1. The Thigh and Knee Compartments Anterior Medial Posterior 2. Knee
3. Biomechanics

2. Fascial Compartments of the Thigh
The thigh is usually divided into three compartments, each supplied by a specific nerve:
Medial fascial compartment of thigh: obturator nerve
Posterior fascial compartment of thigh: sciatic nerve
Anterior fascial compartment of thigh: femoral nerve

3. Compartments of the Thigh: Muscles and other contents
Anterior : sartorius · quadriceps (rectus femoris, vastus lateralis, vastus intermedius, vastus medialis) · articularis genu
Posterior/hamstring: biceps femoris · semitendinosus · semimembranosus
Medial: pectineus · obturator externus · gracilis · adductor (longus, brevis, magnus,minimus)
Fascia Femoral sheath (Femoral canal) · Femoral ring Adductor canal · Adductor hiatus
fascia lata (Iliotibial tract, Lateral intermuscular septum of thigh, Medial intermuscular septum of thigh, Fascia cribrosa/Saphenous opening) · Muscular lacuna

4. Sartorius
The Sartorius muscle – the longest muscle in the human body – is a long thin muscle that runs down the length of the thigh. Its upper portion forms the lateral border of the femoral triangle.
Tailor’ muscle
Origin
inferior to the anterior superior iliac spine
Insertion   
anteromedial surface of the upper tibia in the
pes anserinus
Artery
femoral artery
Nerve
femoral nerve (sometimes from the
intermediate cutaneous nerve of thigh)
Actions
Flexion, abduction, and lateral rotation of the
hip, flexion of the knee[1]

5. Pathology
One of the many conditions that can disrupt the use of the sartorius is pes anserine bursitis. Pes anserine bursitis is an inflammatory condition of the medial portion of the knee. This condition usually occurs in athletes from overuse and is characterized by pain, swelling and tenderness. The Pes anserine is made up from the tendons of the gracilis, semitendinosus, and Sartorius muscles; these tendons attach on to the anteromedial proximal tibia. When inflammation of the bursa underlying the tendons occurs they separate from the tibia.

6. Rectus Femoris
The rectus femoris is situated in the middle of the front of the thigh; it is fusiform in shape, and its superficial fibers are arranged in a bipenniform manner, the deep fibers running straight down to the deep aponeurosis.
Origin
anterior inferior iliac spine and the exterior
surface of the bony ridge which forms the
iliac portion of the acetabulum
Insertion   
inserts into the patellar tendon as one of
the four quadriceps muscles
Artery
lateral femoral circumflex artery
Nerve
femoral nerve
Actions
knee extension; hip flexion
Antagonist
Hamstring

7. Function of rectus femoris
The rectus femoris and sartorius are the only muscles in the quadriceps group that are involved in flexion of the hip, since they are the only ones that originate in the pelvis and not the femur. By crossing the pelvic femoral joint they can act as a lever to flex the leg at the hip.
The rectus femoris is a weaker hip flexor when the knee is extended because it is already shortened and thus suffers from active insufficiency. In essence: the action of raising a straightened leg will recruit more iliacus, psoas major, tensor fasciae latae, and the remaining hip flexors than it will the rectus femoris.
Similarly, the rectus femoris is not dominant in knee extension when the hip is flexed since it is already shortened and thus suffers from active insufficiency. In essence: the action of extending a leg from a seated position is primarily driven by the vastus lateralis, vastus medialis, and vastus intermedius, and less by the rectus femoris.
The rectus femoris is considered a direct antagonist to the hamstrings. The hamstrings oppose the rectus femoris at the hip joint through extension and at the knee joint through flexion.
The rectus femoris can be torn which can be very painful.

8. Vastus Intermedius
The Vastus intermedius (Cruraeus) arises from the front and lateral surfaces of the body of the femur in its upper two-thirds, sitting under Rectus Femoris and from the lower part of the lateral intermuscular septum. Its fibers end in a superficial aponeurosis, which forms the deep part of the Quadriceps femoris tendon.
The Vastus medialis and Vastus intermedius appear to be inseparably united, but when the Rectus femoris has been reflected a narrow interval will be observed extending upward from the medial border of the patella between the two muscles, and the separation may be continued as far as the lower part of the intertrochanteric line, where, however, the two muscles are frequently continuous.

9. Vastrus intermedius Originantero/ lateral femur
nsertion   patellar ligament
Artery femoral artery
Nerve femoral nerve
Actions extends leg
Due to being the deeper middle-most of the quadriceps muscle group, the intermedius is the maximum knee flexion is attained most difficult to stretch once. It cannot be further stretched by hip extension as the rectus femoris can nor is it accessible to manipulate with massage therapy to stretch the fibers laterally.

10. Vastus Lateralis
The Vastus lateralis (Vastus externus) is the largest part of the Quadriceps femoris. It arises by a broad aponeurosis, which is attached to the upper part of the intertrochanteric line, to the anterior and inferior borders of the greater trochanter, to the lateral lip of the gluteal tuberosity, and to the upper half of the lateral lip of the linea aspera; this aponeurosis covers the upper three-fourths of the muscle, and from its deep surface many fibers take origin.
A few additional fibers arise from the tendon of the Glutæus maximus, and from the lateral intermuscular septum between the Vastus lateralis and short head of the Biceps femoris. The fibers form a large fleshy mass, which is attached to a strong aponeurosis, placed on the deep surface of the lower part of the muscle: this aponeurosis becomes contracted and thickened into a flat tendon inserted into the lateral border of the patella, blending with the Quadriceps femoris tendon, and giving an expansion to the capsule of the knee-joint.

11. Vastus lateralis Origin Greater trochanter, Intertrochanteric line,
Linea aspera of the Femur
Insertion   
Patella via the Quadriceps tendon and
Tibial tuberosity via the Patellar ligament
Artery
femoral artery
Nerve
femoral nerve
Actions
Extends and stabilizes knee
Antagonist
Hamstring

12. Vastus Medialis Origin femur Insertion patella Artery femoral artery
Nerve
femoral nerve
Actions
extends leg

13. Vastus medialis obliquus
The vastus medialis, often called the 'teardrop' muscle, is a medially located muscle of the quadriceps.
The vasti appear to act largely in a co-ordinated manner throughout the control of knee extension. Much has been made of the ability of the Vastus Medialis to translate the patella medially, however since approximately 70% of the contractile fibres attach directly to the common extensor tendon (which then inserts centrally to the superior patella) the functional ability to achieve this goal may be overstated, and is likely dwarfed by the bony congruence of the patella in the trochlea notch. However, this does not apply to persons with trochlear aplasia or hypoplasia, which refer to an absence or extreme shallowness of the trochlear groove. Some authorities maintain there is a separate aspect to the Vastus Medialis muscle - the "Vastus Medialis Obliquus" or more commonly the "VMO" which is reported to have a more oblique or horizontal orientation to the bulk of the remainder of the muscle thereby disposing it to be better able to 'pull' the patella medially. Unfortunately careful inspection of many cadavers reveals that the fibres of the Vastus Medialis are largely parallel and there is no significant separate aspect of the contractile fibres fitting this description which would suggest it is time to lay this clinical myth to rest.

14. Femoral (Scarpa’s Triangle)
The femoral triangle (of Scarpa) is an anatomical region of the upper inner human thigh.
It is bounded by:
(superiorly) the inguinal ligament
(medially) the medial border of adductor longus muscle
(laterally) the medial border of sartorius muscle [1]
Its floor is provided laterally by iliacus and psoas major, medially by pectineus and adductor longus.[2] Its roof is formed by the fascia lata.
"SAIL" for Sartorius, Adductor longus and Inguinal Ligament.
The following structures are contained within the femoral triangle
(from lateral to medial):
terminal part of the femoral nerve and its branches
femoral sheath
femoral artery and its branches
femoral veins and its tributaries
deep inguinal lymph nodes
Floor: Roof: Skin and fascia late
iliopsoas
pectineus
adductor longus

15. Clinical significance
Since the femoral triangle provides easy access to a major artery, coronary angioplasty and peripheral angioplasties. often performed by entering the femoral artery at the femoral triangle. Heavy bleeding in the leg can be stopped by applying pressure to points in the femoral triangle. Another clinical significance of the femoral triangle is that the femoral artery is positioned at the midinguinal point (midpoint between the pubic symphysis and the anterior superior iliac spine); medial to it lies the femoral vein. Thus the femoral vein, once located, allows for femoral venopuncture. Femoral venopuncture is useful when there are no superficial veins that can be aspirated in a patient, in the case of collapse. The positive pulsation of the femoral artery signifies that the heart is beating and also blood is flowing to the lower extremity. It is also necessary to appreciate clinically that this is a case where the nerve is more lateral than the vein. In most other cases the a nerve (relative to its associated artery and vein)would be the deepest or more medial followed by the artery and then the vein. But in this case it is the opposite. This must be remembered when venous or arterial samples are required from the femoral vessels. The order of this neurovascular bundle can be remembered using the mnemonic, "NAVY" for Nerve, Artery, Vein, Y -fronts (the British term of a style of men's underwear with a "Y" shaped front that acts as a fly). The "Y" is midline (corresponding with the penis) and the mnemonic always reads from the outside - in, so that the Femoral Nerve is always lateral. An alternate to this mnemonic is "NAVaL" for Nerve, Artery, Vein, and Lymph, to include the deep inguinal lymph nodes located medial to the Femoral vein.

16. Femoral artery Anatomy
The femoral arteries receive blood through the external iliac artery. This connection occurs at the femoral triangle behind the inguinal ligament which is usually near the head of the femur bone. That proximal section of the femoral artery, known specifically as the common femoral artery (CFA), leaves the femoral triangle through an apex beneath the sartorius muscle. It then divides into a deep and superficial femoral. The deep vessel is more commonly known as the Profunda which provides blood to the thigh. The other branch is the superficial femoral artery or SFA. The SFA connects to the popliteal artery at the opening of adductor magnus or hunter's canal towards the end of the femur.

17. Femoral artery Source external iliac artery Branches
Superficial epigastric artery Superficial iliac circumflex Superficial external pudendal Deep external pudendal Deep femoral artery
Vein femoral vein

18. Medial Compartment of the Thigh
The medial fascial compartment of thigh contains the hip adductors.
The obturator nerve is the primary nerve supplying this compartment.
The muscles in the compartment are:
gracilis
adductors
adductor longus
adductor brevis
adductor magnus
The obturator externus muscle is sometimes considered part of this group, and sometimes excluded.(Spatially, it is it in this location, but functionally, it is more similar to the other lateral rotator group muscles).
The pectineus is sometimes included in this group, and sometimes excluded. (It has the same function as the others in this group, but different innervation.)

19. gracilis Origin ischiopubic ramus Insertion tibia (pes anserinus)
Artery medial circumflex femoral artery
Nerve anterior branch of obturator nerve
Actions flexes, medially rotates, and
adducts the hip, flexes the knee
The gracilis muscle is commonly used as a flap in microsurgery. According to the classification of Mathes and Nahai, it presents a type II blood supply, allowing it to be transferred on its artery derived from the medial circumflex femoral artery. This artery enters the muscle about 10 cm from the pubic symphysis. At this point (or 1 cm proximal) the nerve also enters.

20. Pes anserinus
The pes anserinus ("goose's foot") is the insertion of the conjoined tendons of three muscles[1] onto the anteromedial (front and inside) surface of the proximal extremity of the tibia.
The three muscles are (from anterior to posterior):[
sartorius
gracilis
semitendinosus
The conjoined tendon lies superficial to the tibial insertion of the medial collateral ligament (MCL) of the knee.
It is a major cause of chronic knee pain and weakness ("Pes Anserine Bursitis"). If the bursa underlying the tendons of the sartorius, gracilis, and semitendinosus gets irritated from overuse or injury a person can develop this ailment.
It can also be used to surgically repair the anterior cruciate ligament.
Say Grace before Tea, or just plain old G S T, as in Goods and Services Tax

21. Adductor muscles of the thigh
The adductor group is made up of:
Adductor brevis
Adductor longus
Adductor magnus
Adductor minimus
Note:
While the pectineus and gracilis are so called functional adductors of the thigh, and are also part of the medial compartment of thigh, they are not considered part of the adductor group[2] because of their innervation (the femoral nerve and tibial nerve respectively).
Origin pubis
Insertion   femur (linea aspera)
Nerve obturator nerve
Actions adduction of hip

22. Adductor canal
The adductor canal (Subsartorial/Hunter’s canal) is an aponeurotic tunnel in the middle third of the thigh, extending from the apex of the femoral triangle to the opening in the Adductor magnus, the Adductor hiatus. The adductor canal is often referred to as the canal of guyton
It courses between the anterior compartment of thigh and the medial compartment of thigh, and has the following boundaries:
anterolaterally - the Vastus medialis.
posterior - the Adductor longus.
It is covered in by a strong aponeurosis which extends from the Vastus medialis, across the femoral vessels to the Adductor longus and magnus.
Lying on the aponeurosis is the Sartorius muscle.

23. Adductor Canal
The canal contains the femoral artery, femoral vein, and branches of the femoral nerve (specifically, the saphenous nerve, and the nerve to the Vastus medialis). It consists of three foramen: superior, anterior and inferior. Femoral artery with its vein and saphenous nerve go into this canal through superior foramen. Then, saphenous nerve and artery and vein of genus desendens exit through anterior foramen piercing through vastoadductor intermuscular septum. Finally, femoral artery and vein exit via the inferior foramen (usually called hiatus) through gap between m. adductor magnus.

24. Posterior compartment (hamstrings)
As a group, the muscles of the posterior compartment of the thigh are called the hamstrings. To be called a hamstring, the muscle must arise from the ischial tuberosity. The hamstrings are:
biceps femoris (long head)
semimembranosus
semitendinosus
hamstring part of the adductormagnus

25. Posterior Compartment Muscles
Origin
Insertion
Action
Nerve Supply
biceps femoris, long head
ischial tuberosity
head of fibula
flexes and laterally rotates leg, extends thigh
tibial part of sciatic nerve
biceps femoris, short head
shaft of femur
flexes and laterally rotates leg
common peroneal nerve
semitendinosus
upper part medial surface of tibia
flexes and medially rotates leg; extends thigh
tibial part of sciatic
semimembranosus
medial condyle of tibia; forms oblique popliteal ligament
flexes and medially roates leg; extends thigh
adductor magnus (hamstring part)
adductor tubercle of femur
extends thigh
Table of Muscles

26. The muscles of the posterior compartment of the thigh are innervated by the tibial (medial) part of the sciatic nerve. The short head of the biceps is innervated by a branch of the common peroneal nerve.
The arteries of the posterior compartment of the thigh arise from two major arteries:
1. inferior gluteal (upper posterior compartment)
2. perforating branches of the profunda femoris

28. Popliteal fossa
The popliteal fossa is a space or shallow depression located at the back of the knee-joint. The bones of the popliteal fossa are the femur (medial and lateral condyles) and the tibia (medial and lateral condyles) a "knee pit."
Medial
Lateral
Superior
superior and medial: the semitendinosus muscle
and semimembranosus
superior and lateral: the biceps femoris muscle
Inferior
inferior and medial: the medial head of the gastrocnemius muscle
inferior and lateral: the lateral head of the gastrocnemius
and plantaris

29. The roof is formed by (from superficial to deep).
Skin.
Superficial fascia which contains short saphenous vein, three cutaneous nerves i.e, terminal branch of posterior cutaneous nerve of thigh, posterior division of medial cutaneous nerve, and peroneal or sural communicating nerve.
Deep fascia or popliteal fascia.
The floor is formed by.
The popliteal surface of femur
Capsule of knee joint and Popliteal ligament
strong fascia covering the Popliteal muscle

30. Contents of popliteal fossa
The popliteal fossa houses:
popliteal artery, a continuation of the femoral artery, which lies deepest in the fossa
popliteal vein which lies in between the artery and the nerve
tibial nerve and
common peroneal nerve which lies most superficial, and therefore amenable to nerve block
Six or seven popliteal lymph nodes, embedded in the fat
The roof contains a portion of the small saphenous vein and posterior cutaneous nerve of the thigh.
In performing popliteal local anesthetic blocks, it is of value to note that the nerve is the most superficial, than the vein, with the artery the deepest and furthest away from the needle.

31. The knee joint Three articulations in one:
two condyloid joints, one between each condyle of the femur and the corresponding meniscus and condyle of the tibia; and
a third between the patella and the femur, partly arthrodial, but not completely so, since the articular surfaces are not mutually adapted to each other, so that the movement is not a simple gliding one.
The bones are connected together by
the following ligaments:   
Articular Capsule.
Anterior Cruciate.
Ligamentum Patellæ.
Posterior Cruciate.
Oblique Popliteal.
Medial and Lateral Menisci.
Tibial Collateral.
Transverse.
The Fibular Collateral.
The Coronary.

32. The Articular Capsule
The Articular Capsule (capsula articularis; capsular ligament) —The articular capsule consists of a thin, but strong, fibrous membrane which is strengthened in almost its entire extent by bands inseparably connected with it. Above and in front, beneath the tendon of the Quadriceps femoris, it is represented only by the synovial membrane. Its chief strengthening bands are derived from the fascia lata and from the tendons surrounding the joint. In front, expansions from the Vasti and from the fascia lata and its iliotibial band fill in the intervals between the anterior and collateral ligaments, constituting the medial and lateral patellar retinacula.

33. Ligamentum Patellae
It is a strong, flat, ligament, about 10 cm. in length, which originates on the apex of the patella distally and adjoining margins of the patella and the rough depression on its posterior surface; below, it inserts on the tuberosity of the tibia; its superficial fibers are continuous over the front of the patella with those of the tendon of the Quadriceps femoris.
The medial and lateral portions of the tendon of the Quadriceps pass down on either side of the patella, to be inserted into the upper extremity of the tibia on either side of the tuberosity; these portions merge into the capsule, as stated above, forming the medial and lateral patellar retinacula.
The posterior surface of the ligamentum patellæ is separated from the synovial membrane of the joint by a large infrapatellar pad of fat, and from the tibia by a bursa.
It is also sometimes called the "patellar tendon".
Clinical: bone tendon bone autograft for acl reconstruction

34. Anterior Cruciate Ligament
The anterior cruciate ligament (ACL) is a cruciate ligament which is one of the four major ligaments of the human knee. In the quadruped stifle (analogous to the knee), based on its anatomical position, it is referred to as the cranial cruciate ligament.[1]
The ACL originates from deep within the notch of the distal femur. Its proximal fibers fan out along the medial wall of the lateral femoral condyle. There are two bundles of the ACL—the anteromedial and the posterolateral, named according to where the bundles insert into the tibial plateau. The ACL attaches in front of the intercondyloid eminence of the tibia, being blended with the anterior horn of the lateral meniscus. These attachments allow it to resist anterior translation of the tibia, in relation to the femur.

35. Anterior Cruciate Ligament
Primary static restraint to anterior displacement
tense in extension, ‘lax’ in flexion

36. Posterior Cruciate Ligament
The Posterior Cruciate Ligament (ligamentum cruciatum posterius; internal crucial ligament) is stronger, but shorter and less oblique in its direction, than the anterior. It is attached to the posterior intercondyloid fossa of the tibia, and to the posterior extremity of the lateral meniscus; and passes upward, forward, and medialward, to be fixed into the lateral and front part of the medial condyle of the femur.
It connects the posterior intercondylar area of the tibia to the medial condyle of the femur. This configuration allows the PCL to resist forces pushing the tibia posteriorly relative to the femur.
In the quadruped stifle (analogous to the human knee), based on its anatomical position, it is referred to as the caudal cruciate ligament.

37. Posterior Cruciate Ligament
PCL
Primary restraint to post. Displacement - 90%
relaxed in extension, tense in flexion
reinforced by Humphreys or Wrisberg
restraint to varus/valgus force
resists rotation, esp.int rot of tibia on femur

38. Medial Collateral Ligament
It is crossed, at its lower part, by the tendons of the Sartorius, Gracilis, and Semitendinosus, a bursa being interposed. Its deep surface covers the inferior medial genicular vessels and nerve and the anterior portion of the tendon of the Semimembranosus, with which it is connected by a few fibers; it is intimately adherent to the medial meniscus.
The Tibial Collateral Ligament (ligamentum collaterale tibiale; internal lateral ligament) The tibial collateral is a broad, flat, membranous band, situated nearer to the back than to the front of the joint. It is attached, above, to the medial condyle of the femur immediately below the adductor tubercle; below, to the medial condyle and medial surface of the body of the tibia. The fibers of the posterior part of the ligament are short and incline backward as they descend; they are inserted into the tibia above the groove for the Semimembranosus. The anterior part of the ligament is a flattened band, about 10 cm. long, which inclines forward as it descends. It is inserted into the medial surface of the body of the tibia about 2.5 cm. below the level of the condyle

39. Medial side Superficial MCL
Primary valgus restraint % restraining moment of knee
femoral attachment fans out around axis of rot.
Lax in flexion
Semimembranosus (expansion)
internally rot’s tibia on femur
tenses post/med capsular structures that are lax in knee flexion
acts with ACL

40. Lateral Collateral Ligament
Rounded, more narrow and less broad than the medial collateral ligament, the fibular collateral ligament stretches obliquely downward and backwardfrom the lateral epicondyle of the femur above, to the head of the fibula below. In contrast to the medial collateral ligament, it is fused with neither the capsular ligament nor the lateral meniscus. Because of this, the lateral collateral ligament is more flexible than its medial fellow, and the latter is therefore more susceptible to injury.
Immediately below its origin is the groove for the tendon of the Popliteus.
The greater part of its lateral surface is covered by the tendon of the Biceps femoris; the tendon, however, divides at its insertion into two parts, which are separated by the ligament.
Deep to the ligament are the tendon of the Popliteus, and the inferior lateral genicular vessels and nerve.
Lateral Collateral Ligament
Both collateral ligaments are taut when the knee joint is in extension. With the knee in flexion, the radius of curvatures of the condyles is decreased and the origin and insertions of the ligaments are brought closer together which make them lax. The pair of ligaments thus stabilize the knee joint in the coronal plane. Therefore damage and rupture of these ligaments can be diagnosed by examining the knee's mediolateral stability.

41. Lateral Collateral Ligament
Primary varus restraint
lax in flexion
Biceps passes it and blends with insertion
maintains tension?

42. Medial Meniscus
The medial meniscus is a fibrocartilage semicircular band that spans the knee joint medially, located between the medial condyle of the femur and the medial condyle of the tibia. It is also referred to as the internal semilunar fibrocartilage.
The greatest displacement of the meniscus is caused by external rotation, while internal rotation relaxes it.
During rotational movements of the tibia (with the knee flexed 90 degrees), the medial meniscus remains relatively fixed while the lateral part of the lateral meniscus is displaced across the tibial condyle below.
The meniscus attaches to the tibia via meniscotibial (coronary ligaments).
Its anterior end, thin and pointed, is attached to the anterior intercondyloid fossa of the tibia, in front of the anterior cruciate ligament;
Its posterior end is fixed to the posterior intercondyloid fossa of the tibia, between the attachments of the lateral meniscus and the posterior cruciate ligament.
It is fused with the tibial collateral ligament which makes it far less mobile than the lateral meniscus. The points of attachment are relatively widely separated and, because the meniscus is wider posteriorly than anteriorly, the anterior crus is considerably thinner than the posterior crus.

43. Lateral meniscus
Its anterior end is attached in front of the intercondyloid eminence of the tibia, lateral to, and behind, the anterior cruciate ligament, with which it blends; the posterior end is attached behind the intercondyloid eminence of the tibia and in front of the posterior end of the medial meniscus.
The anterior attachment of the lateral meniscus is twisted on itself so that its free margin looks backward and upward, its anterior end resting on a sloping shelf of bone on the front of the lateral process of the intercondyloid eminence.
Close to its posterior attachment it sends off a strong fasciculus, the ligament of Wrisberg, which passes upward and medialward, to be inserted into the medial condyle of the femur, immediately behind the attachment of the posterior cruciate ligament.
The lateral meniscus gives off from its anterior convex margin a fasciculus which forms the transverse ligament.
The lateral meniscus, also called the external semilunar fibrocartilage, is a fibrocartilaginous band that spans the lateral side of the interior of the knee joint. It is nearly circular and covers a larger portion of the articular surface than the medial.
The lateral meniscus is grooved laterally for the tendon of the popliteus, which separates it from the fibular collateral ligament.

44. 2 functions
load bearing
stability
also, joint lubrication
prevent capsule, synovial impingement
shock absorbers
Knee joint stability
mainly rotational
miniscectomy +/- ACL and translation
why differences in lat vs med ?
Structure
attachments

45. Load bearing
-composition;

46. Hoop stress

47. Blood supply of the knee
The femoral artery and the popliteal artery help form the arterial network surrounding the knee joint (articular rete). There are 6 main branches:
1. Superior medial genicular artery
2. Superior lateral genicular artery
3. Inferior medial genicular artery
4. Inferior lateral genicular artery
5. Descending genicular artery
6. Recurrent branch of anterior tibial artery
The medial genicular arteries penetrate the knee joint.

48. Knee joint Ginglymus (hinge) ? Arthodial (gliding) ?
6 degrees of freedom
3 rotations
3 translations

49. Rotations Translations flex/ext - -15 to 140 deg
Varus/valgus deg in extension
int/ext rotation deg in flexion
Translations
AP mm
compression/distraction mm
medio-lateral 1-2mm

50. The Gait Cycle

51. Taking a step
Just prior to heel strike - max extension & max external rotation
heel strike - max valgus
flat foot - flexion & internal rotation progress
swing phase - internal rotation continues, max flexion, max anterior translation.

52. Tibio-femoral arthrokinetics
DURING KNEE EXTENSION
DURING KNEE FLEXION
OPEN CHAIN
CLOSED CHAIN
TIBIA GLIDES ANTERIORLY ON FEMUR
FEMUR GLIDES POSTERIORLY ON TIBIA
TIBIA GLIDES POSTERIORLY ON FEMUR
FEMUR GLIDES ANTERIORLY ON TIBIA
from 20o knee flexion to full extension
from full knee extension to 20o flexion
Tibia rotates externally
Femur rotates internally on stable tibia
Tibia rotates internally
Femur rotates externally on stable tibia

53. “Screw-home” Mechanism
Rotation between the tibia and femur occurs automatically between full extension (0o) and 20o of knee flexion. These figures illustrate the top of the right tibial plateau as we look down on it during knee motion.
                                      
DURING KNEE EXTENSION, the tibia glides anteriorly on the femur.
During the last 20 degrees of knee extension, anterior tibial glide persists on the tibia's medial condyle because its articular surface is longer in that dimension than the lateral condyle's.
Prolonged anterior glide on the medial side produces external tibial rotation, the "screw-home" mechanism.

54. Gliding of the femur over the tibia

55. Bi-pedal ambulation

56. Thank you!