Lower Limb Anatomy Set 4

The talar head is the keystone of the medial
longitudinal arch

The iliopsoas is the strongest flexor of the
hip joint

The lateral ligament consists of the anterior
and posterior talofibular ligaments and the calcaneofibular ligament. The three discrete ligaments are collectively referred to as the lateral
ligament. The fibrous capsule is reinforced
medially by the large, strong medial ligament
(deltoid ligament), which attaches proximally
to the medial malleolus. This ligament consists
of the tibionavicular, tibiocalcaneal, and anterior and posterior tibiotalar ligaments

The ankle is the most frequently injured
major joint in the body. Ankle sprains are most
common. A sprained ankle is nearly always an
inversion injury

A Pott’s fracture-dislocation of the ankle
occurs when the foot is forcibly everted. 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 inferior tibiofibular
joint

The tibial nerve leaves the posterior compartment of the leg by passing deep to the
flexor retinaculum in the interval between
the medial malleolus and calcaneus. The area
involved is from the medial malleolus to the
calcaneus, and the heel pain results from compression of the tibial nerve by the flexor retinaculum

The middle genicular branches of the popliteal artery penetrate the fibrous capsule of the knee joint and supply the cruciate ligaments,
synovial membrane, and peripheral margins of
the menisci

The lateral meniscus is nearly circular
and is smaller and more movable than the
medial meniscus. The tendon of the popliteus
separates the lateral meniscus from the fibular
collateral ligament. A strong tendinous slip,
the posterior meniscofemoral ligament, joins
the lateral meniscus to the posterior cruciate
ligament and the medial femoral condyle.
The lateral meniscus acts like a shock
absorber

The tibialis anterior is the strongest dorsiflexor and invertor of the foot

The lateral meniscus is nearly circular
and is smaller and more movable than the
medial meniscus. The tendon of the popliteus
separates the lateral meniscus from the fibular
collateral ligament. A strong tendinous slip,
the posterior meniscofemoral ligament, joins
the lateral meniscus to the posterior cruciate
ligament and the medial femoral condyle.
The lateral meniscus acts like a shock
absorberThe lateral meniscus is nearly circular
and is smaller and more movable than the
medial meniscus. The tendon of the popliteus
separates the lateral meniscus from the fibular
collateral ligament. A strong tendinous slip,
the posterior meniscofemoral ligament, joins
the lateral meniscus to the posterior cruciate
ligament and the medial femoral condyle.
The lateral meniscus acts like a shock
absorber

Genu varum and genu valgum result in
deviation of the tibia from the midline. In genu
varum, the tibia is diverted medially, and in
genu valgum, the tibia is diverted laterally;
these deformities cause unequal weight distribution. In the varum deformity, the medial side of the knee takes all the pressure, leading to
wear and tear of the medial meniscus

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

The transverse tarsal joint is formed by the
combined talonavicular part of the talocalcaneonavicular and calcaneocuboid joints, two separate joints aligned transversely. Transection across the transverse tarsal joint is a standard method for surgical amputation of the
foot. Inversion and eversion of the foot are the
main movements involving these joints

Fractures of the femoral neck are intracapsular, and realignment of the neck fragments
requires internal skeletal fixation. Femoral neck
fractures are among the most troublesome and
problematic of all fractures

The plantar calcaneonavicular ligamentum
(spring ligament) extends from the sustentaculum tali to the posteroinferior surface of the navicular. It plays an important role in maintaining the longitudinal arch of the foot

Because of its minor role, the plantaris
tendon can be removed for grafting without
causing any disability

The grip of the malleoli on the trochlea is
strongest during dorsiflexion of the foot, because this movement forces the wider, anterior part of the trochlea posteriorly, spreading the
tibia and fibula slightly apart

Shin splints commonly result from traumatic injury or athletic overexertion of muscles
in the anterior compartment—especially the
tibialis anterior

Medial rotators of the hip joint include
anterior fibers of the gluteus medius, gluteus
minimus, and tensor fascia lata; lateral rotators
include the obturator externus, obturator internus, superior gemellus, piriformis, quadratus femoris, and gluteus maximus

The stability of the knee joint depends on
the strength and actions of the surrounding
muscles and their tendons. The ligaments that
connect the femur and tibia are also important.
Of these supports, the muscles are most important; therefore, many sport injuries are preventable through appropriate conditioning
and training. The most important muscle in
stabilizing the knee joint is the large quadriceps femoris, particularly inferior fibers of the vastus medialis and lateralis. The knee joint
will function surprisingly well following a ligament strain if the quadriceps is well conditioned

The ACL may tear when the tibial collateral
ligament ruptures. First, the tibial collateral ligament ruptures, opening the joint on the medial side and possibly tearing the medial meniscus
and ACL. This “unhappy triad of injuries” can
result from clipping in football

Dorsiflexion of the ankle is produced by
the muscles in the anterior compartment of the
leg

The pulse of the dorsalis pedis artery, or
dorsal artery of the foot, is evaluated during a
physical examination of the peripheral vascular system. Dorsalis pedis pulses may be palpated with the feet slightly dorsiflexed

The tendon of the biceps femoris may be
traced by palpating its distal attachment to the
lateral side of the head of the fibula. This tendon
and the neck of the fibula guide the examining finger to the common fibular nerve

Hallux valgus is a foot deformity characterized by lateral deviation of the great toe.
Hammertoe is a deformity in which the proximal phalanx is permanently flexed at the
metatarsophalangeal joint and the middle phalanx is plantarflexed at the interphalangeal joint.
The distal phalanx is also flexed. Claw toes are
characterized by hyperextension of the metatarsophalangeal joints and flexion of the distal
interphalangeal joints. Pes planus is flat feet,
and clubfoot refers to a foot that is twisted. The
foot is inverted, the ankle is plantarflexed, and
the forefoot is adducted