1. The Lower Extremities

2. Function of Lower Limbs
The lower limbs carry our total body weight when we are upright.
Compared to the upper limbs, they are stronger and thicker.

3. Attachment
The lower limbs are attached to the vertebrae at the coxal bones (AKA hip bones)
The coxal bones articulate with the sacrum posteriorly, and anteriorly, they are held together with fibrocartilage.

4. The Coxal Bones Three fused bones per side of the body
Commonly called the “hip bones”
Together with the sacrum and coccyx, they form the pelvic girdle.

5. Although the suture lines are hard to find, each coxal bone is formed by the fusion of 3 different bones:
The ilium
The ishium
The pubis

7. The Ilium It is a large broad bone that forms most of your hips.
The upper edge is the iliac crest and is an important anatomical landmark.
It connects posteriorly with the sacrum at the sacroiliac joint.

9. The Ischium AKA the “sitdown bone”
The most inferior portion of the coxal bones.
Has a rounded, rough curve that is actually what we sit on.

10. Has a small projection called the ischial spine that is an important landmark, esp in pregnant women.
If the spine is too large or long, it can interfere with the delivery during birth.

11. The Pubis The most anterior part of the coxal bones.
Fuses the 2 coxal bones ateriorly at a cartilaginous joint called the pubis symphysis.
This joint is flexible and in women, it is what allows the pelvis to widen and accommodate the developing fetus.

13. The Socket
The ilium, the ishium, and the pubis all meet and fuse at the socket called the acetabulum.
This deep socket is where the head of the femur will attach to the pelvis.

14. The pelvis is divided into two major regions:
The True v False Pelvis
The pelvis is divided into two major regions:
The false pelvis = the area from iliac crest to iliac crest.
The true pelvis = the inferior portion of the pelvis. This is the area that allows a child to pass during childbirth.

15. False Pelvis
True Pelvis

16. The Male vs the Female Pelvis
The female has a larger pubic arch and is more circular
The female bones are thinner
The female ilium flare more laterally
The female sacrum is shorter and less curved

17. Female Pelvis
Male Pelvis

18. The Femoral Region Made up of one bone, the femur.
Is the heaviest and strongest bone of the human body.
The proximal head is ball-like and fits into the acetabulum of the pelvis.

19. The femur slants medially as it runs downward.
This brings the knees in line with the body’s center of gravity.
Head
Patellar surface

20. Distally, the femur has 2 knob-like areas:
The lateral condyle
The medial condyle
Both of these bones articulate with the tibia below.
Anteriorly, the distal femur has a smooth patellar surface where the patella joins to form the knee joint.
Lateral condyle
Medial condyle
Patellar surface

21. The Lower Leg
Made up of 2 bones:
The tibia
The fibula

22. Are connected with an interosseous membrane that hold the 2 bones together along their length.

23. The Tibia AKA the “shin bone”
The larger and more medial of the 2 lower leg bones.
The proximal end has medial and lateral condyles that articulate with the distal part of the femur at the knee.

24. Lateral condyle
Medial condyle

25. The Tibia
The anterior surface of the tibia, the tibial crest is the sharp edge that is easily felt beneath the skin.
Has a distal protrusion that forms the inner part of the ankle called the medial malleolus.

26. The Fibula Is thin bone that lies lateral to the tibia.
Has no part in forming the knee joint.
Has a distal protrusion that forms the outer part of the ankle called the lateral malleolus.

27. The Foot Made up of 26 bones: 7 tarsal bones 5 metatarsal bones
14 phalanges
The foot bones are all held together with ligaments

29. Has 5 small and 2 large tarsal bones:
The calcaneus or the “heel bone”
The talus, sits inferior to and articulates with the tibia
The arch of the foot is made up the metatarsal bones. (numbered 1 – 5, medial to lateral)
The toes of the foot are the phalanges. (numbered 1 – 5, starting with the hallux)