Osteology Lower Limb,by Dr Iram

Osteology of Femur & Tibia Dr Iram Iqbal

Sequence G features and attachments of Femur  Ossification and blood supply of femur  Applied anatomy  G features and attachments of Tibia  Ossification and blood supply of  Applied anatomy  Development  Conclusion  References 

FEMUR 

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Longest and strongest bone in human body Two ends (proximal and distal) and shaft Shaft runs obliquely from proximal to distal end Right Femur (Anterior View)

FEMORAL HEAD Directed medially, upwards and slightly forwards • Articulates with the acetabulum to form hip joint • A roughened pit is situated just below and behind the centre of the head called fovea 1.

Left Femur (Posterior View)

1.FEMORAL NECK • •

• • • •

It is about 5 cm long It connects the head to the shaft at an angle of(120 -135°) (angle of inclination or neck-shaft angle) Neck–shaft angle facilitates movements at the hip joint Femoral neck has two borders and two surfaces Upper & Lower border Anterior & Posterior surface

Left Femur (Posterior View)

°(Angle Of Inclination Or Neck-shaft Angle) ( Torsion Angle Of Femur)

2. FEMORAL NECK  The

upper border is concave and meets the shaft at the greater trochanter  The lower border is straight and meets the shaft near the lesser trochanter  The anterior surface is flat and meets the shaft at the intertrochanteric line  The posterior surface is convex and meets the shaft at the intertrochanteric crest

Left Femur (Posterior View)

3.GREATER TROCHANTER . The greater trochanter is

large and quadrangular, projecting up from the junction of the neck and shaft •Rough, depressed area on the medial surface is the trochanteric fossa •The anterior surface bears a rough impression • Its lateral surface is divided into two areas by an oblique flat strip, which crosses it down and forwards

Left Femur (Posterior View)

4. LESSER TROCHANTER 

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A conical posteromedial projection of the shaft Its anterior surface is rough, and posterior surface at the distal end of the inter-trochanteric crest is smooth

Left Femur (Posterior View)

5.INTER-TROCHANTERIC LINE • A prominent ridge at the junction of the anterior surface of the neck and shaft • It descends medially and continuous below with the spiral line in front of the lesser trochanter Left Femur (Anterior View)

6.INTER-TROCHANTERIC CREST . Smooth ridge at the

junction of posterior surface of neck with the shaft  A little above its centre there is a low, rounded quadrate tubercle

Left Femur (Posterior View)

B.

Convex

SHAFT

forwards, narrowest centrally Directed obliquely downwards and medially In the upper 1/3 of the shaft,the two lips of the linea aspera diverge Four surfaces in upper third, Three in middle third, and four in lower third

Right Femur (Posterior View)

F.   

DISTAL END

Right Femur (Inferior View)

It consists of two massive condyles (a medial and a lateral condyle), inter-condylar fossa and a large articular surface Anteriorly the condyles unite and continue into the shaft Posteriorly they are separated by a deep inter-Condylar fossa

DISTAL END

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The articular surface forms a broad area, like an inverted U and is divisible into patellar and tibial surface

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The patellar surface extends over the anterior surface of both condyles but more on the lateral condyle It is concave from side to side The tibial surface covers the inferior and posterior surfaces of both the condyles It is separated posteriorly by intercondylar fossa and merges anteriorly with the patellar surface

Distal End Left Femur

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Medial condyle has a bulging on convex medial aspect that can be palpated Its uppermost part has a small projection called adductor tubercle Below and little in front of adductor tubercle is medial epicondyle Lateral condyle is not so prominent as the medial condyle but is stouter and stronger The most prominent point on its lateral aspect is is the lateral epicondyle Intercondylar fossa

Right Femur (Inferior View)

Right Femur (Posterior View)

Muscular attachments

OSSIFICATION OF FEMUR 

Femur ossifies from five centers (one primary in the shaft, and four secondary- each in head, greater trochanter, lesser trochanter and distal end)

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Other than the clavicle, it is the first long bone to ossify The primary center for the shaft appears in the 7th week of intra -uterine life The secondary center for the lower end at the end of the 9th month of intra-uterine life

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The secondary center for the head appears during the first 6 months of life Secondary center for the greater trochanter appears during the 4th year And for the lesser trochanter during the 12th year

Blood supply

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Vascular supply blood supply of the femoral head is derived from an arterial ring around the neck, just outside the attachment of the fibrous capsule, constituted by the medial and lateral circumflex arteries with minor contributions from the superior and inferior gluteal vessels. From this ring, ascending cervical branches pierce the capsule to ascend the neck beneath the reflected synovial membrane. These vessels become the retinacular arteries and form a sub synovial intra-articular ring. Here the vessels are at risk with a displaced fracture of the femoral neck. Interruption of blood supply in this way can lead to avascular necrosis of the femoral head. If the fracture is intra-articular then not only is the interosseous blood supply damaged but the retinacular vessels can also be vulnerable. If the fracture is extra capsular, the retinacular vessels will remain intact and avascular necrosis of the femoral head does not occur.

Blood supply of head of femur

Clinical Anatomy

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The distal end of the femur is the only epiphysis in which ossification constantly starts just before birth, a most reliable indicator that a dead newborn child was viable Since the growth in length takes place chiefly from the lower epiphysial cartilage so surgeon needs to be careful Lower epiphyseal line passes through the adductor tubercle Neck represents the upper end of shaft b/c it ossifies from the primary centre.

injuries

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Below the age of 16 there is spiral fracture of the shaft Bucket handle tear of the medial meniscus b/e the age of 14-40 yrs Over 60 fracture of the femoral neck is common because of osteoporotic changes in ageing bones. Women are more liable, their bones being lightly built Pott,s fracture of the leg b/e the age of 40-60 Avascular necrosis of head of femur in intra-articular displaced fracture of femoral neck

BUCKET HANDLE TEAR

Spiral fracture of the shaft

"Bucket-handle Tear”  . These large tears tend to occur in younger patients, and are always traumatic injuries.  bucket-handle tear is a  tear around the rim of the meniscus, causing the central portion (the bucket-handle) to displace into the joint. These types of tears generally involve large amounts of the meniscus, and are often amenable tomeniscus repair (rather than removal of the meniscus). 

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Patients with these bucket-handle tears may have limited motion of the knee joint if the meniscus tear is large enough to get caught inside the knee.

Pott fracture, dislocation of ankle joint 

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A Pott

fracturedislocation of the ankle occurs when the foot is forcibly averted. (combined abduction external rotation from an eversion force) This action pulls on the extremely strong medial ligament, often tearing off the medial malleolus. The talus then moves laterally, shearing off the lateral malleolus or, more commonly, breaking the fibula superior to the tibiofibular syndesmosis. If the tibia is carried anteriorly, the posterior margin of the distal end of the tibia is also sheared off by the talus.

"trimalleolar fracture" 

The combined fracture of the medial malleolus, lateral malleolus, and the posterior margin of the distal end of the tibia is known as a "trimalleolar fracture.“In a "trimalleolar fracture" the posterior distal end of the tibia is erroneously labeled as a malleolus.

Avascular necrosis of head of femur

Coxa Vara and Coxa Valga The angle of inclination varies with age, sex, and development of the femur (e.g., consequent to a congenital defect in ossification of the femoral neck). It also may change with any pathological process that weakens the neck of the femur (e.g., rickets). When the angle of inclination is decreased, the condition is Coxa vara, when it is increased, the condition is . Coxa valga causes a mild passive abduction of the hip.

Coxa Vara and Coxa Valga

Fracture of femur 

Fracture of upper end (neck) – Intracapsular   

Sub capital Trans cervical basal

– Extra capsular 

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Intrtrochanteric

Fracture of shaft

– Type I - Spiral or transverse (most common) – Type II - Comminuted – Type III - Open

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Associated injuries are common.

Classification based on appearance of hip on AP view of Xray – stageI : incomplete fracture of the neck (so-called abducted or impacted) – stage II : complete without displacement – stage III: complete with partial displacement: – stage IV : this is a complete femoral neck fracture with full displacement:

OVERVIEW OF LIGAMENTS

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The knee is stabilized by four main ligaments: 2 collateral ligaments (medial and lateral) and 2 cruciate ligaments both anterior (front) and posterior (back). The cruciate ligaments attach to the femur (thigh bone) and travel within the knee joint to the upper surface of the tibia (shin bone). The ligaments pass each other in the middle of the joint forming a cross shape, hence the name 'cruciate'.  The role of the Anterior Cruciate Ligament is to prevent forward movement of the Tibia from underneath the femur. The Posterior Cruciate Ligament prevents movement of the Tibia in a backwards direction. Together these two ligaments are vitally important to the stability of the knee joint, especially in contact sports and those that involve fast changes in direction and twisting movements.

How does a torn ACL occur? 

A torn ACL or ACL injury is a relatively common knee injury amongst sports people. A torn ACL usually occurs through a twisting force being applied to the knee whilst the foot is firmly planted on the ground or upon landing. A torn ACL can also result from a direct blow to the knee, usually the outside, as may occur during a football or rugby tackle. This injury is sometimes seen in combination with a medial meniscus  tear and MCL injury, which is termed O’Donohue’s triad. (unhappy triad)

“Unhappy Triad”

ANTERIOR CRUCIATE LIGAMENT INJURY

OVERVIEW OF INJURY

Posterior Cruciate Ligament

Injury to PCL 

The incidence of injuries of the PCL is less than that of theanterior cruciate ligament. This is mainly due to the greater thickness and strength of the PCL. Nevertheless, the most common way in which the PCL is injured is by direct impact to the front of the tibia itself, usually when the knee is bent. This may occur in a front-on tackle or collision or when falling with the knee bent. The injury is commonly associated with injuries to other structures in the rear compartment of the knee joint such as lateral meniscus tears. In addition the articular cartilage may also be damaged.

ILLUSTRATION

ligament sprains

The most common knee injuries in contact sports are ligament sprains , which occur when the foot is fixed in the ground . If a force is applied against the knee when the foot cannot move, ligament injuries are likely to occur. The tibial and fibular collateral ligaments (TCL and FCL) are tightly stretched when the leg is extended, normally preventing disruption of the sides of the knee joint.  The firm attachment of the TCL to the medial meniscus is of considerable clinical significance because tearing of this ligament frequently results in concomitant tearing of the medial meniscus. 

oVERVIEW OF MENISCI

Meniscal tears 

Meniscal tears usually involve the medial meniscus. The lateral meniscus does not usually tear because of its mobility.

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Pain on lateral rotation of the tibia on the femur indicates injury of the lateral meniscus , whereas pain on medial rotation of the tibia on the femur indicates injury of the medial meniscus

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Most meniscal tears occur in conjunction with TCL or ACL tears. Peripheral meniscal tears can often be repaired or may heal on their own because of the generous blood supply to this area. Meniscal tears that do not heal or cannot be repaired are usually remove.

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Knee joints from which the menisci have been removed suffer no loss of mobility; however, the knee may be less stable and the tibial plateaus often undergo inflammatory reactions.

MENISCUS DEGENERATION 

degenerative tears seen in patients with early signs of wear and tear in the knee.

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Medial bone of leg

TIBIA

After femur longest bone Tibia has a proximal end, shaft and distal end The medial side of the distal end projects downwards and forms medial malleolus Anterior border of the shaft is most prominent, sharp and sub-cutaneous

PROXIMAL END

It is expanded and has a medial condyle, lateral condyle, intercondylar area and tibial tuberosity

Right Tibia Fibula

Medial condyle  

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Is larger than the lateral condyle Doesn’t overhang so much as the lateral condyle on posterior aspect The articular surface is oval in outline and concave in all diameters Its lateral border projects upwards forming an elevation called medial intercondylar tubercle Left Tibia (Anterior View)

Lateral condyle 

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It overhangs the shaft especially at posterolateral part A small circular facet for articulation with upper end of fibula Articular surface is nearly circular slightly hollowed in its central part Its medial border extends upwards forming an elevation called lateral intercondylar tubercle

Left Tibia Fibula (Posterior View)

Inter-condylar area 

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It is a roughened area on the superior surface between the articulating surface of the two condyles The area is narrowed in its middle part, elevated to form the intercondylar eminence Intercondylar eminence is flanked by the medial and lateral intercondylar tubercles Left Tibia Fibula (Posterior View)

Tibial tuberosity 

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Present at the upper end of the anterior border of the shaft It is divided into upper smooth and lower roughened region The upper part has attachment of ligamentum patellae The lower part of the tuberosity is subcutaneous Above the tuberosity deep infrapatellar bursa present between the bone and ligamentum patellae

Left Tibia (Anterior View)

SHAFT It is triangular in section  Three borders (anterior, medial and lateral or interosseous)  Three surfaces (lateral, medial and posterior) 

Tibia Fibula Right Leg Cross section (Inferior view)

BORDERS  Anterior border  Medial border  Interosseous border SURFACES Lateral surface • Medial surface (subcutaneous) • Posterior surface (soleal line) •

DISTAL END It is slightly expanded and projected medially to form medial malleolus. It has five surfaces  Anterior  Medial

surface

surface

 Lateral

surfacefibular notch

 Inferior

surface

 Posterior

groove

surface-

Distal End of Right Tibia (Anterior View)

Muscular attachments

Anterior

Posterior aspect

OSSIFICATION OF TIBIA 

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Tibia ossifies from one primary and two secondary centres Primary center appears in the shaft doing the seventh week of intra-uterine life First secondary center for the upper end appears just before birth and fuses with the shaft at 16-18 years Second secondary center for the lower end appears during the first year, forms the medial malleolus by the seventh and joins the shaft in about 16-18 years

Stages in ossification of tibia

Genu Valgum and Genu Varum 

The femur is placed diagonally within the thigh, whereas the tibia is almost vertical within the leg, creating an angle at the knee between the long axes of the bones . The angle between the two bones, referred to clinically as the Q-angle, (10)is assessed by drawing a line from the ASIS to the middle of the patella and extrapolating a second (vertical) line passing through the middle of the patella and tibial tuberosity . The Q-angle is typically greater in adult females, owing to their wider pelves. When normal, the angle of the femur within the thigh places the middle of the knee joint directly inferior to the head of the femur when standing, centering the weightbearing line in the intercondylar region of the knee .

Genu varum

Genu valgum

Genu Valgum and Genu Varum 

A medial angulation of the leg in relation to the thigh, in which the femur is abnormally vertical and the Q-angle is small, is a deformity called genu varum (bowleg) that causes unequal weight-bearing: Excess pressure is placed on the medial aspect of the knee joint, which results in arthrosis (destruction of knee cartilages), and the fibular collateral ligament is overstressed.

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Genu Valgum and Genu Varum 

. A lateral angulation of the leg (large Q-angle, >17°) in relation to the thigh (exaggeration of the knee angle) is called genu valgum (knock-knee) . Because of the exaggerated knee angle in genu valgum, the weight-bearing line falls lateral to the center of the knee. Consequently, the tibial collateral ligament is overstretched, and there is excess stress on the lateral meniscus and cartilages of the lateral femoral and tibial condyles

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The patella, normally pulled laterally by the tendon of the vastus lateralis, is pulled even farther laterally when the leg is extended in the presence of genu valgum so that its articulation with the femur is abnormal.

Development of limbs

References     

Gray’s Anatomy-40th edition Macmann’s Atlas of Anatomy Atlas of Human Anatomy, Frank H.Netter,M.D. Clinical Oriented Anatomy KLM 6th edition Goggle Chrome