BLG 10A/B Lecture Notes - Lecture 15: Costal Cartilage, Rib Cage, Xiphoid Process
11 Apr 2019
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The Thoracic Cage
• Thorax as the chest
• bony underpin lay under the chest are known as thoracic cage
• components:
o ribs (laterally)
▪ 12 pairs of ribs
▪ superior 7 ribs directly attach to the sternum by costal cartilage
▪ remaining 5 ribs are known as false ribs, because they either attach to
the sternum by costal cartilage or don’t even attach
▪ rib pair 11 and 12 are referred to as floating rib or vertebral ribs because
they have no attachment
▪ rib also has a head, neck and shaft
o vertebrae (vertically)
o costal cartilages – secure the ribs to the sternum
o sternum
▪ lies in the middle of the thorax
▪ results from the fusion of three bones:
• manubrain (largest top part)
• the body (middle portion of the sternum)
• xiphoid process (end portion of the sternum)
The Appendicular Skeleton
• bones of the upper and lower limbs
• enables us to carry out movements
The Pectoral (Shoulder) Girdle
• Clavicles
o Collarbones
o Attach to the manubrain on one side and the acromial end on the other
o Clavicles act as braces: holds the scapulae and the arm
o not very strong, can be easily fractured
• Scapulae
o Should blade (thing triangular flat bones)
o Lies on the dorsal surface of the rib cage
o 3 borders:
▪ superior border (shorest, sharpest border)
▪ medial or vertebral border (parallels the vertebral columns)
▪ lateral or axillary border (abuts the armpits)
The Upper Limb (30 bones)
• Arm
o Humerus – long arm bone (largest and longest bone of the upper limb)
o Articulates with the scapula
