Skeletal System: Common Bone Landmarks
Common Names of Skeletal System Landmarks
This video discusses the common names of bone landmarks, which are surface features of bone such as grooves, indentations, holes, and projections. These landmarks are categorized into four types.
I. Landmarks that are Articulating Surfaces (Part of a Joint)
These landmarks are involved in forming joints.
Condyle:
Definition: A large, rounded articulating knob.
Example: The knobby, distal ends of the femur are condyles.
Head:
Definition: A prominent, rounded articulating end of a bone.
Example: The superior, rounded end of the femur is known as the head of the femur.
Facet:
Definition: A small articular surface.
Example: On the atlas (cervical vertebra number one), there is a smooth, small, flat surface on the inside near the vertebral foramen called the articular facet for the dens process.
II. Landmarks that are Projections for Muscle Attachment
These are areas of bone where muscles attach to the bone.
Process:
Definition: A prominent projection or a piece of bone that sticks out.
Examples:
On a thoracic vertebrae, projections include the transverse process (lateral projection) and the spinous process (posterior projection).
On the ulna, the piece at the end near the head is the styloid process.
Crest:
Definition: A narrow, ridge-like projection.
Example: The upper part of the pelvic bone features the iliac crest.
Spine:
Definition: A sharp, slender process.
Examples:
On the facial bone, there is the nasal spine.
On the scapula, there is the scapular spine.
Trochanter:
Definition: A massive process found only on the proximal femur.
Examples: On the proximal end of the femur, the large rounded projection is the greater trochanter, and a smaller projection nearby is the lesser trochanter.
Tubercle:
Definition: A small, rounded process.
Examples: On the proximal end of the humerus, there is a lesser tubercle (small rounded process) and a greater tubercle (another small rounded process, typically larger than the lesser).
Tuberosity:
Definition: A large, roughened process.
Examples:
On the anterior aspect of the proximal tibia, a noticeable bump is called the tibial tuberosity.
On the radius, a rough bump is called the radial tuberosity.
Epicondyle:
Definition: A projection located on top of or above a condyle.
Example: On the femur, situated on the lateral and medial aspects of the condyles, are tiny bumps referred to as the lateral epicondyle and medial epicondyle, respectively.
III. Landmarks that are Depressions or Openings
These landmarks consist of holes, tunnels, or indentations in the bone.
Foramen:
Definition: A hole or a rounded opening through the bone.
Examples:
On the inferior part of the skull, the large hole where the spinal cord exits is the foramen magnum.
A thoracic vertebrae contains a vertebral foramen.
Cervical vertebrae feature additional holes called transverse foramen.
Meatus:
Definition: A tunnel or tube-like passageway through the bone.
Key Point: The only meatus specifically highlighted is the external auditory meatus, also known as the ear canal, responsible for hearing.
Fossa:
Definition: A shallow indentation or groove.
Examples:
On the pelvic bone, there is a shallow indentation referred to as the iliac fossa.
On the skull, after removing the lower jaw, an indentation for its articulation is called the mandibular fossa.
IV. Other Landmarks
These are landmarks that do not fit into the previous three categories.
Body / Shaft:
Definition: The main, central part of a bone.
Examples:
The main, central portion of a vertebrae is called the body.
In long bones like the humerus or femur, the elongated central part is called the shaft.
Neck:
Definition: The area of bone situated between the head and the body (or shaft) of that bone.
Examples:
On the humerus, the area between the head and the shaft is known as the anatomical neck.
On the femur, the region connecting the head to the shaft is referred to as the neck of the femur.