Multiple Choice Questions - Upper Limb Anatomy: Ulna, Carpals, Metacarpals.
Radius and Ulna
Left Human Ulna Bone
This hub is part of a series of multiple choice questions on upper limb anatomy.
The previous hubs in this series are
The ulna is placed medially on the forearm. It has an upper end, shaft and lower end.
The parts of the upper end of the ulna are
Olecranon Process: It has the upper part of the trochlear notch which articulates with the lower end of the humerus
Coronoid Process: It has the lower part of the trochlear notch. It also has the radial notch on its lateral surface.
The shaft of the ulna has
Three borders: lateral border, anterior border and posterior border
Three surfaces: anterior, posterior and medial
The lower end of ulna has styloid process. The lower end articulates with the ulnar notch of the radius and forms the inferior radioulnar joint.
The muscles attached to the ulna are triceps, brachialis, supinator, flexor digitorum superficialis, pronator teres, flexor digitorum profundus, pronator quadratus, flexor carpi ulnaris, extensor carpi ulnaris, anconeus, abductor pollicis longus, extensor pollicis longus and extensor indicis.
Radius and Ulna - Anatomy Tutorial
The Carpal Bones
There are eight carpal bones which are arranged in two rows.
The proximal row has scaphoid (boat shaped), lunate (crescent shaped), triquetral (pyramidal) and pisiform (pea shaped) bones.
The distal row has trapezium (quadrangle shaped), trapezoid (shoe shaped), capitate (round headed) and hamate (wedge shaped) bones.
The muscles attached to the carpal bones are Abductor digiti minimi, Abductor pollicis brevis, Flexor carpi ulnaris, Flexor retinaculum, extensor retinaculum, flexor pollicis brevis, opponens pollicis, flexor carpi radialis and opponens digiti minimi.
The Metacarpal Bones
The metacarpal bones are five in number, small in size even though they are categorized under the long bones and they are numbered from lateral side to medial side.
The heads of the metacarpal bones are round, placed distally and form the knuckles. Each of these bones has a shaft and a base. The attachments to metacarpals are palmar interossei, dorsal interossei, opponens pollicis, abductor pollicis, flexor carpi radialis, extensor carpi radialis longus, adductor pollicis, opponens digit minimi.
There are three phalanges for each finger and two phalanges for the thumb making it a total of 14 phalanges for the hand.
The base of the proximal phalanx articulates with the head of the metacarpal bone.
Each phalange has a shaft, base and a head.
The attachments to the phalanges are
- flexor digitorum profundus
- flexor digigtorum superficialis
- extensor digitorum
- abductor pollicis brevis
- flexor pollicis brevis
- extensor pollicis brevis
- abductor digiti minimi
- flexor digiti minimi.
Wrist and Hand Joints - 3D Anatomy Tutorial
Ossification of Bones of Hand
The carpal bones are ossified from a single center. The capitate and hamate are the first ones to ossify during the first year of life. The pisiform is the last one to ossify around the twelfth year of life.
The metacarpal bones are ossified from two centers. The shaft of the metacarpals ossifies during the eighth or ninth week of fetal life. The ossification of the secondary center appears around 2nd or third year of life and completes by the age of eighteen to twenty years.
The phalanges are also ossified from two centers. The primary center appears around the eighth week of fetal life and secondary center appears around two to four years and completes ossification by sixteen to eighteen years.
Click here to see the other hubs on multiple choice questions by the author