osteology flash cards

Upper Limb Osteology Notes

Objectives

  • Identify all bones of the upper limb
  • Orient all bones of the upper limb
  • Describe and identify general characteristics of all upper limb bones
  • Understand clinical applications of the bones of the upper limb
  • Reference: Moore’s Clinically Oriented Anatomy, 9th Ed: Pages 142-159, 7th Ed: Pages 670-688

Upper Limb: Overview

  • Components:
    • Pectoral girdle: Bony ring formed by scapulae, clavicles, and the manubrium of the sternum
    • Segments:
    • Shoulder
    • Arm (upper arm)
    • Forearm
    • Hand

Bones of the Upper Limb

  • Clavicle
  • Scapula
  • Humerus
  • Radius
  • Ulna
  • Carpal bones
  • Metacarpal bones
  • Phalanges

Clavicle

Orientation
  • Ends:
    • Sternal end: Enlarged and triangular
    • Acromial end: Flattened
  • Surfaces:
    • Superior: Smooth
    • Inferior: Rough
  • Medial two-thirds: Convex anteriorly
  • Lateral third: Concave anteriorly
Bone Markings
  • Conoid tubercle: Attachment for conoid ligament (near acromial end)
  • Trapezoid line: Attachment for trapezoid ligament
  • Subclavian groove: Attachment site for subclavius muscle
  • Impression for costoclavicular ligament: Medially located
Functions
  • Provides rigid support enabling maximum mobility of scapula and humerus
  • Protects axillary neurovascular bundle
  • Transmits shocks from upper limb to axial skeleton
  • Forms the first long bone to ossify (during in utero development) and the last epiphysis to fuse
Clinical Considerations: Fractures
  • Fractures commonly occur between the junction of middle and lateral thirds
  • Mechanisms include falling on an outstretched hand or directly on the shoulder
  • Clinical signs include greenstick fractures in children

Scapula

Orientation
  • Shape: Triangular flat bone
  • Location: Posterolateral aspect of thorax; overlaps ribs 2-7
  • Surfaces:
    • Posterior, Costal, Lateral
  • Borders:
    • Superior, Lateral, Inferior
Important Features
  • Coracoid process: Beak-like projection, serves for muscle attachment
  • Glenoid cavity: Articulates with the head of the humerus
  • Acromion: Articulates with the clavicle
Fracture Considerations
  • Scapula fractures are rare and often associated with severe trauma (e.g., car accidents);
  • Treatment typically requires minimal intervention due to surrounding musculature

Humerus

Orientation
  • Largest bone of the upper limb
  • Proximal End: Articulates with the scapula at the glenohumeral joint
  • Distal End: Articulates with the radius and ulna at the elbow joint
Key Features
  • Bony Landmarks:
    • Head, Greater tubercle, Lesser tubercle, Anatomical neck, Surgical neck, Intertubercular sulcus
  • Surface Anatomy: Palpable landmarks include the greater tubercle, medial and lateral epicondyles
Fracture Types
  • Surgical neck fractures: Common in elderly due to falls
  • Intra-articular fractures: Can lead to complications such as nerve damage (radial or ulnar nerve)

Radius

Overview
  • Role: Lateral and shorter bone in the forearm
  • Distal End: Styloid process is prominent on lateral aspect; allows for articulation with carpal bones
Bony Features
  • Proximal End: Head (discoid and concave), Neck; also includes a radial tuberosity for tendon attachment
  • Surface Anatomy: Radial styloid process and dorsal tubercle easily palpated around the wrist area
Fracture Considerations
  • Colle's fracture: A common injury in older adults (complete transverse fracture of distal radius)

Ulna

Overview
  • Function: Medial and longer bone of the forearm that allows flexion/extension at the elbow;
    does not participate in the wrist joint.
Key Features
  • Proximal End: Includes the olecranon and coronoid process, which provide structure for elbow joint
  • Distal End: Includes a small disc-like head with a styloid process that aids in stabilizing the wrist
Clinical Relevance
  • Fractures: Often occur in conjunction with radius fractures;
  • Surface anatomy is clinically significant for dislocations or injuries to the elbow

Hand

Bones Composition
  • Carpal bones: Eight bones aligned in two rows (proximal and distal)
  • Metacarpal bones: Five bones forming the palm
  • Phalanges: Three per finger (except thumb, which has two)
Carpal Bones Mnemonics
  • Proximal row (lateral to medial): Scaphoid, Lunate, Triquetrum, Pisiform
  • Distal row (lateral to medial): Trapezium, Trapezoid, Capitate, Hamate
  • Mnemonic: "Sally Left The Pub To Take Cathy Home"
Hand Injuries
  • Fractures: Most common carpal fracture is of the scaphoid from falls on an outstretched hand; may result in avascular necrosis
  • Boxer's fracture: Fracture of the fifth metacarpal due to punching
  • Phalanges: Require careful alignment in case of fractures due to functional significance.