The knee joint is a synovial modified-hinge joint, in which condyles of the femur and tibia articulate as does the patella and patellar surface of the femur. The fibula is not part of the knee joint.

Patella



The patella is the largest sesamoid bone. It has circular-triangular shape and embeds in the tendon of quadriceps femoris, anterior to the knee joint.

Menisci



These are crescent shaped fibro-cartilage structures that act as shock absorbers. They sit on grooves on the articular surfaces of the tibial condyles. The medial meniscus is larger and "C" shaped, the lateral meniscus is more of an "O" shape. The menisci are attached to the tibial intercondylar area by their horns and small coronary ligaments.

Cruciate ligaments



These are intracapsular ligaments and there are two:
• The anterior cruciate ligament crosses from the front of the intercondylar area of the tibia to the medial side of the lateral femoral condyle. This ligament prevents hyper-extension and stops forward slip of the tibia on the femur.
• The posterior cruciate ligament crosses from the back of the intercondylar area of the tibia to the lateral side of the medial condyle. It becomes taut in hyper-flexion and resists posterior slip of the tibia on the femur.

Collateral ligaments



• The medial (tibial) collateral ligament consists of superficial and deep parts. The superficial component is attached above to the femoral epicondyle and below to the subcutaneous surface of the tibia. The deep component is firmly attached to the medial meniscus.
• The lateral (fibular) collateral ligament is attached to the femoral epicondyle above and, along with biceps femoris, to the head of the fibula below. Unlike the medial collateral ligament it lies away from the capsule and meniscus.

The collateral ligaments are taut in full extension, limiting extension and aiding in locking.

Capsule



The capsule is attached to the margins of the articular surfaces except anteriorly where it dips downwards. In the anterior part of the capsule there is a large opening through which the synovial membrane is continuous with the suprapatellar bursa. This bursa extends superiorly ~5cm above the patella between the femur and quadriceps. Posteriorly the capsule communicates with another bursa under the medial head of gastrocnemius and often, through it, with the bursa of semimembranosus. Posterolaterally another opening in the capsule permits the passage of the tendon of popliteus.

Behind the knee the oblique popliteal ligament, a reflected extension from the semimembranosus tendon, strengthens the capsule. Anteriorly the capsule is reinforced by the ligamentum patellae and the patellar retinacula. The latter are reflected fibrous expansions arising from vastus lateralis and medialis muscles which blend with the capsule anteriorly

Blood supply



Supplied by the rich anastomosis formed by the genicular branches of the popliteal artery.

Nerve supply: innervated by branches of the femoral, tibial, common peroneal and obturator nerves.

Movements at the knee

• Flexion: semimebranosus, semitendinosus, biceps, gracilis, sartorius (gastrocnemius, plantaris, popliteus)
• Extension: quadriceps femoris, iliotibial tract (gluteus maximum, tensior fascia latae)
• Internal rotation (with knee fixed): semimebranosus, semitendinosus, gracilis, sartorius
• External rotation (with knee fixed): Biceps
  

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The hip joint is the articulation between the head of the femur and the acetabulum of the hip bone. It is a synovial ball and socket joint.

The stability of the joint is determined by the shape of the articular surfaces (a deep socket securely holding the femoral head), the strength of the joint capsule and associated ligaments, and the insertion of muscles crossing the joint, which tend to be at some distance from the centre of movement. Although the hip is a ball and socket joint, when standing erect the femoral head is not completely covered by the acetabulum, the anterosuperior aspect being exposed.

Joint capsule

The fibrous capsule of the hip is very strong and thicker anteriorly, where the head of the femur articulates, and superiorly, enhancing the stability of the joint. Proximally, the capsule surrounds the acetabulum attaching directly to the bone outside the labrum above and behind, and to the bone and outer edge of the labrum in front and below. Opposite the acetabular notch the capsule attaches to the transverse ligament. On the femur the capsule attaches anteriorly to the intertrochanteric line and to the junction of the neck with the trochanters. Posteriorly the capsule has an arched free border and covers the medial two-thirds of the neck only.

Capsular ligaments



1. The iliofemoral ligament is very strong and thick, being situated anterior to the joint.
2. The pubofemoral ligament strengthens the inferior and anterior aspects of the joint capsule. It runs from the iliopubic eminence and superior pubic ramus to the lower part of the intertrochanteric line.
3. The ischiofemoral ligament, posteriorly, is spiral in shape and arises from the body of the ischium behind and below the acetabulum.

The three ligaments, iliofemoral, pubofemoral and ischiofemoral, have important roles in limiting and controlling the various movements of which the hip is capable.

Inside the capsule



The synovial membrane of the hip joint lines the fibrous capsule and covers the:
• Neck of the femur between the attachment of the fibrous capsule and the edge of the articular cartilage of the head
• Nonarticular area of the acetabulum, providing a covering for the ligament of the femoral head.

A synovial protrusion beyond the free margin of the fibrous capsule onto the posterior aspect of the femoral neck forms a bursa for the obturator externus tendon.
The ligament of the head of the femur (Ligamentum teres) is weak and of little importance in strengthening the hip joint. Its wide end attaches to the margins of the acetabular notch and the transverse acetabular ligament. Its narrow end attaches to the pit in the head of the femur. Usually the ligament contains a small artery to the head of the femur.

The fat pad in the acetabular fossa (covered with synovial membrane) fills the part of the acetabular fossa that's not occupied by the femoral head. The malleable nature of the fat pad permits it to change shape to accommodate the varying shape of the head during joint movements.

Blood Supply of the Hip Joint



The arteries supplying the hip joint are:
• Medial and lateral circumflex femoral arteries: usually branches of the deep artery of the thigh but occasionally arising as branches of the femoral artery
• Artery to the head offemur--a branch of the obturator artery--enters through the ligament of the head.

Nerve Supply of the Hip Joint

• Femoral nerve or its muscular branches (anteriorly)
• Accessory obturator nerve, if present (anteriorly)
• Obturator nerve (anterior division) (inferiorly)
• Superior gluteal nerve (superiorly and posteriorly)
• Nerve to quadratus femoris (posteriorly).

Movements of the Hip Joint

Abduction, Adduction, Flexion, Extension, External and Internal rotation

Normal angles

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Going from the heel to the toes, you can see the calcaneus, the talus, the lateral, intermediate and medial cuniform bones; the navicular; and the cuboid bones. Called the tarsal bones, they are the bones which make the transition from the leg to the foot.

The next five bones make up the body of the foot and are called the metatarsal bones. The first metatarsal lines up with the big toe, the fifth with the little toe. The final group are called the phalanges as are the equivalent bones in the fingers. The big toe, like the thumb just has only a proximal and distal phalanx as the other toes have a proximal, medial, and distal phalanges.

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The tibia is the stronger of the two bones of the leg, it is the second largest in the human body, the largest being the femur. It is medial to the fibula. The tibia articulates with the femur and patella superiorly, the fibula laterally and with the talus inferiorly.

The fibula located laterally to the tibia and it is the smaller of the two bones and is one of the most slender long bones. Its upper extremity is small, placed toward the back of the head of the tibia, under the knee joint but not included in the formation of this joint. Its lower part changes to be a little forward and becomes more anterior to that of the upper extremity; it projects below the tibia, and forms the lateral malleolus.

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Being a long bone it has upper and lower ends and a shaft (the body).

Upper end

Head:
Articulates with hip bone at the acetabulum > forming the hip joint.
Has a fovea (pit) for the ligament of the head.

Neck:
Ends anteriorly at the intertochanteric line and posteriorly at the intertrochanteric crest.

Greater trochanter: on its medial surface there is a trochanteric fossa.
Lesser trochanter: near the lower end of the neck.

Shaft

3 borders: Lateral, medial and posterior which has the linea aspera in the middle third.

The linea aspera is broad and has a medial lip which is continuous upwards as the spiral line and it goes downwards giving the medial supracondylar line. The lateral lip is continuous upwards as the gluteal tuberosity and downwards as the lateral supracondylar line.

The area between the 2 supracondylar ridges is called the popliteal surface.

Lower end

2 condyles:
Medial has adductor tubercle (superiorly).
Lateral has popliteal groover (laterally).

2 epicondyles: lateral and medial.

Between the 2 condyles:
Anterior: patellar surface
Posterior: intercondylar notch

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Consists of three parts:
1) Ilium > upper
2) Pubis > lower and anterior
3) Ischium > lower and posterior
They are united around the acetabulum.


1st - Ilium
It has 4 borders:

Anterior:

• Anterior superior iliac spine
• Anterior inferior iliac spine

Posterior

• Posterior superior iliac spine
• Posterior inferior iliac spine
• Greater part of the greater sciatic notch

Upper:

• Iliac crest: contains iliac tubercle anteriorly

Lower:

• Outside: continues with acetabulum
• Inside: arcuate line which indicates margin of pelvis

2 surfaces:

• Gluteal (surface) lateral, contains:

- Inferior gluteal line
- Middle gluteal line
- Posterior gluteal line

• Pelvic (medial) surface:

- Iliac fossa (anterior)
- Sacro-pelvic surface (Auricular line & pelvic part)


2nd - Pubis
It's body has:

3 surfaces

• Anterior
• Posterior = pelvic
• Medial

2 borders

• Lower border continues with pubic arch

Upper has:

• Pubic crest (medial)
• Pubic tubercle (lateral)

2 rami:

• Superior ramus, has 3 surfaces (Pelvic, Obturator and Pectineal)
• Inferior ramus with ishial ramus > from pubic arch

3rd - Ischium:
Body:

2 borders

• Anterior: obturator foramen
• Posterior: has ishial spine dividing the back to give greater and lesser sciatic notchs

3 surfaces:

• Lateral: femoral
• Medial: pelvic
• Posterior: ischial tuberosity that is divided into upper quadrangular and lower triangle

Ramus:

• with inferior pubic ramus form pubic arch

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Bones:

• Hip bone
• Femur
• Tibia
• Fibula
• Foot bones

Joints:

• Hip joint
• Knee joint
• Ankle joint
• Tibio-fibular joints

Muscles, Nerves, Arteries, Veins, Lymph drainage of:

Thigh:

• Anterior & medial side
• Gluteal region & posterior side
• Lateral side

Leg:

• Anterior compartment
• Lateral compartment
• Posterior compartment

Sole of foot

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