Human Anatomy 1st Stage Past Paper PDF

Lac:9 2024-2025 Human anatomy 1st stage Bones of the forearm and hand Dr.Sameeah algenabi College of medicine/University of anbar  Bones of Forearm:...

Lac:9 2024-2025 Human anatomy 1st stage Bones of the forearm and hand Dr.Sameeah algenabi College of medicine/University of anbar  Bones of Forearm: Proximal radioulnar Bones of Forearm included radius & ulna: joint 1-Radius bone: -It is the lat. bone of the forearm. Its has (proximal end, shaft &distal end).  The head is expanded ,circular or round, proximal end of the radius. The upper surface of the head is concave and articulates with the convex capitulum of humerus at elbow joint. The circumference or periphery of the head articulates with the radial notch of ulna at the proximal radioulnar joint. The head of the radius is at its proximal end, whereas the head of the ulna is at distal end. -Below the head, the bone is constricted to form the neck. -Below the neck lies roughened area on the anteromedial, proximal aspect of the radius called the bicipital tuberosity for insertion of biceps m.  Shaft of radius Unlike that of the ulna, is wider below than above. -It has a sharp medial border called interosseous border for attachment of distal radioulnar interosseous membrane that binds radius & ulna together. joint -Pronator tubercle, for the insertion of pronator teres muscle, lies halfway down on its lat. side.  Distal end of radius Distal end has: - Ulnar notch, is the shallow depression on the med. aspect of the distal end of the radius, articulates with head of ulna at the distal radioulnar joint.. -The carpal articular surface forms the distal surface of the radius articulates with scaphoid (laterally)& lunate(medially) at the wrist joint. -The styloid process projects distally from its lateral margin of distal aspect of the radius. This extends lateral to the proximal row of carpal bones. This process projects downward (1.5cm lower than the styloid process of the ulna)Thus, abduction wrist is less than adduction. -Dorsal tubercle is a small tubercle, which is grooved on its med. side by tendon of extensor pollicis longus. During supination both bones are parallel, while during pronation, the radius crosses in-front of the ulna. 2-Ulna It is the med. bone of forearm. Its has:. 1-Proximal end of ulna is large, hook-shaped end & has: -olecranon process; this forms the prominence of elbow &easily palpable. Ulnar It is the site of the insertion of triceps brachii muscle. The beaklike tip of the tuberosity olecranon fits into olecranon fossa of the humerus when the elbow is extended. - Trochlear notch is large, crescent-shaped notch on ant. aspect of proximal end of ulna, & articulates with trochlea of humerus at elbow joint. -The coronoid process is anterior projection forming the inferior end of the hook like proximal end of the ulna. It lies below trochlear notch & contributes to the formation of the trochlear notch. head -The radial notch is shallow smooth notch on the lateral aspect of coronoid process, distal to trochlear notch, it is articulation with head of radius at proximal radioulnar joint. -The ulnar tuberosity is the anterior, distal, roughened aspect of the coronoid process. This provides the insertion of brachialis muscle.  2-Shaft (body) of ulna It is tapers from above down & it has: -The posterior border is rounded & subcutaneous &easily palpated a long its entire length. -The lateral border (interosseous border ) is a sharp border for attachment of interosseous membrane. Below radial notch lies supinator crest that gives origin to supinator muscle. 3-The distal end of ulna forms: -The head is small rounded distal end & has articular surface on its lateral side for articulate with the ulnar notch of the radius at distal radioulnar joint, but it is excluded from wrist joint by the articular disc. -The styloid process is a small projection from the med. Aspect of the distal end of the ulna.  The interosseous membrane Strong fibrous sheet or membrane Connects radius and ulna & connect to their interosseous borders. Run obliquely downward &medially Has a free upper margin (just inferior to the radial tuberosity) Has a small circular aperture in its distal third. It provides attachment for muscles in the anterior and posterior compartments Bones of Hand: There are eight carpal bones, five metacarpal bones & phalanges. -Carpal bones are eight bones, made up of two rows of four bones. 1.Proximal row consists of (from lat. to med.) scaphoid, lunate, triquetral, & pisiform. 2.Distal row consists of (from lat. To med.) trapezium, trapezoid, capitate, & hamate. Together, the bones of the carpus present on their anterior surface a concavity, to the lateral and medial edges of which is attached a strong membranous band called the flexor retinaculum. In this manner, an osteofascial tunnel, the carpal tunnel, is formed for the passage of the median nerve and the flexor tendons of the fingers. The bones of the hand are cartilaginous at birth. The capitate begins to ossify during the first year, and the others begin to Flexor retinaculum ossify at intervals thereafter until the 12th year, when all the bones are ossified. Bones of proximal row: -Scaphoid is largest bone in proximal row, has boat shape and tubercle in distal part of palmer surface & has constricted waist at its middle so its easily fractured. -Lunate is crescent shape with anterior surface larger than the posterior so its easily dislocated anteriorly and compressing the median nerve. -Triquetrum is pyramidal shape -The pisiform smallest bone of proximal row, pear shape lies anterior to (above) the triquetrum, embedded in tendon of flexor carpi ulnaris. Bones of distal row -The trapezium is resemble four sided figure forms saddle joint with the 1st metacarpal bone, allowing great mobility of the thumb, has tubercle on its palmer surface lateral to groove of flexor carpi radialis -Trapizoid is resembles trapezium but smaller than it -Capitate largest of the carpal bones and most centrally in position. -Hamate bone has a hook projecting anteriorly and can be felt one finger distal to the pisiform bone. The scaphoid and lunate articulate with the distal end of radius to form the wrist joint. The bones of each row articulate with each other and with the bones of the other row at the intercarpal joints. Metacarpals & phalanges: There are five metacarpal bones, each of which has a base, a shaft, & a head. lies between the carpal bones and phalanges. The first metacarpal bone of thumb is the shortest & most mobile & does not lie in same plane as the others but occupies a more ant. position. It is also rotated med. through a right angle so that its extensor surface is directed lat. & not backward. The base is the expanded proximal end of the bone. The head is rounded distal end of the bone, its articulates with the proximal phalanges & form a knukle of the hand. Shaft of each metacarpal bone is slightly concave forward. Its has post., lat., & med. Surfaces. There are three phalanges for each of fingers(proximal, middle & distal) but only two for thumb. Bases of metacarpal bones articulate with distal row of carpal bones.