RIB ANATOMY

GENERAL FEATURES

• Ribs are long, curved bones of the thoracic skeleton
• Connect posteriorly to thoracic vertebrae and form the ribcage
• Feature distinct parts: head, neck, body, tubercle, angle, and costal groove

Head of Rib

• Rounded posterior portion of the rib connecting to the thoracic vertebrae
• Contains two articular facets (superior and inferior) separated by the crest of the head (crista capituli)
• Facets articulate with two adjacent thoracic vertebrae
• The crest provides stability for rib articulation

Neck of Rib

• Segment between the head and the tubercle
• Features a roughened crest along the superior border
• Crest serves as an attachment site for the anterior costotransverse ligament
• Ligament stabilizes the rib's articulation with the vertebrae

Body of Rib

• Long main portion of the rib stretching from the neck to the anterior end
• Contains the costal groove along the inferior border
• Costal groove houses and protects the intercostal vessels and nerve, crucial for chest wall supply and sensation

Tubercle of Rib

• Located at the junction of the rib's neck and body
• Features:
  • Articular portion — articulates with the transverse process of the thoracic vertebra
  • Non-articular portion — serves as an attachment site for ligaments

Angle of Rib

• Point where the rib changes direction, creating a bend
• Marks the region where the rib begins to twist along its length

Costal Groove

• Located along the inferior border of the rib's body
• Guides and protects intercostal vessels and nerve
• Ensures efficient supply and sensation along the ribcage

FIRST RIB

• The most curved and typically the shortest rib
• Shape is broad and flat, angling surfaces upward and downward
• Serves as a unique and important anatomical landmark in the thoracic cage

Scalene Tubercle

• Small bony prominence on the inner border of the first rib
• Marks the end of a ridge on the upper surface
• Separates two grooves on the rib
• Provides an attachment point for muscles involved in neck movement

Groove for Subclavian Artery

• Located just behind the scalene tubercle
• Houses the subclavian artery and a nerve network essential for arm function
• Protects and routes these structures efficiently beneath the rib

Groove for Subclavian Vein

• Located in front of the scalene tubercle
• Holds the subclavian vein, responsible for returning venous blood from the upper limb
• Ensures the vein's protection and proper positioning

SECOND RIB

• Approximately twice as long as the first rib, with a similar curvature
• Distinguished by a roughened tuberosity for the serratus anterior muscle

Tuberosity for Serratus Anterior Muscle

• Roughened area on the second rib
• Serves as the anchor point for the serratus anterior muscle
• Functions:
  • Facilitates movement of the shoulder blade
  • Supports proper arm function
  • Stabilizes the shoulder

FLOATING RIBS (ELEVENTH AND TWELFTH RIBS)

• Floating ribs have free anterior ends
• Do not attach to the sternum
• Terminate within the back musculature

Function

• Provide flexibility to the ribcage
• Considered a subset of false ribs, as they do not contribute to the sternum's structure