Lower Limb Bones Flashcards
What are the three types of bone in the foot?
Tarsals - 7 irregularly shaped bones, proximally situated.
Metatarsals - 5 bones that connect phalanges to the tarsal.
Phalanges - bones of the toes, each two has three (great toe has two only).
What are the three rows of tarsal bones and the bones in them?
Proximal - talus and calcaneus.
Intermediate - navicular.
Distal - cuboid and three cuneiforms.
What are the three articulations of the talus?
Superiorly - ankle joint, between talus and tibia and fibula.
Inferiorly - subtalar joint, between talus and calcaneus.
Anteriorly - talonavicular joint, between talus and the navicular.
What is the main function of the talus?
To transmit forces from the tibia to the heel bone (calcaneus).
What are the two articulations of the calcaneus?
Superiorly - subtalar joint, between calcaneus and the talus.
Anteriorly - calcaneocuboid joint, between calcaneus and the cuboid.
What is the main function of the calcaneus?
Transmits forces from the talus to the ground. Also site of attachment for the Achilles tendon.
What gives the navicular its name?
It is boat shaped.
What are the articulations of the navicular?
Posteriorly - talonavicular joint, between navicular and talus.
Anteriorly - with cuneiform bones.
Laterally - with the cuboid bone.
Where does the tibialis posterior tendon attach on the navicular?
On the plantar surface, the tuberosity.
Where is the cuboid situated in relation to the cuneiform bones?
It is the most lateral bone.
What are the articulations of the cuboid?
Posteriorly - with calcaneus bone.
Anteriorly - with two metatarsal bones.
What is the groove for on the inferior surface of the cuboid?
The fibularis muscle.
What are the three cuneiform bones?
Lateral, intermediate, and medial.
What shape are the cuneiform bones?
Wedge shaped.
What are the articulations of the cuneiform bones?
Posteriorly - with navicular bone.
Anteriorly - with metatarsal bones.
Which bones help form the transverse arch of the foot?
The three cuneiforms.
Which tarsal bones are most frequently fractures and why?
The talus and calcaneus as they are involved in transmitting forces from the body to the ground.
What are the fractures possible of the talus?
Neck or body fractures.
What causes neck fractures of the talus?
Excessive dorsiflexion of the foot. The neck of the talus is pushed against the tibia.
What is a complication of a neck fracture of the talus?
The blood supply can be disturbed and lead to avascular necrosis of the bone.
What causes body fracture of the talus?
Jumping from a height.
Why is there little displacement of fragments in talus fractures?
The malleoli of the leg bones hold the fragments together.
How is the calcaneus often fractured?
In a crush type injury, like falling onto the heel from a height - the talus is driven into the calcaneus.
What is a comminuted fracture?
The bone breaks into several pieces.
How does a fractures calcaneus appear on X ray?
Shorter and wider.
What problems come from calcaneus fractures?
The sub-talar joint is disrupted and can cause arthritis in the joint. There will be pain on inversion and eversion so walking on uneven ground is really painful.
How are the metatarsals numbered?
I to V medially to laterally.
What is the location of the metatarsals?
In the midfoot, between tarsals and phalanges.
What is the structure of metatarsals?
They have a distal head and a proximal base, joined by a shaft of bone.
What are the four articulations of the metatarsals?
Proximally – tarsometarsal (metatarsal bases and cuneiforms or cuboid bones)
Laterally – intermetarsal (metatarsal and adjacent metatarsal)
Distally – metatarsophalangeal (metatarsal head and proximal phalanx)
What are the three mechanisms of metatarsal fracture?
Direct blow to the foot - from heavy object dropping on foot, most common.
Stress fracture - incomplete fracture from repeated stress to the bone, common in athletes with metatarsal II, III and IV.
Excessive inversion - foot is violently inverted and fibularis brevis muscle avulses the base of metatarsal V (tear off).
What are the phalanges of the lower limb?
Bones of the toes, each toe has a proximal, intermediate, and distal except from the great toe that only has proximal and distal.
What is the longest bone in the body?
The femur.
What is the main function of the femur?
To transmit forces from the tibia to the hip joint.
What bones articulate at the hip joint?
The proximal end of the femur and the pelvis.
What makes up the proximal area of the femur?
A head, a nack, two bony processes - trochanters, and two bony ridges connecting the two trochanters.
Describe the head of the proximal area of the femur. (Include the surfaces and what attaches and articulates here).
Smooth surface with depression on medial surface - for ligament of the head to attach. Articulates with acetabulum of pelvis at hip joint.
Describe the neck of the proximal area of the femur. (Include its function, shape, and direction of projection).
Connects head of femur with the shaft. Cylindrical and project in superior and medial direction - angle of projection allows for more movement at hip joint.
Describe the greater trochanter of the proximal area of the femur. (Include position, direction of projection, and what attaches here).
Originates from the anterior shaft, just lateral to where the neck joins. Angled superiorly and posteriorly. Site of attachment of the abductor and lateral rotator muscles of the leg.
Describe the less trochanter of the proximal area of the femur. (Include projection, and what attaches here).
Projects form the posteromedial side of the femur, inferior to neck-shaft junction. The psoas major and iliacus muscles attach here.
Describe the intertrochanteric line of the proximal area of the femur. (Include function, attachments, and course).
It runs inferomedial on the anterior surface of the femur to connect the two trochanters together. Iliafemoral ligament attaches here. It becomes the pectineal line as it passes the lesser trochanter on the posterior surface.
Describe the intertrochanteric crest of the proximal area of the femur. (Include function, position, and specific attachments).
It connects the two trochanters, on the posterior surface of the femur. The quadratus femoris attaches to the quadrate tubercle (round tubercle on superior half).
How many people with femoral neck fractures die within a year?
1/3.