Basic anatomy and terminology (2024)

Anatomical terminology

The most basic anatomy concept, and equally the most important, is orientation. All structures and the relationships between them are referenced to the standard anatomical position. In this orientation, the person is considered to be standing upright, with the arms hanging by the side, palms facing forward, and thumbs pointing away from the body. The feet are slightly parallel, and toes oriented to the front.To compare the location of body parts relative to each other, anatomy uses some universal directional terms: anterior, posterior, ventral, dorsal, distal, proximal, medial, lateral, median, superior, inferior, external, internal, frontal, occipital, rostral, caudal, superficial, deep, central, peripheral, ipsilateral, contralateral, cranial, and cephalic.

Learn the basic human terminology with the following study unit.

Apart from the directional terms and relationships, you also need to know from which direction you’re looking. This is provided by the three body planes and axes: coronal (frontal), sagittal, and transverse (axial).

In terms of movements, the human body is capable of many of them. Depending on the type of joint in question (the synovial joint being the most flexible), there is: flexion, extension, abduction, adduction, protrusion, retrusion, elevation, depression, lateral (external) rotation, medial (internal) rotation, pronation, supination, circumduction, deviation, opposition, reposition, inversion, and eversion.

Practice what you've learned above with this integrated quiz on the body movements.

Anatomical regions

The entire human body is divided into regions, an approach called regional anatomy. Each main area (head, neck, thorax, abdomen, upper, and lower extremities) are divided into several smaller regions that aid compartmentalization.

There are many regions in total, so here are some resources to help you learn more about each of them.

In addition to the regional approach, there is the surface anatomy approach. Here, the evident and palpable surface features of the body are described. There are common ones to both males and females, but also gender specific surface markers.

If you want to bring your knowledge one step further than the level of a human body diagram, check out the following study units:

Underneath the surface of the body, there is another ‘anatomical region’. This consists of the cavities of the human body which house many vital organs, neurovasculature, and anatomical structures. There are five major body cavities: cranial, thoracic, abdominal, pelvic, and vertebral cavities. Many of them are subdivided into smaller ones. In particular the thoracic cavity, it consists of the pleural, pericardial, and mediastinal cavities.

If you want to find out more, here are some additional resources from Kenhub.

We prepared a custom quiz for you about all the basic terminology concepts taught in this article:

Human body systems

There are approximately 79 human anatomy organs, although there is no standard or universally accepted number. What would the result be if every one of these organs worked independently? Chaos! Therefore, they function in groups called systems.An organ system consists of many organs working together to accomplish similar tasks and reach a common goal. There are eleven systems in the human body: circulatory(blood supply), respiratory(breathing), digestive(digestion and absorption), nervous(sensation and movement), excretory (waste elimination), endocrine(hormonal control), reproductive, lymphatic (defence), skeletal (support), and muscular(movement) systems. The last two are usually combined together into the musculoskeletal system.

Musculoskeletal system

Let’s take a look at one system in particular, the musculoskeletal one, which is made up of three parts: bones, joints, and muscles. The skeletal part, which functions mainly for support, consists of bones arranged into two skeletons:

• Axial skeleton: skull, auditory ossicles, hyoid bone, ribs, vertebral column, sternum, sacrum, coccyx
• Appendicular skeleton: shoulder girdle, upper limb, pelvic girdle, lower limb

Situated at the junction between two or more bones are structures called joints. There are many in the entire human body, but the most important ones are the cranial sutures, temporomandibular, shoulder, elbow, wrist, hip, knee, and ankle joints.

Muscles are the contractile apparatus attached to the bones that move them around the joints. They act as antagonist pairs. The main muscle type involved in the musculoskeletal system is the skeletal muscle. There are hundreds of muscles, grouped together into five anatomical regions:

• Head muscles: Muscles of facial expression, muscles of mastication(temporal, masseter, pterygoids)
• Neck muscles: Suprahyoidand infrahyoid muscles, scalenes, platysma
• Trunk muscles: Pectoral, intercostal, anterior abdominal, lateral abdominal, and posterior trunk muscles
• Upper extremity muscles: Shoulder, arm, forearm, and hand muscles
• Lower extremity muscles: Gluteal, hip, thigh, leg, and foot muscles

Major arteries, veins and nerves of the body

The neurovasculature of the body is also divided according to the regions. There are thousands upon thousands of arteries, veins, and nerves carrying blood and impulses to and from various anatomical structures. We’ll only mention the most important ones in this page.

The arterial supply of the head and neck is provided by the carotid arteries - common, internal, and external. The internal carotid artery supplies the brain, eyes, and forehead. The external carotid has eight branches which supply the external structures of the head and face, as well as the neck. Venous blood from the face is drained by the facial, supraorbital, frontal, angular, retromandibular, maxillary, and posterior auricular veins. These drain into the jugular veins. The neck is drained by the jugular, vertebral, and subclavian veins that end up in the brachiocephalic veins. Innervation of the head and neck is via the twelve cranial nervesand the cervical plexus.

Moving further, we reach the trunk. The most significant arteries of the thorax, abdomen, and pelvis are the aorta, celiac trunk, superior mesenteric, inferior mesenteric, and common iliac arteries with all their branches. They supply all the muscles, organs, and tissues of these regions. The major veins of the thorax are the superior vena cava, brachiocephalic, azygos, hemiazygos, intercostal, and internal thoracic veins. Those of the abdomen and pelvis are the inferior vena cava, epigastric, iliac(internal, external, common), spinal, hepatic, renal, and gonadal veins.

Nervous supply to the trunk consists of branches of the cervical, brachial, lumbarand sacral plexuses. Other nerves such as the phrenic, vagus (CN X), intercostal, subcostal, iliohypogastric, ilioinguinal, genitofemoral, lateral femoral cutaneous, obturator, gluteal, and pudendal nerves supply various structures of the anterior and posterior trunk. Autonomic innervation is provided by the sympathetic chains, splanchnic nerves, and various organ plexuses.

The hard part of the neurovasculature is now over because we have finished with the intricate regions. The extremities are more structured, systematic, and easier to digest. All the arteries of the upper extremity arise from the aortic arch. They include the subclavian, scapular, axillary, brachial, radial, and ulnar arteries. There are other ones supplying the joints, such as the elbowand wrist.

Venous drainage follows the arterial supply pretty closely, but not identically. The deep veins of the arm include the subclavian, axillary, and brachial veins while the superficial veins are the cephalicand basilic veins. Advancing further down, we meet the radial and ulnar veins of the forearm; as well as the dorsal venous network and the two palmar arches (one deep, one superficial) in the hand. Regarding innervation, all nerves of the upper extremity originate from the brachial plexus. They are called musculocutaneous, axillary, median, ulnar, and radial nerves. They supply all the muscles and regions of the upper extremity.

Last but not least, we have reached the lower extremity. The most important arteries originate from the iliac arteries and include the gluteal, obturator, femoral, circumflex femoral, popliteal, genicular, tibial, fibular, tarsal, and dorsalis pedis arteries. The main veins draining the lower limb are both superficial and deep. The deep system is composed of the iliac, femoral, popliteal, fibular, and tibial veins, together with the deep plantar and dorsal venous arches of the foot. The superficial ones are the small/shortand great/long saphenous veinswith the superficial dorsal and plantar venous networks of the foot.

All the nerves of the lower limb originate from the lumbosacral plexus. The main ones include the femoral cutaneous, femoral, obturator, sciatic, and gluteal nerves. Further down along the extremity we have genicular, tibial, fibular, saphenous, medial, plantar, and digital nerves.

Learn more about the human body systems, arteries, veins and nerves by taking our customized quiz! You can filter and tailor the structure selection to your needs.

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Articles within this topic:

• Anatomical terminology
• Human body systems
• Musculoskeletal system