Trunk and back anatomy

The trunk holds the organs and links the limbs to each other. Its skeleton is the vertebral column, the rib cage (ribs and sternum) and the sacrum at the back of the pelvis. Its muscles form the walls around the body cavities: the diaphragm under the lungs, the layered muscles of the abdominal wall in front and on the sides, and the back muscles along the spine. Inside are the heart and lungs in the thorax, and the digestive and urinary organs in the abdomen and pelvis.

Bones of the trunk and back

Atlas (C1 vertebra)Atlas Axis (C2 vertebra)Axis Cervical vertebrae (C3 to C7)Vertebrae cervicales Lumbar vertebrae (L1-L5)Vertebrae lumbales Ribs (1 to 12)Costae SacrumOs sacrum SternumSternum Thoracic vertebrae (T1-T12)Vertebrae thoracicae

Tables: Rib cage bones · Spine bones

Muscles of the trunk and back

Abdominal muscles 6 with a page · full table →

Rectus abdominisMusculus rectus abdominis External obliqueMusculus obliquus externus abdominis Internal obliqueMusculus obliquus internus abdominis Transversus abdominisMusculus transversus abdominis Quadratus lumborumMusculus quadratus lumborum DiaphragmDiaphragma

Other muscles

External intercostal musclesMusculi intercostales externi IliocostalisMusculus iliocostalis Internal intercostal musclesMusculi intercostales interni LongissimusMusculus longissimus Psoas minorMusculus psoas minor Semispinalis capitisMusculus semispinalis capitis Semispinalis cervicisMusculus semispinalis cervicis SpinalisMusculus spinalis Splenius capitisMusculus splenius capitis Splenius cervicisMusculus splenius cervicis

Organs of the trunk and back

Endocrine glands The ductless glands that send chemical messages through the blood. Heart The muscular pump behind the sternum that drives blood through two circuits. Kidneys and bladder The organs that filter blood, make urine and store it until it leaves the body. Liver and pancreas The glands of the upper abdomen that make bile, enzymes and hormones. Lungs Two spongy organs in the chest where air meets blood. Prostate A walnut-sized gland below the bladder, wrapped around the urethra. Spleen The blood filter of the body, tucked under the lower left ribs. Stomach and intestines The tube that breaks food down, absorbs nutrients and removes waste. Testis The paired glands in the scrotum that make sperm and testosterone.

Test yourself

Name it, find it, light them all on a real 3D body, in 3 levels. Free, in the browser.

Thorax quiz 23 structures in 3 levels. Back quiz 36 structures in 3 levels. Abdomen quiz 17 structures in 3 levels. Pelvis quiz 12 structures in 3 levels. Trunk muscles quiz 23 structures in 3 levels. Organs quiz 22 structures in 3 levels. Skeleton quiz 96 structures in 3 levels.