Appendicular Skeleton Self Test Flashcards
(11 cards)
Why is the clavicle at risk to fracture when a person falls on his or her shoulder?
The clavicle is prone to fracture during falls on the shoulder because it is a slender, superficial bone that acts as a critical load-bearing link between the upper limb and axial skeleton, absorbing much of the shock during impact.
Distinguish between the true pelvis and the false pelvis.
False Pelvis:
* Location: Above pelvic brim
* Boundaries: Iliac crests and lumbar vertebrae
* Function: Supports abdominal organs
* Role in Birth: None
* Structure: Broad and shallow
True Pelvis:
* Location: Below pelvic brim
* Boundaries: Pelvic bones and sacrum
* Function: Involved in childbirth
* Role in Birth: Critical (forms birth canal)
* Structure: Narrow and deep
Describe the anatomical adaptations of the female pelvis for childbirth.
The female pelvis is specifically structured to create a birth canal that is wide, spacious, and minimally obstructive, ensuring that the fetus can safely pass through during labor and delivery.
What are the adaptations of the female pelvis compared to the male pelvis?
Female Pelvis:
* Pelvic Inlet: Wider and more oval
* Pelvic Outlet: Larger and wider
* Pelvic Cavity: Roomier and broader
* Pubic Arch: Broader angle (> 80–90°)
* Sacrum: Shorter, wider, less curved
* Ischial Spines: Farther apart, less prominent
* Overall Pelvis Shape: Shallow and wide (gynecoid type)
Male Pelvis:
* Pelvic Inlet: Narrower and heart-shaped
* Pelvic Outlet: Smaller
* Pelvic Cavity: Narrow and funnel-shaped
* Pubic Arch: Narrower angle (< 70°)
* Sacrum: Longer, narrower, more curved
* Ischial Spines: Closer together, more prominent
* Overall Pelvis Shape: Deep and narrow (android type)
Why is the femur slanted medially?
The femur slants medially to:
* Bring the knees under the center of gravity
* Improve balance and stability
* Enhance walking efficiency
* Knee Joint stability
What is the primary weight-bearing bone in the human body?
The femur (thigh bone) is the primary weight-bearing bone of the human body.
What are the key structural features of the femur?
Aspect:
* Size and Strength: Largest, longest, and strongest bone
* Shape: Slightly curved and slanted medially
* Proximal End: Fits into the acetabulum of the pelvis
* Distal End: Articulates with the tibia and patella
* Cortical Bone Thickness: Thick layer of compact bone
* Spongy Bone in Ends: Contains spongy bone to absorb shocks
Which bony landmark is used to determine where to give an intramuscular injection on the lateral thigh?
The greater trochanter serves as a reliable, easily located landmark for guiding safe and accurate IM injections into the lateral thigh.
Describe the arches of the feet and their functional importance.
The foot has three major arches:
A. Medial Longitudinal Arch:
* Formed by: Calcaneus, talus, navicular, cuneiforms, and first three metatarsals
* Functions: Absorbs shock, supports body weight, helps push off
B. Lateral Longitudinal Arch:
* Formed by: Calcaneus, cuboid, and fourth and fifth metatarsals
* Function: Provides balance and stability
C. Transverse Arch:
* Runs across the foot
* Formed by: Bases of metatarsals and cuneiforms
* Function: Distributes body weight and maintains balance
What does the term ‘flat feet’ mean?
Flat Feet (Pes Planus):
* Cause: Collapse or underdevelopment of the medial longitudinal arch
* Appearance: Foot sole touches the ground entirely when standing
* Consequences: Can cause pain, fatigue, and poor posture
What does the term ‘claw feet’ mean?
Claw Foot (Pes Cavus):
* Cause: Exaggerated high arch, often due to neurological or muscular disorders
* Appearance: Toes are flexed, and heel bears excessive weight
* Consequences: Leads to instability, calluses, and difficulty fitting shoes
