Upper Extremity - Bones & Photos
Humerus
- Head
- Articulates proximally with the scapula
- Neck
- Anatomical neck separates head of the humerus from lesser and greater tubercles; is where the glenohumeral joint capsule attaches to the humerus to help stabilize the shoulder joint
- Shaft
- Greater tubercle arises laterally
- Lesser tubercle rises medially
- Intertubercular groove (aka, sulcus, aka, bicipital groove/sulcus) extends between the greater and lesser tubercles
- Deltoid tuberosity along lateral side of humerus (deltoid muscle attachment site)
- Radial groove (posterior) for radial nerve
- Olecranon fossa (posterior) for olecranon process of ulna
- Epicondyles (medial and lateral)
- Medial epicondyle is more prominent, ulnar nerve runs posteriorly
- Condyle
- Capitulum is lateral rounded projection
- Trochlea is medial pully-shaped projection
- Radial fossa is superior to capitulum
- Coronoid fossa is superior to the trochlea
Radius
Lateral bone of forearm.
- Head
- Disc-shaped to accommodate capitulum of humerus
- Neck
- Between head and shaft; radial tuberosity is medial raised portion
- Shaft is slightly curved
- Styloid process (lateral)
- At distal end, cradles bones of wrist (aka, carpals)
- Ulnar notch (medial)
- Articulates with ulna
Ulna
Medial bone of forearm
- Olecranon process
- Proximal; articulates with humerus via trochlear notch
- Coronoid process
- At base of trochlear notch, rests in the coronoid fossa of the humerus during elbow flexion
- Tuberosity of the ulna
- Inferior to the coronoid process (muscle attachment site)
- Head
- Distal end of ulna
- Radial notch (lateral)
- Where ulna articulates with the radius
- Styloid process (medial)
Hand
8 Carpals:
Distal row, from radial to unlar sides:
- Trapezium
- Irregularly-shaped bone that articulates with the first digit, the thumb
- Trapezoid
- Boot-shaped
- Capitate
- Head-shaped and is the largest carpal
- Hamate
- Hook-like projection
- Scaphoid
- Boat-shaped and articulates with the radius
- Lunate
- Crescent-shaped
- Triquetrium
- Three articular surfaces (hence, tri-quetrium)
- Pisiform
- Pea-shaped, and lies superficial to the triquetrium.
- The pisiform is technically a sesamoid bone, as it is formed within a tendon
- Articulate with carpals, proximally,
- Articulate with phalanges, distally.
- Proximal phalanges articulate with metacarpals
- Distal phalanges comprise the finger-tips.
- Middle phalanges are present on digits 2-5, only, lie between proximal and distal phalanges.
- Digit 1, the thumb, has only proximal and distal phalanges.
Photos from:
https://sites.google.com/a/umich.edu/bluelink/resources/bluelinks/labeled-bones-joints-and-movement-images