Anatomical position9
2.2 Singular and plural9
2.3 Colloquial or correct?9
Studying the medical sciences involves learning a new language, more than half of which is anatomical. A brief excursion into words and grammar is both desirable and necessary, and Table 2.1 gives some of the most commonly occurring words, prefixes and suffixes that you are unlikely to have met before in this context.
| Term | Meaning and example |
|---|---|
| ab- | Away from. Abduct: move away from midline |
| ad- | Towards. Adduct: move towards midline |
| adeno- | Related to glands |
| afferent | Travelling towards. Afferent nerve impulse: towards the brain and spinal cord |
| anastomosis | Network (usually arteries or veins) receiving inputs from more than one source (plural: anastomoses) |
| anterior | Front (with reference to anatomical position); see ventral |
| -blast | Primitive cell or structure which gives rise to other cell type or structure. Osteoblast: primitive bone-forming cell. See-cyte |
| brachial | Pertaining to the arm (shoulder–elbow) |
| branchial | Associated with the entrance to the digestive system derived from primitive buccopharyngeal structures. Branchial structures are the successors of the gill apparatus in fish |
| bronchial | Pertaining to the bronchi |
| cancer | Malignant tumour |
| carcinoma | Cancer of epithelial (rather than connective tissue) origin |
| cardiac, -um | Heart |
| caudal | Nearer the tail (or where it would be). The kidneys are caudal to the diaphragm |
| cephalic | Nearer to, or pertaining to the head |
| coronal | Side-to-side plane which divides the structure into a front portion and a rear portion (not necessarily equal) |
| cranial | Nearer the head |
| -cyte | Cell. Mature cell type. Osteocyte: cell type found in bone. See -blast |
| deep | Far, or further, from the surface (see superficial) |
| distal to | Further away from. The foot is distal to the thigh (see proximal) |
| dorsal | Towards the back (with reference to anatomical position); similar to posterior in erect humans |
| -ectomy | Removal. Appendicectomy: removal of the appendix |
| efferent | Travelling away from. Efferent nerve impulse: away from the central nervous system |
| endo- | On the inside of. Endocardium: lining of the heart. Endometrium: lining of the uterus. Endoscopy: looking inside |
| endocrine | Secretion by a cell into its blood vessels (see exocrine) |
| epi- | On the surface of. Epithelium: all external surfaces. Epidermis: the epithelium of the skin |
| eversion | Turning the sole of the foot outwards (laterally) |
| ex- | Out of |
| exocrine | Secretion by a cell or group of cells into a duct for transport elsewhere (see endocrine) |
| extend | (Usually) straighten |
| extra- | Outside. Extracapsular: outside the capsule |
| fascia | Two meanings: |
| Loose connective and fatty tissue, of variable thickness: superficial fascia, prevertebral fascia | |
| Fairly tough sheath or membrane: deep fascia, clavipectoral fascia | |
| fasciculus | Group of axons of nerves all serving similar functions (same as tract) |
| flex | (Usually) bend |
| fistula | Artificial connection between two epithelial tubes |
| foramen | Opening or passage, often through bone |
| fossa | Depression, hollow, pit |
| ganglion | A swelling. In the context of the nervous system, its commonest usage, a ganglion is a collection of nerve cell bodies in the peripheral nervous system. It may be a sensory ganglion (without synapses), or an autonomic ganglion (with synapses). See nucleus |
| gyrus | Eminence of brain tissue between two sulci (see sulcus) |
| haemo- | Blood. Haemostasis: stagnation or sluggish flow of blood |
| hiatus | Gap, opening |
| hilum | Place where vessels and nerves enter |
| hyper- | Above, increase. Hyperplasia: increased cell division. Hypertrophy: increase in size (see hypo-) |
| hypo- | Below, decrease. Hypogastric: under the gastric area. Hypoplasia: decrease in cell division (see hyper-) |
| inferior | Below (with reference to anatomical position) |
| infundibulum | Funnel, funnel-like part of cavity |
| inter- | Between |
| intra- | Inside. Intracapsular: inside the capsule |
| inversion | Turning the sole of the foot inwards (medially) |
| -itis | Inflammation. Gastritis: inflammation of the stomach. Arthritis: inflammation of joint |
| lapar- | Abdomen. Laparoscopy: looking inside the abdomen. Laparotomy: opening the abdomen |
| lateral | Further from the midline (see medial) |
| ligament | Connective tissue tying together two or more structures (usually) |
| limbus | Edge, rim. Limbus of foramen ovale |
| lumen | Central cavity of a tube (artery, vein, intestine, etc.) |
| meatus | Pathway or passage |
| medial | Nearer the midline (see lateral) |
| median | In the midline |
| meso- | Between |
| metrium | Uterus. Myometrium: uterine muscle; endometrium: uterine lining |
| mucus | Sticky liquid produced by glands. Mucus is a noun (see below) |
| mucous | Sticky (see serous): this is an adjective (see above) |
| myo- | Muscle. Myocardium: muscle of the heart |
| nucleus | In the context of the nervous system, a nucleus is a collection of cell bodies in the central nervous system (brain and spinal cord), all with a similar function. See ganglion |
| -oma | Swelling (tumour, not necessarily malignant). Lipoma: tumour of fat. Osteoma: bone tumour. Lymphoma: tumour of lymphoid tissues. Melanoma: tumour of cells containing melanin. And so on. Carcinoma: malignant tumour of epithelial (surface) derivatives. Sarcoma: malignant tumour of connective (non-surface) tissue (bone, muscle, fat) |
| -ostomy | Making a permanent opening. Colostomy: permanent (or semipermanent) opening of the colon on to the abdominal surface. Tracheostomy: permanent (or semipermanent) opening into the trachea |
| -otomy | Making a small hole or temporary (e.g. emergency) opening. Laryngotomy: emergency opening into larynx |
| para- | By the side of, alongside. Paravertebral: by the side of the vertebral column |
| parietal | Concerning the walls of a cavity |
| peri- | Around or near. Periosteum: membrane covering the surface of bone |
| plexus | Network |
| posterior | Behind or rear (with reference to anatomical position); see dorsal |
| procto- | From proctodaeum – cloacal origin. Proctoscopy: observation of anal canal and terminal rectum |
| proximal to | Nearer to. The thigh is proximal to the foot. See distal |
| raphe | Seam. Line of union of separate parts |
| sagittal | Front-to-back plane which divides the structure into a right portion and a left portion (not necessarily equal) |
| sarcoma | Cancer of connective tissue (rather than epithelial) origin |
| serous | Thin, watery (see mucous) |
| sinus | Cavity or channel |
| somatic | Of, or derived from, body wall or somites: skeleton, skeletal (voluntary) muscle and associated connective tissue, and the skin and its appendages (breast, sweat glands, hair, nails, teeth). Nerves that supply these structures tend to be under voluntary control (if motor) and sensation from these structures tends to be immediately and precisely perceptible |
| sphincter | Muscular valve capable of closing a tube |
| splanchnic | Much the same as visceral – see later (splanchnic is from the Greek, visceral from the Latin. We do not need two terms, but we have them) |
| squamous | Flattened, scale-like |
| stasis | Lack of movement, stagnation. Haemostasis: stagnation of blood |
| synapse | The site where the terminal of one nerve transmits its electrical impulse to another, separate, nerve |
| sulcus | Gutter, depression |
| superficial | Near, or nearer, the surface (see deep) |
| superior | Above (with reference to anatomical position) |
| tendon | Attaching muscle to bone |
| tract | Group of axons of nerves all serving similar functions |
| ventral | Towards the front (belly) (with reference to anatomical position); similar to anterior in erect humans |
| visceral | Concerning internal organs (viscus, viscera). Nerves that supply these structures tend to be under involuntary control (if motor) and sensation from these structures tends to be vague and imprecisely perceptible or even imperceptible |
| viscus | Originally, hollow organ, but now used for any internal organ (liver, spleen, etc.) |
You should:
• be able to describe and demonstrate the anatomical position
• be able to demonstrate planes: coronal, sagittal, transverse
• have a reasonable working knowledge of the terms in Table 2.1
• try to discern the different components of medical and anatomical terms.
2.1. Anatomical position
Many words and descriptions assume the use of a standard position in relation to which surfaces and movements are defined. This is the anatomical position in which the body is pictured as standing erect with the palms of the hands facing forwards. This reference position is used irrespective of posture: your hand is always distal to your elbow, and your head always superior to your chest, even if you are upside down.
Relations: caution!
This word is used a great deal. It simply means geographical neighbours and it passes no comment on similarity. Related structures might be similar (e.g. arch of aorta and pulmonary artery), or they might not (arch of aorta and left main bronchus). The oesophagus is related to the left atrium of the heart – they are close neighbours (and this may matter clinically), but they are dissimilar in form and function.
Planes and movements (Figs 2.1 and 2.2)
Study Figures 2.1 and 2.2 and understand the meaning of the terms: you will need them in clinical work.
2.2. Singular and plural
Many anatomical and medical words are from Latin and Greek with plurals that are formed in ways other than by simply adding ‘s’ or ‘es’. A few of the more obvious examples are given in Table 2.2. Refer back to this table as necessary: as you become more familiar with its contents, you will be able to predict the meanings of new words when you encounter them for the first time.
| Note. Classical languages should not be used wantonly: these words are now English words and so English plurals can be used, I think, wherever possible. The plurals of meatus and plexus are best rendered as meatuses and plexuses: their Latin plurals are meatus and plexus (spelt the same, pronounced differently). But I am not consistent: I prefer bursas to bursae, fossas to fossae, and placentas to placentae, but would not accept diverticulums! | ||
| Change in word ending | Examples | |
|---|---|---|
| Singular | Plural | |
| -um to -a | atrium, diverticulum, epithelium, hilum, etc. | atria, diverticula, epithelia, hila, etc. |
| -a to -ae | bursa, fossa, placenta | bursae, fossae, placentae (but see below) |
| -us to -i | gyrus, sulcus | gyri, sulci (see below for meatus, plexus) |
| -is to -es | metastasis, symphysis, testis | metastases, symphyses, testes |
| Other | foramen | foramina |
| ganglion | ganglia | |
| meninx (rarely used) | meninges | |
| phalanx | phalanges | |
| viscus | viscera | |
2.3. Colloquial or correct?
When you stand in the anatomical position, your head is superior to your chest. In everyday language you say that your head is above your chest. Strict anatomists frown at colloquialisms like this, but they are in common use. In this book I switch between correct and colloquial terms as seems most natural to me. On the whole, I prefer the colloquial in the hope that readability is more important than pedantic fastidiousness. You need to remember, though, that the matter takes on great importance when the patients are lying down, as they so often are.
