Leg – Bones, Ligaments, Muscles & Conditions
Generally, the leg is the entire lower limb of the human body, including the foot, thigh and even the hip or gluteal region. The leg is composed of five distinct sections: upper leg, knee, lower leg, ankle, and foot.Legs are used for standing, and all forms of locomotion including recreational such as dancing, and constitute a significant portion of a person’s mass.
Leg Bones and Joints
The human leg of the human body includes the foot, thigh and even the hip or gluteal region. Legs are used for standing, and all forms of locomotion including recreational such as dancing, and constitute a significant portion of a person’s mass. Female legs generally have greater hip anteversion and tibiofemoral angles, but shorter femur and tibial lengths than those in males
The femur, or thigh bone, is the largest, heaviest, and strongest bone in the human body. Many strong thigh muscles attach to the femur and pull on the femur during movements of the hip and knee joints.
At the proximal end of the femur is a rounded prominence known as the head of the femur. The head of the femur forms the ball and socket hip joint with the acetabulum of the hip bone. The hip joint gives the leg an incredible range of motion while still providing support to the body’s weight.
At the distal end of the femur, two rounded condyles meet the tibia and fibula bones of the lower leg to form the knee joint. The knee is a strong but flexible hinge joint that uses muscles and ligaments to withstand the torques and strains of powerful leg movements. Between the femur and tibia is the meniscus, a layer of tough fibrocartilage that acts as a shock absorber.
In the lower leg, the tibia bears most of the body’s weight while the fibula supports the muscles of balance in the lower leg and ankle. The tibia forms the flexible ankle joint with the tarsal bones of the foot. The calcaneus, or heel bone, is the largest tarsal bone and rests on the ground when the body is standing.
The tarsal bones and the five long metatarsal bones together form the arches of the foot. Like the tarsal bones, the position of the metatarsals can be adjusted to change the shape of the foot and affect balance and posture of the body.
Extending from the distal end of the metatarsals are the tiny phalanges of the toes. The phalanges connect to several muscles in the leg via long tendons. The phalanges can flex or extend to change the shape of the foot for balance, and provide added leverage to the foot during walking.
Common conditions of the bones and joints of the leg include hip osteoarthritis, rheumatoid arthritis of the hip, paget’s disease of bone, hip fracture, blount’s Disease, and shin splints.
A burse is a fluid filled sac that decreases friction between two tissues. Burse are commonly found near a joint, and act as lubricating structures between tendon and bone.
There are two major bursae in the hip that typically become irritated and inflamed. One bursa covers the bony point of the hip bone called the greater trochanter. Inflammation of this bursa is called trochanteric bursitis. Another bursa — the iliopsoas bursa — is located on the inside (groin side) of the hip. When this bursa becomes inflamed, the condition is also sometimes referred to as hip bursitis, but the pain is located in the groin area. This condition is not as common as trochanteric bursitis, but is treated in a similar manner.
There are several bursa in the foot and ankle region. The most common are the retrocalcaneal bursa, subcutaneous calcaneal bursa, and subcutaneous bursa of the medial malleolus. The retrocalcaneal bursa is located between the Achilles tendon and calcaneus (heel) bone. Direct or repetitive trauma such as consistent rubbing or friction can produce bursitis in this area. The subcutaneous calcaneal bursa, also called the Achilles bursa, is lower down near the heel. The subcutaneous bursa of the medial malleolus is located below the edge of the medial malleolus. Tight athletic footwear can produce rubbing and bursitis in this area
Common conditions of the leg bursa include achilles bursitis, retrocalcaneal bursitis, bursitis of the medial malleolus, calcaneal bursitis, metatarsal bursitis, intermetatarsal bursitis, metatarsophalangeal bursitis, trochanteric bursitis, ischial bursitis, greater trochanteric pain syndrome, trochanteric bursitis, and iliopsoas bursitis.
Ligaments are soft tissue structures that attach bone to bone. The primary job of a ligament is to provide stability to a joint.
The ligaments of the hip joint act to increase stability. They can be divided into two groups – intracapsular and extracapsular:
Intracapsular: The only intracapsular ligament is the ligament of head of femur. It is a relatively small structure, which runs from the acetabular fossa to the fovea of the femur.It encloses a branch of the obturator artery (artery to head of femur), a minor source of arterial supply to the hip joint.
Extracapsular: There are three main extracapsular ligaments, continuous with the outer surface of the hip joint capsule:
- Iliofemoral ligament – arises from the anterior inferior iliac spine and then bifurcates before inserting into the intertrochanteric line of the femur. It has a ‘Y’ shaped appearance, and prevents hyperextension of the hip joint. It is the strongest of the three ligaments.
- Pubofemoral – spans between the superior pubic rami and the intertrochanteric line of the femur, reinforcing the capsule anteriorly and inferiorly. It has a triangular shape, and prevents excessive abduction and extension.
- Ischiofemoral– spans between the body of the ischium and the greater trochanter of the femur, reinforcing the capsule posteriorly. It has a spiral orientation, and prevents hyperextension and holds the femoral head in the acetabulum.
There are four main ligaments of the knee. Located on the inner aspect of the knee is the medial collateral (MCL) ligament, and on the outside is the lateral collateral ligament (LCL). These ligaments provide medial and lateral stability to the knee.
Located on the inside of the knee are the anterior cruciate ligament (ACL), and posterior cruciate ligament (PCL). They provide anterior, posterior and rotatory stability to the knee.
Two other soft tissue structures within the knee are the medial and lateral meniscus. These structures are attached to the tibia, and provide added stability and cushioning to the knee joint. They are cartilaginous in nature and when injured can be referred to as a “torn cartilage”.
Four major ligaments hold together the ankle. The medial part of the ankle is supported by the strong and thick deltoid ligament, and runs from the medial malleolus of the tibia to the talus, calcaneus and navicular bone of the foot and ankle complex. On the lateral side of the ankle are three ligaments running from the lateral malleolus of the fibula. Two of these – the anterior talofibular ligament, and the posterior talofibular ligament- attach to the talus. The third calcaneofibular ligament attaches to the calcaneus, or heel bone.
These ligaments give the ankle lateral support and stability. The anterior talofibular ligament is the most commonly injured ligament in the body. Lateral ankle sprains account for 85% of all ankle sprains.
Ligaments in the foot include the plantar calcaneonavicular ligament, the deltoid ligament, the long plantar ligament, and the plantar calcaneocuboid.
The plantar fascia is a thick connective tissue in the foot that runs from the calcaneus or heel bone to the metatarsal heads at the base of the toes. The plantar fascia is found in the sole of the foot, and helps to support the arch of the foot. The plantar fascia can become inflamed, causing a condition known as plantar fasciitis – a common cause of foot pain.
Common conditions of the leg ligaments include hip strains, ruptured ligament of the hip, ACL tear, ACL insufficiency, PCL tear, medial meniscus tear, lateral meniscus tear, meniscus tear, meniscectomy, ACL reconstruction, PCL reconstruction, ankle sprain (Grades 1,2, and 3), lateral ankle sprain, ankle instability, ankle ligament tear, lateral ankle instability, anterior ankle instability foot sprain, plantar fasciitis, ankle sprain, flat feet (Pes Planus)
The muscles of the hip joint are those muscles that cause movement in the hip. Most modern anatomists define 17 of these muscles, although some additional muscles may sometimes be considered. These are often divided into four groups according to their orientation around the hip joint: the gluteal group, the lateral rotator group, the adductor group, and the iliopsoas group.
The muscles surrounding the knee function to both move and stabilize the joint. The two main muscle groups are the quadriceps on the anterior side of the knee and femur, and the hamstrings on the posterior side.
The four muscles of the quadriceps: vastus lateralus, vastus medialus, vastus intermedius and rectus femoris function to extend the knee. The muscles join together to form the common quadriceps tendon. Tendons are part of the muscle, and attach muscle to bone. Within the quadriceps tendon is the patella (knee cap.) The patella is a sesamoid bone, which provides increased leverage to the quadriceps muscle to improve its efficiency.
The three posterior hamstring muscles: biceps femoris, semitendinosis, and semimembranosis function to decelerate, stabilize and bend the knee joint, and attach to the posterior part of the tibia and fibula.
There are two other important muscles of the knee complex. The gastrocnemius pushes the foot down (plantar flexes) and helps bend the knee. The popliteus helps unlock the knee from a straightened or extended position. Two adductor muscles, the adductor magnus and gracilis, cross the knee joint and help rotate the leg and can be a source of inflammation.
The muscles that control ankle movement originate in the lower leg. They are responsible for foot and ankle movement up and down (dorsiflexion and plantar flexion) and turning in and out (inversion and eversion). The muscle bellies are located in the lower leg while the tendons travel and attach to the foot and ankle. Tendons are the part of the muscle that attaches the muscle to the bone.
In addition to movement, strong muscles provide active stability to the ankle as opposed to the passive stabilization of the ligaments. The major muscles of the ankle include the gastrocnemius and soleus (calf) muscles, which push the foot down and allow us to go up on our toes. These two large muscles join at the ankle to form the Achilles tendon.
The two peroneal muscles, longus and brevis, are located on the outside of the ankle, and push the foot down (plantar flexion) and turn it out (eversion). They also support the lateral ankle to prevent sprains. The posterior tibialis is located on the inside of the ankle, and supports the arch of the foot and helps turn the ankle in (inversion). The anterior tibialis muscle attaches to the front of the foot, and helps lift it up (dorsiflexion).
Any damage, weakness, tendonitis or tear of these muscles or tendons can have a profound effect on the function and stability of the foot and ankle. For instance, weakness of the anterior tibialis may produce a condition called foot drop. The result is a dragging of the foot producing a foot slap or tripping while walking.
Common conditions of the leg muscles include hip flexor strain , patella tendinitis, ruptured quadriceps tendon, quadriceps strain, hamstring strain, torn hamstring, muscle strain, gastrocnemius tear and gastrocnemius strain, achilles tendinitis, achilles tendon rupture, posterior tibialis tendonitis, peroneal tendinitis, drop foot, anterior tibialis tendinitis, shin splints, anterior compartment syndrome.
For approximately the first 72 hours following an injury, the RICE regime should be followed to ensure control of inflammation and pain relief.
R – Rest
I – Ice
C - Compression
E - Elevation
Rest from aggravating activity.
Ice should be applied in the first 72 hours or when inflammation persists. Ice should be applied for 15 to 20 minutes at a time. Ice should not be applied directly to the skin, but through a wet towel or cloth.