Skeletal system - arm bones, Biology

ARM BONES -

Each arm contain 30 bones as : humerus in upper arm, radius ulna in forearm, 8 carples in wrist, 5 metacorples in plam, 14 phalnges in fingers.

HUMERUS -

Bone of upper arm. Head of humerus is fitted in glenoid cavity of scapula.

Ball and socket joint is formed.

Head bears a pair of small tuberosities, separated by intertubercular groove.

Trochlea is fitted in sigmoid notch of radius ulna.

A deltoid ridge is present at the anterior surface of humerus.

Above the trochlea supra trochlear foraman is present through which brachial artery passes out. Present in rabbit, but absent in man.

184_humerus.png               369_humerus rabbit.png

RADIUS ULNA -

Bone of fore arm. Ulna is longer than radius.

Radius is situated at thumb side. Olecranon process & sigmoid notch present at proximal end.

363_radius ulna.png                 2238_rabbit radius ulna.png

Note :- In frog radius & ulna both are fused in complete length, so the world radioulna is used instead of radius ulna.

HAND -

In hand wrist, palm & fingers are clear. In wrist carpals bones are present.

In palm metacarpals are present. In fingers phalanges are present.

The digital formula of rabbit and man is 2 3 3 3 3 = 14.

659_hand.png               2245_rabbit hand.png

                                         MAN                                                                                      RABBIT

Posted Date: 10/2/2012 9:15:29 AM | Location : United States







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