The knee, leg, ankle and foot

Question 1

List the bones of the region

Answer 1

The femur
The tibia
The fibula
The patella
The bones of the foot

Question 2

Describe the course of the shaft of the femur

Answer 2

The shaft of the femur is bowed forward and has an oblique course from the neck of the femur to the distal end (Fig. 6.52). As a consequence of this oblique orientation, the knee is close to the midline under the body’s center of gravity.

Question 3

What does the posterior border of the femur form

Answer 3

The medial and lateral borders are rounded, whereas the posterior border forms a broad roughened crest—the linea aspera.

Question 4

Describe the widening of the linea aspera

Answer 4

In proximal and distal regions of the femur, the linea aspera widens to form an additional posterior surface. At the distal end of the femur, this posterior surface forms the floor of the popliteal fossa, and its margins form the medial and lateral supracondylar lines. The medial supracondylar line terminates at a prominent tubercle (the adductor tubercle) on the superior aspect of the medial condyle of the distal end. Just lateral to the lower end of the medial supracondylar line is an elongate roughened area of bone for the proximal attachment of the medial head of the gastrocnemius muscle

Question 5

What is the intercondylar fossa

Answer 5

The distal end of the femur is characterized by two large condyles, which articulate with the proximal head of the tibia. The condyles are separated posteriorly by an intercondylar fossa and are joined anteriorly where they articulate with the patella.

Question 6

Describe the articular surfaces of the condyles of the femur

Answer 6

The surfaces of the condyles that articulate with the tibia are rounded posteriorly and become flatter inferiorly. On each condyle, a shallow oblique groove separates the surface that articulates with the tibia from the more anterior surface that articulates with the patella. The surfaces of the medial and lateral condyles that articulate with the patella form a V-shaped trench, which faces anteriorly. The lateral surface of the trench is larger and steeper than the medial surface.

Question 7

Describe the epicondyles of the femur

Answer 7

Epicondyles, for the attachment of collateral ligaments of the knee joint, are bony elevations on the nonarticular outer surfaces of the condyles (Fig. 6.52). Two facets separated by a groove are just posterior to the lateral epicondyle:
▪
The upper facet is for attachment of the lateral head of the gastrocnemius muscle.
▪
The inferior facet is for attachment of the popliteus muscle.
The tendon of the popliteus muscle lies in the groove separating the two facets.

The medial epicondyle is a rounded eminence on the medial surface of the medial condyle. Just posterosuperior to the medial epicondyle is the adductor tubercle.

Question 8

What is the patella

Answer 8

The patella (knee cap) is the largest sesamoid bone (a bone formed within the tendon of a muscle) in the body and is formed within the tendon of the quadriceps femoris muscle as it crosses anterior to the knee joint to insert on the tibia.

Question 9

Describe the anatomy of the patella

Answer 9

Its apex is pointed inferiorly for attachment to the patellar ligament, which connects the patella to the tibia (Fig. 6.53).
▪
Its base is broad and thick for the attachment of the quadriceps femoris muscle from above.
▪
Its posterior surface articulates with the femur and has medial and lateral facets, which slope away from a raised smooth ridge—the lateral facet is larger than the medial facet for articulation with the larger corresponding surface on the lateral condyle of the femur

Question 10

What is the tibia

Answer 10

The tibia is the medial and larger of the two bones in the leg, and is the only one that articulates with the femur at the knee joint.
The proximal end of the tibia is expanded in the transverse plane for weight-bearing and consists of a medial condyle and a lateral condyle, which are both flattened in the horizontal plane and overhang the shaft

Question 11

Summarise the tibial condyles

Answer 11

The superior surfaces of the medial and lateral condyles are articular and separated by an intercondylar region, which contains sites of attachment for strong ligaments (cruciate ligaments) and interarticular cartilages (menisci) of the knee joint.
The articular surfaces of the medial and lateral condyles and the intercondylar region together form a “tibial plateau,” which articulates with and is anchored to the distal end of the femur. Inferior to the condyles on the proximal part of the shaft is a large tibial tuberosity and roughenings for muscle and ligament attachments.

The tibial condyles are thick horizontal discs of bone attached to the top of the tibial shaft

Question 12

Describe the medial and lateral condyles of the tibia

Answer 12

The medial condyle is larger than the lateral condyle and is better supported over the shaft of the tibia. Its superior surface is oval for articulation with the medial condyle of the femur. The articular surface extends laterally onto the side of the raised medial intercondylar tubercle.
The superior surface of the lateral condyle is circular and articulates above with the lateral condyle of the femur. The medial edge of this surface extends onto the side of the lateral intercondylar tubercle.

Question 13

Describe the non-articular surfaces of the condyles of the tibia

Answer 13

The nonarticular posterior surface of the medial condyle bears a distinct horizontal groove for part of the attachment of the semimembranosus muscle, and the undersurface of the lateral condyle bears a distinct circular facet for articulation with the proximal head of the fibula

Question 14

Describe the intercondylar eminence

Answer 14

Small protrusion in the middle of the tibial plateau
The intercondylar region of the tibial plateau lies between the articular surfaces of the medial and lateral condyles (Fig. 6.54). It is narrow centrally where it is raised to form the intercondylar eminence, the sides of which are elevated further to form medial and lateral intercondylar tubercles.

Question 15

Describe the facets of the intercondylar fossa

Answer 15

The intercondylar region bears six distinct facets for the attachment of menisci and cruciate ligaments. The anterior intercondylar area widens anteriorly and bears three facets:
▪
The most anterior facet is for attachment of the anterior end (horn) of the medial meniscus.
▪
Immediately posterior to the most anterior facet is a facet for the attachment of the anterior cruciate ligament.
▪
A small facet for the attachment of the anterior end (horn) of the lateral meniscus is just lateral to the site of attachment of the anterior cruciate ligament.
The posterior intercondylar area also bears three attachment facets:
▪
The most anterior is for attachment of the posterior horn of the lateral meniscus.
▪
Posteromedial to the most anterior facet is the site of attachment for the posterior horn of the medial meniscus.
▪
Behind the site of attachment for the posterior horn of the medial meniscus is a large facet for the attachment of the posterior cruciate ligament.

Question 16

What is the tibial tuberosity

Answer 16

The tibial tuberosity is a palpable inverted triangular area on the anterior aspect of the tibia below the site of junction between the two condyles (Fig. 6.54). It is the site of attachment for the patellar ligament, which is a continuation of the quadriceps femoris tendon below the patella.

Question 17

Describe the shaft of the tibia

Answer 17

Shaft: triangular in cross-section
Sharp anterior border descending from the tibial tuberosity and line from lateral condyle
Interosseous border descends along lateral aspect - lateral surface smooth and unremarkable
Medial border only sharp in the midshaft - medial surface palpable along leg
Posterior surface is widest superiorly, and is crossed by roughened oblique (soleal) line

Question 18

What is the roughened elevation of the medial surface of the tibia

Answer 18

Medial and somewhat inferior to the tibial tuberosity, this medial surface bears a subtle, slightly roughened elongate elevation. This elevation is the site of the combined attachment of three muscles (sartorius, gracilis, and semitendinosus), which descend from the thigh.

Question 19

What is the fibula

Answer 19

The fibula is the lateral bone of the leg and does not take part in formation of the knee joint or in weight-bearing. It is much smaller than the tibia and has a small proximal head, a narrow neck, and a delicate shaft, which ends as the lateral malleolus at the ankle.

Question 20

What protrusions in the ankle do the distal ends of the tibia and fibula form?

Answer 20

Tibia – medial malleolus

Fibula – lateral malleolus

Question 21

Describe the head of the fibula

Answer 21

The head of the fibula is a globe-shaped expansion at the proximal end of the fibula (Fig. 6.55). A circular facet on the superomedial surface is for articulation above with a similar facet on the inferior aspect of the lateral condyle of the tibia. Just posterolateral to this facet, the bone pro­jects superiorly as a blunt apex (styloid process).
The lateral surface of the head of the fibula bears a large impression for the attachment of the biceps femoris muscle. A depression near the upper margin of this impression is for attachment of the fibular collateral ligament of the knee joint.

Question 22

Describe the neck of the fibula

Answer 22

The neck of the fibula separates the expanded head from the shaft. The common fibular nerve lies against the posterolateral aspect of the neck.

Question 23

Describe the borders and surfaces of the fibula

Answer 23

▪
The anterior border is sharp midshaft and begins superiorly from the anterior aspect of the head.
▪
The posterior border is rounded and descends from the region of the styloid process of the head.
▪
The interosseous border is medial in position.
The three surfaces of the fibula are associated with the three muscular compartments (lateral, posterior, and anterior) of the leg.

Question 24

Where do abduction and adduction take place in the foot

Answer 24

Abduction and adduction of the toes are defined with respect to the long axis of the second digit. Unlike in the hand, where the thumb is oriented 90° to the other fingers, the great toe is oriented in the same position as the other toes. The foot is the body’s point of contact with the ground and provides a stable platform for upright stance. It also levers the body forward during walking.

Question 25

Summarise the bones of the foot

Answer 25

▪ the seven tarsal bones, which form the skeletal framework for the ankle; The tarsal bones are arranged in a proximal group and a distal group with an intermediate bone between the two groups on the medial side of the foot ▪ metatarsals (I to V), which are the bones of the metatarsus; and ▪ the phalanges, which are the bones of the toes—each toe has three phalanges, except for the great toe, which has two.

Question 26

What are the proximal group of tarsal muscles

Answer 26

▪ The talus is the most superior bone of the foot and sits on top of and is supported by the calcaneus (Fig. 6.92B)—it articulates above with the tibia and fibula to form the ankle joint and also projects forward to articulate with the intermediate tarsal bone (navicular) on the medial side of the foot. ▪ The calcaneus is the largest of the tarsal bones—posteriorly it forms the bony framework of the heel and anteriorly it projects forward to articulate with one of the distal group of tarsal bones (cuboid) on the lateral side of the foot.

Question 27

Describe the intermediate tarsal bone

Answer 27

The intermediate tarsal bone on the medial side of the foot is the navicular (boat shaped) (Fig. 6.92). This bone articulates behind with the talus and articulates in front and on the lateral side with the distal group of tarsal bones. One distinctive feature of the navicular is a prominent rounded tuberosity for the attachment of the tibialis posterior tendon, which projects inferiorly on the medial side of the plantar surface of the bone.

Question 28

Describe the distal group of tarsal bones (lateral to medial)

Answer 28

▪ The cuboid (Greek for “cube”), which articulates posteriorly with the calcaneus, medially with the lateral cuneiform, and anteriorly with the bases of the lateral two metatarsals—the tendon of the fibularis longus muscle lies in a prominent groove on the anterior plantar surface, which passes obliquely forward across the bone from lateral to medial. ▪ Three cuneiforms (Latin for “wedge”)—the lateral, intermediate, and medial cuneiform bones, in addition to articulating with each other, articulate posteriorly with the navicular bone and anteriorly with the bases of the medial three metatarsals.

Question 29

Describe the head of the talus

Answer 29

Anteriorly, the head of the talus is domed for articulation with a corresponding circular depression on the posterior surface of the navicular bone. Inferiorly, this domed articular surface is continuous with an additional three articular facets separated by smooth ridges: ▪ The anterior and middle facets articulate with adjacent surfaces on the calcaneus bone. ▪ The other facet, medial to the facets for articulation with the calcaneus, articulates with a ligament—the plantar calcaneonavicular ligament (spring ligament)—which connects the calcaneus to the navicular under the head of the talus.

Question 30

Describe the neck of the talus

Answer 30

The neck of the talus is marked by a deep groove (the sulcus tali), which passes obliquely forward across the inferior surface from medial to lateral, and expands dramatically on the lateral side. Posterior to the sulcus tali is a large facet (posterior calcaneal surface) for articulation with the calcaneus.

Question 31

Describe the superior aspect of the body of the talus

Answer 31

The superior aspect of the body of the talus is elevated to fit into the socket formed by the distal ends of the tibia and fibula to form the ankle joint: ▪ The upper (trochlear) surface of this elevated region articulates with the inferior end of the tibia. ▪ The medial surface articulates with the medial malleolus of the tibia. ▪ The lateral surface articulates with the lateral malleolus of the fibula. Because the lateral malleolus is larger and projects more inferiorly than the medial malleolus at the ankle joint, the corresponding lateral articular surface on the talus is larger and projects more inferiorly than the medial surface.

Question 32

Describe the other key features of the talus

Answer 32

The lower part of the lateral surface of the body of the talus, which supports the lower part of the facet for articulation with the fibula, forms a bony projection (the lateral process). The inferior surface of the body of the talus has a large oval concave facet (the posterior calcaneal articular facet) for articulation with the calcaneus. The posterior aspect of the body of the talus consists of a backward and medially facing projection (the posterior process). The posterior process is marked on its surface by a lateral tubercle and a medial tubercle, which bracket between them the groove for the tendon of the flexor hallucis longus as it passes from the leg into the foot.

Question 33

What is the calcaneus

Answer 33

The calcaneus sits under and supports the talus. It is an elongate, irregular, box-shaped bone with its long axis generally oriented along the midline of the foot, but deviating lateral to the midline anteriorly

Question 34

What is the posterior surface of the calcaneus divided into

Answer 34

The calcaneus projects behind the ankle joint to form the skeletal framework of the heel. The posterior surface of this heel region is circular and divided into upper, middle, and lower parts. The calcaneal tendon (Achilles tendon) attaches to the middle part: ▪ The upper part is separated from the calcaneal tendon by a bursa. ▪ The lower part curves forward, is covered by subcutaneous tissue, is the weight-bearing region of the heel, and is continuous onto the plantar surface of the bone as the calcaneal tuberosity.

Question 35

Describe the calcaneal tuberosity

Answer 35

The calcaneal tuberosity projects forward on the plantar surface as a large medial process and a small lateral process separated from each other by a V-shaped notch (Fig. 6.94B). At the anterior end of the plantar surface is a tubercle (the calcaneal tubercle) for the posterior attachment of the short plantar ligament of the sole of the foot.

Question 36

Describe the lateral surface of the calcaneus

Answer 36

The lateral surface of the calcaneus has a smooth contour except for two slightly raised regions (Fig. 6.94C). One of these raised areas—the fibular trochlea (peroneal tubercle)—is anterior to the middle of the surface and often has two shallow grooves, which pass, one above the other, obliquely across its surface. The tendons of the fibularis brevis and longus muscles are bound to the trochlea as they pass over the lateral side of the calcaneus. Superior and posterior to the fibular trochlea is a second raised area or tubercle for attachment of the calcaneofibular part of the lateral collateral ligament of the ankle joint.

Question 37

Describe the medial surface of the calcaneus

Answer 37

The medial surface of the calcaneus is concave and has one prominent feature associated with its upper margin (the sustentaculum tali; Fig. 6.94A), which is a shelf of bone projecting medially and supporting the more posterior part of the head of the talus. The underside of the sustentaculum tali has a distinct groove running from posterior to anterior and along which the tendon of the flexor hallucis longus muscle travels into the sole of the foot. The superior surface of the sustentaculum tali has a facet (middle talar articular surface) for articulation with the corresponding middle facet on the head of the talus.

Question 38

Describe the anterior and posterior talar facets

Answer 38

Anterior and posterior talar articular surfaces are on the superior surface of the calcaneus itself (Fig. 6.94A): ▪ The anterior talar articular surface is small and articulates with the corresponding anterior facet on the head of the talus. ▪ The posterior talar articular surface is large and is approximately near the middle of the superior surface of the calcaneus.

Question 39

Describe the calcaneal sulcus and the tarsal sinus

Answer 39

Between the posterior talar articular surface, which articulates with the body of the talus, and the other two articular surfaces, which articulate with the head of the talus, is a deep groove (the calcaneal sulcus; Fig. 6.94A,C). The calcaneal sulcus on the superior surface of the calcaneus and the sulcus tali on the inferior surface of the talus together form the tarsal sinus, which is a large gap between the anterior ends of the calcaneus and talus that is visible when the skeleton of the foot is viewed from its lateral aspect

Question 40

Describe the metatarsals

Answer 40

There are five metatarsals in the foot, numbered I to V from medial to lateral (Fig. 6.96). Metatarsal I, associated with the great toe, is shortest and thickest. The second is the longest. Each metatarsal has a head at the distal end, an elongate shaft in the middle, and a proximal base. The head of each metatarsal articulates with the proximal phalanx of a toe and the base articulates with one or more of the distal group of tarsal bones. The plantar surface of the head of metatarsal I also articulates with two sesamoid bones. The sides of the bases of metatarsals II to V also articulate with each other. The lateral side of the base of metatarsal V has a prominent tuberosity, which projects posteriorly and is the attachment site for the tendon of the fibularis brevis muscle.

Question 41

Describe the phalanges of the foot

Answer 41

The phalanges are the bones of the toes (Fig. 6.96). Each toe has three phalanges (proximal, middle, and distal), except for the great toe, which has only two (proximal and distal). Each phalanx consists of a base, a shaft, and a distal head: ▪ The base of each proximal phalanx articulates with the head of the related metatarsal. ▪ The head of each distal phalanx is nonarticular and flattened into a crescent-shaped plantar tuberosity under the plantar pad at the end of the digit. In each toe, the total length of the phalanges combined is much shorter than the length of the associated metatarsal.

Question 42

Where are sesamoid bones found in the foot and which tendon do these bones lie in?

Answer 42

On the dorsal surface of the foot, beneath the metatarsophalangeal joint of the big toe It lies in the tendon of flexor hallucis brevi 2 sesamoid bones Important when on tip-toes- so big toe does not crush under body weight and damage the flexor hallucis brevis

Question 43

Which tarsal bones have tuberosities?

Answer 43

Navicular and cuboid

Question 44

Which bones make up the forefoot, midfoot and hindfoot?

Answer 44

Hindfoot – calcaneus and tallus Midfoot – cuboid, navicular and cuneiforms Forefoot – metatarsals and phalanges Hindfoot is posterior tp transverse tarsal line Forefoot anterior to tarsometatarsal line First half of foot (to tarsometatarsal line) is tarsal bones Second half of foot (anterior to tarsometatarsal line) is metatarsals and phalanges.

Question 45

What is the popliteal fossa

Answer 45

Popliteal fossa: area of transition between thigh and leg - diamond shaped space between muscles of posterior compartments of the leg and thigh

Question 46

Describe the boundaries of the popliteal fossa

Answer 46

The margins of the upper part of the diamond are formed medially by the distal ends of the semitendinosus and semimembranosus muscles and laterally by the distal end of the biceps femoris muscle. ▪ The margins of the smaller lower part of the space are formed medially by the medial head of the gastrocnemius muscle and laterally by the plantaris muscle and the lateral head of the gastrocnemius muscle. ▪ The floor of the fossa is formed by the capsule of the knee joint and adjacent surfaces of the femur and tibia, and, more inferiorly, by the popliteus muscle. ▪ The roof is formed by deep fascia, which is continuous above with the fascia lata of the thigh and below with deep fascia of the leg.

Question 47

List the contents of the popliteal fossa

Answer 47

Popliteal artery and vein Tibial Nerve and Common Peroneal Nerve Short saphenous vein Popliteal lymph nodes

Question 48

Describe the paths of the tibial and common peroneal nerves in the popliteal fossa

Answer 48

The tibial and common fibular nerves originate proximal to the popliteal fossa as the two major branches of the sciatic nerve. They are the most superficial of the neurovascular structures in the popliteal fossa and enter the region directly from above under the margin of the biceps femoris muscle: ▪ The tibial nerve descends vertically through the popliteal fossa and exits deep to the margin of the plantaris muscle to enter the posterior compartment of the leg. ▪ The common fibular nerve exits by following the biceps femoris tendon over the lower lateral margin of the popliteal fossa, and continues to the lateral side of the leg where it swings around the neck of the fibula and enters the lateral compartment of the leg.v

Question 49

Describe the passage of the popliteal artery and vein in the popliteal fossa

Answer 49

The popliteal artery appears in the popliteal fossa on the upper medial side under the margin of the semimembranosus muscle. It descends obliquely through the fossa with the tibial nerve and enters the posterior compartment of the leg where it ends just lateral to the midline of the leg by dividing into the anterior and posterior tibial arteries. The popliteal artery is the deepest of the neurovascular structures in the popliteal fossa and is therefore difficult to palpate; however, a pulse can usually be detected by deep palpation near the midline. In the popliteal fossa, the popliteal artery gives rise to branches, which supply adjacent muscles, and to a series of geniculate arteries, which contribute to vascular anastomoses around the knee. The popliteal vein is superficial to and travels with the popliteal artery. It exits the popliteal fossa superiorly to become the femoral vein by passing through the adductor hiatus.

Question 50

Describe the passage of the small saphenous vein in the popliteal fossa

Answer 50

The most important structure in the superficial fascia is the small saphenous vein. This vessel ascends vertically in the superficial fascia on the back of the leg from the lateral side of the dorsal venous arch in the foot. It ascends to the back of the knee where it penetrates deep fascia, which forms the roof of the popliteal fossa, and joins with the popliteal vein.

Question 51

Describe the passage of the posterior cuteaneous nerve of the thigh in the popliteal fossa

Answer 51

One other structure that passes through the roof of the fossa is the posterior cutaneous nerve of the thigh, which descends through the thigh superficial to the hamstring muscles, passes through the roof of the popliteal fossa, and then continues inferiorly with the small saphenous vein to innervate skin on the upper half of the back of the leg.

Question 52

Describe the formation of the sural nerve

Answer 52

It is formed from a branch of the tibial nerve (medial cutaneous sural nerve) and a smaller branch of the common peroneal nerve (sural communicating branch)

Question 53

What is the knee joint

Answer 53

The knee joint is the largest synovial joint in the body. It consists of: ▪ the articulation between the femur and tibia, which is weight-bearing, and ▪ the articulation between the patella and the femur, which allows the pull of the quadriceps femoris muscle to be directed anteriorly over the knee to the tibia without tendon wear

Question 54

Summarise the features of the knee joint

Answer 54

Largest joint; superficial; primarily a hinge-type synovial joint with some gliding, rolling and rotation. The shapes of the bones involved (distal femur and proximal tibia) do not predict a stable arrangement. Has been described as two balls sitting on a warped table.

Question 55

Describe the articular surfaces of the knee joint

Answer 55

The articular surfaces of the bones that contribute to the knee joint are covered by hyaline cartilage. The major surfaces involved include: ▪ the two femoral condyles, and ▪ the adjacent surfaces of the superior aspect of the tibial condyles. The surfaces of the femoral condyles that articulate with the tibia in flexion of the knee are curved or round, whereas the surfaces that articulate in full extension are flat Medial and lateral femorotibial articulations between medial and lateral condyles respectively.

Question 56

Describe the articular surfaces between the femur and the patella

Answer 56

The articular surfaces between the femur and patella are the V-shaped trench on the anterior surface of the distal end of the femur where the two condyles join and the adjacent surfaces on the posterior aspect of the patella. The joint surfaces are all enclosed within a single articular cavity, as are the intraarticular menisci between the femoral and tibial condyles.

Question 57

What are the menisci

Answer 57

There are two menisci, which are fibrocartilaginous C-shaped cartilages, in the knee joint, one medial (medial meniscus) and the other lateral (lateral meniscus) (Fig. 6.71). Both are attached at each end to facets in the intercondylar region of the tibial plateau.

Question 58

Describe the medial and lateral menisici and their function in stabilisation of the knee joint

Answer 58

The medial meniscus is attached around its margin to the capsule of the joint and to the tibial collateral ligament, whereas the lateral meniscus is unattached to the capsule. Therefore, the lateral meniscus is more mobile than the medial meniscus. The menisci are interconnected anteriorly by a transverse ligament of the knee. The lateral meniscus is also connected to the tendon of the popliteus muscle, which passes superolaterally between this meniscus and the capsule to insert on the femur. The menisci improve congruency between the femoral and tibial condyles during joint movements where the surfaces of the femoral condyles articulating with the tibial plateau change from small curved surfaces in flexion to large flat surfaces in extension.

Question 59

What is the main difference between the medial and lateral menisci

Answer 59

The medial collateral ligament is attached to the medial meniscus The lateral meniscus is separate to the lateral collateral ligament Therefore the medial menisci is most commonly indicated in pathology (will be damaged in stretching of the tibial collateral ligament). In 'twisting' injuries of the knee the medial meniscus is 20 tmes more liable to damage than the lateral.

Question 60

List the ligaments that contribute to the stability of the knee joint

Answer 60

``` Ligaments Anterior cruciate ligament Posterior cruciate ligament Medial collateral ligament Lateral Collateral Ligament Also patellar ligament ```

Question 61

What is the function of the collateral ligaments

Answer 61

The collateral ligaments, one on each side of the joint, stabilize the hinge-like motion of the knee Prevent abduction/adduction of the knee joint

Question 62

Describe the fibular collateral ligament

Answer 62

The cord-like fibular collateral ligament is attached superiorly to the lateral femoral epicondyle just above the groove for the popliteus tendon. Inferiorly, it is attached to a depression on the lateral surface of the fibular head. It is separated from the fibrous membrane by a bursa.

Question 63

Describe the tibial collateral ligament

Answer 63

The broad and flat tibial collateral ligament is attached by much of its deep surface to the underlying fibrous membrane. It is anchored superiorly to the medial femoral epicondyle just inferior to the adductor tubercle and descends anteriorly to attach to the medial margin and medial surface of the tibia above and behind the attachment of the sartorius, gracilis, and semitendinosus tendons.

Question 64

What is meant by the cruciate ligaments

Answer 64

The two cruciate ligaments are in the intercondylar region of the knee and interconnect the femur and tibia (Figs. 6.74D and 6.75). They are termed “cruciate” (Latin for “shaped like a cross”) because they cross each other in the sagittal plane between their femoral and tibial attachments:

Question 65

Describe the cruciate ligaments

Answer 65

The anterior cruciate ligament attaches to a facet on the anterior part of the intercondylar area of the tibia and ascends posteriorly to attach to a facet at the back of the lateral wall of the intercondylar fossa of the femur. ▪ The posterior cruciate ligament attaches to the posterior aspect of the intercondylar area of the tibia and ascends anteriorly to attach to the medial wall of the intercondylar fossa of the femur.

Question 66

Which sides of the intercondylar fossa do the cruciate ligaments attach to

Answer 66

Anterior cruciate – lateral | Posterior cruciate – media

Question 67

Where do the cruciate ligaments cross and what is their function

Answer 67

The anterior cruciate ligament crosses lateral to the posterior cruciate ligament as they pass through the intercondylar region. The anterior cruciate ligament prevents anterior displacement of the tibia relative to the femur and the posterior cruciate ligament restricts posterior displacement

Question 68

Describe the patellar ligament

Answer 68

The patellar ligament is basically the continuation of the quadriceps femoris tendon inferior to the patella (Fig. 6.73). It is attached above to the margins and apex of the patella and below to the tibial tuberosity.

Question 69

Name the bursae that are found around the knee

Answer 69

``` Suprapatellar bursa Subcutaneous pre-patellar bursa Subtendinous pre-patellar bursa Subcutaneous infrapatellar bursa Deep infrapatellar bursa Popliteal bursa Gastrocnemius bursa Semimembranosus bursa Anserine bursa ```

Question 70

Summarise the synovial membrane

Answer 70

The synovial membrane of the knee joint attaches to the margins of the articular surfaces and to the superior and inferior outer margins of the menisci (Fig. 6.72A). The two cruciate ligaments, which attach in the intercondylar region of the tibia below and the intercondylar fossa of the femur above, are outside the articular cavity, but enclosed within the fibrous membrane of the knee joint.

Question 71

Describe the attachments of the synovial joint

Answer 71

Posteriorly, the synovial membrane reflects off the fibrous membrane of the joint capsule on either side of the posterior cruciate ligament and loops forward around both ligaments thereby excluding them from the articular cavity. Anteriorly, the synovial membrane is separated from the patellar ligament by an infrapatellar fat pad. On each side of the pad, the synovial membrane forms a fringed margin (an alar fold), which projects into the articular cavity. In addition, the synovial membrane covering the lower part of the infrapatellar fat pad is raised into a sharp midline fold directed posteriorly (the infrapatellar synovial fold), which attaches to the margin of the intercondylar fossa of the femur.

Question 72

Describe the formation of pouches (bursae) within the synovial membrane

Answer 72

The synovial membrane of the knee joint forms pouches in two locations to provide low-friction surfaces for the movement of tendons associated with the joint: ▪ The smallest of these expansions is the subpopliteal recess (Fig. 6.72A), which extends posterolaterally from the articular cavity and lies between the lateral meniscus and the tendon of the popliteus muscle, which passes through the joint capsule. ▪ The second expansion is the suprapatellar bursa (Fig. 6.72B), a large bursa that is a continuation of the articular cavity superiorly between the distal end of the shaft of the femur and the quadriceps femoris muscle and tendon—the apex of this bursa is attached to the small articularis genus muscle, which pulls the bursa away from the joint during extension of the knee.

Question 73

Describe some of the other bursae associated with the knee joint

Answer 73

Other bursae associated with the knee but not normally communicating with the articular cavity include the subcutaneous prepatellar bursa, deep and subcutaneous infrapatellar bursae, and numerous other bursae associated with tendons and ligaments around the joint (Fig. 6.72B). The prepatellar bursa is subcutaneous and anterior to the patella. The deep and subcutaneous infrapatellar bursae are on the deep and subcutaneous sides of the patellar ligament, respectively.

Question 74

What is meant by bursae

Answer 74

Bursae: fluid filled sacs lined by synovial membranes, containing viscous synovial fluid to cushion bones/tendons/muscles - prevent friction and damage

Question 75

What is bursitis

Answer 75

Inflammation of a bursa is bursitis – very painful. Subpatetllar- commonly affected Effusions into the knee joint ('water on the knee') inevitably distend the bursa as well..

Question 76

Describe the strength of the tibial collateral ligament

Answer 76

Often results in fracture of the neck of the femur before it breaks itself

Question 77

Describe the fibrous membrane of the knee joint

Answer 77

The fibrous membrane of the knee joint is extensive and is partly formed and reinforced by extensions from tendons of the surrounding muscles ( Fig. 6.76 ). In general, the fibrous membrane encloses the articular cavity and the intercondylar region: ▪ On the medial side of the knee joint, the fibrous membrane blends with the tibial collateral ligament and is attached on its internal surface to the medial meniscus. ▪ Laterally, the external surface of the fibrous membrane is separated by a space from the fibular collateral ligament and the internal surface of the fibrous membrane is not attached to the lateral meniscus. ▪ Anteriorly, the fibrous membrane is attached to the margins of the patella where it is reinforced with tendinous expansions from the vastus lateralis and vastus medialis muscles, which also merge above with the quadriceps femoris tendon and below with the patellar ligament.

Question 78

Describe the reinforcements of the fibrous membrane of the knee joint

Answer 78

The fibrous membrane is reinforced anterolaterally by a fibrous extension from the iliotibial tract and posteromedially by an extension from the tendon of the semimembranosus (the oblique popliteal ligament ), which reflects superiorly across the back of the fibrous membrane from medial to lateral. The upper end of the popliteus muscle passes through an aperture in the posterolateral aspect of the fibrous membrane of the knee and is enclosed by the fibrous membrane as its tendon travels around the joint to insert on the lateral aspect of the lateral femoral condyle.

Question 79

What is important to remember about the suprapatellar bursae

Answer 79

Not a true bursa as it is continuous with the upper end of the synovial cavity and extends deep to the quadriceps tendon superior to the upper border of the patella Other bursae include the semimembranosus bursa behind the tendon, which may communicate with the joint, and the subcutanoues prepatellar bursa and upper part of the patella tendon (the bursa of housemaid's knee when it is inflamed- bursitis).

Question 80

Outline the movements possible by the knee joint

Answer 80

Movements: Extension: Produced by the quadriceps femoris, which inserts into the tibial tuberosity. Flexion: Produced by the hamstrings, gracilis, sartorius and popliteus. Lateral rotation: Produced by the biceps femoris. Medial rotation: Produced by five muscles; semimembranosus, semitendinosus, gracilis, sartorius and popliteus. Rotation of the tibia can occur when the knee is partially flexed.

Question 81

Describe the tibiofibular joint

Answer 81

The small proximal tibiofibular joint is synovial in type and allows very little movement ( Fig. 6.82 ). The opposing joint surfaces, on the undersurface of the lateral condyle of the tibia and on the superomedial surface of the head of the fibula, are flat and circular. The capsule is reinforced by anterior and posterior ligaments. is plane type synovial, but capsular ligaments limit movement.

Question 82

Describe the distal end of the tibia

Answer 82

he distal end of the tibia is shaped like a rectangular box with a bony protuberance on the medial side (the medial malleolus ; Fig. 6.81 ). The upper part of the box is continuous with the shaft of the tibia while the lower surface and the medial malleolus articulate with one of the tarsal bones (talus) to form a large part of the ankle joint. The posterior surface of the box-like distal end of the tibia is marked by a vertical groove, which continues inferiorly and medially onto the posterior surface of the medial malleolus. The groove is for the tendon of the tibialis posterior muscle. The lateral surface of the distal end of the tibia is occupied by a deep triangular notch (the fibular notch ), to which the distal head of the fibula is anchored by a thickened part of the interosseous membrane.

Question 83

Describe the shaft of tibia

Answer 83

The shaft of the tibia expands at both the upper and lower ends to support the body's weight at the knee and ankle joints.

Question 84

What is the posterior surface of the fibula marked by

Answer 84

The posterior surface is marked by a vertical crest ( medial crest ), which divides the posterior surface into two parts each attached to a different deep flexor muscle.

Question 85

Describe the distal end of the fibula

Answer 85

The distal end of the fibula expands to form the spade-shaped lateral malleolus ( Fig. 6.85 ). The medial surface of the lateral malleolus bears a facet for articulation with the lateral surface of the talus, thereby forming the lateral part of the ankle joint. Just superior to this articular facet is a triangular area, which fits into the fibular notch on the distal end of the tibia. Here the tibia and fibula are joined together by the distal end of the interosseous membrane. Posteroinferior to the facet for articulation with the talus is a pit or fossa (the malleolar fossa ) for the attachment of the posterior talofibular ligament associated with the ankle joint. The posterior surface of the lateral malleolus is marked by a shallow groove for the tendons of the fibularis longus and fibularis brevis muscles.

Question 86

Describe the distal tibiofibular joint

Answer 86

Fibrous joint The interosseous membrane not only links the tibia and fibula together, but also provides an increased surface area for muscle attachment. The distal ends of the fibula and tibia are held together by the inferior aspect of the interosseous membrane, which spans the narrow space between the fibular notch on the lateral surface of the distal end of the tibia and the corresponding surface on the distal end of the fibula. This expanded end of the interosseous membrane is reinforced by anterior and posterior tibiofibular ligaments . This firm linking together of the distal ends of the tibia and fibula is essential to produce the skeletal framework for articulation with the foot at the ankle joint.

Question 87

Describe the interosseous membrane between the tibia and fibula

Answer 87

The interosseous membrane of the leg is a tough fibrous sheet of connective tissue that spans the distance between facing interosseous borders of the tibial and fibular shafts ( Fig. 6.86 ). The collagen fibers descend obliquely from the interosseous border of the tibia to the interosseous border of the fibula, except superiorly where there is a ligamentous band, which ascends from the tibia to fibula. There are two apertures in the interosseous membrane, one at the top and the other at the bottom, for vessels to pass between the anterior and posterior compartments of the leg.

Question 88

What is important to remember about the proximal and distal tibiofibular joints

Answer 88

Slight movement of both of these joints during dorsiflexion/plantarflexion of the foot