LOWER LIMB CONTENT Flashcards
Define homologous
Equivalent to, the same as
What is present for the rotation of a joint ?
An axis of rotation
What is an axis that moves called?
Instantaneous axis of rotation
What does an axis of rotation imply ?
That there is a plane of movement
Define kinematics
It is the description of movement of the body , or of part of the body
Define kinetics
It is the study of the causes of the movement - the force
What is the plane ?
It is a flat surface that describes how the body part is moving
Where does flexion-extension take place ?
In the sagittal plane about a medial-lateral axis
Where does abduction-abduction take place ?
In the frontal/coronal plane about an anteroposterior axis
Where does medial-lateral rotation take place ?
In the transverse plane about a vertical axis
What are actions of the foot at the subtalar joint?
- inversion
- Eversion
- plantarflexion
- dorsiflexion
What are muscles ?
They contract or shorten to move/rotate joints
What are the 3 types of muscular contraction ?
- concentric
- eccentric
- static/isometric
Define concentric contraction
When a muscles contracts and shortens
Define eccentric contraction
When a muscle is fired and tries to shorten but it is lengthen by some other force, like gravity
Define static/isometric contraction
When a muscle contracts and the joint doesn’t move
What is a nerve
A cable-like structure within the body that transmits an electrical signal for movement and fires muscles
What is a ligament ?
Rope-like structure (made of collagen), that attach bone to another bone across a joint
What do ligaments guide
They guide movement
How do ligaments restrict movement ?
When they get tight, they restrict/limit/stop movement in extreme joint positions
What does the attachment point of bones reveal ?
The actions of each muscle
What does each action of the muscle rely on?
The muscles LOP and where it applies on the bone and on which side of the joint the LOP crosses
What is a fossa
A shallow, hollow area
What is a foramen
A hole
What is a tubercle/tuberosity
A (small) rounded bump
What is a protuberance/process/spine/condyle/eminence/hrom
Something that sticks out, a projection
What is a notch
A sharp indent
What is a canal
A relatively narrow tubular passage or channel
What is a fovea
A pit
What is a line/crest
An elongated marking
Why do our iliac blades face more outwards than that of other animals ?
Bipedalism. And for abduction which is needed for walking and running on two legs
What is the abdominopelvic cavity
It is a continuous cavity, above the iliac crest
Where is the false pelvis ?
Between the pelvic brim/inlet and the iliac crest
Where is the false pelvis ?
Between the pelvic brim/inlet and the iliac crest
What is the true pelvis
It is beneath the pelvic brim/inlet, to the inferior pelvic outlet
Define symphysis
Means “grow together” and a non-synovial/cartilaginous joint
What are the boundaries of the pelvic outlet
- coccyx
- Sacrotuberous lig
- ischial tuberosity
- ischiopubic ramus
- pubic symphysis
What is the pelvic outlet closed off by?
A muscular sheet, the pelvic diaphragm
What is below the pelvic diaphragm ?
The perineum, a region between the anus and genitalia
What is evident in a young pelvis
- hip bone/innominate is comprised of 3 ossification centres
- shows infused ilium, ischium and pubis
- unfused femur head and greater trochanter ossification centres
- shows a clear sacroiliac joint (SIJ)
What is the sacrum ?
A triangular bone just below the lumbar vertebrae
Define nutation
means “nodding” which is a tiny movement within the pelvis of the sacrum relative to the hip bone. It is tiny as the sacrum is tightly held in place by strong thick ligaments
What 3 ligaments hold the sacrum in place
- Sacrotuberous lig
- sacrospinous lig
- sacroiliac joint capsule
What is sacral nutation
It is the tendency of gravitational body weight to cause nutation, to tighten the ligaments to prevent further movement (counternutation is just in the opposite direction movement)
How do different parts of the sacrum move during nutation ?
The promontory moves forward-down and the coccyx moves backward-up
Where is the axis of rotation during nutation
Within the sacroiliac joint, it does not move throughout nutation
Why is the sacrum considered a multiaxial joint
It can move at the SIJ in all 3 cardinal planes - however movement is predominantly in the sagittal place for nutation-counternutation
What muscles/ligs attach on the iliac crest ?
- Quadratus lumborum
- external oblique
- internal oblique
- transversus abdominis
- gluteus Maximus
- iliolumbar lig
- erector spinae
What attaches on the ASIS
- sartorius
- Inguinal lig
- TFL
What attaches on the AIIS
- rectus Femoris
What does the PSIS mark ?
The expansive sacroiliac joint
What does the PIIS mark
Marks the expansive sacroiliac joint
What does the the auricular surface join ?
It joins the auricular surface of the sacrum to form the sacroiliac joint
What attaches to the iliac tuberosity
Dorsal Interosseus sacroiliac lig
What does the arcuate line form part of
The pelvic brim/inlet
What attaches on the iliac fossa
Iliacus muscle
What is the Iliopubic eminence
It is a thickening of the bone where the two bony elements, the pubis and ilium fuse. It is a process that begins in late teens and finishes in early 20s
What attaches of the Pectineal line ?
Pectineus muscle
What attaches on the body of pubis
Hip adductor muscles - mostly adductor Longus and brevis
What attaches in the pubic crest
- Rectus abdominis
- Pyramidalis
What attaches to the pubic tubercle
Inguinal lig
What is the pubic symphysis
It is the cartilaginous joint between the left and right pubic bones
What attaches on the superior pubic ramus
Pectineus - it attaches on the Pectineal line, part of the superior pubic ramus and part of the pubofemoral lig
What does the superior pubic ramus fuse with
It’s lateral end fuses with the ilium at the Iliopubic eminence
What attaches to the inferior pubic ramus
- part of adductor Magnus
- Gracilis
- adductor brevis
- adductor longus
- greater sciatic notch
What passes through the inferior pubic ramus
- Piriformis
- sciatic nerve
- superior and inferior gluteal nerves
- internal pudendal artery and vein
- posterior femoral cutaneous nerve
What attaches to the ischial spine
- sacrospinous lig
- lesser sciatic foramen/notch
What passes through the ischial spine
- Obturator internus
- pudendal curve
- internal pudendal artery and vein
What attaches to the ischial ramus
Adductor Magnus
What attaches to the ischial tuberosity
-Sacrotuberous lig
- hamstring muscles
What attaches to the ischial tuberosity
-Sacrotuberous lig
- hamstring muscles
What does the acetabulum form ?
It joins the head of the femur to form the hip joint
What attaches on the acetabular rim ?
- acetabular labrum
- ## hip joint capsule
What attaches on the obturator foramen
- Obturator membrane
- Obturator externus
- obturator internus
What passes through the Obturator groove
- Obturator nerve, artery and vein
What attaches on the gluteal line muscles
Muscles don’t attach to them, only between them
What attaches on the posterior gluteal line ?
Gluteus max attaches behind it
What muscle attaches to the anterior gluteal line
Gluteus medius attaches behind it
What muscle attaches to the inferior gluteal line
Gluteus minimus attaches above it
What are two sources of difference between the male and female pelves?
- female pelves have to transmit a baby at childbirth therefore any structure that contributes to a widening of the pelvic outlet or inlet will be longer/larger in the female
- males tend to be heavier and have larger muscles therefore, any structure that is mainly weight bearing or is an attachment for a muscle or lig will be larger in the male
What are some key difference between the male and female pelves
- female pubic angle is wider than male (more arch-like vs acute and straight, respectively)
- females pubic body and superior pubic ramus is wider
- acetabulum is larger in male
- distance from pubic symphysis and acetabulum is 1:1 (male) and 2:3 (female)
- female’s greater sciatic notch is wider
- male pelvic inlet is more heart shaped whereas, females is more round. This is because the male sacral promontory juts further forward whereas, this would obstruct the passage of the baby through the pelvic inlet
- the male sacral body is large whilst its alae is relatively smaller
- the male articular surface on the sacrum is large than the female
- male pelvis is narrower, more upright and more chunky
- female pelvis is broader, sleek and smoother
What is the obstetrical dilemma
It is a hypothesis to explain why humans often require assistance from other humans during childbirth to avoid complications, whereas non-human primates give birth unassisted with relatively little difficulty
Why does obstetrical dilemma occur
It occurs due to the tight fit of the fetal head to the maternal birth canal which is convoluted therefore, the head and body of the infant must rotate during childbirth in order to fit (this is not the case for other non-upright walking mammals).
What is the incidence related to the obstetrical dilemma
There tends to be a high incidence of cephalopelvic disproportion and obstructed labour in humans
What are some claims of the obstetrical dilemma
It claims that the differences is due to the biological trade off imposed by two opposing evolutionary pressures in the development of the human pelvis where smaller birth canals in mother and larger brains therefore skulls in the babies
What do proponents believe about the obstetrical dilemma
They believe bipedal locomotion (the ability to walk upright) decreased the size of the bony birth canal and that as the Human skull and brain sizes increased over time, women needed wider hips to give birth which made women inherently less able to walk/run than men and that the babies had to be born earlier to fit through the birth canal
What does the origin and insertion of a muscle reveal
The direction of the LOP
Where is the AOR of the hip joint
It is always in the centre of the head of the femur
What does a front view of the hip joint reveal
Abduction or adduction
What does a side view of the hip joint reveal
Flexion or extension
What does a top view of the hip joint reveal
Internal or external rotation
What are the actions of the hip adductors (not from the anatomical position)
- they always adduct the hip
- they flex from and extend position
- they extend from a flexed position
What does the top part of gluteus max become in position of greater hip flexion
It becomes a greater internal rotator in positions of greater hip flexion
What does the two different parts of glut medius become in reference to internal and extends rotation components
The front part of glut medius increases its internal rotation action from positions of increased hip flexion
What does the two different parts of glut medius become in reference to internal and extends rotation components
The front part of glut medius increases its internal rotation action from positions of increased hip flexion
What is the pubic arch sometimes called
The sub pubic arch
- it is the ischiopubic ramus
What is the adductor hiatus
It is the space between the 2 parts of adductor Magnus
What is the hip joint capsule
It spirals around the neck of the femur as the the lower limbs has rotated medically both in evolution and individual development
What is the hip joint capsule
It spirals around the neck of the femur as the the lower limbs has rotated medically both in evolution and individual development
What are thickenings of the hip joint called
Ligaments
What are the ligaments of the hip joint capsule
- iliofmeorial lig
- pubofemoral lig
- ischiofemoral lig
What does capsular mean
A lot of ligaments
How are ligs categorised
They are passive as they tug on the bone
What do the ligs of the hip joint do around the neck of Femur
They spiral around the neck of the femur
What are the generalised functions of the ligs of the hip joint capsule
- they will become taut quicker in attempted medial femoral rotation
- they unwind in lateral rotation which allows for greater movabilty
What do the ligs on the underside of the capsule become
They become tight in hip abduction, particularly pubofemoral lig
What do the ligs at the top/above the hip joint axis become in abduction
They become tight in abduction
What is another name for the hip joint
Coxofemoral joint
What is the function of the pubofemoral lig
Restricts extreme hip abduction
Which is the strongest lig in the hip joint capsule
Iliofemoral, the one at the front
What is the function of the iliofemoral lig
-fibres restrict extreme hip adduction
- gets tight/taut in extreme hip extension, stopping movement there
What does the iliofemoral lig do during extreme hip extension
- gets tight/taut and stops movement there
- no muscles are then required to act to hold this position
What happens if the force driving hip extension is so high that the lig tears
You have pathology that involves laxity and much increased movability
What is the function for the acetabular labrum
To stabilise the hip joint
How does the femoru move
In a stabilised action
What are key movements of the pelvis, relative to the pelvis
- flexion
- lateral rotation
What is the movement of the pelvis like
It is the same movement of the same joint, the hip joint
What is the LOP of the femur
Muscles that attach to the back of the femur (ilopsoas and hip adductors) apply a LOP on the femur that passes in front of the hip joint AOR
What is the LOP of the femur in relation to rotations
- medial/internal or lateral/external in the transverse/horizontal plane, about a vertical axis
- therefore, they are medial hip rotators from the anatomical position
What muscles attach to the pelvis and act on the hip and knee joint, across the knee (Attach to the leg)
- sartorius
- Gracilis
- semitendinosus
- Semimembranosus
- glut max
- TFL
These also can adjust the posture of the pelvis
What muscles attach to the pelvis and act on the hip and knee joint, across the knee (Attach to the leg)
- sartorius
- Gracilis
- semitendinosus
- Semimembranosus
- glut max
- TFL
These also can adjust the posture of the pelvis
What tendons does pes anserinus comprise of
Medial to lateral
- sartorius muscle
- gracilis tendon
- semitendinosus tendon
What is a bursa
It is a fluid-filled sac that lubricates the location where a soft tissue structure (tendon, lig, fascia, muscle, skin) is pressed against the bone so that the structure can slide over the bone with little friction
What are the borders of the femoral triangle
- Sartorius (medial)
- Inguinal lig (anterior)
- adductor longus (lateral)
What is the floor of the femoral triangle
- iliopsoas
- Pectineus
What is the roof of the femoral triangle
Deep fascia of the thigh (fascia Lata)
What are the contents of the femoral triangle
- femoral nerve, artery, vein and lymphatics
- cutaneous (Sensory) nerves such as the lateral femoral cutaneous nerve
What is the adductor canal also known as
Subsatorial canal
What is the adductor canal
It is at the apex of the femoral triangle, where the sartorius crosses adductor longus (start of the adductor canal) and it continues down the adductor hiatus
What are the walls of the adductor canal
- adductor longus
- adductor Magnus
- sartorius
- vastus medialis
What are the walls of the adductor canal
- adductor longus
- adductor Magnus
- sartorius
- vastus medialis
What are the contents of the adductor canal
- femoral artery and vein
- saphenous nerve
- branch of Femoral nerve to vastus medialis
What are the 4 quadriceps and where do they arise from
- rectus Femoris arises from pelvis (therefore acts on hip)
- 3 vastus arise from the femur
What is the articularis genu
It is the deepest fibres of vastus intermedius and is considered a muscle with a special function
Where do the fibres of articularis genu arise from
From the front of the distal femur and insert into the knee joints fibrous joint capsule
What happens to the articularis genu as the quads contract to extend the knee
This muscle also contracts and pulls the capsule proximal to stop it being trapped and squished between the patella and femur
Definition of a hamstring
- originates from ischial tuberosity
- inserts on the Leg
- extends the hip
- flexes the knee
- supplied by the tibial nerve
What are the 3 hamstrings
- long heap bicep femoris
- semitendinosus
- semimembranosus
Why is the ex-hamstring/ischial part of adductor Magnus not a hamstring
It doesn’t cross the knee
Why is short head bicep femoris not a hamstring
It is not supplied by the tibial nerve and doesn’t arise from the pelvis therefore, it cannot extend the hip
What are the two parts of adductor Magnus
- true adductor part
- “ex-hamstring” part
What is the true adductor part of adductor Magnus
- it has all the other characteristics of the adductor group, supplied by the obturator nerve
- it arises from the pubis
- inserts on the linea aspera
- flexes, abducts and medially rotates the femur/thigh/hip joint
What is the ex-hamstring part of adductor magus
- known as the ischial part
- doesn’t quite cross the knee
- it is supplied by the tibial nerve
- extends and abducts the hip
What is the last part of the hamstring
The medial collateral lig of the knee is the vestigial/remnant of the last part of the hamstring - adductor Magnus
What is the adductor hiatus
It is the space between the two parts of adductor Magnus where the femoral vessels (Arteries and veins) cross the front of the thigh to behind the knee
Where is the knee joint located
Between the femur and tibia, as well as the patella
Is the fibula part of the knee joint?
No
What is the knee joint stabilised by
- bony features
- ligamentous features
- ligaments
How is the knee joints moment arm increased
The presence of sesamoids
- the torque is affected greatly as the perpendicular distance has increased greatly
- therefore, there is more powerful extension of the knee
What distance does the patella maintain
It always stays the same distance from the tibial tuberosity because of the patellar tendon/lig
Where are sesamoid bones located
Within the tendon of a muscle
How do sesamoid bones grow
They grow variably. They are functionally adapted to resist localised compressive stress in the muscles tendon where it presses on the bone
How do sesamoid bones decrease friction
They decrease friction due to their cartilage-covered articulation surface
What is the size of the patella in comparison to others in the body
It is the largest sesamoid in the human body, next largest is the pisiform in the wrist
What is an important functional explanation of the presence of the patella
It moves the quadriceps tendon further from the axis of rotation which increases the muscles moment arm. As a result, it increases the maximum possible extensor torque producible. For a given amount of torque that needs to be produced, the muscles need to contract less strongly which saves energy
What does genu Valgum and Varum present
Excessive frontal plane deviation
- genu valgum = knock-knee of greater than 165 degrees (normal is 125 degree angle of inclination of the proximal femur)
- genu varum = bow-leg of greater than 180 degrees
Describe tibial-on-femoral extension
In relation to knee extension
- the meniscus is pulled towards the contracting quadriceps
- screw home rotation is below the knee joint
Describe femoral-on-tibial extension
In relation the knee extension
- the meniscus is pulled towards the contracting quadriceps
- screw home rotation is above the knee joint
What is the “screw home” locking mechanism
It is the same as the “terminal locking” mechanism. It is a small amount of lateral rotation of the leg relative to the femur at the last part of knee extension
- the curved medial femoral condyle helps to direct the tibia to its externally rotated and locked position
What is the short head bicep femoris
- flexes only the knee
- laterally rotates a flexed leg
- it is an anomaly as it is supplied by the common fibular/peroneal nerve and is evolutionarily derived by muscle that was attached to the back of the pelvis (called tenuissimus)
What is the popliteal fossa
It is a diamond-shaped region behind the knee
What are the borders of the popliteal fossa
- semimembranosus and semitendinosus
- biceps femoris
- both heads of gastrocnemius
What is the roof of the popliteal fossa
Deep fascia
What is the floor of the popliteal fossa
Mostly popliteal surface of the femur and fascia over the popliteus
What are the contents of the popliteal fossa
- common fibular/peroneal nerve
- popliteal artery and vein
- small saphenous vein
- lymph nodes
What is the leg comprised of
It is the tibia and fibula and is from the knee to the ankle
What is the function of the leg
- it is a fixed structure that provides stability for bipedalism
- serves as a stable attachment point for muscles that act on the foot and ankle
What are the 3 places that the fibula and tibia join
- at the top (proximal), the bottom (distal) and along almost the entire length (middle), by an Interosseus membrane
- at each of these points, there is a forming of the tibiofibular joints
What are the 3 tibiofibular joints
1- posterior tibiofibular joint
2- middle/intermediate tibiofibular joint
3- distal tibiofibular joint
Why does an Interosseus membrane exist between the tibia and fibula
It is a re-distributor of stress between the two bones
What is the ankle joint also known as
Talocrural joint
What is the ankle joint also known as
Talocrural joint
What is the talocrucal joint
It is a hinge joint and is the joint between the tibia, fibula and talus
What is the structure of the talocrucal joint
tightly bound-together tibia and fibula and a large trochlea of the talus that has articulated surfaces over its dome and on its sides
What is the talus mostly covered by
Articulate cartilage
How does the talocrucal joint function as a hinge joint
It needs strong, tight collateral ligs
What is the talus comprised of
7 tarsal bones that are between the leg bones and metatarsals
What are the 7 tarsal bones
- talus
- calcaneus
- cuboid
- navicular
- 3 cuneiforms
Since the talus has no muscles or tendons attaching to it, what is its function
- has a large trochela “pulley” for attachment with the tibia and fibula at the ankle joint
- it has a head for attachment with mostly the navicular
- it has a neck
Why does the calcaneus stick out backwards behind the ankle
To provide a larger moment arm for the triceps surae (calcaneus and soleus)
Why does the calcaneus have a ledge that just out medially, on the medial side
Helps hold up the talus
What is the Sustentaculum tali
It joins the cuboid at the front, to hold up the talus
Why does the cuboid have a groove on its underside
For the tendon of inferior of fibularis Longus
What actions take place at the ankle
- dorsiflexion (biological extension)
- plantarflexion (biological flexion)
What is the talar dome/trochela
- it is wider at the front than the back
What happens when you dorsiflex your ankle
- the wider part of the bone is moved in the already “tightish” position space between the tibia and fibula. This tightens the ligs even more which means the articular surfaces are pressed against each other really tightly. This is called the “closed packed” position of the joint (this position exists in every joint)
What is the opposite of a “closed packed” joint
An “open packed” joint
- this is where the legs are slacker, the joint is loose and the articular surface are not tightly pressed against each other
- this is the position where clinicians can assess movement and structural integrity
What factors increases the mechanical stability of the fully dorsiflexed talocrucal joint
- increased passive tension in several connective tissues and muscles
- the trochlea surface of the talus being wider anteriorly than Posteriorly
- the path of dorsiflexion places the concave tibiofibular segment of the mortise in contact with the wider anterior dimension of the talus which causes a wedging effect within the talocrucal joint
What is the talcocrucal joint, joint capsule
- fibrocartilage is present (Spring-like lig)
- all tendons and normal ligs are tendon fibres
- it is intermediate between tendon and cartilage and is stiffer than tendons/ligs
What is special about the soleus and gastrocnemius
- they are the two largest muscles in the leg
Why do soleus and gastrocnemius have the largest torque-producing ability
They have a large movement arm at the ankle, whereby the calcaneus juts out at a posterior distance
Define extrinsic muscles of the foot
Muscles that have their origin outside of the foot
Define intrinsic muscles of the foot
Muscles that are entirely within the foot, including their origin and insertions
What are muscle compartments surrounded by
Deep fascia, and similar fascia called intermuscular septa
What separates gastrocnemius from soleus
A distinct septum
- septum = singular
What is a functional adaption of popliteus muscle
It sometimes has a sesamoid bone in its tendon of origin, called cyamella which is close to the head of the fibula. This explains why sesamoid bones are variably present
As the popliteus tendon passes through the knee joint, what is it described as
Intrascapular tendon which are extrasynovial, meaning they are coved in a lining of synoyium
What is the triceps surae
- formed by the two heads of gastrocnemius and the soleus, and insets into the calcaneal tendon
What are the actions of triceps surae
- plantarfelxion of ankle
- as the tendon inserts onto the back of the calcaneus, it also crosses and therefore can act on the subtalar joint
- it passes through the AOR so it has an insignificant moment arm for inversion or Eversion
Where does ‘Tom Dick an Harry’ all arise from
Deep in the back of the leg, areas on the tibia and fibula as well as the Interosseus membrane
- FDL and TP cross over
What is the extensor retinaculum
It is a thickening of the deep fascia which ensures that when the muscles contract/shorten, they don’t just cut the corner and bowstring without producing any desired joint movement. It holds the muscles down
What is the tarsal tunnel
Space between the talus and calcaneus
What is the roof of the tarsal tunnel
Flexor retinaculum
What tendons/contents pass through the tunnel
- TP
- FDL
- FHL
- Tibial nerve
- posterior tibial artery and vein
What nerve is vulnerable to becoming compressed with the tarsal tunnel
Tibial nerve
What is the function of the peroneal retinaculum
Holds down the tendons of FL and FB on the outside of the calcaneus
What it the start of blood supply of the lower limb
starts as the abdominal aorta
Where does the femoral artery cross deep to
The Inguinal ligament, where it then enters the femoral triangle
Where does the obturator artery pass through
passes through the obturator canal with its nerve (an vein) to enter the medial thigh
Why is one branch of the internal iliac artery important
it is the only artery that provides nutrition to part of the head of the femur. if the artery is occluded or torn, the head of the femur will atrophy (avuscular necrosis), death of bone tissue
What are perforating Arteries
Perforate = pass through
- There are three or four branches off the deep femoral artery perforate gaps in the tendon of insertion of the true adductor part of adductor Magnus
What are perforating Arteries
Perforate = pass through
- There are three or four branches off the deep femoral artery perforate gaps in the tendon of insertion of the true adductor part of adductor Magnus
What type of bundle is the femoral artery
a neurovascular bundle (nerve, artery and vein). It is always with the artery in the middle
Where does the femoral artery pass through
Passes through the adductor canal which is between the lower apex of the femoral triangle and the adductor hiatus
What is the deep femoral artery accompanied by
its two veins known as, “venae commitantes” (accompanying veins)
What are genicular veins
- Genicular =“knee” from “bend”
- There are 6
- They are small and arise from the popliteal artery
- They also anastomose with each other and are hard to find
What are anastomoses
Anastomoses = joins
- When an artery becomes another artery
- There are many arteries and anastomoses between them in the foot
- valves exist close to anastomoses
Define deep veins
The ones that run with the same-named arteries
Define superficial veins
Those that run by themselves in the superficial fascia
What are perforating veins
The many connections between the superficial veins and the deep veins
What are the 3 superficial veins
1- Dorsal venous arch
2- Small saphenous vein
3- Great/long saphenous vein
Where is the dorsal venous arch located
On top of the foot
What is the course of the small saphenous vein
Runs up the outside of the leg then dives deep in the popliteal fossa to anastomose with the popliteal vein
What is the course of the great saphenous vein
Runs all the way up to the medial lower limb to the groin region and dives deep there to anastomose with the femoral vein
Describe muscle pumps in the lower limb
• There is not much blood pressure behind venous blood. Not like the blood pressure behind arterial blood because of the pumping heart (systole).
• Blood thus has difficulty returning to the heart, especially in bipedal humans. Because it is trying to go upwards against gravity with next to no pressure behind it.
• So there are some mechanisms that help venous return.
• The main one is the presence of valves in peripheral veins that prevent backflow of blood.
• Then there is the muscle pump. Often illustrated between soleus and gastrocnemius, but exist elsewhere as well. When we walk or run, for instance, these muscles sequentially contract, then relax, then contract then relax ,…
• When they contract they bulge and compress (squish) the vein running between them. This empties the vein. The valves stop the blood from flowing down (ie in the wrong direction), and thus the blood is forced upwards towards the heart. Then the muscles relax, and the vein can refill from below.
What are some pulse points in the lower limb
- femoral artery
- popliteal artery
- posterior tibial artery
- dorsalis pedis artery
How to best palpate for the pulse of the dorsalis pedis artery
best palpated high up the foot (not at the very top, yet not near the toes). Between the tendons of extensor hallucis longus and the extensor digitorum longus
Describe embryonic development of a body segment
• In each body segment there is a layer of bone tissue, muscle tissue, and skin tissue.
• These are developed from, respectively, a sclerotome, myotome and dermatome.
There is are two nerve arising from the spinal cord at each segment that supplies the skeleton, muscle and skin. – there is always a nerve on each side of the body.
Describe outpouchings/growing elongations
Creatures that have limbs, such as humans, have these limbs developed from outpouchings of some of the segments. These outpouchings (growing elongations) carry their nerves with them.
Describe segmented nature in a bent over position
• In this bent-over posture the segmented nature of our body is more evident (than when standing).
• The segments shown on the far left, and their representation in the skin (dermatomes)
• there is much overlap at (more the edges of) neighbouring dermatomes.
• This has an important clinical implication for therapists – it means that if you wish to test for the integrity of a spinal segment (T2) you need to test sensation (eg pin prick) from the middle of that segment’s patch so you aren’t accidentally testing the neighbouring nerve. That’d be a misdiagnosis.
Describe evolutionary segmentation in adult bodies - with reference to rectus abdominis
Technically an eight pack muscle however refereed to the ‘six pack’ msucle as the lowest segment is too low to see. It starts at the umbilicus. It is two side, has a left and right part that is separated by the linea alba. Segmented vertically into its ¾ muscle parts that are also separated by thing lines of collagenous connective tissue – has no functional explanation. We have evolved from creates that had segmentation
Describe evolutionary segmentation in adult bodies - with reference to the thorax
Each segment has a single intercostal nerve. There are 3 elements supplied by that nerve – 3 intercostal muscles, a single rib and a single strip of skin over the rib, on each side
Describe the spinal nerve, as one segment
• Anterior (ventral) root which is purely motor (which means it has only motor neurons in it). Cell body of these in the front (ventral) part of the grey horn of the spinal cord (the “H” in this diagram).
• Posterior (dorsal) root which is purely sensory (has only sensory neurons in it). Cellsbodies in the dorsal root ganglion.
• Where these two roots join is the beginning of the mixed spinal nerve. Called mixed because it now has both motor and sensory neurons in it.
• Distal to this are the two main branches – the dorsal and ventral primary rami.
What does the dorsal ramus supply
The intrinsic back, bones, muscles and skin
What does the ventral ramus supply
Everything else - the side and front body wall, bone, muscle and skin
What is a plexus
- Intermingling in the neck and in the lowest part of the spine
- Plexus = “braiding” or “interweaving”
- Important for therapists/clinicians
What are the parts of the plexus
- There are more proximal parts of the lumbosacral plexus
- We focus on the named peripheral nerves the neurons end up in
- The parts of the brachial plexus of the upper limb are important
What is a plexus root
- A mixed spinal nerve, ie sensory and motor neurons in it
- Dorsal root of the typical spinal nerves is purely sensory
- Ventral root is purely motor
What are the key locations that a nerve would be susceptible to damage
- It is superficial.
- It passes close to a joint – if the joint dislocates, it could damage the nerve.
- it passes far from a joint (you could say, in a very daggy fashion, that it has a large moment arm!). This means that when the joint is moved, the nerve could be stretched and perhaps torn. It has greater excursion.
- It passes through a muscle. When the muscle contracts the nerve could be compressed.
- It passes through a bony opening – could become impinged.
- It lies on a bone – if the bone breaks there, the sharp edges of the break could cut into the nerve.
What are other mechanisms of potential nerve damage
- Where the nerve could be pressed by external forces. Such as at your buttocks when sitting, or your feet while walking, or your bicycle handlebars while riding etc.
- Surgical damage.
-Tumours. - CANS damage.
What are individual variations in the course of parts of the sciatic nerve
A variation seen in a few specimens is whereby the common fibular part of the sciatic nerve passes through piriformis. This makes it more susceptible to being compressed or worn by the contraction of piriformis (“piriformis syndrome”??). The odd thing is, though, and this picture doesn’t show it, is that in most cases the nerve pierces the muscle between two different parts of that muscle – there is almost always a space/gap for the nerve to pass through, which is useful. And not surprising from an evolutionary perspective with the assumption that nerves are incredibly important and need to be protected
What are motor nerves
Nerves which fire muscles
What are motor nerves of the lumosacral plexus
- Femoral nerve supplies front of thigh/muscle compartment.
- Obturator nerve supplies inner thigh.
- Tibial nerve supplies back of thigh, back of leg and plantar side of foot.
- Deep fibular nerve supplies front of leg and top of foot.
- Superficial fibular nerve supplies lateral leg.
What are cutaneous nerves of the entire body and lower limb
For clinical diagnoses of peripheral nerve damage
- Any nerve that crosses a joint, provides ‘twigs’ to that joints which are proprioceptive
- Areas of skin and joint movements
- Areas of skin supplied by named nerves
- Branches that run with the branches that fire muscles
- They are sensory neurons - send the signals to fire a compartment of the lower limb
- Purple patch = supplied by the femoral nerve
- When testing for sensation in a nerve, must test in the middle of the parch - as there is an overlap between the segments/compartments (therefore this could result in a missed diagnosis)
- Patches of skin supplied by named nerves
What is a dermatome
the area of skin supplied by one segment of the spinal cord.
What is a cutaneous nerve
the area of skin supplied by a named nerve (regardless of how many segments are in it).
What is the relationship between dermatomes and cutaneous sensory nerves
These two are just two different ways of viewing the same sensory neurons – one is the named nerve they end up in (cutaneous supply), the other is which part of the spinal cord they came from (dermatome).
What is spinal nerves and herniation
Usually affects only one side of the body, at the spinal level and only that spinal level. The levels below are unaffected
What are spinal nerve and herniation
Usually affects only one side of the body, at the spinal level and only that spinal level. The levels below are unaffected
What is a joint movement test
a summary of the myotome(s) responsible for that movement or other structures like muscles
What is a joint movement test
a summary of the myotome(s) responsible for that movement or other structures like muscles
What is a skin sensory test
test the named nerve responsible, and the dermatome responsible for that location.
What is a reflex test, test
test the muscle spindle of as well as the normal (alpha) nerve that supplies the muscle(s) of that tendon
Example of a reflex test
test L5 reflex of your medial hamstrings (semitendinosus and semimebranosus).
What is the procedure for assent the effect of any nerve lesion on joint action/movements
1- decide which muscles are still intact and which ones are lost. This depends on which nerve is servered and where it is severed
2- for every possible joint action, Otis the muscles lost/paralysed and those that are unaffected
3- decided for every possible joint action whether it is either lost completely, weakened or unaffected
4- decide if there are any areas of skin that have lost sensation. This depends on which nerve is severed and where it is severed
5- Hilton’s Law = any joint is supplied (sensation) by each nerve that crosses it
