Medical Terminology Chapter 3: Skeletal System

Thoracic Cavity

• Also known as the rib cage, it protects the heart and lungs.
• Composed of ribs, sternum, and the upper portion of the spinal column extending from the neck to the diaphragm.

Ribs

• Consist of twelve pairs that attach to the thoracic vertebrae posteriorly.

Types of Ribs

• True Ribs: First seven pairs that attach anteriorly to the sternum.
• False Ribs: Three pairs following true ribs, connecting to cartilage linking them to the sternum.
• Floating Ribs: Last two pairs that only attach posteriorly to vertebrae without anterior connections.

Sternum

• A flat bone located in the middle of the chest, which has three parts.

Parts of the Sternum

• Manubrium: Upper portion of the sternum.
• Body: Middle portion of the sternum.
• Xiphoid Process: Lower portion made of cartilage.

Shoulders

• Composed of the pectoral girdle which supports the arms and hands, consisting of the clavicle, scapula, and acromion.

Clavicle

• Known as the collarbone, it connects the manubrium to the scapula.

Scapula

• Also referred to as the shoulder bone.

Acromion

• An extension of the scapula that forms the highest point of the shoulder.

Arm Bones

• Humerus: Upper arm bone.
• Radius: Smaller, shorter bone in the forearm.
• Ulna: Larger, longer bone in the forearm, with the olecranon process being its large projection.

Wrist and Hand

• Carpal Bones: Eight bones that form the wrist and five metacarpal bones form the palms of the hand.
• Phalanges: Fourteen bones of the fingers; each finger has three bones, while the thumb has two.

Spinal Column

• Protects the spinal cord and supports the head, consisting of 26 vertebrae.

Structures of Vertebrae

• Body: Anterior portion providing strength.
• Lamina: Posterior portion of the vertebra.
• Vertebral Foramen: Opening allowing passage of the spinal cord.

Types of Vertebrae

• Cervical Vertebrae: Set of 7 (C1-C7), forming the neck.
• Thoracic Vertebrae: Set of 12 (T1-T12), each with a pair of ribs attached.
• Lumbar Vertebrae: Set of 5 (L1-L5), largest and strongest, bearing most body weight.
• Sacrum: Forms lower back, fused from five separate bones at birth.
• Coccyx: Known as the tailbone, made of four fused bones at the spine's end.

Pelvis

• Protects internal organs and supports lower extremities.

Parts of the Pelvis

• Ilium: Forms the back and sides of the pelvic bone.
• Sacroiliac: Joint between sacrum and ilium.
• Ischium: Lower posterior portion supporting body weight when sitting.
• Pubis: Anterior portion of the pelvic bone.
• Pubic Symphysis: Cartilaginous joint uniting left and right pubic bones.
• Acetabulum: Circular cavity in the pelvis connecting with the femur to form the hip joint.

Lower Limb

• Femurs: The largest bones in the body.
• Patella: Known as the kneecap.
• Popliteal: Relating to the area behind the knee.
• Cruciate Ligaments: Ligaments in the knee providing stability.