1. Which of the following is the largest and most complex
of the synovial joints?
A.knee
B.hip
C.elbow
D.wrist
E.ankle
ANS.A
EXPLANTION:-
The knee is the largest human
joint in terms of its volume and surface area of articulating cartilage. The
knee joint is also the most complex articulation in the body, and has the
greatest susceptibility to injury, age-related wear and tear, inflammatory
arthritis, and septic arthritis
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2. Which ligament originates from the anterior
intercondylar area of the tibia and extends to the lateral condyle of the
femur?
A.posterior cruciate
B.anterior cruciate
C.medial meniscus
D.lateral meniscus
E.
ANS.B
EXPLANTION:-
The anterior cruciate ligament
(ACL) is an important stabilizing ligament of the knee that is frequently
injured by athletes and trauma victims.The primary function of the anterior
cruciate ligament (ACL) is to control anterior translation of the tibia. The
ACL also is a secondary restraint to tibial rotation as well as varus or valgus
stress .The ACL originates at the posteromedial aspect of the lateral femoral
condyle. It courses distally in an anterior and medial fashion to the
anteromedial aspect of the tibia between the condyles. The position on the
tibia is approximately 15 mm behind the anterior border of the tibial articular
surface, and medial to the attachment of the anterior horn of the lateral
meniscus .The ACL is often said to be comprised of two bundles: an anteromedial
bundle that is tight in flexion and a posterolateral bundle that is tight in
extension. The blood supply to the ACL is from branches of the middle
geniculate artery and its innervation comes from the posterior articular nerve,
a branch of the tibial nerve.
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3. Which bone articulates with the distal tibia and
fibula?
A.Talus
B.calcaneus
C.navicular
D.cuboid
E.
ANS.A
EXPLANTION:-
The foot can be divided into three
functional parts: the hindfoot, midfoot, and forefoot [ 1 ]. The hindfoot,
which consists of the talus and the calcaneus, connects to the midfoot at the
midtarsal (Chopart) joint. The midfoot contains the navicular, the cuboid, and
the three cuneiform bones; it connects to the forefoot at the Lisfranc joint.
The forefoot includes everything distal to the Lisfranc joint, including the
metatarsals, sesamoids, and phalanges
The foot has 28 bones, including
14 phalanges, seven tarsal bones (talus, calcaneus, cuboid, navicular, and
three cuneiforms), five metatarsals, and two sesamoids. The bones that are
clinically significant can be organized according to their dynamic
articulations
The foot has four joints: the
ankle (mortise), subtalar (talocalcaneal), midtarsal (Chopart), and midfoot
(Lisfranc).The distal tibia and fibula form the roof of the ankle joint. The
dome of the talus fits snugly into the tibia and fibula. The primary plane of
movement at the ankle joint is plantarflexion/dorsiflexion.
The subtalar joint is composed of
the anterior, middle, and posterior articulations between the talus and the
calcaneus. They are separated laterally by the sinus tarsi and medially by the
tarsal canal. The subtalar joint is responsible for hindfoot inversion/eversion
and abduction/adduction.
The talonavicular and
calcaneocuboid articulations comprise the midtarsal joint and demarcate the
hindfoot from the midfoot. They are responsible for "unlocking" the
midfoot during subtalar pronation, allowing the foot to absorb more shock, and
for "locking" the midfoot during subtalar supination, allowing the
foot to become a rigid lever for propulsion.
The midfoot or Lisfranc joint is
the articulation between the three cuneiforms and the proximal second
metatarsal. It provides rigid stability to optimize efficiency through the
medial column of the foot.Ligaments —
The ankle has three main groups of ligaments
Lateral ligament complex– This
complex has three components:
The anterior talofibular ligament
(ATFL) connects the talus and distal fibula anteriorly.
The calcaneofibular ligament (CFL)
connects the calcaneus and distal fibula directly inferior to the lateral
malleolus.
The posterior talofibular ligament
(PTFL) connects the talus and fibula posteriorly.
Medial ligament complex – The
deltoid ligament, located on the medial side of the ankle, is a broad band of
connective tissue that has four separate divisions that connect the distal
tibia with the talus, calcaneus, and the navicular bones.
Tibiofibular ligament complex –
The tibiofibular complex consists of the anterior and posterior tibiofibular
and the interosseous membrane and ligament. This complex is responsible for
maintaining the relationship between the distal tibia and fibular and
preventing them from splaying apart with a cephalad force from the talus
The plantar fascia is the primary
aponeurosis that originates on the plantar aspect of the calcaneus and fans out
to attach to the base of each of the five metatarsal heads. It acts to
reinforce the medial arch during the propulsion phase of gait. Its windlass
effect on the medial longitudinal arch is important to the biomechanics of the
foot during the toe-off phase.
Muscles — The muscles of the foot and ankle originate
above the ankle (extrinsics) and within the foot (intrinsics).
The extrinsic muscles permit the
larger force-generating muscles to be located away from the foot and to avoid
interference with the intrinsic structure of the foot.
The anterior or extensor
compartment of the leg includes the following muscles:
The tibialis anterior originates
on the proximal anterior tibia and courses distally in its synovial sheath
beneath the extensor retinaculum to insert on both the medial cuneiform and the
medial base of the first metatarsal. It dorsiflexes and inverts the foot.
The extensor hallucis longus (EHL)
inserts on the dorsal aspect of the base of the distal phalanx of the great
toe. It extends the great toe and dorsiflexes the foot.
The extensor digitorum longus
(EDL) has a distal attachment on the middle and distal phalanges of the lateral
four digits and acts to extend these lateral four digits and dorsiflex the
foot.
The peroneus tertius inserts on
the base of the fifth metatarsal bone and acts in a minor role in dorsiflexion
and eversion of the foot.
The lateral compartment of the leg
contains the peroneus longus and peroneus brevis. The peroneus longus inserts
on the base of the first metatarsal bone and medial cuneiform bone and acts to
evert the foot and weakly plantarflex it. The peroneus brevis inserts on the
base of the fifth metatarsal and has the same action as does the peroneus
longus.
The superficial posterior
compartment of the leg contains the triceps surae (the gastrocnemius and soleus
complex), which insert via the Achilles tendon into the posterior surface of
the calcaneus. They are the force generators that plantarflex the foot and
weakly evert the heel.
The deep posterior compartment of
the leg contains the tibialis posterior (TP), flexor digitorum longus (FDL),
and flexor hallucis longus (FHL) muscles.
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