Lower Limb Bones Flashcards
1
Q
What are the three types of bone in the foot?
A
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).
2
Q
What are the three rows of tarsal bones and the bones in them?
A
Proximal - talus and calcaneus.
Intermediate - navicular.
Distal - cuboid and three cuneiforms.
3
Q
What are the three articulations of the talus?
A
Superiorly - ankle joint, between talus and tibia and fibula.
Inferiorly - subtalar joint, between talus and calcaneus.
Anteriorly - talonavicular joint, between talus and the navicular.
4
Q
What is the main function of the talus?
A
To transmit forces from the tibia to the heel bone (calcaneus).
5
Q
What are the two articulations of the calcaneus?
A
Superiorly - subtalar joint, between calcaneus and the talus.
Anteriorly - calcaneocuboid joint, between calcaneus and the cuboid.
6
Q
What is the main function of the calcaneus?
A
Transmits forces from the talus to the ground. Also site of attachment for the Achilles tendon.
7
Q
What gives the navicular its name?
A
It is boat shaped.
8
Q
What are the articulations of the navicular?
A
Posteriorly - talonavicular joint, between navicular and talus.
Anteriorly - with cuneiform bones.
Laterally - with the cuboid bone.
9
Q
Where does the tibialis posterior tendon attach on the navicular?
A
On the plantar surface, the tuberosity.
10
Q
Where is the cuboid situated in relation to the cuneiform bones?
A
It is the most lateral bone.
11
Q
What are the articulations of the cuboid?
A
Posteriorly - with calcaneus bone.
Anteriorly - with two metatarsal bones.
12
Q
What is the groove for on the inferior surface of the cuboid?
A
The fibularis muscle.
13
Q
What are the three cuneiform bones?
A
Lateral, intermediate, and medial.
14
Q
What shape are the cuneiform bones?
A
Wedge shaped.
15
Q
What are the articulations of the cuneiform bones?
A
Posteriorly - with navicular bone.
Anteriorly - with metatarsal bones.
16
Q
Which bones help form the transverse arch of the foot?
A
The three cuneiforms.
17
Q
Which tarsal bones are most frequently fractures and why?
A
The talus and calcaneus as they are involved in transmitting forces from the body to the ground.
18
Q
What are the fractures possible of the talus?
A
Neck or body fractures.
19
Q
What causes neck fractures of the talus?
A
Excessive dorsiflexion of the foot. The neck of the talus is pushed against the tibia.
20
Q
What is a complication of a neck fracture of the talus?
A
The blood supply can be disturbed and lead to avascular necrosis of the bone.
21
Q
What causes body fracture of the talus?
A
Jumping from a height.
22
Q
Why is there little displacement of fragments in talus fractures?
A
The malleoli of the leg bones hold the fragments together.
23
Q
How is the calcaneus often fractured?
A
In a crush type injury, like falling onto the heel from a height - the talus is driven into the calcaneus.
24
Q
What is a comminuted fracture?
A
The bone breaks into several pieces.
25
How does a fractures calcaneus appear on X ray?
Shorter and wider.
26
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.
27
How are the metatarsals numbered?
I to V medially to laterally.
28
What is the location of the metatarsals?
In the midfoot, between tarsals and phalanges.
29
What is the structure of metatarsals?
They have a distal head and a proximal base, joined by a shaft of bone.
30
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)
31
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).
32
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.
33
What is the longest bone in the body?
The femur.
34
What is the main function of the femur?
To transmit forces from the tibia to the hip joint.
35
What bones articulate at the hip joint?
The proximal end of the femur and the pelvis.
36
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.
37
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.
38
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.
39
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.
40
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.
41
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.
42
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).
43
How many people with femoral neck fractures die within a year?
1/3.
44
What are the two main groups of femoral neck fracture?
Intracapsular and extracapsular.
45
Who are intracapsular femoral neck fractures common in?
Elderly women.
46
What causes intracapsular femoral neck fractures?
A minor trip or stumble.
47
What is a complication of intracapsular femoral neck fractures?
The fracture happens in the capsule of the hip joint, and it can damage the femoral circumflex artery and thus cause avascular necrosis of the femoral head.
48
What is the clinical appearance of intracapsular femoral neck fractures?
The leg looks shorter with the toes pointing laterally due to the distal fragment being pulled upwards and rotated laterally.
49
How do extracapsular fractures of the the femoral neck present?
The leg is shortened and laterally rotated.
50
What is the difference between intracapsular and extracapsular fractures of the femoral neck?
Intra is in the capsule but extra is not, so with extra, you don't get avascular necrosis as the blood supply is maintained.
51
What direction does the shaft of the femur descend in?
Slight medial direction to bring the knees closer to the body's centre of gravity for stability.
52
What are the linea aspera on the shaft of the femur?
Roughened ridges of bone on the posterior surface of the shaft.
53
What are the medial and lateral borders of the linea aspera on the shaft of the femur?
Medial - pectineal line.
| Lateral - gluteal tuberosity.
54
What attaches at the gluteal tuberosity?
The gluteus maximus.
55
What forms the floor, medial and lateral supracondylar lines of the popliteal fossa?
The linea aspera as it widens forms the floor.
| The medial and lateral borders form the medial and lateral supracondylar lines respectively.
56
Where does the medial supracondyle line stop and what attaches?
Adductor tubercle, the adductor magnus attaches.
57
What can cause fractures of the femoral shaft?
A lot of fore, like in a vehicular accident.
58
How does a spiral fracture of the femoral shaft present?
With leg shortening as the fragments override, pulled by the attached muscles.
59
What is a possible sequelae of a femoral shaft fracture?
Femoral nerve palsy.
60
Why must the blood supply from the femoral artery be checked in femoral shaft fractures?
Because it has to supply the rest of the lower limb.
61
What forms the knee joint?
The medial and lateral condyles on the distal femur articulating with the tibia and patella.
62
Describe the medial and lateral condyles. (Include their shape, and their articulations).
They are rounded areas at the end of the femur. The posterior and inferior surfaces articulate with the tibia and menisci of the knee. Anterior surface articulates with the patella.
63
Describe the medial and lateral epicondyles. (Include what they, and what attaches).
Bony elevations on the non articular areas of the condyles. Some muscles and collateral ligaments of the knee joint attach here.
64
Describe the intercondylar fossa. (Include what it is, and what attaches).
A depression on the posterior surface of the femur between the two condyles. The internal knee ligaments attach to the two facets.
65
Describe the facet for attachment of the posterior cruciate ligament. (Include where it is, its shape, and what attaches).
On medial wall of the intercondylar fossa, has large rounded flat face. The posterior cruciate ligament of the knee attaches here.
66
Describe the facet for attachment of the anterior cruciate ligament. (Include where it is, and what attaches).
On the lateral wall of the intercondylar fossa. The anterior cruciate ligament of the knee attaches here.
67
Where is the patella located?
Within the patellofemoral groove of the femur.
68
Where does the patella attach?
Superiorly - to the quadriceps tendon.
| Inferiorly - to the patellar ligament.
69
What type of bone is the patella?
A sesamoid type, it's within a tendon. The largest sesamoid bone in the body.
70
What are the two facets of the patella and what do they articulate with?
Medial facet - articulates with the medial condyle of the femur.
Lateral facet - articulates with the lateral condyle of the femur.
71
What is the shape of the patella and what gives it its shape?
It is triangular - apex sits inferiorly and is connected to the tibial tuberosity by the patella ligament, the base forms the superior aspect of the bone, and provides the attachment area for the quadriceps tendon.
72
What are the main functions of the patella?
Leg extension - enhances leverage that the quadriceps tendon can exert on the femur to increase efficiency.
Protection - protects anterior aspect of knee joint from physical trauma.
73
What happens in patella dislocation?
The bone is displaced out of the patellofemoral groove.
74
What are the normal causes of patella dislocation?
High force impact on the patella from causing lateral dislocation or forceful sudden twisting.
75
How are patella fractures caused?
From direct trauma to the bone or sudden contraction of the quadriceps muscle.
76
What happens to the fragments if the patella fragments in fracture?
They separate, proximal fragment is displaced superiorly by the quadriceps tendon and the distal fragment is pulled inferiorly by the patellar ligament.
77
What does the tibia articulate to form at its proximal and distal end?
Proximal - knee joint.
| Distal - ankle joint.
78
How do the size and function of the tibia relate?
Its function is weight bearing so it is the second largest bone in the body.
79
What widens the tibia at the proximal end?
The medial and lateral condyles to form the flat tibial plateau surface.
80
What does the proximal end of the tibia articulate with?
The femoral condyles to form the major articulation of the knee joint.
81
What is between the two condyles of the tibia?
The intercondylar eminance - two tubercles and a roughened area.
82
What attaches at the intercondylar eminance?
The ligaments and the menisci of the knee joint.
83
Where is the tibial tuberosity?
On the anterior surface of the proximal tibia, inferior to the condyle.
84
What attaches at the tibial tuberosity?
The patella ligament.
85
What are the three surfaces of the shaft of the tibia?
Anterior, posterior, and lateral.
86
What is the anterior border of the shaft of the tibia?
Start is marked by the tibial tuberosity - palpable down the surface of the leg as the shin. The periosteal covering the tibia is susceptible to damage that presents as bruising.
87
What is the posterior border of the shaft of the tibia?
Marked by the soleal line (a ridge of bone). It runs inferomedially and blends with the medial border of the tibia eventually where the soleus muscle originates.
88
What is the lateral border of the shaft of the tibia?
The interosseous border, attachment site for the interossesous membrane that binds the tibia and fibula together.
89
Why does the distal end of the tibia widen?
To help with weight bearing.
90
What is the medial malleolus on the distal end of the tibia?
The bony projection continuing inferiorly on the medial side.
91
What forms the ankle joint?
The medial malleolus and the tarsal bones articulating.
92
Where does the tibialis posterior muscle attach to the tibia?
On the posterior surface.
93
What is the fibular notch?
The notch on the distal end of the tibia, where the fibula is bound to the tibia.
94
Who suffers most commonly with fractures of the tibia?
Middle aged and elderly.
95
When is fragment displacement minimal with tibia fractures?
When the fibula is not fractured so can support the weight of the leg instead.
96
What part of the tibia fractures most commonly?
The proximal end, from traumatic accidents like vehicular accidents.
97
What happens in a proximal fracture of the tibia?
The condyles may be broken up, and the ligaments of the knee can be damaged.
98
What can cause ankle fractures?
Overinversion so the talus of the foot is forced against the medial malleolus, causing a spiral fracture.
99
Where is the fibula?
Lateral to the tibia.
100
What is the main function of the fibula?
To be a site of attachment for muscles.
101
Why has the proximal end of the fibula got an enlarged head?
It's a facet for articulation with the lateral condyle of the tibia.
102
Where is the common fibular nerve?
On the posterior and lateral surface of the fibular neck.
103
What are the three surfaces of the fibular shaft?
Anterior, lateral, and posterior.
104
What is the lateral malleolus?
The inferior lateral surface of the fibula.
105
Where is the fibula prone to fracture?
At the ankle, the lateral malleolus is susceptible.
106
What are the two methods of fibula fracture?
External rotation or eversion.
107
How can external rotation of the ankle fracture the fibula?
The force of the talus against the bone causes a spiral fracture of the lateral malleolus.
108
How can eversion of the foot fracture the fibula?
The foot is twisted outwards and the talus presses against the lateral malleolus to cause a transverse fracture.
