The Patella

From WikiMD
Jump to navigation Jump to search

Anatomy > Gray's Anatomy of the Human Body > II. [Osteology]] > 6c. 4. The Patella

Henry Gray (1821–1865). Anatomy of the Human Body. 1918.

6c. 4. The Patella

(Knee Cap)


The patella (Figs. 255, 256) is a flat, triangular bone, situated on the front of the knee-joint. It is usually regarded as a sesamoid bone, developed in the tendon of the Quadriceps femoris, and resembles these bones (1) in being developed in a tendon; (2) in its center of ossification presenting a knotty or tuberculated outline; (3) in being composed mainly of dense cancellous tissue. It serves to protect the front of the joint, and increases the leverage of the Quadriceps femoris by making it act at a greater angle. It has an anterior and a posterior surface three borders, and an apex.


image255.gif


FIG. 255– Right patella. Anterior surface. (Picture From the Classic Gray's Anatomy)


image256.gif


FIG. 256– Right patella. Posterior surface. (Picture From the Classic Gray's Anatomy)


Surfaces—The anterior surface is convex, perforated by small apertures for the passage of nutrient vessels, and marked by numerous rough, longitudinal striæ. This surface is covered, in the recent state, by an expansion from the tendon of the Quadriceps femoris, which is continuous below with the superficial fibers of the ligamentum patellæ. It is separated from the integument by a bursa. The posterior surface presents above a smooth, oval, articular area, divided into two facets by a vertical ridge; the ridge corresponds to the groove on the patellar surface of the femur, and the facets to the medial and lateral parts of the same surface; the lateral facet is the broader and deeper. Below the articular surface is a rough, convex, non-articular area, the lower half of which gives attachment to the ligamentum patellæ; the upper half is separated from the head of the tibia by adipose tissue.

Borders—The base or superior border is thick, and sloped from behind, downward, and forward: it gives attachment to that portion of the Quadriceps femoris which is derived from the Rectus femoris and Vastus intermedius. The medial and lateral borders are thinner and converge below: they give attachment to those portions of the Quadriceps femoris which are derived from the Vasti lateralis and medialis.

Apex—The apex is pointed, and gives attachment to the ligamentum patellæ.

Structure—The patella consists of a nearly uniform dense cancellous tissue, covered by a thin compact lamina. The cancelli immediately beneath the anterior surface are arranged parallel with it. In the rest of the bone they radiate from the articular surface toward the other parts of the bone.

Ossification—The patella is ossified from a single center, which usually makes its appearance in the second or third year, but may be delayed until the sixth year. More rarely, the bone is developed by two centers, placed side by side. Ossification is completed about the age of puberty.

Articulation—The patella articulates with the femur.


Gray's Anatomy


W8MD logo

Ad. Tired of being overweight?. W8MD's insurance weight loss can HELP*

Lose weight King of Prussia, PA | Lose weight NYC | Lose weight NJ | Lose weight Philadelphia | Advertise
Other languages:
English

Disclaimer: The entire contents of WIKIMD.ORG are for informational purposes only and do not render medical advice or professional services. If you have a medical emergency, you should CALL 911 immediately! Given the nature of the wiki, the information provided may not be accurate, misleading and or incorrect. Use the information on this wiki at your own risk! See full Disclaimer. * Individual results may vary for weight loss from our sponsors.

Our sponsors WikiMD is supported by W8MD weight loss, sleep and medical aesthetic centers.