TBL 7 Flashcards
Which mesoderm forms the shoulder and upper limb?
Chondroblasts and osteoblasts of the parietal layer of lateral plate mesoderm.
Which mesoderm forms the hip bones and bones of the lower limb?
What are the differences between morphogenesis of the upper and lower limbs?
There are TWO main differences in morphogenesis between upper and lower limbs:
1) Morphogenesis of the lower limbs is 1-2 days behind the upper limbs.
2) During the 7th week, upper limbs rotate 90 degrees laterally, placing the extensor muscles on the posterior/lateral surfaces and the thumb laterally. Whereas the** lower limb rotates 90 degrees medially, placing the extensor muscles on the anterior surface and the big toe medially**.
From the vertebral column, where is the weight of the upper body transmitted and what structures are responsible for this transmission?
The weight of the upper body, which is centrally supported by the vertebral column, then gets divided and directed laterally to the sacrum and to the thick portions of the bilateral ilia via the sacroilliac joints.
What structures stabilize the weight-bearing sacrum and ilia, and where are these structures located?
The rami of the pubis are joined centrally at the pubis symphysis to stabilize the weight-bearing sacrum and ilia.
To what structures do the ilia transfer the body weight?
The ilia transfer the body weight to the femurs (specifically the heads and necks of the femur when standing)
The fusion of what structures forms the hip bone? Which part of the hip bone articulates with the head of the femur?
The fusion of the ilium, pubis, and ischium form the hip bone. The acetabulum articulates with the head of the femur.
What structures reinforce the joint capsule of the femur?
The iliofemoral, pubofemoral, and ishiofemoral ligaments reinforce the joint capsule of the femur.
Explain the relationship between the ligaments of the femoral joint capsule and extension of the femur.
The ligaments (iliofemoral, pubofemoral, ischiofemoral) pass in a spiral fashion from the hip bones to the femur.
Extension of the femur causes the ligamentous spiral to become more tightly wound, which:
a) increases joints stability and
b) restricts extension to 10-20 degrees beyond the standing vertical position.
Explain the relationship between the ligaments of the femoral joint capsule and flexion of the femur.
The ligaments (iliofemoral, pubofemoral, ischiofemoral) pass in a spiral fashion from the hip bones to the femur.
Flexion of the femur causes this ligamentous spiral to unwind, which:
a) increases joint mobility
and
b) allows flexion of the femur 90 degrees or more beyond standing vertical position.
What is the common result of relative weakness in the ischiofemoral ligament?
Relative weakness in the ischiofemoral ligament typically results in hip dislocations most commonly in the posterior direction.
When standing, how is overabduction and hyperextension of the hip joint prevented?
The iliofemoral ligament (anterior/superior) is arguably the strongest ligament of the body and prevents hyperextension by “screwing” the femoral head into the acetabulum via its spiral conformation.
The pubofemoral ligament (anterior/inferior) tightens during both extension and abduction, but mainly prevents overabduction of the hip joint.
What forms the iliac crest and what are the attachment sites for tendons of the anterior thigh muscles?
The iliac fossa thickens at its superior border to form the iliac crest. The attachment sites for tendons of the anterior thigh muscles are the anterior superior iliac spine (ASIS) and the anterior inferior iliac spine.
What are avulsion fractures of the hip bone?
Avulsion fractures of the hip bone typically occur during sports that require sudden acceleration or deceleration forces (sprinting or kicking in football, soccer, hurdles, bball, martial arts).
A small part of bone with a piece of a tendon or ligament attached is torn away (avulsed). These usually occur at apophyses (bony projections that lack secondary ossification centers).
Identify structures A through F in the image below.
Identify structures A through G in the image below.
How do spiral fractures and comminuted fractures of the femur differ?
A spiral fracture of the femur is when the femur fragments override causing foreshortening of the bone.
A comminuted fracture of the femur is when the bone is broken into several pieces with the pieces displaced in various directions as a result of muscle pull.
Identify structures A through F in the image below.
What causes Osgood-Schlatter disease and what are its symptoms?
Osgood-Shlatter disease is inflammation of the tibial tuberosity and chronic recurring pain caused by disruption of the epiphyseal plat at the tibial tuberosity.
Describe the angulation of the femur and tibia, and what is the significance of this?
The adult femur has an angle (usually 126 degrees) between the neck of the femur and the shaft of the femur.
This angle allows the articulation of the femur and tibia (knees) to be closer to the axial line of the body and more directly inferior to the trunk, thus the center of gravity returns to the vertical axes of the supporting legs and feet, ideal for bipedal walking.
Why is fracture of the neck of the femur more common in the elderly?
Fracture of the neck of the femur is more common in the elderly because the angle of inclination becomes more and more acute with increasing age. So with increasing age, there is increasing strain on the neck of the femur.
Describe the minisci of the knee joint.
There are two, the lateral and medial menisci. They are incomplete rings of dense connective tissue paritally covering the articular surface of the tibial condyles.
What is the most stable position of the knee joint?
The most stable position of the knee joint is when it is in the erect, extended position where contact of the articular surfaces is maximized and the primary ligaments of the knee are taut.
What is the purpose of the lateral collateral ligament?
The lateral (fibular) collateral ligament (LCL) attaches the lateral epicondyle of the femur to the fibular head.
What is the purpose of the medial collateral ligament?
The medial (tibial) collateral ligament attaches the medial epicondyle of the femur to the superomedial surface of the tibia.
The tendon of what muscle separates the lateral meniscus and LCL?
The tendon of the popliteus muscle separates the lateral meniscus and LCL.
In the center of the knee joint, which two muscles cross each other obliquely like the letter X?
The Anterior Cruciate Ligament (ACL) and the Posterior Cruciate Ligament (PCL) cross each other obliquely in the center of the knee joint.
What are the attachments of the PCL and what is its role?
The Posterior Cruciate Ligament (PCL) arises from the posterior intercondylar area of the tibia and attaches anteriorly to the medial condyle of the femur.
The PCL prevents anterior displacement of the femur on the tibia and hyperflexion of the knee.
What are the attachments of the ACL and what is it’s role?
The Anterior Cruciate Ligament (ACL) arises from the anterior intercondylar area of the tibia and attaches posteriorly to the lateral condyle of the femur.
The ACL prevents posterior displacement of the femur on the tibia and hyperextension of the leg.
Which is stronger.. the PCL or ACL?
PCL
How can twisting of the flexed knee create the “unhappy triad” injury?
Twisting of the knee in the flexed position often sprains or disrupts the TCL (1/3), which is directly connected to the medial meniscus, thereby often also tears and/or detaches the medial meniscus from the joint capsule (2/3). Also since the ACL is a pivot for rotary movements of the knee and is taut during flexion, the ACL is often concomitantly disrupted/torn, which completes the “unhappy triad” of disrupted knee ligaments (3/3).
What are the anterior and posterior drawing signs?
Anterior Drawer Sign:
The ACL prevents hyperextension of the knee and prevents the femur from sliding posteriorly on the tibia. Therefore, if the ACL is torn, drawing the tibia anteriorly from the femur should be relatively easy.
Posterior Drawer Sign:
The PCL prevents the femur from sliding anteriorly on the tibia. Therefore, if the PCL is torn, drawing the tibia posteriorly from the femur should be relatively easy.
Describe the tissue that makes up the sliding area of the knee joint.
The sliding area of the knee joint (articular cartilage) is made of hyaline cartilage lacking perichondrium, which is a self-lubricating shock absorber with low friction properties.
What do the menisci provide for the knee joint?
The menisci are wedges of fibrocartilage known as articular discs that project into the synovial cavity and provide shock absorption and load distribution. They also lack perichondrium.
What type of tissue lines the joint capsule of the knee and all joints of the upper and lower limbs, and what does it do?
Joint capsules in the upper and lower limbs are lined by a synovial membrane (synovium), which consists of a simple cuboidal epithelium that produces synovial fluid for lubrication of the articular surfaces.
What is the pathogenesis of osteoarthritis?
Osteoarthritis is the most common form of arthritis and it is primarily a disease of the articular cartilage with the following pathological characteristics which ultimately leads to rapid deterioration of movement and function:
- degradation of extracellular matrix (ECM) due to enhanced matrix metalloproteinase enzyme activity
- decreased glycosaminoglycan content of the ECM*
- increased water content of the ECM*
- altered chondrocyte metabolism*
- loss of cartilage which results in bone-on-bone contact in synovial joints*
What does the deep fascia of the thigh become as it travels inferiorly? What is the cause of the lateral thickening of the fascia lata?
The deep fascia of the thigh is continuous with the deep fascia of the leg. The fascia lata is thickened and reinforced by the longitudinal fibers of the iliotibial tract.
The union of what two veins forms the subcutaneous great saphenous vein? The union of what two veins forms the subcutaneous small saphenous vein?
Great Saphenous Vein:
Dorsal Vein of the Big Toe + Dorsal Venous Arch of the Foot
Small Saphenous Vein:
Dorsal Vein of the Little Toe + Dorsal Venous Arch of the Foot
Describe the path of the Great Saphenous Vein (use landmarks).
The Great Saphenous Vein:
- ascends anterior to the medial malleolus
- passes posterior to the medial condyle of the femur
- anastomoses freely with the small saphenous vein
- traverses the saphenous opening in the fascia lata
- ultimately empties into the femoral vein.
Describe the path of the Small Saphenous Vein (use landmarks).
The Small Saphenous Vein:
- ascends posterior to the lateral malleolus as a continuation of the lateral marginal vein.
- passes along the lateral border of the calcaneal tendon
- inclines to the midline of the fibula and penetrates the deep fascia
- ascends between the heads of the gastrocnemius muscle
- ultimately empties into the popliteal vein in the popliteal fossa
What vessels accompany the great and small saphenous veins respectively, and where do these accompanying vessels drain into?
The superficial lympatic vessels accompany the great and small saphenous veins.
The ones close to the great saphenous vein drain into the superficial inguinal lymph node.
The ones close to the small saphenous vein drain into the popliteal lymph node.
Identify the nerves that innervate regions A through G in the image below:
The femoral cutaneous nerve, obturator cutaneous nerve, lateral cutaneous nerve, and posterior cutaneous nerve innervate the anterior, medial, lateral, and posterior cutaneous regions of the thigh, respectively.
Identify the nerves that supply sensory innervation to regions A through C in the image below:
Why does the great saphenous vein or its tributaries often become varicose? Why can a deep vein thrombus in the lower limb be fatal?
Varicose veins are veins that dilated so that the cusps of their valves do not fully close. When this occurs in the great saphenous veins and its tributaries, instead of only allowing blood flow in the superior direction, blood can now leak back down through the incomplete valves in the inferior direction due to gravity.
When is a saphenous cutdown required and where can sensory loss occur after the procedure?
A Saphenous Cutdown is required whenever access to the venous circulation is too difficult as is often the case in infants, obese people, or in patients in shock whose veins are collapsed.
This procedure allows access to the great saphenous vein by cutting the skin anterior to the the medial malleolus.
Sensory loss can occur along the medial border of the foot if the saphenous nerve, which accompanies the great spahenous vein anterior to the medial malleolus, is accidently cut.
Fill in the blank:
Muscles of the lower limb are derivatives of myoblasts in the ________ layer of ___________ mesoderm.
Muscles of the lower limb are derivatives of myoblasts in the parietal layer of lateral plate mesoderm.
For the iliopsoas muscle:
a) What two muscles form it?
b) what is the distal attachment?
c) what is its function?
For the iliopsoas muscle:
a) it is formed by the union of an abdominal muscle (psoas major) and a pelvic muscle (iliacus)
b) It’s distal attachment is the lesser trochanter of femur.
c) it is the chief flexor of the thigh when lifting the lower limbs for walking.
For the sartorius muscle:
a) what is its proximal attachment?
b) what is its distal attachmen?
c) what is its function?
For the sartorius muscle:
a) its proximal attachment is the ASIS (Anterior superior iliac spine)
b) its distal attachment is to the superomedial tibia
c) its works synergistically with other stronger muscles to flex the hip and knee joints.
What is the strongest muscle of the body? What muscles form it and what does it do?
The strongest muscle of the body is the quadriceps femoris, formed by FOUR muscles:
- 1) Rectus femoris*
- 2) Vastus lateralis*
- 3) Vastus medialis*
- 4) Vastus intermedius*
It functions in actions that extend the knee to lift or move the entire body weight such as squat lifts or accelerating during running and jumping.
What does the quadriceps tendon eventually become and attach to?
The quadriceps tendon eventually becomes the patellar ligament that attaches to the tibial tuberosity.
Describe the physical orientation of the patella and define its function.
The patella is a sesamoid bone embedded in the patellar ligament and its function is…
- to provide a bony surface that is able to withstand the compression placed on the quadriceps tendon during kneeling and the friction occuring when the knee is flexed and extended during running.
- to provide additional leverage for the quadriceps in placing the tendon more anteriorly, farther from the joint’s axis, allowing it to approach the tibia from a position of greater mechanical advantage.
What is a unique function of the rectus femoris?
The rectus femoris is the only quadriceps muscle that attaches proximally to the anteriior inferior iliac spine so it contributes to flexion of the thigh and extension of the legwhen the thigh is extended and the leg is flexed (kicking a soccer ball)
Where do the vastus lateralis, vastus intermedius, and vastus medialis attach proximally?
Proximal Attachments:
- Vastus lateralis* - greater trochanter and lateral lip of linea aspera of femur
- Vastus medialis* - Intertrochanteric line and medial lip of linea aspera of femur
- Vastus intermedius* - Anterior and lateral surfaces of shaft of femur
What structure is the synovial cavity of the knee joint continuous with? What is the function of this structure?
The synovial cavity of the knee joint is continuous with the suprapatellar bursa, which functions to cushion the qudriceps tendon as it extends the leg by pulling lengthwise across the joint.
How is suprapatellar bursitis related to popliteal (Baker) cysts?
Suprabursitis is caused by abrasions or penetrating wounds that allow bacteria to enter the suprapatellar bursa and cause an infection.
Popliteal cysts are abnormal fluid-filled sacs of synovial membrane in the region of the popliteal fossa, usually a complication of chronic knee joint effusion.
Envision abduction/adduction of the hip joint.
Here’s some help:
What does the medial portion of the adductor magnus contribute to?
The medial portion of the abductor magnus contributes to the hamstring muscle (to be studied later).
For the gracilis muscle:
a) proximal attachment?
b) distal attachment?
c) function?
For the Gracilis muscle:
a) proximal attachment - ischiopubic ramus
b) distal attachment - superomedial tibia
c) function - synergist with stronger muscles during adduction of the thigh and flexion of the leg
Describe a “hip pointer”.
“hip pointer”
- this sports injury referes to a contusion of the iliac crest that usually occurs at its anterior part where the sartorius attaches to the ASIS. One of the most common sports injuries to the hip region.
Describe a “charley horse”.
“charley horse”
- this sports injury refers to the cramping of an individual thigh muscles because of ischemia or refers to a contusion and rupture of blood vessels sufficient enough to form a hematoma. Usually the consequence of tearing fibers of the rectus femoris (sometimes the quadriceps tendon is also partially torn).
Describe a “groin pull”.
“groin pull”
- this sports injury refers to the strain, stretching, and likely tearing of the proximal attachments of the anteromedial thigh muscles. Usually involves the flexor and adductor thigh muscles whose proximal attachment is the inguinal region (groin). Usually occurs in sports requiring quick starts (sprinting) or stretching (gymnastics).
What structure forms the superior boundary of the femoral triangle?
The superior boundary of the femoral triangle is formed by the inguinal ligament, which extends between the ASIS and body of the pubis.
What forms the lateral and medial boundaries of the femoral triangle?
The lateral boundary is formed by the sartorius muscle.
The medial boundary is formed by the adductor longus muscle.
For the Femoral Nerve:
a) from where does it originate?
b) what specific site does it enter in the femur?
c) what does it innervate?
d) what is its terminal branch?
For the Femoral Nerve:
a) it originates from spinal cord segments L2-L4
b) it leaves the abdominopelvic cavity and enters the lateral aspect of the femoral triangle
c) it innervates the anterior thigh muscles
d) the saphenous nerve is its terminal branch
What lesions might cause diminution or loss of the patellar tendon reflex?
Tapping the ligament activates muscle spindles in the quadriceps. Afferent impulses from the spindles travel in the femoral nerve to the L2-L4 segments of the spinal cord. From here, efferent impulses are transmitted via motor fibers in the femoral nerve to the quadriceps, resulting in a jerk-like contraction of the musle and extension of the leg at the knee joint (“knee jerk”).
Diminution or absense of the patellar tendon reflex may result from any lesion that interrupts the innervation of the quadriceps (ex: peripheral nerve disease)
For the Obturator Nerve:
a) from where does it originate?
b) where does it travel in relation to the femoral nerve?
c) from what site does it exit the abdominopelvic cavity?
d) what does it innervate?
For the Obturator Nerve:
a) it originates from spinal cord segments L2-L4
b) it travels parellel to the femoral nerve on the posterior abdominal wall
c) it exits the abdominopelvic cavity via the obturator foramen
d) it innervates the medial thigh muscles
What does the deep fascia of the iliopsoas muscle extend under and what is its role in this area?
The deep fascia of the iliopsoas muscle extends under the inguinal ligament as the femoral sheath.
This sheath surrounds the femoral artery and vein in the femoral triangle allows them to glide under the inguinal ligament during movements of the hip joint.
For the Femoral Canal:
a) what forms it?
b) what vessels travel through it?
c) what is the purpose of the small oval femoral ring at the base of the canal
For the Femoral Canal:
a) it is formed by the femoral sheath
b) lymphatic vessels from the inguinal lymph nodes travel through it
c) the small oval femoral ring enables the lymph vessels to enter the abdominopelvic cavity where they drain into resident lymph nodes.
The femoral artery is a continuation of what artery? What does the femoral artery supply?
The femoral artery is a continuation of the external iliac artery and it supplies the anterior and anteromedial thigh.
Where does the deep artery of the thigh originate from and what other artery usually branches from it?
The deep artery of the thigh (profunda femoris artery) originates from the femoral artery.
The medial circumflex femoral artery usually arises from the deep artery of the thigh.
What are the distributions of:
- a) the deep artery of the thigh*
- b) the medial circumflex femoral artery*
a) the deep artery of the thigh supplies muscles in the:
- medial compartment
- posterior compartment
- lateral part of the anterior compartment.
b) the medial circumflex femoral artery:
- supplies most of the blood to the head and neck of femur
- its transverse branch takes part in cruciate anastomosis of thigh
- its ascending branch joins inferior gluteal artery
Why can aseptic vascular necrosis of the displaced femoral head occur after femoral neck fractures?
In a femoral neck fracture, the retinacular arteries which arise from the medial circumflex artery and supply the head of the femur often get severed, leaving only the artery to the ligament of the femoral head as the main source of blood flow to the femoral head, which is usually inadequate.
Visualize inversion and eversion of your foot.
Visualize dorsiflexion and plantarflexion of your foot.
Good job.
For the Tibialis Anterior:
a) what is the proximal attachment?
b) what is the distal attachment?
c) what innervates it?
d) what is its function?
Tibialis Anterior:
a) proximal attachment - tibia
b) distal attachment - plantar surface (sole) of the medial foot
c) innervation - deep fibular nerve
d) function - dorsiflexes ankle and inverts foot
For the Extensor Digitorum Longus and Extensor Hallicus Longus:
a) name their proximal attachments.
b) name their distal attachments.
c) what innervates them?
d) what is their function?
For the Extensor Digitorum Longus and Extensor Hallicus Longus:
a) proximal attachment - tibia
b) distal attachment - dorsum of the toes
c) innervation - deep fibular nerve
EDL function - extends lateral four digits & dorsiflexes ankle
EHL function - extends great toe & dorsiflexes ankle
For Fibularis Longus and Fibularis Brevis:
a) proximal attachment?
b) distal attachment?
c) innervation?
d) function?
For Fibularis Longus and Fibularis Brevis:
a) proximal attachment - fibula
b) distal attachment - plantar surface & lateral side of foot, respectively
c) innervation - superficial fibular nerve
d) function - everts foot and weakly plantarflexes ankle
Describe the evolution of the femoral artery as it travels inferiorly down the lower limb (what arteries does it become?).
The femoral artery diagonally crosses the distal femur and becomes the popliteal artery that in the proximal leg, bifurcates into the anterior tibial artery and posterior tibial artery.
What does the anterior tibial artery become?
The anterior tibial artery, which supplies the anterior and lateral leg, continues onto the dorsum of the foot as the dorsal pedis artery that extends to the first interosseous space to provide digital arteries to the big toe.
Where is the dorsal pedis pulse palpated and what is the most common cause of its dimunition or absence?
The dorsal pedis pulse is palpated as seen in the image below, with the feet slightly dorsiflexed.
