SURFACE FEATURES OF BONES

Some help for students of Biology 213 and 214, introductory Anatomy and Physiology

Page by Dr. Joe Camp and Dr. Richard Hengst, Biology Dept. Purdue University / North Central Campus


Surface features can be divided into articulating surfaces (those which form joints) and those which are important for muscle or ligament attachments, for the passage of other structures, or for bone reinforcement. We loosely group things into the following four categories.
ARTICULATING SURFACES

-- A rounded projection set off from the body of a bone by a constriction (the neck) ex. head of femur -- Any large articulating surface, may be concave or convex; usually meshes with an opposing condyle. ex. condyle on the end of the femur and the opposing surface of the tibia. -- A smooth, flat surface, generally small. ex. articulating surfaces of vertebrae with vertebrae and that of the vertebrae with the rib. -- A shallow depression - THIS MAY OR MAY NOT BE AN ARTICULATING SURFACE. ex. (of articulating surface) glenoid fossa of the scapula or mandibular fossa of the temporal bone. ex. (non-articulating surface) subscapular fossa.

 

DEPRESSIONS

(a sharp deep groove) -- a sharp, narrow, cleftlike opening between the parts of a bone that allows for the passage of blood vessels and nerves. ex. Superior orbital fissure of the sphenoid. (a groove, but shallower and a less abrupt cleft than a fissure) -- a shallow, wide groove on the surface of a bone that allows for the passage of blood vessels, nerves and tendons. ex. intertubercular sulcus of the humerus, alternately known as the bicepital groove. (notch) -- a deep indentation on the border of a bone. ex. greater sciatic incisure or notch of the os coxa. -- a small, very shallow depression. ex. fovea capitus on the head of the femur accepts a tendon from the hip socket or Acetabulum.

OPENINGS

-- an opening through which blood vessels, nerves or ligaments pass. ex. Foramen magnum of the occipital bone, mental foramen of the mandible. (canal) -- a tubelike passage running through a bone. ex. the acoustic meatus of the temporal bone. 

ENLARGEMENTS & PROCESSES

-- the most generic term for bone projection that serves as a point for attachment of other structures. ex. acromion process of the scapula, transverse process of vertebrae.  -- a projection or swelling to the side of a condyle (or above, in some cases). ex. medial and lateral epicondyles of femur.  -- a sharp, slender projecting process. ex. spinous process of vertebrae, spine of the scapula.  -- a small rounded process. ex greater and lesser tubercles of humerus.  -- a large, rounded, roughened process. ex. ischial tuberosity of the ischium.  -- a large blunt projection for muscle attachments on the femur. ex. greater and lesser trochanters of the femur. (basically, a tuberosity taken to an extreme)  -- a prominent elevated ridge or border of a bone. ex. iliac crest of the Ilium (os coxa). (line) -- a small crest, usually somewhat straighter than a crest. ex. linea aspera of femur. -- a major branch or division off of the main body of a bone. This may have its own articulations or processes for ex. the coronoid and condylar processes of the mandible are subdivisions of the major ramus that angles off of the main body of the bone. -- a slight narrowing of the body of the bone that supports the head. ex. necks of the humerus and femur.  -- a very thin layer of bone. ex. the neural arch of the cervical vertebrae is an excellent example.