2a - Bones of the Lower Extremity

Question 1

Fovea capitis - Bone, location, and interactions.

Answer 1

The fovea capitis is the small pit on the head of the femur. It houses a ligament that anchors the femur to the acetabulum.

Question 2

Describe the trochanteric structures in the femur.

Answer 2

The greater and lesser trochanters are found inferior to the neck of the humerus. They’re connected by the intertrochanteric line anteriorly and the intertrochanteric crest posteriorly. These trochanters are sites of muscle attachment.

Question 3

Describe the markings on the shaft of the femur.

Answer 3

Gluteal tuberosity - Inferior to the intertrochanteric crest on the proximal end of the posterior shaft. The inferior portion blends with the linea aspera.
Linea aspera - a vertical line midway of the posterior shaft.
Lateral and medial supracondylar line - Extend superiorly from their respective condyles and meet onto the linea aspera.

Question 4

Describe the distal end of the femur.

Answer 4

At the inferior portion of the femur on the posterior side are the lateral and medial condyles that are joints that articulate with the tibia. These condyles are separated by an intercondylar fossa.
On the anterior side, there is the patella surface that articulates with the patella (knee cap).
On the side of the condyles are the lateral and medial epicondyles that muscles and ligaments attach to.
Superior to the medial epicondyle is the adductor tubercle.

Question 5

Describe interactions between the tibia and fibula.

Answer 5

The tibia and fibula articulate at superior and inferior joints. Unlike the radioulnar joints, they provide no movement.
There is also an interosseous membrane between the two bones spanning the entire length.

Question 6

Describe the proximal end of the tibia.

Answer 6

On the superior surface are the lateral and medial condyles of the tibia, which interact with their respective condyles on the femur. In between the two condyles are the intercondylar eminence that borders the condyles.
On the inferior portion of the lateral condyle is a facet that articulates with the fibula to form the superior tibiofibular joint.
On the anterior surface of the tibia just inferior to the condyles is the tibial tuberosity, a site of attachment for the patellar ligament.

Question 7

Describe the shaft and distal end of the tibia.

Answer 7

The shaft is triangular in cross-section with a sharp anterior border.
The distal end of the tibia is flat to articulate with the talus of the foot. Medial to this joint is the medial malleolus, which makes the medial bulge of the ankle. Lateral to the joint is the fibular notch that articulates with the fibula to form the inferior tibiofibular joint.

Question 8

Describe the fibula.

Answer 8

Lateral to the tibia.
Heavily ridged shaft.
Proximal end is the head of the fibula.
Distal end is the lateral malleolus and forms lateral bulge of the ankle. Articulates with the talus of the foot.
Doesn’t bare any weight, but muscles originate on this bone.

Question 9

What are two important functions of the foot?

Answer 9

1) Support body weight

2) Act as a lever to propel the body during movement

Question 10

Name the 7 tarsals and locations.

Answer 10

Calcaneus is located in the heel of the foot.
Talus is found on top of the calcaneus.
Navicular is anterior to the talus.
The remain four surround the anterior and lateral borders of the navicular. In anterior to lateral order: Medial Cuneiform, Intermediate Cuneiform, Lateral cuneiform, and Cuboid.

Question 11

Talus - Location, Interactions, and Markings.

Answer 11

Located between in the ankle superior to the heel of the foot.
Articulates with the tibia superiorly at the trochlea of the talus. Articulates with the calcaneus inferiorly.

Question 12

Calcaneus - Location, Interactions, and Markings.

Answer 12

Found in the heel of the foot.
Superior surface articulates with talus. Tendons of the calf attaches to the posterior surface.
The calcaneus has two markings. The calcaneal tuberosity is the surface that touches the ground and the sustentaculum tali (or talar shelf) is the medial shelflike projection.

Question 13

Describe the metatarsus.

Answer 13

There are five metatarsals labeled I to V from medial to lateral that make up the metatarsus. These are more parallel to each other than the metacarpals.
Distally articulates with the proximal phalanges of the toes.
The first metacarpal has an enlarged head distally that forms the ball of the foot.

Question 14

Describe the phalanges.

Answer 14

There are 14 phalanges in the toes. Each toe has a distal, middle, and proximal phalange except the hallux (big toe).

Question 15

Name the arches of the foot.

Answer 15

1) Medial longitudinal arch
2) Lateral longitudinal arch
3) Transverse arch

Question 16

Medial longitudinal arch - Location, Structure, and Keystone.

Answer 16

Found on the medial side of the foot. The arch has a high curve.
It starts at the calcaneus, rises to the talus, and descends to the three medial metatarsals. The talonavicular joint is the keystone of this arch.

Question 17

Lateral longitudinal arch - Location, Structure, and Keystone.

Answer 17

Found on the lateral side of the foot. Curves low.
Starts at the calcaneus, rises to the cuboid bone, then descends onto the fifth metatarsal. Redistributes weight to the calcaneus and the head of the fifth metatarsal.
The keystone is the cuboid bone.

Question 18

Transverse arch - Location and Structure.

Answer 18

Found perpendicular to the direction of the foot.

Runs obliquely following line of joints between tarsals and metatarsals. Uses both longitudinal arches as pillars.