Consists of 30 bones (all paired up) Humerus in the arm Ulna and radius in the forearm 8 carpals, 5 metacarpals, and 14 phalanges in the hand
Humerus Longest and largest bone of the upper limb Articulates with the scapula at the shoulder and both the ulna and radius at the elbow
Ulna Located on the medial side of the forearm (pinky side) Longer than the radius
Radius Located on the lateral side of the forearm (thumb side)
Proximal end consists of a head that articulates with the scapula’s glenoid cavity and an anatomical neck where the epiphyseal plate used to be Humerus Bone Surface Markings
The body contains the deltoid tuberosity, a roughened V-shaped area where the deltoid muscle attaches
At the distal end, the capitulum articulates with the head of the radius. The radial fossa is a depression that receives the head of the radius when the forearm is bent.
The trochlea is a spool- shaped surface that articulates with the ulna. The coronoid fossa receives part of the ulna when the forearm is bent. The olecranon fossa is a depression on the back of the bone that receives the ulna when the forearm is straightened.
The olecranon forms the prominence of the elbow on the proximal end. The coronoid process along with the olecranon receives the trochlea of the humerus in the trochlear notch. Ulna Bone Surface Markings
The radial notch is a depression for the head of the radius. A styloid process is at the distal end.
Disc-shaped head at the proximal end articulates with the capitulum of the humerus and radial notch of the ulna Radial tuberosity is a raised, roughened area that is where the biceps brachii muscle attaches to the bone Radius Bone Surface Markings
The distal end of the radius articulates with three carpal bones There’s a styloid process at the distal end (similar to the ulna)
Carpus (Wrist) 8 carpals Held together by ligaments with four bones in each row Named for their shapes Short bones
The carpals in the top row are the: Scaphoid, Lunate, Triquetrum, and Pisiform The carpals in the bottom row are the: Trapezium, Trapezoid, Capitate, and Hamate
Metacarpus (Palm) 5 metacarpals Each consists of a proximal base, an intermediate body, and a distal head Numbered I-V starting with the thumb Long bones
Phalanges (Fingers) 14 in each hand Thumb has two (proximal and distal) In each of the other four digits, there are three (proximal, middle, and distal)
Checkpoint Questions Which bones make up a pectoral girdle? What is the function of the pectoral girdle? With which part of the scapula does the humerus articulate? What part of the ulna is called the “elbow”? What part of which bones are commonly called the “knuckles”? What bones form the upper limb, from proximal to distal?