BONES OF THE UPPER LIMB

OVERVIEW

• The upper limb comprises two main bone groups: the pectoral girdle and the free part of the upper limb
• The pectoral girdle includes the scapula and clavicle, which connect the limb to the trunk and provide support for arm mobility
• The free part of the upper limb consists of:
  • The humerus in the upper arm
  • The radius and ulna in the forearm
  • The bones of the hand, including the carpal bones, metacarpals, and phalanges

SHOULDER GIRDLE (PECTORAL GIRDLE)

Components

• Scapula (shoulder blade)
• Clavicle (collarbone)

Scapula

• Flat, triangular bone
• Features two broad surfaces with unique borders and angles
• Lateral angle forms the glenoid cavity (socket for humerus, creating the shoulder joint)

Clavicle

• Articulates medially with the manubrium of the sternum
• Extends laterally to connect with the acromion of the scapula
• Slender, S-shaped bone lying horizontally across the chest
• Functions to keep the shoulder blade in place, allowing arm mobility

BONES OF THE FREE UPPER LIMB

Humerus

• Location: Upper arm
• Connections:
  • To scapula at the shoulder joint
  • To radius and ulna at the elbow joint
• Features:
  • Longest and largest bone of the upper limb

Radius

• Location: Thumb side of forearm
• Features:
  • Large lower end with two joints
  • Joint 1: Articulates with wrist bones
  • Joint 2: Meeting with the ulna

Ulna

• Location: Parallel to radius on the lateral side
• Features:
  • Larger at the upper end, forming a substantial portion of the elbow joint
  • Tapers to a smaller lower end
  • Separated from the wrist by a triangular articular disc

Hand Skeleton

• The hand skeleton has the following sections:
  • Carpal bones: Forming the wrist
  • Metacarpal bones: Forming the palm
  • Phalanges: Finger bones