Lecture 27 – Bones – Lower Extremities – Femur, Tibia, and Fibula

Femur – Larger and heavier than other bones.  Proximally, there is a greater and a lesser trochanter.  (Muscles attach to the greater trochanter.)

Distally, you will find the lateral and medial epicondyles.  The neck of the femur is the most frequent and common site of fracture, especially in older people.  The patella, kneecap is between the condyles.  The patella is sesamoid, or shaped like a sesame seed.  The tendon of the quad surrounds the patella.  In other words, the patella is housed in the tendon of quadricepts femoris.  Its job is to stabilize the knee joint.

The epiphyseal plate is where bones grow.  This bone growth ceases by age 21.  X-rays can assist in identifying age.

The tibia is the weight bearing bone of the lower extremity (medial).  It is triangular shaped.  You can feel the apex of the triangle of the tibia through the skin.  There is no muscle on it.  It is only covered with periosteum, that is filled with nerve fibers.  Do you remember the mischievous children who would kick someone in the shins?  Ouch!

The tibia articulates on the proximal end with the femur and the fibula.  The tibia articulates distally with the ankle bone (talus) and fibula.  The fibula is thin and slender.  (I have shared the silly joke before.  We once had a childcare provider named Fibiola.  She loved my youngest child and held him for hours.  She spoke Portuguese and we did not.  It was hilarious.  She was adorable and came highly recommended by her English-speaking relatives.  We just smiled, drew pictures, and spoke body language.  Needless to say, I will never forget her.  The point is, she was tall and thin, like the fibula.)  Use any mental picture you can use to honestly pass the test.

The protrusion, or medial aspect of the distal tibia, which is the medial malleolus, or hammer.

To Review:

Fibula – long, thin and lateral – not weight bearing, muscle attachments, only.

Proximal articulation – tibia; distally it articulates with the talus.

The lateral malleolus is usually larger and is part of the leg.  Many people think it is part of the ankle.

Tarsal bones (7) true ankle bones

2 largest –        calcaneus – heel bone- the Achilles tendon attaches to it

talus

Metatarsals – sole of the foot – 5

1st is the largest and is weight bearing

The 5th is frequently fractured – the dancer’s fracture – 5th metatarsal

Phalanges – Big toe has 2, just like the thumb.  All others have three.

We should be able to cover my final thoughts on bones in two more sessions.  We will make some brief comments of joints, cartilage, and bone formation.  As promised, we will do an extensive survey of blood before going on to some popular muscles.  Do well with this information.

Advertisements

Leave a comment

Filed under The Skeletal System

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s