts tension on the oblique fibres from the radius, transmitting to the ulna Inferiorly, the head of the ulna articulates with the ulnar notch, covered inferiorly by the fibrocartilage fibrous articular disc. Therefore the ulna doesn't articulate at the wrist. Both bones have inferior styloid processes for the attachment of strong ligaments

Answer 214

Scaphoid, lunate, triquetral, pisiform Trapezoid, trapezium, capitate and hamate Arranged in two rows Remembered using mnemonic: Some lovers try positions that they cannot handle

Answer 215

1. Wrist joint proper (radiocarpal): Fibrous articular disc articulates with scaphoid, lunate and triquetral. Responsible for flexion/extension, abduction/adduction and some rotation 2. Midcarpal: Between the rows of carpal bones. Responsible for some flexion/extension 3. Carpal-metacarpal joint: Between distal carpals and medial 4 metacarpals. Practically immobile.

Answer 216

The flexor retinaculum is a fibrous strap running from pisiform and hamate to scaphoid and trapedium, forming the medial half of the wrist (not into radial side). It forms the carpal tunnel, within which are the long flexor tendons. The palmar aponeurosis is a sheet fanning from the distal flexor retinaculum.

Answer 217

- Pronator teres: Medial supracondylar ridge to radius - Flexor capri radialis: Common flexor tendon to base of 2nd metacarpal. Travels under flexor retinaculum - Palmaris longus: Common flexor tendon to proximal phalanges of fingers, attaches to palmar aponeurosis to anchor skin to palm. Superficial to flexor retinaculum - Flexor carpi ulnaris: common flexor tendon to pisiform bone, with ligaments then reaching to metacarpals four and five. Superficial to flexor retinaculum. PT, FCT and PL innervated by median nerve FCU innervated by ulnar nerve

Answer 218

Flexor digitorum superficialis: From radius, IO membrane and humero-ulnar joint to middle phalanges of fingers. Travels under flexor retinaculum Innervated by median nerve

Answer 219

- Flexor digitorum profundus: From ulna to distal phalanges. Flex fingers - Flexor pollicis longus: From radius to distal thumb. Flex thumb - Pronator quadratus: From med. ulna to lateral radius. Helps pull radius during pronation. All innervated by median nerve (apart from med. FDP, innervated by ulnar)

Answer 220

Palmaris longus and flexor carpi ulnaris run over it | The rest, as well as the radial artery, ulnar artery and nerve, run underneath it.

Answer 221

It runs beneath pronator teres and flexor carpi radialis, emerving between FCR and PL. Then travels medially, giving off an ant. interosseous nerve to supply PQ, FPL and lat. FDP. Beneath the flexor retinaculum it splits into a recurrent branch (thenars), a palmar cutaneous branch, and proper palmar digital nerves for the lateral 2.5 fingers (cutaneous)

Answer 222

Dips around the medial epicondyle of the humerus, re-emerging from between FCU and med. FDP. Here it gives off a palmar cutaneous branch. Towards the hand it gives off a dorsal cutaneous branch, deep branch (for most intrinsic hand muscles) and proper palmar digital nerves for the medial 1.5 fingers

Answer 223

Brachial artery splits into ulnar and radial arteries. Ulnar splits into common interosseous Common interosseous gives off post. and ant. interosseous, on the post. and ant. sides of the IO membrane. Both the radial and the ulnar arteries give off a deep and a superficial branch within the hand.

Answer 224

First carpometacarpal joint: Saddle joint, allowing thumb flexion/extension, abduction/adduction and some rotation (for opposition). Others: hinge joints with 2 condyles, allowing flexion/extension only. Medial 4 Metacarpophalangeal joints: Condyloid joints with 1 condyle, allowing flexion/extension and abduction/adduction. Stopped from rotating by ligaments. Thumb: hinge joint Interphalangeal joints: hinge joints.

Answer 225

Deep transverse metacarpal ligaments run transversely from the distal ends of each metacarpal. They prevent excessive spreading of the digits, and attach to the palmar ligaments of the MCP joints. Palmar ligaments are found in the IP and MCP joints, preventing rotation. They also form a soft, feltlike channel for the long flexor tendons.

Answer 226

The digits are surrounded by fibrous sheaths, inside of which are synovial sheaths, making it easier for the fingers to flex and extend. The Digitti minimi bursa is continuous with the common synovial sheath of the carpal tunnel, so if the little finger's bursa becomes infected it could lead to carpal tunnel syndrome, where the common synovial sheath swells so much the nerves are compressed

Answer 227

Dorsal interossei muscles: They abduct the fingers (apart from DM and P) They are bipennate, so have two origins (on the metacarpal they move and the neighboring one) and insert into the midline of the extensor hood They are supplied by the deep ulnar nerve. Remember using DIMAB Dorsal Interosseis insert into the Midline for ABduction.

Answer 228

Palmar interossei muscles They adduct the fingers (apart from the third phalange, which IS the midline) They attach out from the midline and insert into the extensor hood. They are supplied by the deep ulnar nerve. Remember using POMAD Palmar interosseis insert Out from the Midline to ADduct.

Answer 229

The Adductor pollicis muscle Runs from third metacarpal to the base of the thumb's proximal phalanx. Adducts thumb for opposition. Supplied by deep ulnar nerve. Also overlies the radial artery.

Answer 230

Lumbrical muscles. First and second are unipennate, third and fourth are bipennate. Run from tendon of FDP tendons to lateral corners of extensor hoods. Allow flexion of the digits while extending IP joints (like a puppet grip) Bipennates supplied by ulnar, unipennates supplied by median. Remember by LIL: Lumbricals insert laterally.

Answer 231

It's a fibrous sheath on the posterior side of the digits that surrounds the MCP joints and runs along the posterior aspect of the digits. They allow a puppet grip to occur, as the contraction of the lumbricals and interossei can be channeled into it, pulling it back even while FDP fires.

Answer 232

Thenar muscles: Abductor pollicis brevis, flexor pollicis brevis and opponens pollicis. APB and FPB run from flexor retinaculum to the base of the prox. phalanx. Opponens is from lateral side of first metacarpal to roll the thumb inwards in opposition. Flex, abduct and oppose the thumb. Supplied by median nerve Hypothenar muscles: Abductor dig. minimi, flexor dig. minimi and opponens dig. minimi. Same story as thenars but opponens is on the medial side of the 5th metacarpal. Flex, abduct and oppose little finger. Supplied by deep ulnar nerve. The thenars and hypothenars are laid out as mirror images of one another- flexors towards the midline, abductors away from the midline and opponens deep.

Answer 233

ULNAR NERVE: splits into deep and superficial branches beneath flex. retinaculum. Superficial brach splits into common palmar digital nerves for the medial 2 digits, and then each splits again into proper palmar digital nerves, each supplying adjacent sides of neighbouring fingers. Superficial is cutaneous, deep supplies all muscles apart from those innervated by the median nerve MEDIAN NERVE: recurrent branch just distal to flex. retinaculum supplies thenar muscles. Then splits into common palmar nerves (supply lumbricals 1 and 2) and again into proper palmar digital nerves, which supply the lateral 3.5 fingers.

Answer 234

Dorsal branch of ulnar nerve supplies medial 1.5 fingers and the associated back of the hand Superficial radial nerve supplies back of hand to the lateral 3.5 fingers apart from fingertips (Medial nerve)

Answer 235

If there is numbness in the index finger, although sensation in the lateral anterior wrist (where a small branch of the medial nerve passes over the flex. ret) then carpal tunnel is likely.

Answer 236

- Superficial branches of the R and U nerves anastomose in the anterior palm, - These branch into superficial palmar arteries and branch again into common palmar digital arteries. - Their terminal branches are the proper palmar digital arteries, which supply the digits. - The deep ulnar artery and the 'deep' radial artery anastomose in the dorsal hand in the deep palmar arch - They give off palmar metacarpal arteries, which anastomose with the superficial palmar arteries.

Answer 237

- Brachioradialis: From lateral supracondylar ridge to base of radial styloid. Flexes elbow, shunt muscle - Anconeus: From lateral supracondylar ridge to the ulna. Extends elbow. - Extensor carpi radialis longus: Lateral supracondylar ridge to base of MC II. Flexes and abducts the wrist. - Extenso carpi radialis brevis: from common extensor tendon to base of MC III. Flexes and abducts the wrist. - Extensor digitorum: Largest. From common extensor tendon to extensor hood. Extends fingers - Extensor digitti minimi: From common extensor tendon to little finger. Extends little finger - Extensor carpi ulnaris: From common extensor tendon to base of MC V. Extends and adducts wrist. All supplied by radial nerve/

Answer 238

They're arranged like a rectangle: FCU in anteromedial corner: flexes and adducts. FCR in anterolateral corner: flexes and abducts ECRB and ECRL in posterolateral corner: extend and abduct ECU in posteromedial corner: extend and adduct. Allows a great variety of movements to be acheived. Also allow thumb to move independently of the wrist.

Answer 239

The gap formed between the tendons of APL/EPB and EPL. | Used to identify tendons

Answer 240

- Supinator: Radial tuberosity to lat. epocondyle of humerus and IO membrane. Pull to supinate arm. - Abductor pollicis longus: Posterior forearm to base of 1st metacarpal. Abducts thumb - Extensor pollicis brevis: Posterior forearm to base of proximal phalanx. Extend thumb - Extensor pollicis longus: Posterior forearm to base of distal phalanx. Extend thumb. - Extensor indicis: Posterior forearm to extensor hood of index finger. Bypasses intertendinous bands to allow pinching motion. All supplied by radial nerve

Answer 241

They move superficially to cover the tendons of the ECR muscles, leading to them being called the outcropping muscles.

Answer 242

- Emerges from posterior cord through the triangular interval, covered by triceps. Here it supplies triceps, anconeus, brachioradialis and ECRL. - In the cubital fossa it branches into superficial and deep branches. The deep branch is covered by supinator. Here it supplies ECRB and supinator. - Once it has emerged from supinator it is the posterior interosseous nerve. Here is supplies the ED and EDM, ECU, APL, EPL, EI and EPB muscles.

Answer 243

Movement disorders are the most common symptom, due to the fact that the muscles may no longer be under voluntary control. This includes troke, epilepsy, parkinsons, spinal cord injuries...

Answer 244

- Volunary movement - Reflexes (withdrawl, vestibular, stretch) - Rhythmic motor patterns (semi voluntary- walking, breathing etc.)

Answer 245

The forebrain takes care of voluntary movement, and communicates with the basal ganglia, brainstem and spinal cord, before passing the action potentials to the muscles. The spinal cord and brainstem also directly interface with the muscles to control reflexes and rhythmic motor patterns. Because of this, the motor neurons are located from spinal cord and brainstem (aside from cranial nerves 1, 2, and 8) to muscles.

Answer 246

Alpha: Innervate extrafusal (main) muscle fibers. Directly responsible for generation of movement. - Can be fast (type IIB) or slow (Type I) Gamma: Control excitability of stretch receptors in muscle spindles by innervating intrafusal muscle fibres (located in the tapered ends of muscle spindles).

Answer 247

SNS motor neurons go directly from CNS to target tissue and use ACh to activate skeletal muscle. ANS motor neurons either - Synapse at ganglia in the PNS before using NA on target tissue - Synapse with an intermediate neuron in the target tissue first.

Answer 248

A motor unit is the anatomical and functional unit of the motor system. Made up of: - Cell body of an a motor neuron - Axon and its branches - Neuromuscular junctions from single motoneuron - All muscle fibers innervated by the single neuron.

Answer 249

FF type: - Few units but large. Generate great tension fast, but fatigue rapidly. Respire anaerobicly, and are recruited last. S type: - Many units, but small. Generate small tension slowly, but fatigue rarely. Respire aerobically and recruited early (some fire constantly)

Answer 250

S motor units are always recruited first, while FF are only recruited for high amounts of muscle force. This means: - Some S types fire almost always - S type units are best for sustained small loads (posture) - Weak contractions are graded more precisely - Necessary to exercise to prevent FF atrophy

Answer 251

- Use frequency of action potentials (summation, tetanus) | - Use recruitment of additional units

Answer 252

- Most muscles have slow and fast fibers mixed together apart from the soleus (slow) and gastrocnemius (fast) exception. - This allowed the discovery of proof that the motoneurons and the fibers they innervate affect both the type of contraction and the biochemistry of the muscle- the two are matched.

Answer 253

- Descending tracts (eg. pyramidal) - Spinal interneurons - Propriospinal neurons (for movement coordination) - Muscle spindles themselves

Answer 254

- Muscles spindles in parallel with extrafusal muscle- monitor muscle length and speed of length change. Very sensitive - Golgi tendon organs in series with extrafusal muscle- monitor muscle tension - Joint receptors (monitor position) These are the proprioreceptors (deep) - Also nociceptors in the skin, monitoring pain.

Answer 255

- Allow awareness of the body's starting position for movement - Allow information about how the joint is moving - Initiate movements via reflexes

Answer 256

``` Stretch/Myotactic/Tendon reflex Golgi Tendon/Inverse Myotactic/Reverse Myotactic reflex Withdrawal/Flexion/Flexor reflex Each involves: - Receptor - Afferent fibres - Central relay/s - Efferent fibres - Effectors ```

Answer 257

Receptor: Annulo-spiral endings of muscle fibres Afferents: 1a afferents Central relay: GLUT on alpha motoneurons in ventral horn of the spinal cord Efferents: excitatory alpha motoneurons Effectors: synergistic muscles (plus inhibition of antagonistic muscles)

Answer 258

Occurs during myotactic reflex- at the same time gaba is released on synergistic alpha motoneurons, inhibitory interneurons are activated to relax antagonistic muscles.

Answer 259

Biceps jerk- C5/6 | Knee jerk- L3/4

Answer 260

Receptors: golgi receptors fire when a muscle has been overexerted Afferents- 1b Central synapses: interneuron in the spinal cord Efferent: alpha motor neuron Effector: muscle There is a reverse of the reciprocal inhibition- antagonistic muscles are concurrently excited

Answer 261

- Also used to protect muscles from overloading, and to compensate for muscle fatigue when muscle tension decreases - In upper motoneuron disease, the threshold for the reflex is higher

Answer 262

Receptors: Nociceptors in the skin Afferents: Type III and IV (slow) Synaptic relays: Interneurons in multiple segments excite flexor alpha motorneurons Efferents: Alpha motoneurons Effectors: Flexor muscles However, on the contralateral side, there is a crossed-extension reflex- the extensors of the same body part are activated to maintain balance.

Answer 263

- The fact that they are activated with alpha motorneurons means they activate intrafusal muscle fibres. These control the length of the spindle, allowing them to provide information about muscle length during contraction and lengthening- if the muscle contracted and there was no change in spindle length, the fibre would be loose and the sensory neurons would provide little relevant information.