BONES OF THE UPPER LIMB

BONES OF THE UPPER LIMB The upper limb consists of 30 bones per limb in the following arrangement; - Arm (brachium): 1 bone - Forearm (antebrachium): 2 bones - Wrist (carpus: 8 bones - Hand (manus): 19 bones (5 metacarpals and 14 phalanges) The Humerus The only bone in the brachium (arm) Major Features include; - Proximal humerus o Head ! Smooth hemispherical projection that forms an articulation with Glenoid fossa of scapula ! Periphery lines by anatomical neck (between head and shaft of the bone) o Greater and lesser tubercles ! Sites for muscle attachment o Intertubercular/ Bicipital sulcus ! Elongated groove that guides the tendon of biceps brachii muscle - Distal Humerus o Medial epicondyle – medical projection ! Provides origin point for several flexor muscles of antebrachium (forearm) o Lateral epicondyle – Lateral projection ! Provides origin point for several extensor muscles of antebrachium o Capitulum – articulates with fovea of head of radius o Trochlea – Articulates with trochlear notch of ulna o Olecranon fossa: accommodates olecranon process of ulna bone Bones of the Forearm: Ulna - There are 2 bones that form the antebrachium - The Ulna is the medial forearm bone. Major features include; Feature Description Trochlear notch Deep C shaped indentation that forms articulation with the humerus Olecranon Process Posterior prominence of trochlear notch Coronoid process Anterior prominence of trochlear notch Radial notch Accommodates head of radius Head (distal end) Separated from bones of wrist by a fibrocartilage pad Radius - Lateral forearm bone. Major features include; Feature Description Head (Distictive disk of Articulates with capitulum of humerus and radial notch of ulna proximal aspect) Radial tuberosity Attachment point for biceps brachii muscle Ulnar notch Point of articulation with distal aspect of ulna Styloid process Bony prominence at distal aspect that can be felt adjacent to the thumb Bones of the Carpus (wrist) 8 Carpal bones form the skeleton of the wrist - Located in the wrist (carpus) which is actually the proximal aspect of the hand - Carpal bones are organised into 2 rows (proximal and distal) of 4 bones each - Proximal: Scaphoid, Lunate, Triquetrum, Pisiform bones - Distal: Trapezium, Trapezoid, Capitate, Hamate bones - Scaphoid and lunate carpals articulate with the radius - Pisiform is a sesamoid bone within tendon of flexor carpi ulnaris muscle (tiny bone the size of pea) - Scared lovers try proposals that they can’t handle